Memory Mapped Networks a new deal for Distributed Shared Memories The SciFS experience
operating system《操作系统》ch09-virtual memory-70
Example of a page table snapshot:
Frame #
….
valid-invalid bit
v v v v i
i i
page table
During address translation, if valid–invalid bit in page table entry is I page fault
Copy-on-Write (COW) allows both parent and child processes to initially share the same pages in memory If either process modifies a shared page, only then is the page copied COW allows more efficient process creation as only modified pages are copied Free pages are allocated from a pool of zeroed-out pages
9.22
Need For Page Replacement
9.23
Basic Page Replacement
1. Find the location of the desired page on disk
2. Find a free frame:
- If there is a free frame, use it
page fault 1. Operating system looks at another table to decide:
现代操作系统(第三版)答案
MODERNOPERATINGSYSTEMSTHIRD EDITION PROBLEM SOLUTIONSANDREW S.TANENBAUMVrije UniversiteitAmsterdam,The NetherlandsPRENTICE HALLUPPER SADDLE RIVER,NJ07458Copyright Pearson Education,Inc.2008SOLUTIONS TO CHAPTER1PROBLEMS1.Multiprogramming is the rapid switching of the CPU between multiple proc-esses in memory.It is commonly used to keep the CPU busy while one or more processes are doing I/O.2.Input spooling is the technique of reading in jobs,for example,from cards,onto the disk,so that when the currently executing processes arefinished, there will be work waiting for the CPU.Output spooling consists offirst copying printablefiles to disk before printing them,rather than printing di-rectly as the output is generated.Input spooling on a personal computer is not very likely,but output spooling is.3.The prime reason for multiprogramming is to give the CPU something to dowhile waiting for I/O to complete.If there is no DMA,the CPU is fully occu-pied doing I/O,so there is nothing to be gained(at least in terms of CPU utili-zation)by multiprogramming.No matter how much I/O a program does,the CPU will be100%busy.This of course assumes the major delay is the wait while data are copied.A CPU could do other work if the I/O were slow for other reasons(arriving on a serial line,for instance).4.It is still alive.For example,Intel makes Pentium I,II,and III,and4CPUswith a variety of different properties including speed and power consumption.All of these machines are architecturally compatible.They differ only in price and performance,which is the essence of the family idea.5.A25×80character monochrome text screen requires a2000-byte buffer.The1024×768pixel24-bit color bitmap requires2,359,296bytes.In1980these two options would have cost$10and$11,520,respectively.For current prices,check on how much RAM currently costs,probably less than$1/MB.6.Consider fairness and real time.Fairness requires that each process be allo-cated its resources in a fair way,with no process getting more than its fair share.On the other hand,real time requires that resources be allocated based on the times when different processes must complete their execution.A real-time process may get a disproportionate share of the resources.7.Choices(a),(c),and(d)should be restricted to kernel mode.8.It may take20,25or30msec to complete the execution of these programsdepending on how the operating system schedules them.If P0and P1are scheduled on the same CPU and P2is scheduled on the other CPU,it will take20mses.If P0and P2are scheduled on the same CPU and P1is scheduled on the other CPU,it will take25msec.If P1and P2are scheduled on the same CPU and P0is scheduled on the other CPU,it will take30msec.If all three are on the same CPU,it will take35msec.2PROBLEM SOLUTIONS FOR CHAPTER19.Every nanosecond one instruction emerges from the pipeline.This means themachine is executing1billion instructions per second.It does not matter at all how many stages the pipeline has.A10-stage pipeline with1nsec per stage would also execute1billion instructions per second.All that matters is how often afinished instruction pops out the end of the pipeline.10.Average access time=0.95×2nsec(word is cache)+0.05×0.99×10nsec(word is in RAM,but not in cache)+0.05×0.01×10,000,000nsec(word on disk only)=5002.395nsec=5.002395μsec11.The manuscript contains80×50×700=2.8million characters.This is,ofcourse,impossible tofit into the registers of any currently available CPU and is too big for a1-MB cache,but if such hardware were available,the manuscript could be scanned in2.8msec from the registers or5.8msec from the cache.There are approximately27001024-byte blocks of data,so scan-ning from the disk would require about27seconds,and from tape2minutes7 seconds.Of course,these times are just to read the data.Processing and rewriting the data would increase the time.12.Maybe.If the caller gets control back and immediately overwrites the data,when the writefinally occurs,the wrong data will be written.However,if the driverfirst copies the data to a private buffer before returning,then the caller can be allowed to continue immediately.Another possibility is to allow the caller to continue and give it a signal when the buffer may be reused,but this is tricky and error prone.13.A trap instruction switches the execution mode of a CPU from the user modeto the kernel mode.This instruction allows a user program to invoke func-tions in the operating system kernel.14.A trap is caused by the program and is synchronous with it.If the program isrun again and again,the trap will always occur at exactly the same position in the instruction stream.An interrupt is caused by an external event and its timing is not reproducible.15.The process table is needed to store the state of a process that is currentlysuspended,either ready or blocked.It is not needed in a single process sys-tem because the single process is never suspended.16.Mounting afile system makes anyfiles already in the mount point directoryinaccessible,so mount points are normally empty.However,a system admin-istrator might want to copy some of the most importantfiles normally located in the mounted directory to the mount point so they could be found in their normal path in an emergency when the mounted device was being repaired.PROBLEM SOLUTIONS FOR CHAPTER13 17.A system call allows a user process to access and execute operating systemfunctions inside the er programs use system calls to invoke operat-ing system services.18.Fork can fail if there are no free slots left in the process table(and possibly ifthere is no memory or swap space left).Exec can fail if thefile name given does not exist or is not a valid executablefile.Unlink can fail if thefile to be unlinked does not exist or the calling process does not have the authority to unlink it.19.If the call fails,for example because fd is incorrect,it can return−1.It canalso fail because the disk is full and it is not possible to write the number of bytes requested.On a correct termination,it always returns nbytes.20.It contains the bytes:1,5,9,2.21.Time to retrieve thefile=1*50ms(Time to move the arm over track#50)+5ms(Time for thefirst sector to rotate under the head)+10/100*1000ms(Read10MB)=155ms22.Block specialfiles consist of numbered blocks,each of which can be read orwritten independently of all the other ones.It is possible to seek to any block and start reading or writing.This is not possible with character specialfiles.23.System calls do not really have names,other than in a documentation sense.When the library procedure read traps to the kernel,it puts the number of the system call in a register or on the stack.This number is used to index into a table.There is really no name used anywhere.On the other hand,the name of the library procedure is very important,since that is what appears in the program.24.Yes it can,especially if the kernel is a message-passing system.25.As far as program logic is concerned it does not matter whether a call to a li-brary procedure results in a system call.But if performance is an issue,if a task can be accomplished without a system call the program will run faster.Every system call involves overhead time in switching from the user context to the kernel context.Furthermore,on a multiuser system the operating sys-tem may schedule another process to run when a system call completes, further slowing the progress in real time of a calling process.26.Several UNIX calls have no counterpart in the Win32API:Link:a Win32program cannot refer to afile by an alternative name or see it in more than one directory.Also,attempting to create a link is a convenient way to test for and create a lock on afile.4PROBLEM SOLUTIONS FOR CHAPTER1Mount and umount:a Windows program cannot make assumptions about standard path names because on systems with multiple disk drives the drive name part of the path may be different.Chmod:Windows uses access control listsKill:Windows programmers cannot kill a misbehaving program that is not cooperating.27.Every system architecture has its own set of instructions that it can execute.Thus a Pentium cannot execute SPARC programs and a SPARC cannot exe-cute Pentium programs.Also,different architectures differ in bus architecture used(such as VME,ISA,PCI,MCA,SBus,...)as well as the word size of the CPU(usually32or64bit).Because of these differences in hardware,it is not feasible to build an operating system that is completely portable.A highly portable operating system will consist of two high-level layers---a machine-dependent layer and a machine independent layer.The machine-dependent layer addresses the specifics of the hardware,and must be implemented sepa-rately for every architecture.This layer provides a uniform interface on which the machine-independent layer is built.The machine-independent layer has to be implemented only once.To be highly portable,the size of the machine-dependent layer must be kept as small as possible.28.Separation of policy and mechanism allows OS designers to implement asmall number of basic primitives in the kernel.These primitives are sim-plified,because they are not dependent of any specific policy.They can then be used to implement more complex mechanisms and policies at the user level.29.The conversions are straightforward:(a)A micro year is10−6×365×24×3600=31.536sec.(b)1000meters or1km.(c)There are240bytes,which is1,099,511,627,776bytes.(d)It is6×1024kg.SOLUTIONS TO CHAPTER2PROBLEMS1.The transition from blocked to running is conceivable.Suppose that a processis blocked on I/O and the I/Ofinishes.If the CPU is otherwise idle,the proc-ess could go directly from blocked to running.The other missing transition, from ready to blocked,is impossible.A ready process cannot do I/O or any-thing else that might block it.Only a running process can block.PROBLEM SOLUTIONS FOR CHAPTER25 2.You could have a register containing a pointer to the current process tableentry.When I/O completed,the CPU would store the current machine state in the current process table entry.Then it would go to the interrupt vector for the interrupting device and fetch a pointer to another process table entry(the ser-vice procedure).This process would then be started up.3.Generally,high-level languages do not allow the kind of access to CPU hard-ware that is required.For instance,an interrupt handler may be required to enable and disable the interrupt servicing a particular device,or to manipulate data within a process’stack area.Also,interrupt service routines must exe-cute as rapidly as possible.4.There are several reasons for using a separate stack for the kernel.Two ofthem are as follows.First,you do not want the operating system to crash be-cause a poorly written user program does not allow for enough stack space.Second,if the kernel leaves stack data in a user program’s memory space upon return from a system call,a malicious user might be able to use this data tofind out information about other processes.5.If each job has50%I/O wait,then it will take20minutes to complete in theabsence of competition.If run sequentially,the second one willfinish40 minutes after thefirst one starts.With two jobs,the approximate CPU utiliza-tion is1−0.52.Thus each one gets0.375CPU minute per minute of real time.To accumulate10minutes of CPU time,a job must run for10/0.375 minutes,or about26.67minutes.Thus running sequentially the jobsfinish after40minutes,but running in parallel theyfinish after26.67minutes.6.It would be difficult,if not impossible,to keep thefile system consistent.Sup-pose that a client process sends a request to server process1to update afile.This process updates the cache entry in its memory.Shortly thereafter,anoth-er client process sends a request to server2to read thatfile.Unfortunately,if thefile is also cached there,server2,in its innocence,will return obsolete data.If thefirst process writes thefile through to the disk after caching it, and server2checks the disk on every read to see if its cached copy is up-to-date,the system can be made to work,but it is precisely all these disk ac-cesses that the caching system is trying to avoid.7.No.If a single-threaded process is blocked on the keyboard,it cannot fork.8.A worker thread will block when it has to read a Web page from the disk.Ifuser-level threads are being used,this action will block the entire process, destroying the value of multithreading.Thus it is essential that kernel threads are used to permit some threads to block without affecting the others.9.Yes.If the server is entirely CPU bound,there is no need to have multiplethreads.It just adds unnecessary complexity.As an example,consider a tele-phone directory assistance number(like555-1212)for an area with1million6PROBLEM SOLUTIONS FOR CHAPTER2people.If each(name,telephone number)record is,say,64characters,the entire database takes64megabytes,and can easily be kept in the server’s memory to provide fast lookup.10.When a thread is stopped,it has values in the registers.They must be saved,just as when the process is stopped the registers must be saved.Multipro-gramming threads is no different than multiprogramming processes,so each thread needs its own register save area.11.Threads in a process cooperate.They are not hostile to one another.If yield-ing is needed for the good of the application,then a thread will yield.After all,it is usually the same programmer who writes the code for all of them. er-level threads cannot be preempted by the clock unless the whole proc-ess’quantum has been used up.Kernel-level threads can be preempted indivi-dually.In the latter case,if a thread runs too long,the clock will interrupt the current process and thus the current thread.The kernel is free to pick a dif-ferent thread from the same process to run next if it so desires.13.In the single-threaded case,the cache hits take15msec and cache misses take90msec.The weighted average is2/3×15+1/3×90.Thus the mean re-quest takes40msec and the server can do25per second.For a multithreaded server,all the waiting for the disk is overlapped,so every request takes15 msec,and the server can handle662/3requests per second.14.The biggest advantage is the efficiency.No traps to the kernel are needed toswitch threads.The biggest disadvantage is that if one thread blocks,the en-tire process blocks.15.Yes,it can be done.After each call to pthread create,the main programcould do a pthread join to wait until the thread just created has exited before creating the next thread.16.The pointers are really necessary because the size of the global variable isunknown.It could be anything from a character to an array offloating-point numbers.If the value were stored,one would have to give the size to create global,which is all right,but what type should the second parameter of set global be,and what type should the value of read global be?17.It could happen that the runtime system is precisely at the point of blocking orunblocking a thread,and is busy manipulating the scheduling queues.This would be a very inopportune moment for the clock interrupt handler to begin inspecting those queues to see if it was time to do thread switching,since they might be in an inconsistent state.One solution is to set aflag when the run-time system is entered.The clock handler would see this and set its ownflag, then return.When the runtime systemfinished,it would check the clockflag, see that a clock interrupt occurred,and now run the clock handler.PROBLEM SOLUTIONS FOR CHAPTER27 18.Yes it is possible,but inefficient.A thread wanting to do a system callfirstsets an alarm timer,then does the call.If the call blocks,the timer returns control to the threads package.Of course,most of the time the call will not block,and the timer has to be cleared.Thus each system call that might block has to be executed as three system calls.If timers go off prematurely,all kinds of problems can develop.This is not an attractive way to build a threads package.19.The priority inversion problem occurs when a low-priority process is in itscritical region and suddenly a high-priority process becomes ready and is scheduled.If it uses busy waiting,it will run forever.With user-level threads,it cannot happen that a low-priority thread is suddenly preempted to allow a high-priority thread run.There is no preemption.With kernel-level threads this problem can arise.20.With round-robin scheduling it works.Sooner or later L will run,and eventu-ally it will leave its critical region.The point is,with priority scheduling,L never gets to run at all;with round robin,it gets a normal time slice periodi-cally,so it has the chance to leave its critical region.21.Each thread calls procedures on its own,so it must have its own stack for thelocal variables,return addresses,and so on.This is equally true for user-level threads as for kernel-level threads.22.Yes.The simulated computer could be multiprogrammed.For example,while process A is running,it reads out some shared variable.Then a simula-ted clock tick happens and process B runs.It also reads out the same vari-able.Then it adds1to the variable.When process A runs,if it also adds one to the variable,we have a race condition.23.Yes,it still works,but it still is busy waiting,of course.24.It certainly works with preemptive scheduling.In fact,it was designed forthat case.When scheduling is nonpreemptive,it might fail.Consider the case in which turn is initially0but process1runsfirst.It will just loop forever and never release the CPU.25.To do a semaphore operation,the operating systemfirst disables interrupts.Then it reads the value of the semaphore.If it is doing a down and the sema-phore is equal to zero,it puts the calling process on a list of blocked processes associated with the semaphore.If it is doing an up,it must check to see if any processes are blocked on the semaphore.If one or more processes are block-ed,one of them is removed from the list of blocked processes and made run-nable.When all these operations have been completed,interrupts can be enabled again.8PROBLEM SOLUTIONS FOR CHAPTER226.Associated with each counting semaphore are two binary semaphores,M,used for mutual exclusion,and B,used for blocking.Also associated with each counting semaphore is a counter that holds the number of up s minus the number of down s,and a list of processes blocked on that semaphore.To im-plement down,a processfirst gains exclusive access to the semaphores, counter,and list by doing a down on M.It then decrements the counter.If it is zero or more,it just does an up on M and exits.If M is negative,the proc-ess is put on the list of blocked processes.Then an up is done on M and a down is done on B to block the process.To implement up,first M is down ed to get mutual exclusion,and then the counter is incremented.If it is more than zero,no one was blocked,so all that needs to be done is to up M.If, however,the counter is now negative or zero,some process must be removed from the list.Finally,an up is done on B and M in that order.27.If the program operates in phases and neither process may enter the nextphase until both arefinished with the current phase,it makes perfect sense to use a barrier.28.With kernel threads,a thread can block on a semaphore and the kernel canrun some other thread in the same process.Consequently,there is no problem using semaphores.With user-level threads,when one thread blocks on a semaphore,the kernel thinks the entire process is blocked and does not run it ever again.Consequently,the process fails.29.It is very expensive to implement.Each time any variable that appears in apredicate on which some process is waiting changes,the run-time system must re-evaluate the predicate to see if the process can be unblocked.With the Hoare and Brinch Hansen monitors,processes can only be awakened on a signal primitive.30.The employees communicate by passing messages:orders,food,and bags inthis case.In UNIX terms,the four processes are connected by pipes.31.It does not lead to race conditions(nothing is ever lost),but it is effectivelybusy waiting.32.It will take nT sec.33.In simple cases it may be possible to determine whether I/O will be limitingby looking at source code.For instance a program that reads all its inputfiles into buffers at the start will probably not be I/O bound,but a problem that reads and writes incrementally to a number of differentfiles(such as a compi-ler)is likely to be I/O bound.If the operating system provides a facility such as the UNIX ps command that can tell you the amount of CPU time used by a program,you can compare this with the total time to complete execution of the program.This is,of course,most meaningful on a system where you are the only user.34.For multiple processes in a pipeline,the common parent could pass to the op-erating system information about the flow of data.With this information the OS could,for instance,determine which process could supply output to a process blocking on a call for input.35.The CPU efficiency is the useful CPU time divided by the total CPU time.When Q ≥T ,the basic cycle is for the process to run for T and undergo a process switch for S .Thus (a)and (b)have an efficiency of T /(S +T ).When the quantum is shorter than T ,each run of T will require T /Q process switches,wasting a time ST /Q .The efficiency here is thenT +ST /QT which reduces to Q /(Q +S ),which is the answer to (c).For (d),we just sub-stitute Q for S and find that the efficiency is 50%.Finally,for (e),as Q →0the efficiency goes to 0.36.Shortest job first is the way to minimize average response time.0<X ≤3:X ,3,5,6,9.3<X ≤5:3,X ,5,6,9.5<X ≤6:3,5,X ,6,9.6<X ≤9:3,5,6,X ,9.X >9:3,5,6,9,X.37.For round robin,during the first 10minutes each job gets 1/5of the CPU.Atthe end of 10minutes,C finishes.During the next 8minutes,each job gets 1/4of the CPU,after which time D finishes.Then each of the three remaining jobs gets 1/3of the CPU for 6minutes,until B finishes,and so on.The fin-ishing times for the five jobs are 10,18,24,28,and 30,for an average of 22minutes.For priority scheduling,B is run first.After 6minutes it is finished.The other jobs finish at 14,24,26,and 30,for an average of 18.8minutes.If the jobs run in the order A through E ,they finish at 10,16,18,22,and 30,for an average of 19.2minutes.Finally,shortest job first yields finishing times of 2,6,12,20,and 30,for an average of 14minutes.38.The first time it gets 1quantum.On succeeding runs it gets 2,4,8,and 15,soit must be swapped in 5times.39.A check could be made to see if the program was expecting input and didanything with it.A program that was not expecting input and did not process it would not get any special priority boost.40.The sequence of predictions is 40,30,35,and now 25.41.The fraction of the CPU used is35/50+20/100+10/200+x/250.To beschedulable,this must be less than1.Thus x must be less than12.5msec. 42.Two-level scheduling is needed when memory is too small to hold all theready processes.Some set of them is put into memory,and a choice is made from that set.From time to time,the set of in-core processes is adjusted.This algorithm is easy to implement and reasonably efficient,certainly a lot better than,say,round robin without regard to whether a process was in memory or not.43.Each voice call runs200times/second and uses up1msec per burst,so eachvoice call needs200msec per second or400msec for the two of them.The video runs25times a second and uses up20msec each time,for a total of 500msec per second.Together they consume900msec per second,so there is time left over and the system is schedulable.44.The kernel could schedule processes by any means it wishes,but within eachprocess it runs threads strictly in priority order.By letting the user process set the priority of its own threads,the user controls the policy but the kernel handles the mechanism.45.The change would mean that after a philosopher stopped eating,neither of hisneighbors could be chosen next.In fact,they would never be chosen.Sup-pose that philosopher2finished eating.He would run test for philosophers1 and3,and neither would be started,even though both were hungry and both forks were available.Similarly,if philosopher4finished eating,philosopher3 would not be started.Nothing would start him.46.If a philosopher blocks,neighbors can later see that she is hungry by checkinghis state,in test,so he can be awakened when the forks are available.47.Variation1:readers have priority.No writer may start when a reader is ac-tive.When a new reader appears,it may start immediately unless a writer is currently active.When a writerfinishes,if readers are waiting,they are all started,regardless of the presence of waiting writers.Variation2:Writers have priority.No reader may start when a writer is waiting.When the last ac-tive processfinishes,a writer is started,if there is one;otherwise,all the readers(if any)are started.Variation3:symmetric version.When a reader is active,new readers may start immediately.When a writerfinishes,a new writer has priority,if one is waiting.In other words,once we have started reading,we keep reading until there are no readers left.Similarly,once we have started writing,all pending writers are allowed to run.48.A possible shell script might beif[!–f numbers];then echo0>numbers;ficount=0while(test$count!=200)docount=‘expr$count+1‘n=‘tail–1numbers‘expr$n+1>>numbersdoneRun the script twice simultaneously,by starting it once in the background (using&)and again in the foreground.Then examine thefile numbers.It will probably start out looking like an orderly list of numbers,but at some point it will lose its orderliness,due to the race condition created by running two cop-ies of the script.The race can be avoided by having each copy of the script test for and set a lock on thefile before entering the critical area,and unlock-ing it upon leaving the critical area.This can be done like this:if ln numbers numbers.lockthenn=‘tail–1numbers‘expr$n+1>>numbersrm numbers.lockfiThis version will just skip a turn when thefile is inaccessible,variant solu-tions could put the process to sleep,do busy waiting,or count only loops in which the operation is successful.SOLUTIONS TO CHAPTER3PROBLEMS1.It is an accident.The base register is16,384because the program happened tobe loaded at address16,384.It could have been loaded anywhere.The limit register is16,384because the program contains16,384bytes.It could have been any length.That the load address happens to exactly match the program length is pure coincidence.2.Almost the entire memory has to be copied,which requires each word to beread and then rewritten at a different location.Reading4bytes takes10nsec, so reading1byte takes2.5nsec and writing it takes another2.5nsec,for a total of5nsec per byte compacted.This is a rate of200,000,000bytes/sec.To copy128MB(227bytes,which is about1.34×108bytes),the computer needs227/200,000,000sec,which is about671msec.This number is slightly pessimistic because if the initial hole at the bottom of memory is k bytes, those k bytes do not need to be copied.However,if there are many holes andmany data segments,the holes will be small,so k will be small and the error in the calculation will also be small.3.The bitmap needs1bit per allocation unit.With227/n allocation units,this is224/n bytes.The linked list has227/216or211nodes,each of8bytes,for a total of214bytes.For small n,the linked list is better.For large n,the bitmap is better.The crossover point can be calculated by equating these two formu-las and solving for n.The result is1KB.For n smaller than1KB,a linked list is better.For n larger than1KB,a bitmap is better.Of course,the assumption of segments and holes alternating every64KB is very unrealistic.Also,we need n<=64KB if the segments and holes are64KB.4.Firstfit takes20KB,10KB,18KB.Bestfit takes12KB,10KB,and9KB.Worstfit takes20KB,18KB,and15KB.Nextfit takes20KB,18KB,and9 KB.5.For a4-KB page size the(page,offset)pairs are(4,3616),(8,0),and(14,2656).For an8-KB page size they are(2,3616),(4,0),and(7,2656).6.They built an MMU and inserted it between the8086and the bus.Thus all8086physical addresses went into the MMU as virtual addresses.The MMU then mapped them onto physical addresses,which went to the bus.7.(a)M has to be at least4,096to ensure a TLB miss for every access to an ele-ment of X.Since N only affects how many times X is accessed,any value of N will do.(b)M should still be atleast4,096to ensure a TLB miss for every access to anelement of X.But now N should be greater than64K to thrash the TLB, that is,X should exceed256KB.8.The total virtual address space for all the processes combined is nv,so thismuch storage is needed for pages.However,an amount r can be in RAM,so the amount of disk storage required is only nv−r.This amount is far more than is ever needed in practice because rarely will there be n processes ac-tually running and even more rarely will all of them need the maximum al-lowed virtual memory.9.The page table contains232/213entries,which is524,288.Loading the pagetable takes52msec.If a process gets100msec,this consists of52msec for loading the page table and48msec for running.Thus52%of the time is spent loading page tables.10.(a)We need one entry for each page,or224=16×1024×1024entries,sincethere are36=48−12bits in the page numberfield.。
微软Hyper-V虚拟化概述和安全指南说明书
WMI Provider
VM Service
VM Worker Processes
Guest Partitions
Guest Applications
Ring 3: User Mode
Provided by:
Windows Hyper-V ISV
Server Core
Virtualization
Windows Kernel
{ Guest OS
SAP
Dept File / Print
VM Host
Guest VMs can not see/detect threats in the VM host due to the virtualizing behavior of the host.
This attack approach is similar, yet much more insidious, than the approach rootkits take to hide their presence.
Requires hardware assisted virtualization
AMD AMD-V Intel VT
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Hyper-V Architecture
Root Partition
Virtualization Stack
Hosted virtualization Hypervisor virtualization
Virtual Machine Monitor Arrangements
Hosted Virtualization
Guest 1 Guest 2
nRF52840产品简介版本2.0说明书
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IoT
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32-bit ARM Cortex-M4F @ 64MHz Up to 111 dB link budget for Bluetooth long range mode Full-speed 12Mbs USB controller NFC Tag-A Software stacks available as downloads Application development independent of protocol stack Programmable output power from +8dBm to -20dBm -96dBm Sensitivity for Bluetooth low energy On-air compatible with nRF51, nRF24L and nRF24AP Series Arm CryptoCell CC310 crytographic security module High-precision RSSI Wide supply voltage range + 1.7V to 5.5V QSPI/SPI/2-wire/I²S/PDM/QDEC Programmable Peripheral Interface - PPI High speed SPI interface 32MHz Quad SPI interface 32MHz EasyDMA for all digital interfaces RAM mapped FIFO using EasyDMA 12bit/200K SPS ADC 128 bit AES/ECB/CCM/AAR co-processor Single-ended antenna output (on-chip balun) On-chip DC-DC buck converter Quadrature demodulator Regulated supply for external components up to 25mA
生物信息学主要英文术语及释义
生物信息学主要英文术语及释义Abstract Syntax Notation (ASN.l)（NCBI发展的许多程序，如显示蛋白质三维结构的Cn3D等所使用的内部格式）A language that is used to describe structured data types formally, Within bioinformatits,it has been used by the National Center for Biotechnology Information to encode sequences, maps, taxonomic information, molecular structures, and biographical information in such a way that it can be easily accessed and exchanged by computer software.Accession number（记录号）A unique identifier that is assigned to a single database entry for a DNA or protein sequence.Affine gap penalty（一种设置空位罚分策略）A gap penalty score that is a linear function of gap length, consisting of a gap opening penalty and a gap extension penalty multiplied by the length of the gap. Using this penalty scheme greatly enhances the performance of dynamic programming methods for sequence alignment. See also Gap penalty. Algorithm（算法）A systematic procedure for solving a problem in a finite number of steps, typically involving a repetition of operations. Once specified, an algorithm can be written in a computer language and run as a program.Alignment（联配/比对/联配）Refers to the procedure of comparing two or more sequences by looking for a series of individual characters or character patterns that are in the same order in the sequences. Of the two types of alignment, local and global, a local alignment is generally the most useful. See also Local and Global alignments. Alignment score（联配/比对/联配值）An algorithmically computed score based on the number of matches, substitutions, insertions, and deletions (gaps) within an alignment. Scores for matches and substitutions Are derived from a scoring matrix such as the BLOSUM and PAM matrices for proteins, and aftine gap penalties suitable for the matrix are chosen. Alignment scores are in log odds units, often bit units (log to the base 2). Higher scores denote better alignments. See also Similarity score, Distance in sequence analysis.Alphabet（字母表）The total number of symbols in a sequence-4 for DNA sequences and 20 for protein sequences.Annotation（注释）The prediction of genes in a genome, including the location of protein-encoding genes, the sequence of the encoded proteins, anysignificantmatches to other Proteins of known function, and the location of RNA-encoding genes. Predictions are based on gene models; e.g., hidden Markov models of introns and exons in proteins encoding genes, and models of secondary structure in RNA.Anonymous FTP（匿名FTP）When a FTP service allows anyone to log in, it is said to provide anonymous FTP ser-vice. A user can log in to an anonymous FTP server by typing anonymous as the user name and his E-mail address as a password. Most Web browsers now negotiate anonymous FTP logon without asking the user for a user name and password. See also FTP.ASCIIThe American Standard Code for Information Interchange (ASCII) encodes unaccented letters a-z, A-Z, the numbers O-9, most punctuation marks, space, and a set of control characters such as carriage return and tab. ASCII specifies 128 characters that are mapped to the values O-127. ASCII tiles are commonly called plain text, meaning that they only encode text without extra markup.BAC clone（细菌人工染色体克隆）Bacterial artificial chromosome vector carrying a genomic DNA insert, typically 100–200 kb. Most of the large-insert clones sequenced in the project were BAC clones.Back-propagation（反向传输）When training feed-forward neural networks, a back-propagation algorithm can be used to modify the network weights. After each training input pattern is fed through the network, the network’s output is compared with the desired output and the amount of error is calculated. This error is back-propagated through the network by using an error function to correct the network weights. See also Feed-forward neural network.Baum-Welch algorithm（Baum-Welch算法）An expectation maximization algorithm that is used to train hidden Markov models.Baye’s rule（贝叶斯法则）Forms the basis of conditional probability by calculating the likelihood of an event occurring based on the history of the event and relevant background information. In terms of two parameters A and B, the theorem is stated in anequation: The condition-al probability of A, given B, P(AIB), is equal to the probability of A, P(A), times the conditional probability of B, given A, P(BIA), divided by the probability of B, P(B). P(A) is the historical or prior distribution value of A, P(BIA) is a new prediction for B for a particular value of A, and P(B) is the sum of the newly predicted values for B. P(AIB) is a posterior probability, representing a new prediction for A given the prior knowledge of A and the newly discovered relationships between A and B. Bayesian analysis（贝叶斯分析）A statistical procedure used to estimate parameters of an underlyingdistribution based on an observed distribution. See also Baye’s rule.Biochips（生物芯片）Miniaturized arrays of large numbers of molecular substrates, often oligonucleotides, in a defined pattern. They are also called DNA microarrays and microchips.Bioinformatics （生物信息学）The merger of biotechnology and information technology with the goal of revealing new insights and principles in biology. /The discipline of obtaining information about genomic or protein sequence data. This may involve similarity searches of databases, comparing your unidentified sequence to the sequences in a database, or making predictions about the sequence based on current knowledge of similar sequences. Databases are frequently made publically available through the Internet, or locally at your institution.Bit score （二进制值/ Bit值）The value S' is derived from the raw alignment score S in which the statistical properties of the scoring system used have been taken into account. Because bit scores have been normalized with respect to the scoring system, they can be used to compare alignment scores from different searches.Bit unitsFrom information theory, a bit denotes the amount of information required to distinguish between two equally likely possibilities. The number of bits of information, AJ, required to convey a message that has A4 possibilities is log2 M = N bits.BLAST （基本局部联配搜索工具，一种主要数据库搜索程序）Basic Local Alignment Search Tool. A set of programs, used to perform fast similarity searches. Nucleotide sequences can be compared with nucleotide sequences in a database using BLASTN, for example. Complex statistics areapplied to judge the significance of each match. Reported sequences may be homologous to, or related to the query sequence. The BLASTP program is used to search a protein database for a match against a query protein sequence. There are several other flavours of BLAST. BLAST2 is a newer release of BLAST. Allows for insertions or deletions in the sequences being aligned. Gapped alignments may be more biologically significant.Block（蛋白质家族中保守区域的组块）Conserved ungapped patterns approximately 3-60 amino acids in length in a set of related proteins.BLOSUM matrices（模块替换矩阵，一种主要替换矩阵）An alternative to PAM tables, BLOSUM tables were derived using local multiple alignments of more distantly related sequences than were used for the PAM matrix. These are used to assess the similarity of sequences when performing alignments.Boltzmann distribution（Boltzmann 分布）Describes the number of molecules that have energies above a certain level, based on the Boltzmann gas constant and the absolute temperature.Boltzmann probability function(Boltzmann概率函数)See Boltzmann distribution.Bootstrap analysisA method for testing how well a particular data set fits a model. For example, the validity of the branch arrangement in a predicted phylogenetic tree can be tested by resampling columns in a multiple sequence alignment to create many new alignments. The appearance of a particular branch in trees generated from these resampled sequences can then be measured. Alternatively, a sequence may be left out of an analysis to deter-mine how much the sequence influences the results of an analysis.Branch length（分支长度）In sequence analysis, the number of sequence changes along a particular branch of a phylogenetic tree.CDS or cds （编码序列）Coding sequence.Chebyshe, d inequalityThe probability that a random variable exceeds its mean is less than or equal to the square of 1 over the number of standard deviations from the mean. Clone （克隆）Population of identical cells or molecules (e.g. DNA), derived from a singleancestor.Cloning Vector （克隆载体）A molecule that carries a foreign gene into a host, and allows/facilitates the multiplication of that gene in a host. When sequencing a gene that has been cloned using a cloning vector (rather than by PCR), care should be taken not to include the cloning vector sequence when performing similarity searches. Plasmids, cosmids, phagemids, YACs and PACs are example types of cloning vectors.Cluster analysis（聚类分析）A method for grouping together a set of objects that are most similar from a larger group of related objects. The relationships are based on some criterion of similarity or difference. For sequences, a similarity or distance score or a statistical evaluation of those scores is used.CobblerA single sequence that represents the most conserved regions in a multiple sequence alignment. The BLOCKS server uses the cobbler sequence to perform a database similarity search as a way to reach sequences that are more divergent than would be found using the single sequences in the alignment for searches.Coding system (neural networks)Regarding neural networks, a coding system needs to be designed for representing input and output. The level of success found when training the model will be partially dependent on the quality of the coding system chosen. Codon usageAnalysis of the codons used in a particular gene or organism. COG（直系同源簇）Clusters of orthologous groups in a set of groups of related sequences in microorganism and yeast (S. cerevisiae). These groups are found by whole proteome comparisons and include orthologs and paralogs. See also Orthologs and Paralogs.Comparative genomics（比较基因组学）A comparison of gene numbers, gene locations, and biological functions of genes in the genomes of diverse organisms, one objective being to identify groups of genes that play a unique biological role in a particular organism. Complexity (of an algorithm)（算法的复杂性）Describes the number of steps required by the algorithm to solve a problem as a function of the amount of data; for example, the length of sequences to be aligned.Conditional probability（条件概率）The probability of a particular result (or of a particular value of a variable) given one or more events or conditions (or values of other variables). Conservation （保守）Changes at a specific position of an amino acid or (less commonly, DNA) sequence that preserve the physico-chemical properties of the original residue.Consensus（一致序列）A single sequence that represents, at each subsequent position, the variation found within corresponding columns of a multiple sequence alignment. Context-free grammarsA recursive set of production rules for generating patterns of strings. These consist of a set of terminal characters that are used to create strings, a set of nonterminal symbols that correspond to rules and act as placeholders for patterns that can be generated using terminal characters, a set of rules for replacing nonterminal symbols with terminal characters, and a start symbol. Contig （序列重叠群/拼接序列）A set of clones that can be assembled into a linear order. A DNA sequence that overlaps with another contig. The full set of overlapping sequences (contigs) can be put together to obtain the sequence for a long region of DNA that cannot be sequenced in one run in a sequencing assay. Important in genetic mapping at the molecular level.CORBA（国际对象管理协作组制定的使OOP对象与网络接口统一起来的一套跨计算机、操作系统、程序语言和网络的共同标准）The Common Object Request Broker Architecture (CORBA) is an open industry standard for working with distributed objects, developed by the Object Management Group. CORBA allows the interconnection of objects and applications regardless of computer language, machine architecture, or geographic location of the computers.Correlation coefficient（相关系数）A numerical measure, falling between -1 and 1, of the degree of the linear relationship between two variables. A positive value indicates a direct relationship, a negative value indicates an inverse relationship, and the distance of the value away from zero indicates the strength of the relationship. A value near zero indicates no relationship between the variables.Covariation (in sequences)（共变）Coincident change at two or more sequence positions in related sequencesthat may influence the secondary structures of RNA or protein molecules. Coverage (or depth) （覆盖率/厚度）The average number of times a nucleotide is represented by a high-quality base in a collection of random raw sequence. Operationally, a 'high-quality base' is defined as one with an accuracy of at least 99% (corresponding to a PHRED score of at least 20).Database（数据库）A computerized storehouse of data that provides a standardized way for locating, adding, removing, and changing data. See also Object-oriented database, Relational database.DendogramA form of a tree that lists the compared objects (e.g., sequences or genes in a microarray analysis) in a vertical order and joins related ones by levels of branches extending to one side of the list.Depth （厚度）See coverageDirichlet mixturesDefined as the conjugational prior of a multinomial distribution. One use is for predicting the expected pattern of amino acid variation found in the match state of a hid-den Markov model (representing one column of a multiple sequence alignment of proteins), based on prior distributions found in conserved protein domains (blocks).Distance in sequence analysis（序列距离）The number of observed changes in an optimal alignment of two sequences, usually not counting gaps.DNA Sequencing （DNA测序）The experimental process of determining the nucleotide sequence of a region of DNA. This is done by labelling each nucleotide (A, C, G or T) with either a radioactive or fluorescent marker which identifies it. There are several methods of applying this technology, each with their advantages and disadvantages. For more information, refer to a current text book. High throughput laboratories frequently use automated sequencers, which are capable of rapidly reading large numbers of templates. Sometimes, the sequences may be generated more quickly than they can be characterised. Domain （功能域）A discrete portion of a protein assumed to fold independently of the rest of the protein and possessing its own function.Dot matrix（点标矩阵图）Dot matrix diagrams provide a graphical method for comparing two sequences. One sequence is written horizontally across the top of the graph and the other along the left-hand side. Dots are placed within the graph at the intersection of the same letter appearing in both sequences. A series of diagonal lines in the graph indicate regions of alignment. The matrix may be filtered to reveal the most-alike regions by scoring a minimal threshold number of matches within a sequence window.Draft genome sequence （基因组序列草图）The sequence produced by combining the information from the individual sequenced clones (by creating merged sequence contigs and then employing linking information to create scaffolds) and positioning the sequence along the physical map of the chromosomes.DUST （一种低复杂性区段过滤程序）A program for filtering low complexity regions from nucleic acid sequences. Dynamic programming（动态规划法）A dynamic programming algorithm solves a problem by combining solutions to sub-problems that are computed once and saved in a table or matrix. Dynamic programming is typically used when a problem has many possible solutions and an optimal one needs to be found. This algorithm is used for producing sequence alignments, given a scoring system for sequence comparisons.EMBL （欧洲分子生物学实验室，EMBL数据库是主要公共核酸序列数据库之一）European Molecular Biology Laboratories. Maintain the EMBL database, one of the major public sequence databases.EMBnet （欧洲分子生物学网络）European Molecular Biology Network: / was established in 1988, and provides services including local molecular databases and software for molecular biologists in Europe. There are several large outposts of EMBnet, including EXPASY.Entropy（熵）From information theory, a measure of the unpredictable nature of a set of possible elements. The higher the level of variation within the set, the higher the entropy.Erdos and Renyi lawIn a toss of a “fair” coin, the number of heads in a row that can be expected is the logarithm of the number of tosses to the base 2. The law may begeneralized for more than two possible outcomes by changing the base of the logarithm to the number of out-comes. This law was used to analyze the number of matches and mismatches that can be expected between random sequences as a basis for scoring the statistical significance of a sequence alignment.EST （表达序列标签的缩写）See Expressed Sequence TagExpect value (E)（E值）E value. The number of different alignents with scores equivalent to or better than S that are expected to occur in a database search by chance. The lower the E value, the more significant the score. In a database similarity search, the probability that an alignment score as good as the one found between a query sequence and a database sequence would be found in as many comparisons between random sequences as was done to find the matching sequence. In other types of sequence analysis, E has a similar meaning.Expectation maximization (sequence analysis)An algorithm for locating similar sequence patterns in a set of sequences. A guessed alignment of the sequences is first used to generate an expected scoring matrix representing the distribution of sequence characters in each column of the alignment, this pattern is matched to each sequence, and the scoring matrix values are then updated to maximize the alignment of the matrix to the sequences. The procedure is repeated until there is no further improvement.Exon （外显子）。
Personal Statement for CS 计算机专业文书分享
Personal StatementEmbarking on the field of Artificial Intelligence is a journey of self-discovery, where episodes of hardship and disappointments alternate with excitement and joy. Never could I forget the excitement that I felt when I first heard about how a technical company utilized AI to process a large set of medical images, drastically boosting the diagnosis accuracy and efficiency. Neither did the thrill I had, as the revolutionary power of AI unfolded in front of me with each project, fade from my memories. Nor did I forget about the frustration I experienced when grappling with technical challenges in my projects.My interest towards AI was ignited by an enlightening lecture from the chief advisor at a technology firm. This fascination led me to make a pivotal decision—changing my major from XXXX to artificial intelligence. The transaction was challenging, urging me to immerse myself in a new academic field and complete a variety of courses. Introductory Courses—Operating Systems, Data Structures, and Linux Fundamentals—enhanced my understanding of the operating mechanism of computer systems, allowing me to develop and optimize the codes more efficiently. Moreover, my practical skills were developed and refined by taking classes such as Machine Learning, Machine Vision, and Natural Language Processing. With the course of Machine Vision, I gained essential image processing techniques, such as image segmentation and XXXX. The Machine Learning course enabled me to apply a variety of algorithms, including Linear Regression, XXXX, and Decision Trees. The course in Natural Language Processing illustrated how computers comprehend and synthesize human language, preparing me for internships in speech recognition, text mining, and sentiment analysis. In addition, my grasp of statistics—the foundation of AI—aided me in comprehending and processing data.Fueled by my passion for AI, I pursued not only academic excellence but also industrial expertise. My internship at XXXXX enhanced both my programming and reinforcement learning skills, while participation in the XXXX Contest honed my abilities in data processing and visualization.During my internship at XXXX, I participated in a project about the distribution of red packets. This helped me improve my skills in both reinforcement learning and programming. The primary goal of this project was to create an intelligent model that autonomously distribute red packets to users, thus enhancing its user engagement and loyalty. After a thorough study and comparison of several reinforcement learning algorithms, including deep Q-networks and policy gradients, I decided to prepare the intelligent model with the XXXXX algorithm. I then implemented this algorithm with Python and TensorFlow, and thereby built an intelligent model incorporated with convolutional neural network and fully-connected network. Next, in order to train this model, a training environment and a reward mechanism were prepared. Through undergoing continuous tuning, the intelligent model could apply optimal strategies forred packet distribution autonomously. Such experience proved invaluable, enhancing my proficiency with reinforcement learning algorithms and programming. In addition to supplementing my knowledge of reinforcement learning algorithms, those experience improved my programming skills, specifically in implementing deep learning algorithms with Python and TensorFlow.In pursuit of my passion for AI, apart form seeking internship opportunities, I participated in various competitions. Among them, the XXXX Contest proved most beneficial, prompting me to solve various challenges. Facing and overcoming those challenges during the contest, such as processing massive datasets at optimal speed and visualizing user buying behaviors, enhanced my skills in data processing, data visualization, and machine learning. Tackling the issue of managing large datasets, I refined the codes and adopted efficient data processing methods.Utilizing tools like Pandas, I cleaned and processed the data, enhancing efficiency and accelerating the analysis workflow. At the same time, I worked on improving the accuracy of visualization for user purchasing behaviors. I developed an effective visualization plan by conducting comprehensive literature research and drawing inspiration from industry professionals.With XXXX and XXX, I created a distribution map reflecting users’ purchasing frequency and a heat map illustrating users’ purchasing behavior patterns. Machine learning methods, including cluster analysis, were employed to detect various types of user purchase behavior patterns. Such process of problem-solving, though demanding, has sharpened my abilities in data processing, data visualization, and machine learning.Based on my academic interest and project experiences, I have mapped out my career path. My ultimate goal is to be a globally recognized AI expert and entrepreneur, building my own brand and impact in the technical industry. To this end, I have set my short-term career objective as becoming an AI algorithm engineer or machine learning engineer, acquiring expertise and staying abreast of the latest trends in the dynamic field of AI. A maser degree in AI, I believe, is a must to fulfill those career objectives.In view of my academic background, career objectives and project experience, I am well aware of the importance of advancing my education in the AI field. The master’s degree in AI at XXXX University, seamlessly aligning with my academic interest and career aspirations, is an ideal match for me. Aside from the core courses of machine learning and basics of AI, its curriculum offers a wide range of study areas and research topics. Considering your program’s evident strength in faculty members and research resource, it makes an important component of my professional goals. And I am eager to learn from professors with extensive research experience and industry expertise. In addition, the program’s recognition by the British Computer Society is a testament to its quality.。
莫卡产品说明书
Copyright © 2019 Moxa Inc. Released on August 14, 2019About MoxaMoxa is a leading manufacturer of industrial networking, computing, and automationsolutions. With over 25 years of industry experience, Moxa has connected more than 30 million devices worldwide and has a distribution and service network that reaches customers in more than 70 countries. Moxa delivers lasting business value byempowering industry with reliable networks and sincere service for automation systems. Information about Moxa’s solutions is available at . You may also contact Moxa by email at *************. How to Contact Moxa Tel: +886-2-8919-1230 How to Use the TIA Portal to Set a Siemens PLC and the MGate 5103Moxa Technical Support Team****************Contents1 Application Description ...................................................................2 2 System Topology .............................................................................3 3Required Equipment and Components (4)A. TIA Portal V14 ............................................................................................ 4B.Modbus Slave (4)C. MGate 5103 Firmware .................................................................................. 4 D. MGate 5103’s GSDML File .. (4)4MGate 5103 Settings (5)A. Protocol Conversion ..................................................................................... 5B.Configure Modbus Commands (5)C. Configure PROFINET Setting ......................................................................... 7 D. I/O Data Mapping . (7)5 Siemens PLC Setting ....................................................................... 8 6Communication Test (21)A. Status Monitoring ...................................................................................... 21 B. Fault Protection .. (26)1Application DescriptionThe TIA Portal is Siemens’s new software platform to configure and program S7-300/400/1200/1500 PLCs. This technical note demonstrates how to configure the Siemens S7-300 to connect with the MGate 5103 in TIA Portal V14.The MGate 5103 supports a variety of maintenance functions, such as ProtocolDiagnostics, Traffic Monitoring, Status Monitoring, and Fault Protection. The Status Monitoring function notifies a PLC/DCS/SCADA system when a Modbus device getsdisconnected or does not respond. If a command has run successfully, the status bit’s value will be 1. If a command has failed, the status bit’s value will then be 0. In this case, themaster device will be aware of the failure status of the slave device. When a PROFINETconnection is disconnected, the Fault Protection function executes actions on end devices identified by a pre-defined value set by the user.This technical note also demonstrates how the PROFINET IO controller (Siemens PLC) receive these Modbus command statuses by sending PROFINET Acyclic Read commands, as well as how the Fault Protection function works. We also demonstrated how to use the Protocol Diagnostics and Traffic Monitoring functions for troubleshooting.2System TopologyThis technical note demonstrates how to exchange data between a PROFINET IO controller and six Modbus RTU slaves. The Modbus RTU slave IDs 1-3 use Modbus Read command, and shows the Status Monitoring function. The Modbus RTU slave IDs 4-6 use Modbus Write command, and shows the Fault Protection function.We use Siemens S7-300 as the PROFINET IO controller to connect the MGate 5103. Ona PC, we run Modbus Slave tools to simulate Modbus RTU slaves and connect to the MGate5103’s serial port.3Required Equipment and ComponentsA.TIA Portal V14As a registered Siemens’s customer, you can download the trial software for the TIAPortal V14 and test it for 21 days.Version: V14Download Website:https:///cs/document/109740158/simatic-step-7-(tia-portal)-v14-trial-download?dti=0&lc=en-WWB.Modbus SlaveModbus Slave is a very popular Modbus slave simulator to test and debug of yourModbus devices. It supports Modbus RTU/ASCII and Modbus TCP/IP.Version: V6+Download Website:/download.htmlC.MGate 5103 FirmwareVersion: V.1.0 or higherDownload Website: D.MGate 5103’s GSDML FileThe GSDML (General Station Description Mark-Up Language) file is an electronic devicedatasheet or device database file that identifies the PROFINET IO device. This file can beinstalled into the PROFINET Engineering Tool, e.g., the TIA Portal, so that this PROFINETEngineering Tool can configure the PROFINET IO Device.Version: GSDML-V2.2-Moxa-Device0202-20170502.xml/GSDML-V2.3-Moxa-Device0202-20170502.xmlDownload Website: Note: For wiring, please refer to the MGate 5103’s User’s Manual.4 MGate 5103 SettingsFor details, please refer to the MGate 5103 user’s manual. You can download it from A. Protocol ConversionLog in to the MGate 5103’s Web Console. Set Protocol Conversion : Role 1 as PROFINET IO Device , Role 2 as Modbus RTU/ASCII Master .B. Configure Modbus CommandsUnder Modbus RTU/ASCII setting , set Modbus as RTU , Max. retry as 0. The default of this value is 3. Change this value to 0 in order to quickly detect when a Modbus command failed.Then add the commands below to poll Slave ID1-ID3’s register 0, and add Function Code 06 commands to write Slave ID4-ID6’s register 0.For ID4 command’s Fault Protection, keep it as Keep latest data.For ID5 command’s Fault Protection, choose Clear all data bit to 0 and set Fault timeout as 10000 ms.For ID6 command’s Fault Protection, choose Set to user defined value and set Fault value as 0xFF 0xFF . Fault timeout is set as 10000 ms.C.Configure PROFINET SettingOnly the Device Name needs to be set. Set it as mgate-dev.D.I/O Data MappingAllow the MGate to automap the data on both sides of the MGate’s IO Internal Memory.Check I/O Data Mapping with Data flow direction: PROFINET IO Controller →Modbus RTU/ASCII Slave or PROFINET IO Controller ← Modbus RTU/ASCIISlave. Make sure the PROFINET Output or Input Slot Size is fully and correctlymapped to Modbus Internal Address.5Siemens PLC Setting(1)Create a new project.(2)After the project is successfully created, click Configure a device to add thePLC.According to the actual PLC’s CPU model, select it from “Controllers → S7-300 →CPU ” as below:(3) Click PLC’s PROFINET interface_1 to set its IP Address .(4) Click Add new subne t to create subnet as PN/IE_1.(5) Click Options Manage general station description to install the MGate5103’s GSD file.Select the latest version of the MGate 5103, V2.3, and then click Install .Make sure the installation is successful.(6) In the Hardware catalog window, filter “moxa” to search the MGate 5103. Choose the Moxa PROFINET Device 0202 device icon, and drag and drop to PN/IE_1 subnet.(7)Under Network view, it shows that the MGate 5103 is in the PN/IE_1subnet. Click Not assigned to assign the MGate 5103 to PN/IE_1.Then MGate 5103 is set into the PLC_1’s PROFINET IO System.If your MGate 5103 Device Name is not mgate-dev, you can modify it via Properties → General → Name”.(8)Under the MGate 5103’s Device view, drag and drop Input 006 Byte to Slot 1. Assign the I address to 0-5.Drag and drop Output 006 Byte to Slot 2. Assign the Q address to 0-5.(9)We want to get the register values of Modbus ID1- ID3 and make sure these Modbus commands’ responses are valid. If a Modbus command’s response is invalid or times out, the register value will show 0xFFFF . We will show the details later . We created these tags below:Click Main [OB1] to edit program.Drag and Drop the RDREC function block to Network 1. DB setting pops up to add RDREC Instance. Click OK to apply it.Fill in the input/output parameters as below:Parameter descriptions:①.REQ: If this bit is true, the request will be sent to the MGate 5103.②.VALID: Bit memory M11.1 indicates whether a new data record was received andvalid.③.BUSY: Bit memory M11.2 indicates whether the read process has been terminated.④.ERROR: Bit memory M11.3 indicates whether an error occurred while processing thefunction.⑤.STATUS: The bit memory - double word MD12 contains block status or errorinformation.⑥.ID: It is the PN-IO diagnostic address, which is 2041, as below. This address isused for PROFINET acyclic read/write for the MGate 5103 to do some pre-define diagnoses.If you use the CPU 1200 or 1500 Series, then the ID should be taken from System constants or the General->PROFINET interface->Hardware identifier field.⑦. INDEX: Data record number . For the MGate 5103, the command status startingaddress is 30000.⑧. MLEN: The maximum length of bytes of the data record information to be fetched.In this demo, we only need one byte to get command 1-3 status (Bit 0-2). ⑨. RECORD: The destination area for the read data record. We use MB10 to store it.Other Networks’ programs are illustrated as below:(10)Execute Compile and make sure there is no error.(11)Execute Download.Click Start Search to search an accessible PLC.When an accessible PLC has been found, execute Load .The TIA Portal will check hardware and software consistency. After checking for any errors, click Load to download.After loading, enable Start all to start modules, then click Finish.6Communication TestA.Status Monitoring(1)PC runs the Modbus Slave tool to connect to the MGate 5103’s Serial port.Add slave ID1-ID3 and set each one’s register 0’s value as 1, 2, 3, respectively.(2)Click Add new watch table to create the Watch table_1.Add the tags below to be monitored:(3)Click Go online,then click Monitor all.If ReqBit status is not True, you can input True under the Modify value column, click the Modify button to enable send request.We can see RecordByte shows a value of 7, pointing out that the commands 1-3 are successful. The ID1Value-ID3Value are running as 1, 2, 3, respectively.(4) We can use the MGate’s Protocol Diagnostics tool on the Web Console to checkModbus and PROFINET communication status:Via System Monitoring → Protocol Status → Modbus RTU/ASCII Diagnose , we can see its Received Valid response counter is equal to the Sent request counter .Via System Monitoring → Protocol Status → Modbus RTU/ASCII Traffic , we can log Modbus RTU communication traffic:Via System Monitoring → Protocol Status → PROFINET Diagnose, we can see its Connected PLC MAC Address:Via System Monitoring → Protocol Status → I/O Data View, we can choose PROFINET IO Controller ← Modbus RTU/ASCII Slave data flow side to see theModbus slave input data:(5)Disable Modbus Slave ID 2 on Modbus Slave tool, so Modbus Command 2can’t receive any responses. Check Watch table, RecordByte shows a value of 5 and ID2value is updated as 0xFFFF.Check Modbus RTU/ASCII Diagnose, the Timeout counter is increasing:B.Fault Protection(1)Add slave ID4-ID6 on the Modbus Slave tool as below:(2)On Watch table, we set Modify value under QW0 as 0x0004, QW2 as 0x0005,QW4 as 0x0006. Then click the Modify button.(3)Check Modbus Slave ID 4-ID6; they are updated as 0x0004, 0x0005, 0x0006.Via System Monitoring → Protocol Status → I/O Data View, we can choosePROFINET IO Controller → Modbus RTU/ASCII Slave data flow side to see thePROFINET output data:(4)Shut down the PLC. After 10000 ms, the Fault Timeout is on. Check whetherModbus Slave ID 4’s register 0 value still is 0x0004. Slave ID 5’s register 0value is updated as 0x0000, and Slave ID 6’s register 0 value is updated as0xFFFF.Check PROFINET IO Controller Modbus RTU/ASCII Slave data flow side; they all updated as its Fault Value:Check PROFINET Diagnose. Its Connected PLC MAC Address shows NotConnected:。
生物信息学主要英文术语及释义
生物信息学主要英文术语及释义Abstract Syntax Notation (ASN.l)（NCBI发展的许多程序，如显示蛋白质三维结构的Cn3D 等所使用的内部格式）A language that is used to describe structured data types formally, Within bioinformatits,it has been used by the National Center for Biotechnology Information to encode sequences, maps, taxonomic information, molecular structures, and biographical information in such a way that it can be easily accessed and exchanged by computer software.Accession number（记录号）A unique identifier that is assigned to a single database entry for a DNA or protein sequence. Affine gap penalty（一种设置空位罚分策略）A gap penalty score that is a linear function of gap length, consisting of a gap opening penalty and a gap extension penalty multiplied by the length of the gap. Using this penalty scheme greatly enhances the performance of dynamic programming methods for sequence alignment. See also Gap penalty.Algorithm（算法）A systematic procedure for solving a problem in a finite number of steps, typically involving a repetition of operations. Once specified, an algorithm can be written in a computer language and run as a program.Alignment（联配/比对/联配）Refers to the procedure of comparing two or more sequences by looking for a series of individual characters or character patterns that are in the same order in the sequences. Of the two types of alignment, local and global, a local alignment is generally the most useful. See also Local and Global alignments.Alignment score（联配/比对/联配值）An algorithmically computed score based on the number of matches, substitutions, insertions, and deletions (gaps) within an alignment. Scores for matches and substitutions Are derived from a scoring matrix such as the BLOSUM and PAM matrices for proteins, and aftine gap penalties suitable for the matrix are chosen. Alignment scores are in log odds units, often bit units (log to the base 2). Higher scores denote better alignments. See also Similarity score, Distance in sequence analysis.Alphabet（字母表）The total number of symbols in a sequence-4 for DNA sequences and 20 for protein sequences. Annotation（注释）The prediction of genes in a genome, including the location of protein-encoding genes, the sequence of the encoded proteins, anysignificantmatches to other Proteins of known function, and the location of RNA-encoding genes. Predictions are based on gene models; e.g., hidden Markov models of introns and exons in proteins encoding genes, and models of secondary structure in RNA.Anonymous FTP（匿名FTP）When a FTP service allows anyone to log in, it is said to provide anonymous FTP ser-vice. A user can log in to an anonymous FTP server by typing anonymous as the user name and his E-mail address as a password. Most Web browsers now negotiate anonymous FTP logon without asking the user for a user name and password. See also FTP.ASCIIThe American Standard Code for Information Interchange (ASCII) encodes unaccented letters a-z, A-Z, the numbers O-9, most punctuation marks, space, and a set of control characters such as carriage return and tab. ASCII specifies 128 characters that are mapped to the values O-127. ASCII tiles are commonly called plain text, meaning that they only encode text without extra markup.BAC clone（细菌人工染色体克隆）Bacterial artificial chromosome vector carrying a genomic DNA insert, typically 100–200 kb. Most of the large-insert clones sequenced in the project were BAC clones.Back-propagation（反向传输）When training feed-forward neural networks, a back-propagation algorithm can be used to modify the network weights. After each training input pattern is fed through the network, the network’s output is compared with the desired output and the amount of error is calculated. This error is back-propagated through the network by using an error function to correct the network weights. See also Feed-forward neural network.Baum-Welch algorithm（Baum-Welch算法）An expectation maximization algorithm that is used to train hidden Markov models.Baye’s rule（贝叶斯法则）Forms the basis of conditional probability by calculating the likelihood of an event occurring based on the history of the event and relevant background information. In terms of two parameters A and B, the theorem is stated in an equation: The condition-al probability of A, given B, P(AIB), is equal to the probability of A, P(A), times the conditional probability of B, given A, P(BIA), divided by the probability of B, P(B). P(A) is the historical or prior distribution value of A, P(BIA) is a new prediction for B for a particular value of A, and P(B) is the sum of the newly predicted values for B. P(AIB) is a posterior probability, representing a new prediction for A given the prior knowledge of A and the newly discovered relationships between A and B.Bayesian analysis（贝叶斯分析）A statistical procedure used to estimate parameters of an underlyingdistribution based on an observed distribution. See a lso Baye’s rule.Biochips（生物芯片）Miniaturized arrays of large numbers of molecular substrates, often oligonucleotides, in a defined pattern. They are also called DNA microarrays and microchips.Bioinformatics （生物信息学）The merger of biotechnology and information technology with the goal of revealing new insights and principles in biology. /The discipline of obtaining information about genomic or protein sequence data. This may involve similarity searches of databases, comparing your unidentified sequence to the sequences in a database, or making predictions about the sequence based on current knowledge of similar sequences. Databases are frequently made publically available through the Internet, or locally at your institution.Bit score （二进制值/ Bit值）The value S' is derived from the raw alignment score S in which the statistical properties of the scoring system used have been taken into account. Because bit scores have been normalized with respect to the scoring system, they can be used to compare alignment scores from different searches.Bit unitsFrom information theory, a bit denotes the amount of information required to distinguish between two equally likely possibilities. The number of bits of information, AJ, required to convey a message that has A4 possibilities is log2 M = N bits.BLAST （基本局部联配搜索工具，一种主要数据库搜索程序）Basic Local Alignment Search Tool. A set of programs, used to perform fast similarity searches. Nucleotide sequences can be compared with nucleotide sequences in a database using BLASTN, for example. Complex statistics are applied to judge the significance of each match. Reported sequences may be homologous to, or related to the query sequence. The BLASTP program is used to search a protein database for a match against a query protein sequence. There are several other flavours of BLAST. BLAST2 is a newer release of BLAST. Allows for insertions or deletions in the sequences being aligned. Gapped alignments may be more biologically significant.Block（蛋白质家族中保守区域的组块）Conserved ungapped patterns approximately 3-60 amino acids in length in a set of related proteins.BLOSUM matrices（模块替换矩阵，一种主要替换矩阵）An alternative to PAM tables, BLOSUM tables were derived using local multiple alignments of more distantly related sequences than were used for the PAM matrix. These are used to assess the similarity of sequences when performing alignments.Boltzmann distribution（Boltzmann 分布）Describes the number of molecules that have energies above a certain level, based on the Boltzmann gas constant and the absolute temperature.Boltzmann probability function(Boltzmann 概率函数)See Boltzmann distribution.Bootstrap analysisA method for testing how well a particular data set fits a model. For example, the validity of the branch arrangement in a predicted phylogenetic tree can be tested by resampling columns in a multiple sequence alignment to create many new alignments. The appearance of a particular branch in trees generated from these resampled sequences can then be measured. Alternatively, a sequence may be left out of an analysis to deter-mine how much the sequence influences the results of an analysis.Branch length（分支长度）In sequence analysis, the number of sequence changes along a particular branch of a phylogenetic tree.CDS or cds （编码序列）Coding sequence.Chebyshe, d inequalityThe probability that a random variable exceeds its mean is less than or equal to the square of 1 over the number of standard deviations from the mean.Clone （克隆）Population of identical cells or molecules (e.g. DNA), derived from a single ancestor.Cloning Vector （克隆载体）A molecule that carries a foreign gene into a host, and allows/facilitates the multiplication of that gene in a host. When sequencing a gene that has been cloned using a cloning vector (rather than by PCR), care should be taken not to include the cloning vector sequence when performingsimilarity searches. Plasmids, cosmids, phagemids, Y ACs and PACs are example types of cloning vectors.Cluster analysis（聚类分析）A method for grouping together a set of objects that are most similar from a larger group of related objects. The relationships are based on some criterion of similarity or difference. For sequences, a similarity or distance score or a statistical evaluation of those scores is used.CobblerA single sequence that represents the most conserved regions in a multiple sequence alignment. The BLOCKS server uses the cobbler sequence to perform a database similarity search as a way to reach sequences that are more divergent than would be found using the single sequences in the alignment for searches.Coding system (neural networks)Regarding neural networks, a coding system needs to be designed for representing input and output. The level of success found when training the model will be partially dependent on the quality of the coding system chosen.Codon usageAnalysis of the codons used in a particular gene or organism.COG（直系同源簇）Clusters of orthologous groups in a set of groups of related sequences in microorganism and yeast (S. cerevisiae). These groups are found by whole proteome comparisons and include orthologs and paralogs. See also Orthologs and Paralogs.Comparative genomics（比较基因组学）A comparison of gene numbers, gene locations, and biological functions of genes in the genomes of diverse organisms, one objective being to identify groups of genes that play a unique biological role in a particular organism.Complexity (of an algorithm)（算法的复杂性）Describes the number of steps required by the algorithm to solve a problem as a function of the amount of data; for example, the length of sequences to be aligned.Conditional probability（条件概率）The probability of a particular result (or of a particular value of a variable) given one or more events or conditions (or values of other variables).Conservation （保守）Changes at a specific position of an amino acid or (less commonly, DNA) sequence that preserve the physico-chemical properties of the original residue.Consensus（一致序列）A single sequence that represents, at each subsequent position, the variation found within corresponding columns of a multiple sequence alignment.Context-free grammarsA recursive set of production rules for generating patterns of strings. These consist of a set of terminal characters that are used to create strings, a set of nonterminal symbols that correspond to rules and act as placeholders for patterns that can be generated using terminal characters, a set of rules for replacing nonterminal symbols with terminal characters, and a start symbol.Contig （序列重叠群/拼接序列）A set of clones that can be assembled into a linear order. A DNA sequence that overlaps with another contig. The full set of overlapping sequences (contigs) can be put together to obtain thesequence for a long region of DNA that cannot be sequenced in one run in a sequencing assay. Important in genetic mapping at the molecular level.CORBA（国际对象管理协作组制定的使OOP对象与网络接口统一起来的一套跨计算机、操作系统、程序语言和网络的共同标准）The Common Object Request Broker Architecture (CORBA) is an open industry standard for working with distributed objects, developed by the Object Management Group. CORBA allows the interconnection of objects and applications regardless of computer language, machine architecture, or geographic location of the computers.Correlation coefficient（相关系数）A numerical measure, falling between - 1 and 1, of the degree of the linear relationship between two variables. A positive value indicates a direct relationship, a negative value indicates an inverse relationship, and the distance of the value away from zero indicates the strength of the relationship. A value near zero indicates no relationship between the variables.Covariation (in sequences)（共变）Coincident change at two or more sequence positions in related sequences that may influence the secondary structures of RNA or protein molecules.Coverage (or depth) （覆盖率/厚度）The average number of times a nucleotide is represented by a high-quality base in a collection of random raw sequence. Operationally, a 'high-quality base' is defined as one with an accuracy of at least 99% (corresponding to a PHRED score of at least 20).Database（数据库）A computerized storehouse of data that provides a standardized way for locating, adding, removing, and changing data. See also Object-oriented database, Relational database. DendogramA form of a tree that lists the compared objects (e.g., sequences or genes in a microarray analysis) in a vertical order and joins related ones by levels of branches extending to one side of the list. Depth （厚度）See coverageDirichlet mixturesDefined as the conjugational prior of a multinomial distribution. One use is for predicting the expected pattern of amino acid variation found in the match state of a hid-den Markov model (representing one column of a multiple sequence alignment of proteins), based on prior distributions found in conserved protein domains (blocks).Distance in sequence analysis（序列距离）The number of observed changes in an optimal alignment of two sequences, usually not counting gaps.DNA Sequencing （DNA测序）The experimental process of determining the nucleotide sequence of a region of DNA. This is done by labelling each nucleotide (A, C, G or T) with either a radioactive or fluorescent marker which identifies it. There are several methods of applying this technology, each with their advantages and disadvantages. For more information, refer to a current text book. High throughput laboratories frequently use automated sequencers, which are capable of rapidly reading large numbers of templates. Sometimes, the sequences may be generated more quickly than they can becharacterised.Domain （功能域）A discrete portion of a protein assumed to fold independently of the rest of the protein and possessing its own function.Dot matrix（点标矩阵图）Dot matrix diagrams provide a graphical method for comparing two sequences. One sequence is written horizontally across the top of the graph and the other along the left-hand side. Dots are placed within the graph at the intersection of the same letter appearing in both sequences. A series of diagonal lines in the graph indicate regions of alignment. The matrix may be filtered to reveal the most-alike regions by scoring a minimal threshold number of matches within a sequence window.Draft genome sequence （基因组序列草图）The sequence produced by combining the information from the individual sequenced clones (by creating merged sequence contigs and then employing linking information to create scaffolds) and positioning the sequence along the physical map of the chromosomes.DUST （一种低复杂性区段过滤程序）A program for filtering low complexity regions from nucleic acid sequences.Dynamic programming（动态规划法）A dynamic programming algorithm solves a problem by combining solutions to sub-problems that are computed once and saved in a table or matrix. Dynamic programming is typically used when a problem has many possible solutions and an optimal one needs to be found. This algorithm is used for producing sequence alignments, given a scoring system for sequence comparisons.EMBL （欧洲分子生物学实验室，EMBL数据库是主要公共核酸序列数据库之一）European Molecular Biology Laboratories. Maintain the EMBL database, one of the major public sequence databases.EMBnet （欧洲分子生物学网络）European Molecular Biology Network: / was established in 1988, and provides services including local molecular databases and software for molecular biologists in Europe. There are several large outposts of EMBnet, including EXPASY.Entropy（熵）From information theory, a measure of the unpredictable nature of a set of possible elements. The higher the level of variation within the set, the higher the entropy.Erdos and Renyi lawIn a toss of a “fair” coin, the number of heads in a row that can be expected is the logarithm of the number of tosses to the base 2. The law may be generalized for more than two possible outcomes by changing the base of the logarithm to the number of out-comes. This law was used to analyze the number of matches and mismatches that can be expected between random sequences as a basis for scoring the statistical significance of a sequence alignment.EST （表达序列标签的缩写）See Expressed Sequence TagExpect value (E)（E值）E value. The number of different alignents with scores equivalent to or better than S that are expected to occur in a database search by chance. The lower the E value, the more significant the score. In a database similarity search, the probability that an alignment score as good as the one found between a query sequence and a database sequence would be found in as many comparisonsbetween random sequences as was done to find the matching sequence. In other types of sequence analysis, E has a similar meaning.Expectation maximization (sequence analysis)An algorithm for locating similar sequence patterns in a set of sequences. A guessed alignment of the sequences is first used to generate an expected scoring matrix representing the distribution of sequence characters in each column of the alignment, this pattern is matched to each sequence, and the scoring matrix values are then updated to maximize the alignment of the matrix to the sequences. The procedure is repeated until there is no further improvement.Exon （外显子）。
Meru APs 6.0 Captive Portal Bridged Mode功能介绍说明书
Bridge Mode Captive PortalIntroduction (1)System Requirements (2)Internal Captive Portal (3)Internal Captive Portal with Radius (5)External Captive Portal (IDM) (5)Roaming with Captive Portal (6)Configuration Tasks (7)Additional Notes (8)IntroductionWith SD 6.0 the Meru APs will be able to provide Captive Portal authentication on bridged mode SSID's. The feature is similar to the tunneled mode operation, but the traffic is intercepted locally by the AP before user authentication. When a user connected to a Guest SSID, opens a web browser the request will be redirected to a Captive Portal page hosted by the controller or to an external device like Meru Identity Manager. After successful authentication, the Guest user will be given network / Internet access by the AP. The APs are compatible with external RADIUS guest access provisioning systems such as IDM to provide a paid hot-spot feature to meet enterprise business requirements. This feature helps to provide Guest access in geographically dispersed remote branch offices with controller placed in the centralized location. This guide discusses the various aspects of Bridged Captive portal deployment scenarios and explains the necessary configuration requirements.Figure 1 illustrates Captive Portal in Bridged Mode..System RequirementsFor bridged mode Captive Portal, you will need:•System Director Release 6.0-2-0 or later.•AP Models : AP110, AP10xx, AP332, AP832, AP400Internal Captive PortalBy using the internal captive portal feature, the AP redirects guest user to the controller hosted default captive portal Page. Customized Captive Portal Pages are also supported by the APs in bridged mode. The Guest user Database is maintained in the controller and the AP forwards the user credentials to controller for validation. After successful authentication by the controller, the guest users are redirected to the originally requested URL.Figure 2: The Internal Captive Portal redirection with local user database maintained in controller.Figure 3: The controller hosted default Captive portal Page.Internal Captive Portal with RadiusUser authentication can also be achieved using RADIUS for Internal Captive Portal. All Captive Portal configuration requirements remain same as compared to the above section, except having Radius profiles configured for authentication and accounting.Figure4: The Internal Captive Portal redirection with RADIUS authentication.External Captive Portal (IDM)The provisioning of Captive portal pages and user authentication is handled by an external Guest management solution like Identity Manager. An external Captive Portal URL configured in the Controller redirects guest user to the portals defined in the external system. Additional configuration requirements for this feature are explained later in this document.Figure5: The External Captive redirection with Identity Manager.Roaming with Captive PortalCaptive Portal in Bridge mode is supported in all RF virtualization modes. In V-Cell/V-port deployments, client authentication status is included in the hand-off messages so that a station does not go through captive portal authentication once roamed to a new AP.L3 User Session time-out is a configurable parameter which is maintained in the controller to preserve the Captive Portal Session of clients. A client which has to go through a hard hand-off in a Native Cell deployment scenario or if there is am L2 re-association, it will be prompted with the Captive Portal page only if the L3 User session time-out is expired.Configuration TasksEnable Bridged mode in an ESS by choosing the Dataplane mode as Bridged.Figure 6 : ESS profile ConfigurationFigure 7: Security Profile configurationIn the security Profile which is mapped to the above ESS, enable WebAuth and choose the Captive Portal Authentication Method to be internal or externalFigure 8 : Captive Portal Configuration1) If external WebAuth is selected in the Security Profile, define the External redirection URL under Configuration Captive Portal in the UI.With IDM, the URL format would be https://<idm-ip or hostname>/portal/<controller-ip or hostname>?MeruInitialRedirectIf any certificates are used, ensure that the hostname defined for the controller matches the CN in the certificate.2) Select the captive portal authentication type from the 3 available options, local, RADIUS, and local-radius. For External Captive Portal, the authentication type should be RADIUS and for Internal Captive Portal it can be either local or local-radius.3) If using RADIUS, map the configured radius profiles for authentication and accounting respectively.Additional Notes1) If the controller is not reachable no Captive Portal authentication takes place as the guest user database is maintained in the controller. The same rule applies for Internal Captive portal with Radius and External Captive Portal since the controller is still the Radius Client.2) No logout is supported for Internal Captive Portal3) The session time-out, activity time-out & L3 User session time-out values set in the controller is also applicable for bridged mode Captive Portal Clients. Copied below is the station-logs captured during a successful authentication of a Bridged mode Captive Portal Client.Note: The session_time and idle_time values returned by the controller are same as the behavior you may observe for clients connecting in tunneled mode.2013-Sep-10 09:24:22.260494 | b0:65:bd:4b:59:7d | CP User Authentication |<User=CPuser> <ipaddr=172.18.144.11> Guest User Authenticated Successfullysession_time=3600> <idle_time=600><4) The AP CLI command "brcp show" displays the Captive Portal authentication status of client in bridged mode.。
FortiOS 7.4 操作系统用户手册说明书
FortiOS Is the Foundation of the Fortinet Security FabricExecutive SummaryFortiOS, Fortinet’s operating system, is the foundation of the Fortinet SecurityFabric. The Security Fabric is the industry’s highest-performing and most expansivecybersecurity platform, organically built on a common management and securityframework. FortiOS ties all of the Fabric’s security and networking componentstogether to ensure seamless integration. This enables the convergence ofnetworking and security functions to deliver a consistent user experience andresilient security posture across all manner of environments. On-premises, cloud,hybrid, and converging IT/OT/IoT infrastructure are included.FortiOS 7.4 is packed with powerful new features that give IT leadersunprecedented visibility and enforcement across even the most complex hybridenvironments. Updates include:"FortiOS … improves operational efficiency and provides consistent security no matter where users or applications are distributed.”1SOLUTION BRIEF n Industry-first unified networking and security architecture for OT, IoT, and IT devicesn Industry-first unified management and analytics capabilities across Fortinet’s entire secure networking portfolio through FortiAnalyzern Greater automation and real-time response capabilities for SOC teams to protect against and reduce time to resolution for sophisticated attacks such as weaponized AI attacks, targeted ransomware, and criminal-sponsored APTsn Enhancements to reduce alert triage and incident investigation across early detection solutions including FortiEDR,FortiXDR, FortiRecon, and FortiDeceptorn New features to reduce risk across converging OT/IT/IoT environmentsFortiOS and the Fortinet Security Fabric Enable Broad, Integrated, and Automated SecurityFigure 1: The Fortinet Security FabricHaving one unifying operating system that spans the entire distributed Security Fabric ensures:n Consistent, centralized management and orchestration of security policy and configurationsn Broad reach and control across the expanded attack surface and at every step of the attack cyclen High-performance enforcement of context-aware security policyn Artificial intelligence (AI)-based threat detection and recommendationsn AI-based data correlation for analysis and reporting across a unified Fabric-level datasetn Automated, multipronged response in real time to cyberattacks across the attack surface and throughout the attack cyclen Improved threat response and reduced risk through enhanced security orchestration, automation, and response (SOAR) capabilitiesFortiOS 7.4 Delivers New CapabilitiesFortiOS uniquely empowers organizations to run their businesses without compromising performance, protection, or puttingthe brakes on innovation. A few of the key FortiOS 7.4 and Security Fabric enhancements designed to address today’s unique challenges are listed below.Secure networking and managementNew innovations to Fortinet’s Secure Networking Portfolio and FortiOS 7.4 span FortiManager, hybrid mesh firewall, Secure SD-WAN, single-vendor SASE, Universal zero-trust network access (ZTNA), and secure WLAN/LAN.Unified management and analytics across hybrid networksFortiManager provides IT leaders with unprecedented visibility and enforcement across all secure networking elements, including hybrid mesh firewall, single-vendor SASE, Universal ZTNA, Secure SD-WAN, and secure WLAN/LAN.Hybrid mesh firewall for data center and cloudFortiGate 7080F is a new series of next-generation firewalls (NGFWs) that eliminates point products, reduces complexity, and delivers higher performance through purpose-built ASIC technology and AI/ML-powered advanced security.FortiFlex is a points-based consumption program with support for hybrid mesh firewall deployments and a variety of products, such as virtual machines, FortiGate appliances, and SaaS-based services, among others.Secure SD-WAN for branch officesFortinet Secure SD-WAN enables consistent security and superior user experience for business-critical applications, whether in the cloud or on-premises, and supports a seamless transition to single-vendor SASE. New enhancements include automation in overlay orchestration to accelerate site deployments and a redesign of the monitoring map view to provide global WAN status for each.Single-vendor SASE for remote users and branch officesFortiSASE converges cloud-delivered security and networking to simplify operations across hybrid networks. FortiSASEnow integrates with FortiManager, allowing unified policy management for Secure SD-WAN and SASE along with unmatched visibility across on-premises and remote users.Universal ZTNA for remote users and campus locationsFortinet Universal ZTNA provides the industry’s most flexible zero-trust application access control no matter where the user or application is located. Universal ZTNA now delivers user-based risk scoring as part of our continuous checks for ongoing application access.“Via the power of the FortiOS operating system, FortiGate delivers one of the top secure SD-WAN solutions, includes a powerful LAN edge controller, enables the industry’s only Universal ZTNA application gateway, and facilitates the convergence of NOC and SOC.”2WLAN/LAN for branch offices and campus locationsFortiAP secure WLAN access points now integrate with FortiSASE, marking theindustry’s first AP integration with SASE. This enables secure micro-brancheswhere an AP is deployed to send traffic to a FortiSASE solution and ensurecomprehensive security of all devices at the site.Prevention, early detection, and real-time responseFortinet has added new real-time response and automation capabilities acrossthe Security Fabric to enable SOC teams to protect against and reduce time toresolution for sophisticated attacks such as weaponized AI attacks, targetedransomware, and criminal-sponsored APTs. New solutions and enhancementsacross five key areas include:Endpoint security and early responseFortiEDR and FortiXDR now provide additional interactive incident visualizationwith enriched contextual incident data using multiple threat intelligence feeds toenable customers to simplify and expedite investigations.FortiNDR Cloud combines robust artificial intelligence, complemented by pragmatic analysis and breach protectiontechnology. The solution provides 365-day retention and visibility into network data, built-in playbooks, and threat hunting capabilities to detect anomalous and malicious behavior on the network. Choose from a self-contained, on-premisesdeployment powered by the Fortinet Virtual Security Analyst, or a new guided SaaS offering maintained by advanced threat experts from FortiGuard Labs.FortiRecon , supported by threat experts from FortiGuard Labs, now delivers enhanced proactive threat intelligence into critical risks associated with supply chain vendors and partners, including external exposed assets, leaked data, and ransomware attack intelligence.FortiDeceptor now offers vulnerability outbreak defense. When a vulnerability is reported by FortiGuard Labs, it is automatically pushed as a feed to the outbreak decoy to redirect attackers to fake assets and quarantine the attack early in the kill chain.Further, a SOAR playbook can automatically initiate the creation of and strategically place deception assets to gather granular intel and stop suspicious activities. FortiDeceptor also now offers a new attack exchange program that allows FortiDeceptor users to anonymously exchange valuable intel on the most current attacks and take proactive steps to avoid a breach.SOC automation and augmentationFortiAnalyzer enables more sophisticated event correlation across different types of log sources using a new intuitive rules editor that can be mapped to MITRE ATT&CK use cases.FortiSOAR now offers a turnkey SaaS subscription option, inline playbook recommendations driven by machine learning, extensive OT security features and playbooks, and unique no/low-code playbook creation enhancements.FortiSIEM now includes new link graph technology that allows for easy visualization of relationships between users, devices, and incidents. The solution is also now powered by an advanced machine learning framework, which enhances protection by detecting anomalies and outliers that may be missed by traditional methods.FortiGuard SOC-as-a-Service now offers AI-assisted incident triage as well as new SOC operations readiness andcompromise assessment services from FortiGuard Labs.AI-powered threat intelligenceFortiGuard Industrial Security Service significantly reduces time to protection with enhanced automated virtual patching for both OT and IT devices based on global threat intelligence, zero-day research, and Common Vulnerabilities and Exposures (CVE) query service.FortiGuard IoT Service enhances granular OT security at the industry level with Industrial-Internet-of-Things (IIoT) and Internet-of-Medical-Things (IoMT) device convergence.FortiSIEM unified security analytics dashboards now incorporate mapping of industrial devices and communication paths to the Purdue model hierarchy, include new OT-specific playbooks for threat remediation, and use of the ICS MITRE ATT&CK matrix for OT threat analysis.Identity and accessFortiPAM privileged account management provides remote access for IT and OT networks. It now includes ZTNAcontrols when users try to access critical assets. The ZTNA tags can be applied to check device posture continuously for vulnerabilities, updated AV signatures, location, and machine groups.Application securityFortiDevSec provides comprehensive application security testing for application code and runtime applications. The solution incorporates SAST, DAST, and SCA, for early vulnerability and misconfigurations detection, and protection including secret discovery. Risk reduction for cyber-physical and industrial control systemsFortinet’s portfolio of solutions and our Security Fabric for OT are designed specifically for cyber-physical security. New enhancements include:FortiGate 70F Rugged Next-Generation Firewall (NGFW) is the latest addition to Fortinet’s rugged portfolio designed for harsh environments. It features a new compact design with converged networking and security capabilities on a single processor. FortiDeceptor Rugged 100G is now available as an industrially hardened rugged appliance, ideal for harsh industrial environments. FortiPAM offers enterprise-grade privileged access management for both IT and OT ecosystems.FortiSIEM unified security analytics dashboards now include event correlation and mapping of security events to the Purdue model. FortiSOAR now offers features to reduce alert fatigue and enable security automation and orchestration across IT andOT environments.FortiGuard Industrial Security Service now includes more than 2,000 application control signatures for OT applications and protocols that support deep packet inspection.Fortinet Cyber Threat Assessment Program (CTAP) for OT validates OT network security effectiveness, application flows, and includes expert guidance.OT tabletop exercises for OT security teams are led by FortiGuard Incident Response team facilitators with expertise in threat analysis, mitigation, and incident response.FortiOS and the Fortinet Security Fabric Address Current and Emerging Security Challenges FortiOS 7.4 provides features and enhancements to support today’s fast-changing hybrid networking and security needs. FortiOS is continually updated to ensure organizations stay ahead of today’s ever-evolving threat landscape. With an expansive Fortinet Security Fabric solution in place, organizations of any size can be assured that they have the tools they need to address all their security and networking challenges, no matter how broadly their users and networks are distributed, today and in the future.1 “Ken Xie Q&A: Growth, Differentiators, and FortiSP5,” Fortinet, February 13, 2023.2 John Maddison, “Setting the Record Straight on Competitor Misinformation,” Fortinet, November 11, 2022. Copyright © 2023 Fortinet, Inc. All rights reserved. Fortinet, FortiGate, FortiCare and FortiGuard, and certain other marks are registered trademarks of Fortinet, Inc., and other Fortinet names herein may also be registered and/or common law trademarks of Fortinet. All other product or company names may be trademarks of their respective owners. Performance and other metrics contained herein were attained in internal lab tests under ideal conditions, and actual performance and other results may vary. Network variables, different network environments and other conditions may affect performance results. Nothing herein represents any binding commitment by Fortinet, and Fortinet disclaims all warranties, whether express or implied, except to the extent Fortinet enters a binding written contract, signed by Fortinet’s General Counsel, with a purchaser that expressly warrants that the identified product will perform according to certain expressly-identified performance metrics and, in such event, only the specific performance metrics expressly identified in such binding written contract shall be binding on Fortinet. For absolute clarity, any such warranty will be limited to performance in the same ideal conditions as in Fortinet’s internal lab tests. Fortinet disclaims in full any covenants, representations, and guarantees pursuant hereto, whether express or implied. Fortinet reserves the right to change, modify, transfer, or otherwise。
Intel Optane DC Persistent Memory 100 Series 产品指南说
Figure 1. Intel Optane DC Persistent Memory Module (DCPMM)Did you know?Intel Optane DC Persistent Memory modules (DCPMMs) have the form factor of a DDR4 DIMM, but the persistence and capacity of data storage of a solid-state drive. This means the DCPMMs have performance characteristics similar to that of TruDDR4 DIMMs, the storage capacity of an SSD, and the ability to stay active after a power cycle or reboot of the server. These features open up a new way of performing data I/O to application developers and new levels of server performance to customers.Click here to check for updatesFigure 2. Intel Optane DC Persistent Memory Module (top) and Lenovo TruDDR4 DIMM (bottom) BenefitsIntel Optane DC Persistent Memory provides benefits in the following application types:Larger memory footprint: For applications with performance characteristics that place greateremphasis on memory capacity over memory bandwidth or memory latency, the use of DCPMMs can mean a significant increase in overall system performance compared to the use of TruDDR4DIMMs.Cloud and Infrastructure-as-a-service (IaaS) applicationsMore virtual machines and cloud containers per serverLarger memory allocation to each VMIn-memory databases: With DCPMMs, database applications have store much larger databases in persistent memory rather than on disk, and database performance will be improved significantly. For existing applications that use system RAM for in-memory databases, the use of persistent memory will mean no delays at boot time having to copy the databases from disk into memory.Storage caching layers: TruDDR4 DIMMs can be used for the fastest memory access - bestthroughput and lowest latency, and DCPMMs can be used for the caching layer that offers memory-like performance with the persistence of SSD storage.NFV infrastructure: Network Function Virtualization (NFV) can make use of increased memorycapacity and performance with the addition of DCPMMs.The following figure shows DCPMMs and TruDDR4 DIMMs installed in the system board of a ThinkSystem SR950. In this full configuration, there is one DCPMM and one TruDDR4 DIMM installed in each memorychannel (6 DCPMMs and 6 DIMMs per processor).Figure 3. Intel Optane DCPMMs installed in a ThinkSystem SR950 system boardApp Direct Mode requirementsThe following table lists the supported combinations in App Direct mode.Table 3. App Direct Mode requirementsTotal RDIMMs per CPU Total PMem per CPU Total Available Memory per CPU*Quantity of memory RDIMMs(per CPU)Quantity of PMem modules (per CPU)16GB 1Rx416GB 2Rx832GB 64GB 64GB 3DS RDIMM 128GB 3DS RDIMM 128GB PMem 256GB PMem 512GB PMem 96 GB 128 GB 224 GB 6 1 96 GB 128 GB 224 GB 6 1 192 GB 128 GB 320 GB 6 1 384 GB 128 GB 512 GB 6 1 384 GB 128 GB 512 GB 6 1 768 GB 128 GB 896 GB 61 96 GB 256 GB 352 GB 6 1 96 GB 256 GB 352 GB 6 1 192 GB 256 GB 448 GB 6 1 384 GB 256 GB 640 GB 6 1 384 GB256 GB640 GB61768 GB 256 GB 1 TB 6 1 96 GB 512 GB 608 GB 6 196 GB 512 GB 608 GB 6 1192 GB 512 GB 704 GB 6 1384 GB 512 GB 896 GB 6 1384 GB 512 GB 896 GB 6 1768 GB 512 GB 1.25 TB 6 164 GB 256 GB 320 GB 4 2 64 GB 256 GB 320 GB 4 2 128 GB 256 GB 384 GB 4 2 256 GB 256 GB 512 GB 4 2 256 GB 256 GB 512 GB 4 2 512 GB 256 GB 768 GB 42 64 GB 512 GB 576 GB 4 2 64 GB 512 GB 576 GB 4 2 128 GB 512 GB 640 GB 4 2 256 GB 512 GB 768 GB 4 2 256 GB 512 GB 768 GB 4 2 512 GB 512 GB 1 TB 4 2 64 GB 1 TB 1.063 TB 4 264 GB 1 TB 1.063 TB 4 2128 GB 1 TB 1.125 TB 4 2256 GB 1 TB 1.25 TB 4 2256 GB 1 TB 1.25 TB 4 2512 GB 1 TB 1.5 TB 4 296 GB 256 GB 352 GB 6 2 96 GB 256 GB 352 GB 6 2 192 GB 256 GB 448 GB 6 2 384 GB 256 GB 640 GB 6 2 384 GB 256 GB 640 GB 6 2 768 GB 256 GB 1 TB 62 96 GB 512 GB 608 GB 6 2 96 GB 512 GB 608 GB 6 2 192 GB 512 GB 704 GB 6 2 384 GB 512 GB 896 GB 6 2 384 GB 512 GB 896 GB 6 2 768 GB 512 GB 1.25 TB 6 2 96 GB 1 TB 1.094 TB 6 296 GB 1 TB 1.094 TB 6 2192 GB 1 TB 1.188 TB 6 2384 GB 1 TB 1.375 TB 6 2384 GB 1 TB 1.375 TB 6 2768 GB1 TB1.75 TB62Total RDIMMs per CPU Total PMem per CPU Total Available Memory per CPU*(per CPU)modules (per CPU)16GB 1Rx416GB 2Rx832GB 64GB 64GB 3DS RDIMM 128GB 3DS RDIMM 128GB PMem 256GB PMem 512GB PMem128 GB 256 GB 384 GB 8 2 128 GB 256 GB 384 GB 8 2 256 GB 256 GB 512 GB 8 2 512 GB 256 GB 768 GB 8 2 512 GB 256 GB 768 GB 8 2 1 TB 256 GB 1.25 TB 82 128 GB 512 GB 640 GB 8 2 128 GB 512 GB 640 GB 8 2 256 GB 512 GB 768 GB 8 2 512 GB 512 GB 1 TB 8 2 512 GB 512 GB 1 TB 8 2 1 TB 512 GB 1.5 TB 8 2 128 GB 1 TB 1.125 TB 8 2128 GB 1 TB 1.125 TB 8 2256 GB 1 TB 1.25 TB 8 2512 GB 1 TB 1.5 TB 8 2512 GB 1 TB 1.5 TB 8 21 TB 1 TB 2 TB 8 296 GB 512 GB 608 GB 6 4 96 GB 512 GB 608 GB 6 4 192 GB 512 GB 704 GB 6 4 384 GB 512 GB 896 GB 6 4 384 GB 512 GB 896 GB 6 4 768 GB 512 GB 1.25 TB 64 96 GB 1 TB 1.094 TB 6 4 96 GB 1 TB 1.094 TB 6 4 192 GB 1 TB 1.188 TB 6 4 384 GB 1 TB 1.375 TB 6 4 384 GB 1 TB 1.375 TB 6 4 768 GB 1 TB 1.75 TB 6 4 96 GB 2 TB 2.094 TB 6 496 GB 2 TB 2.094 TB 6 4192 GB 2 TB 2.188 TB 6 4384 GB 2 TB 2.375 TB 6 4384 GB 2 TB 2.375 TB 6 4768 GB 2 TB 2.75 TB 6 496 GB 768 GB 864 GB 6 6 96 GB 768 GB 864 GB 6 6 192 GB 768 GB 960 GB 6 6 384 GB 768 GB 1.125 TB 6 6 384 GB 768 GB 1.125 TB 6 6 768 GB 768 GB 1.5 TB 66 96 GB1.5 TB1.594 TB66Total RDIMMs per CPU Total PMem per CPU Total Available Memory per CPU*(per CPU)modules (per CPU)16GB 1Rx416GB 2Rx832GB 64GB 64GB 3DS RDIMM 128GB 3DS RDIMM 128GB PMem 256GB PMem 512GB PMem256 GB 512 GB 512 GB 1:2 4 2 256 GB 512 GB 512 GB 1:2 4 2 64 GB 1 TB 1 TB 1:164 264 GB 1 TB 1 TB 1:16 4 2128 GB 1 TB 1 TB 1:8 4 2256 GB 1 TB 1 TB 1:4 4 2256 GB 1 TB 1 TB 1:4 4 2512 GB 1 TB 1 TB 1:2 4 296 GB 256 GB 256 GB 1:2.676 2 96 GB 256 GB 256 GB 1:2.67 6 2 96 GB 512 GB 512 GB 1:5.336 2 96 GB 512 GB 512 GB 1:5.33 6 2 192 GB 512 GB 512 GB 1:2.67 6 2 96 GB 1 TB 1 TB 1:10.676 296 GB 1 TB 1 TB 1:10.67 6 2192 GB 1 TB 1 TB 1:5.33 6 2384 GB 1 TB 1 TB 1:2.67 6 2384 GB 1 TB 1 TB 1:2.67 6 296 GB 512 GB 512 GB 1:5.336 4 96 GB 512 GB 512 GB 1:5.33 6 4 192 GB 512 GB 512 GB 1:2.67 6 4 96 GB 1 TB 1 TB 1:10.676 4 96 GB 1 TB 1 TB 1:10.67 6 4 192 GB 1 TB 1 TB 1:5.33 6 4 384 GB 1 TB 1 TB 1:2.67 6 4 384 GB 1 TB 1 TB 1:2.67 6 4 192 GB 2 TB 2 TB 1:10.67 6 4384 GB 2 TB 2 TB 1:5.33 6 4384 GB 2 TB 2 TB 1:5.33 6 4768 GB 2 TB 2 TB 1:2.67 6 496 GB 768 GB 768 GB 1:86 6 96 GB 768 GB 768 GB 1:8 6 6 192 GB 768 GB 768 GB 1:4 6 6 384 GB 768 GB 768 GB 1:2 6 6 384 GB 768 GB 768 GB 1:2 6 6 96 GB 1.5 TB 1.5 TB 1:166 6 96 GB 1.5 TB 1.5 TB 1:16 6 6 192 GB 1.5 TB 1.5 TB 1:8 6 6 384 GB 1.5 TB 1.5 TB 1:4 6 6 384 GB 1.5 TB 1.5 TB 1:4 6 6 768 GB 1.5 TB 1.5 TB 1:2 6 6 192 GB 3 TB 3 TB 1:16 6 6384 GB3 TB3 TB1:866Total RDIMMs per CPU Total PMem per CPU TotalAvailable Memory per CPU*Ratio (RDIMM:Pmem)†(per CPU)modules (per CPU)16GB 1Rx416GB 2Rx832GB 64GB 64GB 3DS RDIMM 128GB 3DS RDIMM 128GB PMem 256GB PMem 512GB PMem384 GB 3 TB 3 TB 1:8 6 6768 GB3 TB3 TB1:466Total RDIMMs per CPU Total PMem per CPU TotalAvailable Memory per CPU*Ratio (RDIMM:Pmem)†Quantity of memory RDIMMs(per CPU)Quantity of PMem modules (per CPU)16GB 1Rx416GB 2Rx832GB 64GB 64GB 3DS RDIMM 128GB 3DS RDIMM 128GB PMem 256GB PMem 512GB PMem * In Memory Mode, the available memory = persistent memory installed. The actual user capacity of PMem modules is less than the stated amount. For example, a 128GB PMem module has 126.7GB usable storage.† Ratio of system memory to persistent memory, RDIMM:PMem; Memory Mode only supports DIMM:Pmem ratios of between 1:2 and 1:16. Ratios between 1:2 and 1:4 require the latest firmware.Mixed Mode requirementsMixed Memory Mode is a combination of Memory Mode and App Direct Mode, where a portion of the capacity of the DCPMMs is used for the Memory Mode operations, and the remaining capacity of the DCPMMs is used for the App Direct Mode operations.In Mixed Mode, all installed TruDDR4 DIMMs are hidden from the operating system and act as a caching layer for portion of the DCPMMs in Memory Mode. Like Memory Mode, the ratio of total of the memory DIMMs to the total of the volatile (memory) portion of DCPMMs should be between 1:4 and 1:16.When you enable Mixed Memory Mode in UEFI or you specify Mixed Memory Mode when building a CTO (configure-to-order) configuration (feature B52A), you will also be asked to specify the percentage of the DCPMM total capacity will be allocated to Memory Mode. The remaining DCPMM capacity will be allocated to App Direct Mode.The following tables show the allowed percentage for each DCPMM part number and what the effective amount of App Direct persistent memory will be available to applications. Only a set number of percentages are available to choose from and the amount of App Direct persistent memory that is allocated will be in increments of 32 GB multiplied by the number of DCPMMs installed.Table 5. Available ratios available for Mixed Mode - 128 GB DCPMMVolatile memory percentage requested (selected in UEFI or quantity of feature code B52D selected in CTO):Resulting Persistent percentage calculated (quantity of feature code B52E in CTO)DCPMM capacity reserved forApp Direct Mode DCPMM capacity reserved for Memory Mode 24%76%96 GB 32 GB 49%51%64 GB 64 GB 75%25%32 GB96 GBTable 6. Available ratios available for Mixed Mode - 256 GB DCPMMVolatile memory percentage requested (selected in UEFI or quantity of feature code B52D selected in CTO):Resulting Persistentpercentage calculated(quantity of feature codeB52E in CTO)DCPMMcapacityreserved forApp Direct ModeDCPMMcapacityreserved forMemory Mode11%89%224 GB32 GB 24%76%192 GB64 GB 37%63%160 GB96 GB 49%51%128 GB128 GB 62%38%96 GB160 GB 75%25%64 GB192 GB 87%13%32 GB224 GBTable 7. Available ratios available for Mixed Mode - 512 GB DCPMMVolatile memory percentage requested (selected in UEFI or quantity of feature code B52D selected in CTO):Resulting Persistentpercentage calculated(quantity of feature codeB52E in CTO)DCPMMcapacityreserved forApp Direct ModeDCPMMcapacityreserved forMemory Mode4%96%480 GB32 GB11%89%448 GB64 GB17%83%416 GB96 GB24%76%384 GB128 GB30%70%352 GB160 GB36%64%320 GB192 GB43%57%288 GB224 GB49%51%256 GB256 GB55%45%224 GB288 GB62%38%192 GB320 GB68%32%160 GB352 GB75%25%128 GB384 GB81%19%96 GB416 GB87%13%64 GB448 GB94%6%32 GB480 GBThe following table shows the supported combinations of DCPMMs and DIMMs. The key requirement for support is ensuring that the ratio of the total memory DIMMs capacity to the total of the volatile (memory) portion of DCPMMs should be between 1:2 and 1:16. Ratios between 1:2 and 1:4 require the latest firmware.Table 8. Mixed Mode requirementsTotal RDIMMs per CPU Total PMemper CPURatio(RDIMM:Pmem)†Quantity of memory RDIMMs(per CPU)Quantity of PMemmodules (per CPU)16GB1Rx416GB2Rx832GB64GB64GB3DSRDIMM128GB3DSRDIMM128GBPMem256GBPMem512GBPMem64 GB512 GB1:84264 GB512 GB1:842128 GB512 GB1:44264 GB 1 TB1:1642 64 GB 1 TB1:1642 128 GB 1 TB1:842 256 GB 1 TB1:442 256 GB 1 TB1:442 96 GB256 GB1:2.676296 GB256 GB1:2.676296 GB512 GB1:5.336296 GB512 GB1:5.3362192 GB512 GB1:2.676296 GB 1 TB1:10.6762 96 GB 1 TB1:10.6762 192 GB 1 TB1:5.3362 384 GB 1 TB1:2.6762 384 GB 1 TB1:2.6762 96 GB512 GB1:5.336496 GB512 GB1:5.3364192 GB512 GB1:2.676496 GB 1 TB1:10.676496 GB 1 TB1:10.6764192 GB 1 TB1:5.3364384 GB 1 TB1:2.6764384 GB 1 TB1:2.676496 GB 2 TB1:21.3364 96 GB 2 TB1:21.3364 192 GB 2 TB1:10.6764 384 GB 2 TB1:5.3364 384 GB 2 TB1:5.3364 768 GB 2 TB1:2.6764 96 GB768 GB1:86696 GB768 GB1:866192 GB768 GB1:46696 GB 1.5 TB1:166696 GB 1.5 TB1:1666192 GB 1.5 TB1:866384 GB 1.5 TB1:466384 GB 1.5 TB1:46696 GB 3 TB1:3266Server supportIntel Optane DC Persistent Memory is only supported in servers with second-generation Intel Xeon Scalable processors. The following table lists the ThinkSystem servers that are compatible.The following tables list the ThinkSystem servers that are compatible.Table 10. Server support (Part 1 of 3)PartNumber Description Edge1S IntelV2AMD V3Intel V34ZC7A15110ThinkSystem 128GB TruDDR42666MHz (1.2V) Intel Optane DCPersistent MemoryN N N N N N N N N N N N N N N N N N N4ZC7A15111ThinkSystem 256GB TruDDR42666MHz (1.2V) Intel Optane DCPersistent MemoryN N N N N N N N N N N N N N N N N N N4ZC7A15112ThinkSystem 512GB TruDDR42666MHz (1.2V) Intel Optane DCPersistent Memory N N N N N N N N N N N N N N N N N N N SE35(7Z46/7D1X)SE35V2(7DA9)SE36V2(7DAM)SE45(7D8T)SE455V3(7DBY)ST5V2(7D8K/7D8J)ST25V2(7D8G/7D8F)SR25V2(7D7R/7D7Q)SR635V3(7D9H/7D9G)SR655V3(7D9F/7D9E)SR645V3(7D9D/7D9C)SR665V3(7D9B/7D9A)SR675V3(7D9Q/7D9R)ST65V3(7D7B/7D7A)SR63V3(7D72/7D73)SR65V3(7D75/7D76)SR85V3(7D97/7D96)SR86V3(7D94/7D93)SR95V3(7DC5/7DC4)Table 11. Server support (Part 2 of 3)Part NumberDescriptionDense V32S Intel V2AMD V1Dense V24S V28S4ZC7A15110ThinkSystem 128GBTruDDR4 2666MHz (1.2V)Intel Optane DC Persistent Memory N N N N N N N N N N N N N N N N N N NY 4ZC7A15111ThinkSystem 256GBTruDDR4 2666MHz (1.2V)Intel Optane DC Persistent Memory N N N N N N N N N N N N N N N N N N NY 4ZC7A15112ThinkSystem 512GBTruDDR4 2666MHz (1.2V)Intel Optane DC Persistent MemoryN N N N N N N N N N N N N N N N N N NYTable 12. Server support (Part 3 of 3)Part NumberDescription4S V11S Intel V12S Intel V1Dense V14ZC7A15110ThinkSystem 128GB TruDDR42666MHz (1.2V) Intel Optane DC Persistent Memory Y Y Y N N N N N N N Y Y Y Y N Y N Y Y4ZC7A15111ThinkSystem 256GB TruDDR42666MHz (1.2V) Intel Optane DC Persistent Memory Y Y Y N N N N N N N Y Y Y Y N Y N Y Y4ZC7A15112ThinkSystem 512GB TruDDR42666MHz (1.2V) Intel Optane DC Persistent MemoryY Y Y N N N N N N N Y Y Y Y N Y N Y YMost ThinkSystem servers have 12 DIMM slots per processor and 2 DIMMs per channel across all channels, thereby supporting 1 DCPMM in every memory channel. However, some servers have fewer slots, and as a result, not all combinations of DIMMs and DCPMMs are supported.S D 665 V 3 (7D 9P )S D 665-N V 3 (7D A Z )S D 650 V 3 (7D 7M )S D 650-I V 3 (7D 7L )S T 650 V 2 (7Z 75 / 7Z 74)S R 630 V 2 (7Z 70 / 7Z 71)S R 650 V 2 (7Z 72 / 7Z 73)S R 670 V 2 (7Z 22 / 7Z 23)S R 635 (7Y 98 / 7Y 99)S R 655 (7Y 00 / 7Z 01)S R 655 C l i e n t O S S R 645 (7D 2Y / 7D 2X )S R 665 (7D 2W / 7D 2V )S D 630 V 2 (7D 1K )S D 650 V 2 (7D 1M )S D 650-N V 2 (7D 1N )S N 550 V 2 (7Z 69)S R 850 V 2 (7D 31 / 7D 32)S R 860 V 2 (7Z 59 / 7Z 60)S R 950 (7X 11 / 7X 12)S R 850 (7X 18 / 7X 19)S R 850P (7D 2F / 2D 2G )S R 860 (7X 69 / 7X 70)S T 50 (7Y 48 / 7Y 50)S T 250 (7Y 45 / 7Y 46)S R 150 (7Y 54)S R 250 (7Y 52 / 7Y 51)S T 550 (7X 09 / 7X 10)S R 530 (7X 07 / 7X 08)S R 550 (7X 03 / 7X 04)S R 570 (7Y 02 / 7Y 03)S R 590 (7X 98 / 7X 99)S R 630 (7X 01 / 7X 02)S R 650 (7X 05 / 7X 06)S R 670 (7Y 36 / 7Y 37)S D 530 (7X 21)S D 650 (7X 58)S N 550 (7X 16)S N 850 (7X 15)TrademarksLenovo and the Lenovo logo are trademarks or registered trademarks of Lenovo in the United States, other countries, or both. A current list of Lenovo trademarks is available on the Web athttps:///us/en/legal/copytrade/.The following terms are trademarks of Lenovo in the United States, other countries, or both:Lenovo®ThinkSystem®TruDDR4XClarity®The following terms are trademarks of other companies:Intel®, Intel Optane™, and Xeon® are trademarks of Intel Corporation or its subsidiaries.Linux® is the trademark of Linus Torvalds in the U.S. and other countries.Microsoft®, Windows Server®, and Windows® are trademarks of Microsoft Corporation in the United States, other countries, or both.Other company, product, or service names may be trademarks or service marks of others.Intel Optane Persistent Memory 100 Series (withdrawn product)21。
罗克威尔自动化SLC 500系列处理器操作系统Series C操作系统升级说明书
Release NotesSLC 5/03, SLC 5/04 Processors Operating System Series C, FRN 11 and SLC 5/05 Processors Operating System Series C, FRN 11 (for Hardware Series A/B) and FRN 13 (for Hardware Series C)Purpose of This DocumentRead this document before using SLC™ 5/03 (OS302), SLC 5/04 (OS401) Series C, FRN 11 and SLC 5/05 (OS501) Series C, FRN 13 operating system firmware. Keep this document with your SLC 500 Instruction Set Reference Manual, publication 1747-RM001.This document directs you to information on Operating System Series C, FRN 11/13 features.New FeaturesFor information on the following features, refer to the SLC 500 Instruction Set Reference Manual, publication 1747-RM001. T o view and download a PDF file, go to the Literature Library at /literature/. T o order a printed copy, contact your local Allen-Bradley Distributor or Rockwell Automation sales office.FRN 11 includes the following features:•Modbus RTU Master capability on RS232 Channel 0•PID instruction: Added rational approximation method for better calculation accuracy FRN 13(1) (SLC 5/05 Hardware Series C processors only) includes the following features:•All abovementioned features for FRN 11•Product update with upgraded hardware and new Mac ID range support.• A rare anomaly which could cause a memory loss fault has been corrected. This improves resilience to delays and errors which were seen on large area networks.RSLogix 500 programming software, version 8.10 or higher, is required to configure and program these new features.(1)FRN 12 was an internal only release.Publication 1747-RN013C-EN-P - November 2012Supersedes Publication 1747-RN013B-EN-P - December 2011Copyright © 2012 Rockwell Automation, Inc. All rights reserved. Printed in Singapore.Rockwell Automation SupportRockwell Automation provides technical information on the Web to assist you in using its products. At /support/, you can find technical manuals, a knowledge base of FAQs, technical andapplication notes, sample code and links to software service packs, and a MySupport feature that you can customize to make the best use of these tools.For an additional level of technical phone support for installation, configuration, and troubleshooting, we offer TechConnect support programs. For more information, contact your local distributor or Rockwell Automation representative, or visit /support/.Installation AssistanceIf you experience a problem within the first 24 hours of installation, please review the information that's contained in this manual. You can also contact a special Customer Support number for initial help in getting your product up and running.New Product Satisfaction ReturnRockwell Automation tests all of its products to ensure that they are fully operational when shipped from the manufacturing facility. However, if your product is not functioning and needs to be returned, follow these procedures.Documentation FeedbackYour comments will help us serve your documentation needs better. If you have any suggestions on how to improve this document, complete this form, publication RA-DU002, available at /literature/.United States or Canada1.440.646.3434Outside United States orCanada Use the Worldwide Locator at /support/americas/phone_en.html , or contact your localRockwell Automation representative.United StatesContact your distributor. You must provide a Customer Support case number (call the phone number above to obtain one) to your distributor to complete the return process.Outside United StatesPlease contact your local Rockwell Automation representative for the return procedure.Allen-Bradley, Rockwell Automation, SLC, and T echConnect are trademarks of Rockwell Automation, Inc.T rademarks not belonging to Rockwell Automation are property of their respective companies.Roc kw ell Otomasyon Ticaret A .Ş., K ar Plaza İş Mer k ezi E B lo k K at:6 34752 İçeren köy, İstanbul, T el: +90 (216) 5698400。
自动化专业英语课后单词及课后句子总结
P3U1architecture n. 体系结构instruction set 指令集binary-coded adj. 二进制编码的central processing unit (CPU) 中央处理器processor n. 处理器location n. （存储）单元word length 字长access v. 存取，接近fetch v., n. 取来field n. 域，字段opcode n. 操作码operand n. 操作数address n. 寻址single-precision adj. 单精度的floating-point adj. 浮点的terminal n. 终端complement v. 补充，求补decode v. 解码，译码request n. 请求inactive n. 不活动，停止I/O-mapped adj. 输入/输出映射的（单独编址）memory-mapped adj. 存储器映射的（统一编址）难句翻译[1] …how the instruction execution cycle is broken down into its various components.……指令执行周期怎样分解成不同的部分。
[2] One way to achieve meaningful patterns is to divide up the bits into fields…一种得到（指令）有效形式的方法是将（这些）位分成段……[3] The majority of computer tasks involve the ALU, but a great amount of data movement is required in order to make use of the ALU instructions.计算机的大多数工作涉及到ALU(逻辑运算单元)，但为了使用ALU指令，需要传送大量的数据。
吉林大学计算机导论复习重点
Chapter 1 Computer and DataKnowledge point:1.1The computer as a black box.1.2von Neumann model1.3The components of a computer: hardware, software, and data.1.4The history of computers.REVIEW QUESTIONS1.How is computer science defined in this book?A：Issues related to the computer.2.What model is the basis for today’s computers? ( Knowledge point 1.2)A：The von Neumann model.3.Why shouldn’t you call a computer a data processor? ( Knowledge point 1.1)A：Computer is general-purpose machine. it can do many different types of tasks.4.What does a programmable data processor require to produce output data? ( Knowledgepoint 1.1)A：The input data and the program.5.What are the subsystems of the von Neumann computer model? ( Knowledge point 1.2) A：Memory, arithmetic logic unit, control unit, and input/output.6.What is the function of the memory subsystem in von Neumann’s model? ( Knowledgepoint 1.2)A：Memory is the storage area. It is where programs and data are stored during processing.7.What is the function of the ALU subsystem in von Neumann’s model? ( Knowledge point1.2)A：ALU is where calculation and logical operations take place.8.What is the function of the control unit subsystem in von Neumann’s model? ( Knowledgepoint 1.2)A：It controls the operations of the memory, ALU, and the input/output subsystem.9.What is the function of the input/output subsystem in von Neumann’s model?( Knowledge point 1.2)A：The input subsystem accepts input data and the program from outside the computer; the output subsystem sends the result of processing to the outside.pare and contrast the memory contents of early computers with the memory contentsof a computer based on the von Neumann model? ( Knowledge point 1.2)A：Computer based on the von Neumann model stores both the program and its corresponding data in the memory. Early computers only stored the data in the memory.11.How did the von Neumann model change the concept of programming? ( Knowledgepoint 1.2)A：A program in the von Neumann model is made of a finite number of instructions. The instructions are executed one after another.12.The first electronic special-purpose computer was called c( Knowledge point1.4)a. Pascalb. Pascalinec. ABCd. EDV AC13.One of the first computers based on the von Neumann model was called d( Knowledge point 1.4)a. Pascalb. Pascalinec. ABCd. EDV AC14.The first computing machine to use the idea of storage and programming was calledd( Knowledge point 1.4)a. the Madelineb. EDV ACc. the Babbage machined. the Jacquard loom15.d separated the programming task from the computer operation tasks.( Knowledge point 1.3)a. Algorithmsb. Data processorsc. High-level programming languagesd.Operating systems30. According to the von Neumann model, can the hard disk of today be used as input or output? Explain. ( Knowledge point 1.2)A：Yes. When the hard disk stores data that results from processing, it is considered an output device; when you read data from the hard disk, it is considered an input device. 32. Which is more expensive today, hardware or software? ( Knowledge point 1.3)A：Software.Chapter 2 Data RepresentationKnowledge point:2.1 Data Types.2.2 Data inside the Computer.2.3 Representing Data.2.4 Hexadecimal and Octal notation.REVIEW QUESTIONS five types of data that a computer can process. ( Knowledge point2.1)A：Numbers, text, images, audio, and video.2.How does a computer deal with all the data types it must process? ( Knowledge point 2.2) A：All data types are transformed into bit pattern.3.4.What is the difference between ASCII and extended ASCII? ( Knowledge point 2.3)A：ASCII is a bit pattern made of 7 bits and extended ASCII is a bit pattern made of 8 bits.5.What is EBCDIC? ( Knowledge point 2.3)A：Extended Binary Coded Decimal Interchange Code.6.How is bit pattern length related to the number of symbols the bit pattern can represent?( Knowledge point 2.3)A：The relationship is logarithmic.7.8.9.What steps are needed to convert audio data to bit patterns? ( Knowledge point 2.3)A：Sampling, Quantization, and Coding.10.What is the relationship between image data and video data? ( Knowledge point 2.3)A：Video is a representation of images in time.34. A company has decided to assign a unique bit pattern to each employee. If the company has 900 employees, what is the minimum number of bits needed to create this system of representation? How many patterns are unassigned? If the company hires another 300employees, should it increase the number of bits? Explain your answer. ( Knowledge point 2.3)A：log2900≈10,210-900=124,Yes, 900+300>210Chapter 3 Number RepresentationKnowledge point:3.1 Convert a number from decimal, hexadecimal, and octal to binary notation and vice versa.3.2 Integer representation: unsigned, sign-and-magnitude, one’s complement, and two’s complement.3.3 Excess system.3.4 Floating-point representation.REVIEW QUESTIONS5. What are three methods to represent signed integers? (Knowledge point 3.2)A：Sign-and-Magnitude, One’s Complement, and Two’s Complement.9. Name two uses of unsigned integers. ( Knowledge point 3.2)A：Counting and Addressing.10. What happens when you try to store decimal 130 using sign-and-magnitude representation with an 8-bit allocation? ( Knowledge point 3.2)A：Overflow.11. Compare and contrast the representation of positive integers in sing-and-magnitude, one’s complement, and two’s complement. ( Knowledge point 3.2)A：The representation of positive integers in sing-and-magnitude, one’s complement, and two’s complement is the same.14. Compare and contrast the range of numbers that can be represented in sign-and-magnitude, one’s complement, and two’s complement. ( Knowledge point 3.2)A：Sign-and-Magnitude range –(2N-1-1)～+(2N-1-1)One’s Complement range –(2N-1-1)～+(2N-1-1)Two’s Complement range –(2N-1)～+(2N-1-1)16. What is the primary use of the Excess_X system? ( Knowledge point 3.3)A：The primary use of the Excess_X system is in storing the exponential value of a fraction.17. Why is normalization necessary? ( Knowledge point 3.4)A：A fraction is normalized so that operations are simpler.Chapter 4 Operation On BitsKnowledge point:4.1 Arithmetic operations.4.2 Logical operations.4.3 Mask.4.4 Shift operations.REVIEW QUESTIONS3. What happens to a carry form the leftmost column in the final addition? ( Knowledge point4.1)A：The carry is discarded.5. Define the term overflow. ( Knowledge point 4.1)A：Overflow is an error that occurs when you try to store a number that is not within the range defined by the allocation.8. Name the logical binary operations. ( Knowledge point 4.2)A：NOT, AND, OR, and XOR.10. What does the NOT operator do? ( Knowledge point 4.2)A：It inverts bits.(it changes 0 to 1 and 1 to 0)11. When is the result of an AND operator true? ( Knowledge point 4.2)A：Both bits are 1.12. When is the result of an OR operator true? ( Knowledge point 4.2)A：Neither bit is 0.13. When is the result of an XOR operator true? ( Knowledge point 4.2)A：The two bits are not equal.17. What binary operation can be used to set bits? What bit pattern should the mask have? ( Knowledge point 4.3)A：OR. Use 1 for the corresponding bit in the mask.18. What binary operation can be used to unset bits? What bit pattern should the mask have? ( Knowledge point 4.3)A：AND. Use 0 for the corresponding bit in the mask.19. What binary operation can be used to flip bits? What bit pattern should the mask have? ( Knowledge point 4.3)A：XOR. Use 1 for the corresponding bit in the mask.Chapter 5 Computer OrganizationKnowledge point:5.1. three subsystems that make up a computer5.2. functionality of each subsystem5.3. memory addressing and calculating the number of bytes5.4. addressing system for input/output devices.5.5. the systems used to connect different components together.Review questions:1. What are the three subsystems that make up a computer?(Knowledge point 5.1) Answer: the CPU, main memory, and the input/output (I/O) subsystem.2. What are the parts of a CPU? (Knowledge point 5.1)Answer: The CPU performs operations on data and has a ALU, a control unit, and a set of registers.3. What‘s the function of the ALU? (Knowledge point 5.2)Answer: The ALU performs arithmetic and logical operations.Exercises:78. A computer has 64MB of memory. Each word is 4 bytes. How many bits are needed toaddress each single word in memory? (Knowledge point 5.3)Solution:The memory address space is 64 MB, that is 2 raised to the power 26. The size of each word in bytes is 2 raised to the power 2. So we need 24(subtract 2 from 26) bits to address each single word in memory.79. How many bytes of memory are needed to store a full screen of data if the screen is made of 24 lines with 80 characters in each line? The system uses ASCII code, with each ASCII character store as a byte. (Knowledge point 5.3)Solution:The quantity of bytes in a full screen is 1920 (24*80) while the system uses ASCII code with each ASCII character store as a byte. So we need 1920 bytes of memory to store the full screen of data.87. A computer uses isolated I/O addressing. Memory has 1024 words. If each controller has 16 registers, how many controllers can be accessed by this computer? (Knowledge point 5.4) Solution:Memory has 1024 words. So the address space is 1024. Each controller has 16 registers. Then we get 64 (divide 16 by 1024)controllers which can be accessed by this computer.88. A computer uses memory-mapped I/O addressing. The address bus uses 10 lines. If memory is made of 1000 words, how many four-register controllers can be accessed by this computer? (Knowledge point 5.4)Solution:The address bus uses 10 lines. So, the address space is 1024(2 raised to the power 10). The memory is made of 1000 words and each controller has four registers. Then we get (1024-1000)/4 = 6 four-register controllers which can be accessed by this computer.Chapter 6 Computer NetworksKnowledge point:6.1. OSI model6.2. TCP/IP protocol6.3. three types of networks6.4. connecting devices6.5. client-server modelReview questions:2. Name the layers of the OSI model? (6.1)Answer: Physical layer, Data link layer, Network layer, Transport layer, Session layer, Presentation layer and Application layer.3. Name the layers of the TCP/IP protocol suite. (6.2)Answer: The layers of the TCP/IP protocol suite are: physical and data-link layers network layer, transport layer, and application layer.8. What are the three common topologies in LANs? Which is the most popular today? (6.3) Answer: bus topology, star topology, ring topology, star topology9. Name four types of network connecting devices. (6.4)Answer: the four types of network connecting devices are repeater, bridge, router and gateway.Chapter 7 Operating SystemsKnowledge point:7.1. the definition of an operating system7.2. the components of an operating system7.3. Memory Manager7.4. Process manager7.5. deadlockReview questions:4. What are the components of an operating system? (7.2)Answer: An operating system includes: Memory Manager, Process Manager, Device Manager and File Manager13. What kinds of states can a process be in? (7.4)Answer: ready state, running state, waiting state.15. If a process is in the running state, what states can it go to next? (7.4)Answer: ready state, waiting state.What’s the definition of an operating system? (7.1)Answer: An operating system is an interface between the hardware of a computer and user(programs or humans) that facilitates the execution of other programs and the access to hardware and software resources.What are the four necessary conditions for deadlock? (7.5)Answer: mutual exclusion, resource holding, no preemption and circular waiting.51. A multiprogramming operating system uses paging. The available memory is 60 MB divided into 15 pages, each of 4MB. The first program needs 13 MB. The second program needs 12MB. The third program needs 27 MB. How many pages are used by the first program? How many pages are used by the second program? How many pages are used by the third program? How many pages are unused? What is the total memory wasted? What percentage of memory is wasted? (7.3)Answer:Each page is 4MB. The first program needs 13 MB. It is obviously that 4*3<13<4*4. So the first program uses 4 pages and wastes 3(16-3) MB. The second program needs 12 MB. It is obviously that 12=4*3. So the second program uses 3 pages and wastes 0 MB. The third program needs 27 MB. It is obviously that 4*6<27<4*7. So the first program uses 7 pages and wastes 1(28-27) MB. There are 1(15-4-3-7) page unused. There are totally 4(3+0+1) MB memory wasted. The percent of memory wasted is 4/(60-4*1)=7%.Chapter 8 AlgorithmsKnowledge point:8.1. the concepts of an algorithm and a subalgorithm8.2. three constructs for developing algorithms8.3. basic algorithms8.4. tools for algorithm representation8.5. recursionReview questions:1. What is the formal definition of an algorithm? (8.1)Answer: An ordered set of unambiguous steps that produces a result and terminates in a finite time.2. Define the three constructs used in structured programming. (8.2)Answer: The three constructs in structured programming are Sequence, Decision and Repetition.10. What are the three types of sorting algorithms? (8.3)Answer: bubble sort, selection sort and insertion sort.12 What is the purpose of a searching algorithm? (8.3)Answer: The purpose is to find the location of a target among a list of objects.13. What are the two major types of searches? How are they different? (8.3)Answer: sequential search and binary search. The difference is whether the list is ordered or not.55. A list contains the following elements. Using the binary search algorithm, trace the steps followed to find 20. At each step, show the values of first, last and mid.3, 7, 20, 29, 35, 50, 88, 200 (8.3)Solution:index 0---1---2---3---4---5---6---73, 7, 20, 29, 35, 50, 88, 200First=0, Last=7, Mid=(0+7)/2=3The data is D(3)=29, 20 smaller than the D(3), so remove the data from index 3 to 7. Change the new point First=0, Last= mid-1=2, and Mid=(0+2)/2=1The data is D(1)=7, 20 bigger than the D(1), so remove the data from index 0 to 1. Change the new point First=mid+1=2, Last=2, and Mid=(2+2)/2=2The data is D(2)=20, we find the data 20 in index=258. Write a recursive algorithm to find the combination of n objects taken k at a time using following definition.C(n,k)=1 , if k=0 or n=kC(n,k)=C(n-1,k)+(n-1,k-1) , if n>k>0 (8.5)Solution:A: CInput : n and kIf(k==0 or n==k)Then return 1End ifIf(n>k and k>0)Then Return C(n-1,k)+(n-1,k-1)End ifEnd。
计算机专业英语教案
fast-paced adj.快节奏的，快速的
lap n.膝盖上
logic n.逻辑（线路）
maze n.迷宫，混乱
microsecond n.微秒
millisecond n.毫秒
multiplyvt.&vi.乘，做乘法
nanosecond n.纳秒
objective n.目的
教学方法
Lecture
重点、难点
Notes to the Passage
时间分配
教学内容
板书或课件版面设计
New Words
accessible adj.易接近的，可访问的
add-on adj.添加的
animation n.动画片
architecture n.构造，体系结构
bank n.存储单元
bit n.比特，（二进制）位
New Words
available adj.可用的
category n.种类，类型
code n.码，代码，编码
community n.社区，社会
component n.组件，元件，部件
computer-related adj.与计算机有关的
contain vt.包含，包括
convert vt.转换，变换
hardware n.硬件
input n.输入
instruction n.指令，指导
internal adj.内部的
laser-etched adj.激光蚀刻的
layout n.安排，版面布置
manipulate vt.操作，控制，使用
memory n.记忆，存储，内存
monitor n.监视器，显示器
Memory Mapped I／O
• The device is connected directly to certain main memory locations.
• Two types of information to/from the device
– Status – Value read/write
Why use Memory Mapped I/O
• The receiver control will have a 1 in the rightmost bit when there is a value ready to be read. It will have a 0 in that bit otherwise.
• The receiver data will have the character pressed on the keyboard (only when the receiver control has a 1 in the rightmost bit)
andi $t1, $t1, 1 #get rightmost bit
beqz $t1, again #if not ready check again
lw
$t0, 4($t4) #get char. from rec. data
Display
• Again 2 registers
– Transmitter control (0xffff008)
– Transmitter data (0xffff000c)
li
$t4, 0xffff0000
again: lw $t1, 8($t4)
Memory Mapped I／O
• Two types of information to/from the device
– Status – Value read/write
Why use Memory Mapped I/O
• Recall that the processor is attached to a bus, memory is attached to the bus, I/O devices are attached to the bus.
– When the bus sees certain addresses, it knows they are not memory addresses, but are addresses for accessing I/O devices.
Communicating with the Keyboard
• The keyboard has 2 registers associated with it
– Receiver control at address xffff0000 – Receiver data at address xffff0004
Polling
• To read, you go: do you have something now? Now? Now? Now? Ok now read th00 #rec. control addr
again: lw $t1,0($t4) #get rec. control value
• A real MIPS system (not one simulated by Spim) will have many more control/data register pairs for all of the devices.
国家标准软件说明书
NA TIONAL INSTRUMENTS The Software is the Instrument MITE ™, NI-VISA ™, NI-VXI ™, and TIC ™ are trademarks of National Instruments Corporation. Product and company names are trademarks or trade names of their respective companies.321245A-01 © Copyright 1996 National Instruments Corp. All Rights Reserved.April 1996R E L E A S E N O T E SNI-VXI S OFTWARE E NHANCEMENTS FOR THE VXI/VME-PCI8040 K IT FOR M ACINTOSHThank you for purchasing the NI-VXI bus interface software from National Instruments. These release notes describe new features of the NI-VXI bus interface software along with enhancements of existing features. This document also includes information you need for upgrading the optional NI-VISA software to work with the PCI-MXI-2.New Features and TerminologyNew functionality has been added to NI-VXI in four major areas to exploit features in MXI-2 and the MITE ASIC. These features are as follows:•Window mapping •DMA •Shared memory • Remote controllersWindow MappingThe MITE architecture allows much more flexibility in low-levelmapping of VXI address spaces. In particular, the CPU-MXI interface of the MITE has windows that can be dynamically resized and relocated from CPU space to VXI space. The NI-VXI low-level functions have new extensions that reflect this feature. Refer to Chapter 6, Low-Level VXIbus Access Functions , in the NI-VXI Software Reference Manual for C for more information.As in earlier versions of NI-VXI, MapVXIAddress() checks whether a window that can be shared already maps to the desired address space and location. If so, it returns a pointer to that window. If the desired space is not already mapped, MapVXIAddress() sets up a new MITE window to the VXI address and returns a pointer to the new window.The success of this allocation depends on the availability of three factors:• MITE windows• CPU address space• Memory for allocating data structures for the mapMITE WindowsThe MITE has eight CPU windows. NI-VXI uses three of these windows, leaving five for user applications.CPU Address SpaceThe PCI-MXI-2 can decode any 32-bit address on the PCI bus as a VXI cycle, giving 4 GB of addressability, which can be used for windows on the PCI-MXI-2. The operating system or computer architecture may limit which addresses can be assigned to the PCI-MXI-2.Memory for Allocating Data StructuresMemory is needed to set up the necessary page tables. If you request a very large window—hundreds of megabytes, for example—you may run out of memory.The MapVXIAddressSize() function is the standard mechanism for specifying how large a window the driver should map on a call to MapVXIAddress(). The default size of a mapped window is 64 KB. The MapVXIAddressSize() function is described later in this document.DMAThe MITE has two DMA channels, which NI-VXI uses to improve thethroughput of block transfers to and from the VXI system. The DMAchannels can use various high-speed bus protocols, such as the following:• MXI block• MXI synchronous• Burst mode (on the PCI bus)• VME64 (on the VXI bus)The DMA channels can transfer data between a VXI device and localmemory, or between VXI devices. The DMA channel can handlecontiguous or noncontiguous local memory. If it is handlingnoncontiguous memory, it can perform scatter-gather operations on thenoncontiguous memory.The VXImove() function automatically uses appropriate bus protocolsand transfer types to efficiently perform the data transfer specified in thefunction. You can also use some extra configuration options and functionparameters to instruct the NI-VXI software to use DMA channels forparticular types of operations and to designate what protocols the channelshould use. See Chapter 7, High-Level VXIbus Access Functions, in theNI-VXI Software Reference Manual for C for complete descriptions ofVXImove() and other high-level functions. However, previously writtenNI-VXI code will use the DMA capabilities without modification.To take full advantage of the throughput of the DMA channels, youshould perform 32-bit transfers where both the source and the destinationare longword aligned. If you need to transfer character data betweendevices of different byte orders—for example, between a big-endiandevice and an Intel 80x86-based Windows NT PC—transfer the data aslongwords but adjust the byte-ordering parameters in VXImove() to getthe correct data in the most efficient manner.Examples:/* Transferring 32-bit data t o a big-endian A32 device */V X I m o v e (0 x0 , u s e r B u f f e r , 0x 3, d e v i c e O f f s e t, n u m D a t a P o i n t s , 4) ;/* Transferring 8-bit data t o a big-endian A32 device */VX I m o ve (0 x80 , u se r B u ff e r , 0 x3 , d e v i ce O f f se t, nu m D a ta P o i nt s/ 4 , 4);Because Macintosh computers are big endian, you do not need to adjustthe byte order when accessing big-endian instruments.Shared MemoryYou can share a portion of your system RAM in VXI space, as onprevious drivers. In addition, MITE-based boards have SIMM slots forinstalling onboard RAM. On a PCI-MXI-2, this RAM can be shared in aVXI address space. Furthermore, you can divide the VXI space assignedto your device into two halves, sharing the onboard RAM in one half andsystem RAM in the other. The configuration options, such as byte-ordering, can be different for each half of the region of VXI space you aresharing. For more information review the options of the PCI-MXI-2Logical Address Configuration Editor in Chapter 6, NI-VXIConfiguration Utility, of Getting Started with Your VXI/VME-PCI8040and the NI-VXI Software for Macintosh.Remote ControllersIf you are using a VXI-MXI-2 VXIbus extender in your system, you haveremote controller capability. Each VXI-MXI-2 has a full MITE chip setonboard. Although it does not have a CPU connected to it, this MITEchip set gives the VXI-MXI-2 many of the same features as thePCI-MXI-2, including onboard memory, DMA channels, TIC-basedtriggering, and interrupt mapping. This means that a MXI-2 system has atleast one full-featured bus controller residing in each VXI chassis,controlled by and communicating with the local controller via the VXIbusand the MXIbus. These MITE-based bus controllers are called remotecontrollers.In previous versions of NI-VXI, the CPU-MXI-based controller wascalled an external controller, and VXI-MXI boards on the same MXIbusas the external controller were called extending controllers. Theextending controllers and the external controller together made up oneextended controller. The presence of the full-featured remote controllershas led to a slight change in this model. The CPU-MXI is still an externalcontroller, but instead of having extending controllers, each parent-sideVXI-MXI-2 is a separate remote controller. Other VXI-MXI-2 boards aretreated simply as extenders that may have additional memory present, butmay not perform bus access, trigger, or interrupt services. This definitionassigns one remote controller to each chassis, resolving any resourcearbitration issues for the system.Any NI-VXI function that previously accepted a controller parameter—whether extended, external, embedded, or local—will now accept a remote controller as well. A new option in VXItedit determines which controller is associated with the value of -1 in the controller parameter of an NI-VXI function. This new option indicates whether the -1 value is referring to the PCI-MXI-2 (the local controller) or the first remoteVXI/VME-MXI-2 controller. For more details, refer to the Default Controller (LA -1) section in Chapter 6, NI-VXI Configuration Utility, of your getting started manual.Remote controllers, when configured to detect asynchronous events such as a VXI interrupt or VXI trigger, need to inform the local controller that such an asynchronous event has occurred. The remote controllers report these events back to the local controller via a VXI IRQ line. This IRQ line is called the system IRQ line. You can use the NI-VXI utility VXItedit to select which VXI interrupt line the remote controller uses to report remote events to the local controller. You need to map the system IRQ line back to the local controller to receive remote controller interrupts. This mapping is performed automatically by the Resource Manager in the parent-side VXI-MXI-2 controllers, but not in other mainframe extenders. You can map interrupts by using the Interrupt Configuration Editor in VXItedit, or by using the MapVXIint() function, which is described in Chapter 13, VXIbus Extender Functions, in the NI-VXI Software Reference Manual for C.Notice the following differences in how the system IRQ line is treated differently than other IRQ lines used by NI-VXI.• The system IRQ line is always acknowledged by the Resource Manager (Logical Address 0).• The system IRQ line cannot be disabled on the Resource Manager.Calling DisableVXIint() on the system IRQ line does notdisable it.• Devices other than remote controllers can also interrupt on the system IRQ line, provided that the device at Logical Address 0 is the handler for the interrupt.• Routing the system IRQ to the signal queue is not recommended.Because the system IRQ cannot be disabled, it is possible that thisrouting could cause interrupts to be lost.Enhancements to the NI-VXI SoftwareThe NI-VXI software for the PCI-MXI-2 makes use of many newfeatures available in MXI-2 and on the MITE ASIC. You have twooptions for controlling these features—through new configuration optionsin VXItedit, or by extensions to the NI-VXI Application ProgrammingInterface (API). Refer to Chapter 6, NI-VXI Configuration Utility, andChapter 7, Using the NI-VXI Software, in your getting started manual formore information on the new configuration options.NI-VXI API ExtensionsThe following paragraphs discuss the additional options beyond what wasdocumented in the NI-VXI Software Reference Manual for C.CompatibilityNI-VXI applications that follow the guidelines in the NI-VXI SoftwareReference Manual for C will work with NI-VXI for the PCI-MXI-2 witha few exceptions. These exceptions deal primarily with low-level VXIbusaccess functions.NI-VXI for the PCI-MXI-2 is a fully PowerPC-native architecture. Youmust recompile your application to be PowerPC native. 680x0development is not supported in this release.Applications that set the context bits directly for use in SetContext()may not be compatible with the new format for context. Because thePCI-MXI-2 allows more flexible window mapping, extra bits have beenadded to this field to reflect these new features. In general, werecommend that you do not manipulate the context bits.System Configuration FunctionsThe mainframe extender/controller information field of the DevInfostructure (field 17) defines a new bit. Bit 13 reports if the extender is aremote controller. This bit is now significant in any function that uses themainframe extender/controller information field, includingGetDevInfo(), SetDevInfo(), GetDevInfoShort(),SetDevInfoShort(), and FindDevLA(). NI-VXI automatically setsbit 13. Do not change the value of this bit in a program, even via thedocumented API calls.If a remote controller is sharing its onboard RAM, you can find the size,space, and offset of that RAM in the VXI system by callingGetDevInfo() for the remote controller’s logical address.Do not make any assumptions about the size and features of a windowreturned from MapVXIAddress(). You should use GetWindowRange()to determine the size of a window.The 32-bit value returned from GetContext() and passed toSetContext() has a new format.A new function, MapVXIAddressSize(), has been added to thelow-level VXIbus access functions. Its description follows.MapVXIAddressSizeMapVXIAddressSize() is the interface for requesting a particularwindow size for all successive calls to MapVXIAddress().Syntax:ret = MapVXIAddressSize(size)Action:Sets the default size for the window returned fromMapVXIAddress().Remarks:Input Parameter:size uint32Size in bytes of window tobe mappedOutput Parameters:noneReturn Value:ret int16Return Status0 = SuccessfulExample:/* Set the size of future mappings to 1 MB */ret = MapVXIAddressSize(0x100000);As previously mentioned, VXImove() has new bits defined in the srcParm and destParm fields for using features of the MITE DMA channel.• Bit 11—Use programmed I/O (PIO) instead of DMA. DMA is used by default and setting this bit forces NI-VXI to use PIO instead ofDMA. In general, DMA is more efficient than PIO. However, when virtual memory is involved, a DMA channel needs to lock downmemory before it can be used (locking is done by the NI-VXI DMA manager automatically). Because of the amount of time required for buffer locking, it may be more efficient to transfer buffers by PIO.• Bit 12—No increment. Do not increment the address. This is used when the source or destination is a FIFO buffer and is valid for any address space, whether local, A16, A24, or A32.• Bit 13—Disable MXI block mode. MXI block mode is enabled by default in VXImove() when VXImove() is called from a CPU-MXI because it makes MXI transfers more efficient, and MXI block mode is supported by the VXI/VME-MXI-2. However, if you arecommunicating with a MXI device that does not support MXI block mode, you need to disable this mode by setting this bit.• Bit 14—Disable MXI synchronous mode. MXI synchronous mode is enabled by default in VXImove() when VXImove() is called from a CPU-MXI because it makes MXI transfers more efficient, and MXI synchronous mode is supported by the VXI/VME-MXI-2. However, if you are communicating with a MXI device that does not support MXI synchronous mode, you need to disable this mode by settingthis bit.In addition to the above bits, two new access privileges have been added to the srcParm and destParm fields to support the VME64 protocol.• Access Privilege 6—VME64 nonprivileged block access.• Access Privilege 7—VME64 privileged block access.Setting these access privileges will cause VXImove() to perform the VME64 protocol on the VXI bus. Ensure that the device you are communicating with is capable of responding to these special cycles before using these privileges.For best performance, keep the following in mind when using VXImove().• Make sure your buffers are 32-bit aligned.• Transfer 32-bit data whenever possible.• VXImove() must lock the user buffer in memory on virtual memory systems, so locking the buffer yourself will optimize VXImove().• Because VXImove() must build a scatter-gather list for the user buffer on paged memory systems, using a contiguous buffer willoptimize VXImove().• Using VXI block access privileges will significantly improve performance to devices that are capable of accepting block transfers.• VXImemAlloc() will return 32-bit aligned, page-locked, contiguous buffers, which work efficiently with VXImove().Local Resource Access FunctionsVXImemAlloc() does not allocate onboard RAM on the PCI-MXI-2; it allocates system RAM only on the motherboard. If you want to access onboard RAM on the PCI-MXI-2, access it as if it were VXI memory—that is, by using high-level or low-level VXIbus access functions. You can use GetDevInfo() on the PCI-MXI-2 device to determine the VXI address space and VXI address of this onboard RAM.VXI Interrupt FunctionsEvery function that takes a controller’s logical address as an argument can now accept the local controller or a remote controller’s logical address as well.VXI Trigger FunctionsEvery function that takes a controller’s logical address as an argument can now accept the local controller or a remote controller’s logical address as well.TIC functionality is now available on the local controller and on every remote controller.System Interrupt Handler FunctionsEvery function that takes a controller’s logical address as an argument can now accept the local controller or a remote controller’s logical address as well.Updating NI-VISAIf you want to use NI-VISA with your VXI/VME-PCI8040 kit forMacintosh, you need to install a VISA patch. NI-VISA should beinstalled before adding this patch. If you have not already installedNI-VISA, refer to the Read Me First document that describes how toinstall NI-VISA for Macintosh/Power Macintosh.Follow these instructions to install the VISA patch.1.Insert the disk containing the NI-VXI software and double-click onthe Install NI-VXI icon.2.Click on Show Other Installations at the top of the Installerwindow. Notice that the VISA patch is not installed by the TypicalNI-VXI Installation option.3.Select and drag the VISA patch icon to your hard disk.4.Restart your Macintosh when prompted to do so.。
通信英语文章
计算机与因特网插件指南Life on-line can be a much richer experience when you aren't restricted to just written words and still pictures. Even if you're new to the Net, you've probably heard aobut multimedia on-line--listening to audio, watching animations and videos, even playing in three-dimensional space. Sound and movement make information come alive.To experience it, you'll need special pieces of software called plug-ins. The term "plug-in" refers to a small, add-on piece of software which extends the capabilities of your web browser, like Netscape Navigator or Microsoft Explorer, turning your computer into a radio or TV.When you arrive at a web page which contains a file requiring a plug-in which you don't have, you will usually receive a message asking if you want to get it by downloading it and installing it into your computer. Most of the time, the installation will be automatic.Occasionally, you'll run into a downloaded file which needs to be decompressed or un-zipped before installation. Once installed, plug-ins run automatically, without you having to do anything.Many multimedia controls still need to be obtained from the developer but are installed automatically.Shockwave is a good example of this. All you need to do is go to the Macromedia site and click on the link to install the ActiveX control. The rest happens automatically. The next time you go to a "Shocked" website, the Shockwave control loads and plays the movie.Most plug-ins and controls can be downloaded for free on the Internet, although not all will work with every system. Some of them, for instance, only work with windows95.当你不再仅仅限于文字和静止图片时，网上生活会丰富多彩得多。
历年英语四级深度阅读真题及答案汇总之欧阳引擎创编
2010年12月大学英语四级阅读与词汇真题及答案欧阳引擎（2021.01.01）Part Ⅳ Reading Comprehension (Reading in Depth) (25 minutes) Section ADirections: In this section, there is a passage with ten blanks. You are required to select one word for each blank from a list of choices given in a word bank following the passage. Read the passage through carefully before making your choices. Each choice in the bank is identified by a letter. Please mark the corresponding letter for each item on Answer Sheet 2 with a single line through the centre. You may not use any of the words in the bank more than once. Questions 47 to 56 are based on the following passage.What determines the kind of person you are? What factors make you more or less bold, intelligent, or able to read a map? All of these are influenced by the interaction of your genes and the environment in which you were 47 . The study of how genes and environment interact to influence 48 activity is known as behavioral genetics. Behavioral genetics has made important 49 to the biological revolution, providing information about the extent to which biology influences mind, brain and behavior.Any research that suggests that 50 to perform certain behaviors are based in biology is controversial. Who wants to be told that there are limitations to what you can 51 based on something that is beyond your control, such as your genes? It is easy to accept that genes control physical characteristics such as sex, race and eye color. But can genes also determine whether people will get divorced, how 52 they are, or what career they are likely to choose? A concern of psychological scientists is the 53 to which all of these characteristics are influenced by nature and nurture(养育), by genetic makeup and the environment. Increasingly, science 54 that genes lay the groundwork for many human traits. From this perspective, people are born 55 like undeveloped photographs: The image is already captured, but the way it 56 appears can vary based on the development process. However, the basic picture is there from the beginning.注意：此部分试题请在答题卡2上作答。
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SCI adapters from Dolphin InterConnect Solutions conform to IEEE 1596 SCI standard [5]. Figure 1 describes remote memory access principle using a PCI-SCI adapter. A
The SCI adapters converts the local PCI address into an SCI address according to an Address Translation Table (ATT). An SCI address is composed of a remote node identifier and a physical address. This way, SCI provides a hardware support for a global address space. A remote SCI read or write operation is sent to the remote node using the SCI address. The receiving adapter can then perform the local memory access at the physical address stored in the SCI address.
Finally, we evaluate various consistency models with scientific computing applications from the Splash benchmark. We observe that, even if the rough network performance is good, it is not sufficient to obtain acceptable results with applications that require fine grain parallelism. However, we show that memory mapped networks provide an efficient hardware support to implement software DSM systems without requiring complex relaxed consistency models. This way, DSM design can be greatly simplified using this technology.
part of the PCI address space is allocated to the PCI-SCI board. When a process wants to access the memory of a remote node, the process virtual address is first translated to a physical PCI address.
Process A
ATT
PCI-SCI bridge
Memory bus
Physical memory
Process B
Virtual address space
PCI bus
SCI
inter-
PCI-SCI
connect
birdge
PCI
bus
Virtual address space
Figure 1. Remote memory mapping principle
We first show the respective advantages of two communications techniques with SCI: programmed IO (PIO) and remote DMA (RDMA). Then, we describe how to build a scalable page transfer mechanism by mixing PIO and RDMA. Despite the lack of a broadcast mechanism with SCI, we demonstrate that it is possiblபைடு நூலகம் to build scalable synchronization primitives using PIO.
We have implemented a distributed shared memory system, called SciFS, that manages physical memory as in a NUMA (Non Uniform Memory Access) architecture. The average memory access time is lowered by using dynamic page migration and replication mechanism, combined with the use of idle remote memory instead of disk swap. SciFS provides sequential consistency but also a relaxed memory consistency model implementation: Lazy Release Consistency. SciFS relies on a lower layer, SciOS, which we also have developed. SciOS offers basic services for SCI clusters, such as messages, remote procedure calls, memory allocation, deallocation and invalidation, and debugging facilities like timers, traces and statistics. Our goal is not to develop another DSM system but to evaluate the contribution of memory mapped networks to software DSM.
Memory Mapped Networks: a new deal for Distributed Shared Memories ? The SciFS experience
Emmanuel Cecchet INRIA Rhône-Alpes, Sardes project
emmanuel.cecchet@inrialpes.fr
We find that a file system interface with the file mapping mechanism allows a good integration of SCI with the operating system’s virtual memory system. The distributed shared memory paradigm hides the complexity of the underlying architecture to the end-user. Thus, it becomes easy to develop any kind of applications on top of such systems because the programmer no longer has to care about low level communications and data transfers.
1. Introduction
Memory-mapped networks such as IO-based Scalable Coherent Interface (SCI) adapters can perform remote memory transfers without involving the operating system, thereby inducing very low processor overhead. This feature, combined with a low latency and a large bandwidth, has motivated several groups to implement message passing interfaces for SCI networks. This technology is also well suited to implement software based Distributed Shared Memories as it allows efficient remote read and write operations. Reliability is ensured by the hardware but coherency is the user’s responsibility.
Abstract
Distributed Shared Memories (DSM) performance has always suffered from high network latencies and software communication layers with a large overhead. Memory mapped networks such as Scalable Coherent Interface (SCI) allow to reliably access remote memory without involving the operating system. To show how DSM systems can benefit from this technology, we have developed SciFS, a DSM tightly integrated with the operating system, that exploits the high performance and the remote memory access capabilities of SCI.