微型计算机的硬件及软件介绍

微型计算机的硬件及软件介绍

Computer Hardware

A computer is a fast and accurate symbol processing system. It can accept，store， process data and produce output results. A computer can automatically process data without human intervention. However， it must be given a set of instruction to guide it， step by step， through processes. The set of instructions is called a program， The program is stored physically inside the machine， making it a program.

All computer systems of interest to us are similar. They contain hardware components for input， central processing unit and output. The system on the small-scale is called a microcomputer or minicomputer. Continuing up the size scale， the mainframe computer is one that may offer a faster processing speed and a greater storage capacity than a typical mini. Finally comes the supercomputer， designed to process complex scientific applications， which is the largest and fastest.

Although the capacity of computers' storage locations is varied， every computer stores numbers， letters， and other characters in a coded form.

Every character in the storage is represented by a string of 0s and 1s， the only digits founded in the binary numbering system. BCD and ASCII are popular computer codes.

Memory

Primary memory is known as random access memory RAM and simple named memory. It is the storage area within the computer that holds programs and

data during processing. Memory is only temporary storage area; when processing is complete， memory is cleared. The user needs to load or enter data and programs into the computer memory when using any application on the computer.

Different computers have different amounts of memory space， referred to

as memory size， ranging from 4， 8 megabytes to 64megabytes. Today， the memories of some microcomputers even can be expandable to hundreds of megabytes.

CPU

CPU is the abbreviation of Central Processing Unit， which is the heart of a computer like the head of a family. Once the power of a computer is turned on， all the behaviors are under the control of CPU. CPU is in an iron box together with other devices such as disk drives， a main memory and a switching power supply etc. In Chinese， the iron box is conventionally called the mainframe. On the back of the mainframe box， there are various ports，with which CPU may be linked with input and output devices.

Computer software

Most people think of software as all of the amazing application programs available today for microcomputers. But there are other forms of computer software that make it possible to use application programs. Software is the collective name for all the programs and instructions that direct a computer's operations. Generally software can be divided into three types： system software， application software and support software， system software monitors and controls the system's hardware. Application software performs specific tasks for the user. Support software is a series of software， which support development and maintenance of other software. Software is created through the use of programming languages.

The computer Language

The role of a program is to deliver user's intention to a computer and direct it to work. That is to say， a program is a dialogue tool for interacting between a man and a computer， as well as a bridge to transmit information. In general， the characters， phases and their syntax rules for programming are generally called “programming language”。

Programming languages are divided into three types： machine language，which is also called an instruction system， is the only one used directly by computers. The assembler language is a kind of symbolic language. It adopted some mnemonic symbols which can show the instructional functions to present the content of the program. The high-level language is a programming language based on English. Its operators and expressions are similar to ordinary mathematical formulas. General users can easily master a high-level language and make programs in it.

Programming

Programming is， at its simplest， the way people tell computers what to do， when to do it， and how to do it. A program is a specific set of