Fundamentals

System software • A collection of programs written for computer system management. • These are developed by the manufacturer. Operating system • Integrated collection of programs which makes the computer operational & helps in executing user programs. • It acts as an interface between man & machine. • It manages computer resources like memory, processors, input & output devices & files. • Ex : DOS, UNIX, LINUX, Windows Xp etc. Language Processors – they are basically translators used to translate programs written in programming language to machine level language. Interpreter注释机 注释机 • It translates high level language into machine level language one statement at a time & executes it.
Programming language • Is designed to目的在于 describe a set of actions动作 to be executed被执行 by a computer. • It is a practical实际 way for us (humans) to give instructions to a computer. The 3 types of programming languages are, 1. Low level/Machine level language(LLL/MLL) • The only language which the computer can understand. • Uses only 2 symbols 0 and 1 (binary) as a sequence顺序 of numbers. • Can be directly executed马上执行, fast and efficient有效率. • Machine dependent–non portable. • Difficult to understand, modify and debug不容易理解，修改和除错. 2. • • • Assembly level language(ALL)汇编语言 汇编语言 Uses mnemonic助记符 or symbolic符号 instructions指令. Machine dependent and efficient. Cannot be directly executed. Needs translation翻译 into MLL by an assembler.
Memory – the device 装置where information or data (values to be operated on) is stored存储. Instructions 指令 – statements语句 written to perform specific operations执 行特殊操作 on data. Processors 处理器– devices that performs sequence of operations specified执 行指定的操作顺序 by instruction in memory. Address – memory locations存储单元 are specified by addresses, where each address identifies a specific规定一个 byte, word etc. Program程序 – well defined set of instructions. [passive] 程序 Programming 程序编制– the art of writing instructions for a computer to solve specific task任务. Process – a program in execution运行. [active] Thread线程 – 2 or more processes running(executing) simultaneously.同时的 线程
• The process of translating HLL program into MLL statement by statement is called Interpretation. • Ex: BASIC, JAVA, VB Compiler编译器 编译器 • It is a program which accepts an entire HLL program into MLL at a time. • The process of translating HLL program into MLL statement by statement is called Compilation. • Ex: C, C++, PASCAL, TC compilers. Assemblers汇编器 汇编器 • It’s a program that accepts assembly language program & converts to MLL along with information for the loader. • Ex: TASM(turbo assembler), MASM(macro assembler) Translator (compiler/interp reter/assembler)
Fundamentals基本原理
What is a Computer? Computer is an electronic device装置 that accepts raw生的 data & processes it & converts 转变into meaningful information using programs. The word ‘Computer’ is derived由。。。而来 from the Greek希腊语 word ‘Compute计算’ which means ‘Calculation计算’. Data – is raw figures图标 and facts without any proper特有 meaning. Information – meaningful information which helps in decision making判定. BIT (BInary digiT) – Nibble – Byte – Halfword – Word – Doubleword – 0 or 1 4 bits 8 bits 2 bytes 4 bytes 8 bytes 1Kilobyte(KB) = 1024 bytes 1Megabyte(MB) = 1024 Kbs 1Gigabyte(GB) = 1024Mbs 1Terabyte(TB) = 1024Gbs
3. High level language(HLL) • Uses English like statements. Uses alphabets, digits, punctuations & some special symbols.字母数字标点符号和一些特殊符号 • Cannot be directly executed. Needs translation into MLL by a compiler or an interpreter.注释器 注释器 • Easy to understand, write, modify and debug修改和改错. • Slower and less efficient than MLL and ALL比.机器语言慢和汇编语言少 • Machine independent - portable. Source code(program)源代码 源代码 • Collection of statements语句集 written in some human-readable人类易懂 computer programming language (HLL or ALL). • Needs a translator (compiler/interpreter/assembler) to convert转变 into MLL so that it can be understood & executed by the computer. • This is the part before the translation process. Object code(program)目标代码 目标代码 • The part after translation into MLL. It will be in the form of 0’s and 1’s but still not ready for direct execution.
Programmers Operators End users
Operating system Language processors – compiler, interpreter, assembler System utilities实用工具 – linker, loader
Hardware – all the mechanical & electronic parts of a computer that can be touched & seen. Ex: input & output devices. Firmware – a combination组合 of hardware & software which aids in the functioning 运行of the computer. Ex: chips, RAM Liveware – people who are working on the computer, for the computer & are using the computer. Ex: system analyst, software engineer. Software – a collection of programs used to execute a particular task特别的 任务. It makes the computer hardware to work. Application software – a collection of programs written by the users to solve a particular problem in his/her area of interest. Ex: college management, library managem ent, MS Office, adobe reader