北邮 计算机学院 数据结构 期末试题

O S TEST1．Fill in the blanks with the proper words.( 10 cents)1. Operating system is a program that acts as an intermediary between _____ and______.2.To prevent user programs from interfering with the proper operation of the system,the hardware has two modes: _________, __________.3.___________ is the separation of user ______ from physical memory. User wouldbe able to write programs for an extremely large __________ space, simplifying the programming task.4.The file system consists of two distinct parts: _______, each storing related dataand _______, which organizes and provides information about all the files in the system.5.System call provide the interface between _____ and _____ .6.________ provide an object-oriented way of implementing file systems, and itallows the same system call interface (the API) to be used for different types of file systems.7. A process is a program in execution. A process needs certain resources, including____, ______, files, and ______ to accomplish its task.8.Disk-scheduling algorithms can improve _________, _________, and ________.9.The primary distinction between long-term scheduler and short-term scheduler is_______.10.The device drivers present a uniform device-access interface to ______ , much assystem calls provide a standard interface between the application and the operating system.2. Choose the best answer, and each blank has one answer. (23 cents) 1. Operating system is a kind of(1) , (2) is not the main problem it handles.(1). A. Application software;B. System software;C. Common software;D. Software package;(2). A. managing the bar-machine;B. designing, providing the interface between user program and hardwaresystem;C. managing the information resource of the computer;D. the compiling of the high-level program-designing language.2. The utilization of the memory can be improved by __(1)___. Its basic task is__(2)_ for each program; and each program can run safely and separately, main by __(3)____.(1), (3): A. memory-allocating B. memory-protectingC. address-mappingD. swapping(2): A. the diversion from logical address to physical addressB. the swapping between memory and backing store;C. the address space of the user’s applications can be larger than the memoryspace;D. allocation the memory.3. The response time of time-sharing system depends on_(1)___; while the response time of the real-time system depends on __(2)__.A. the size of time quantum;B. the number of users;C. the speed of the computer;D. the waiting time the users can accept;E. the time delay the object controlled can accept;F. the real-time scheduling.4. In a single-processor system, there are 5 processes, then _(1)___ processes can be in the ready queue, __(2)__ processes can be in the waiting queue.A. 5 ;B. 4;C. 3;D. 2;E. 1;F. 0;5. In the producer-consumer problem, the mutex-semaphore mutex, the resource-semaphore full and empty. Their initial value are 1, _(1)____ and __(2)__ respectively.A. 0;B. 1;C. 1;D.-1;E.-n;F. +n.6. The maximum capacity of the virtual storage of a computer system depends on __(1)____, and the pratical capacity depends on __(2)____.A. the length of the computer word;B. the memory capacity;C. the capacity of the hard disk;D. the capacity of the memory and disk;E. the address structure of the computer;7. The basic intention of the file system is _(1)__, and it can be realized by __(2)_, and the most important intention of the file system is _(3)__.A. accessing files by names;B. directory-managing;C. file-protecting;D. boost the speed of the file-accessing;E. improve the utilization of storage;8. In the algorithms below, __(1)____ can only be implemented by the nonpreemptive method, __(2)__ can only be implemented by preemptive method, while the rest can be implemented by both.A. Priority scheduling;B. Round-Robin scheduling;C. FCFS scheduling;D. Shortest-Job-First scheduling.9. Suppose there are 10 processes in the ready queue, with round-robin scheduling, the time quantum is 300 ms, and the CPU-switch costs 10 ms, then the percent of the system spending is about__(1)___; if the number of the processes in the ready queue adds up to 20, the percent will __(2)___.(1): A. 1%; B. 3%; C.5%; D. 10%; E. 30%;(2): A. increase; B. decrease; C. not change.10. When looking up a file by hash-table, you find the according directory item isempty , and this represents __(1)_; if the file name in that directory matches the file name you are looking up, it represents__(2)__; if it doesn’t match, it represents _(3)__.A. the file name has been modified;B. there is no file name you are searching in the system;C. new file just created;D. it is a collision;E. you has the accessing right;F. you find the right file;3. Please answer the questions given below.1.What are the differences between a process and a thread? Please draw the diagramof the process states。