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计算机英语
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.
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.
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.
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 highlevel 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 instructions written by one or more people, which direct the action of
a computer system. It may be a very simple or complicated set of
instructions. It may be written by a beginning computer user or by a top
computer expert. It may be written in simple English or in a language
spoken only by computers. Just as writing a fiction , programming is a
process of creating art.
What is Object Oriented Programming?
Object oriented programming (OOP) is a new way of approaching the
job of programming that differs from traditional programming because it
uses objects as data structures to enhance productivity , simplify
programming, get reusability and improve software reliability. All object
oriented programming languages have three characteristics in common:
objects , polymorphism and inheritance. Let's take a look at these
concepts.
Object is a data structure that contains both structured information
and related operations. An object can contain other objects. In this way,
the object is given both data properties and behaviors , and so object
oriented programs can better reflect the real world they are trying to
simulate. Polymorphism essentially means that one name can be used for
several related but slightly different purposes. Inheritance is the process
by which one object can acquire the properties of another object. This is
important because it supports the concept of classification. For
example , a red delicious apple is a part of the classification apple ,
which in turn is a part of the fruit class , which is under the larger class
food.
计算机的硬件
计算机是一种快速、精确的符号加工系统,它能接收、存储、处理数据
并产生输出结果。计算机可以在不需要人工干预的情况下自动处理数据,然
而必须给它一组指令去引导它,使之逐步地通过一个个处理过程,这组指令
称之为程序。
我们目前所使用的计算机,其硬件成分都是相似的,它们的硬件设备均
包含输入设备,中央处理器和出设备。小规模的系统叫做微型计算机或小型
计算机。随着规模的增加,形成了大型计算机,它比一般的小型计算机有更
快的处理速度和更大的存储容量。最后是超型计算机,它用于处理更复杂的
科学问题,这种计算机规模最大、速度最快。
尽管计算机存储单元的存储能力不同,但是每一个计算机都以编码的形
式存储数字、字母和其它的字符。每一个存储的字符都被表示成 0 或 1 组成
的串,0 和 1 是二进制编码系统中仅有的数字。BCD 码和 ASCII 码都是流行
的计算机代码。
附注:BCD (Binary-Coded Decimal):二进制编码的十进制
附 注 : ASCII(American National Standard Code for Information
Interchange):美国国家信息交换标准代码
中央处理单元
CPU 是中央处理单元的英文缩写。它是计算机的心脏,好比一家之主一
样。计算机一旦通电运行,则所有的行为都要在它的控制之下运行。CPU 同
其它设备如磁盘驱动器、内存和开关稳压电源等被装在一个铁箱子中。 在中
文里,这个箱子被习惯地称为主机。在主机箱的背后, 有各种端口,用来沟
通 CPU 和其它输入输出设备的联系。
内存
主存储器又称为随机存取存储器,简称内存。它是计算机在处理过程中
存储程序和数据的区域。内存只是一个临时的存储区域,处理完成后内存就
被清空了。用户在使用应用程序需将数据和程序调入计算机内存。
不同的计算机具有不同的内存空间,内存空间是指内存的大小,从 4 兆
8 兆到 32 兆不等。目前有些微机的内存甚至可以扩充到上百兆。
计算机软件
很多人认为软件就是目前微机上使用的所有令人惊奇的应用程序。但是
还有一些其它形式的用以支持应用程序运行的计算机软件。 软件是所有指挥
计算机操作的指令和程序的统称。 通常软件被划分成三类: 系统软件、 应
用软件和支撑软件。 系统软件负责监视和控制计算机硬件 ;应用软件为用户
完成具体的任务; 支撑软件是支撑其它软件的开发与维护的一系列软件。软
件都是使用程序设计语言创造出来的。
计算机语言
程序的作用就是向计算机转达用户的意图,指挥计算机工作, 也就是说,
程序是人机对话的工具,是人与电脑交流信息的桥梁。 通常,程序设计所使
用的符号、短语及其语法规则通称为程序设计语言。
程序设计语言分为机器语言、汇编语言和高级语言三类。机器语言是计
算机唯一能直接使用的语言,也叫做计算机指令系统;汇编语言是一种符号语
言,它采用一些能反映指令功能的助记符表达程序的内容;高级语言是一种以
英文为基础的设计语言, 其中的运算符和表达式都和通常的数学公式类似。
一般用户也能很容易地掌握一种高级语言, 并可以用它来编制程序。
附注:mnemonic symbol
助记符
程序设计
程序设计,简单地说, 就是人们告诉计算机做什么,什么时候做以及怎
样做的方式。 一个程序就是一组指令的集合,由一个或多人编写,用于指导
计算机系统的动作。这个指令的集合可能非常简单,也可能十分复杂。它可
能是一个初学计算机的用户编写的也有可能是由高级计算机专家编写的。 它
可以用简单的英语编写,也可以用只有计算机“说”的语言编写。如同写小说
一样,程序设计也是一个艺术创造的过程。
何为面向对象的程序设计
与传统的编程方法不同, 面向对象的程序设计(OOP)是一种新的编程方
法,它使用对象作为其数据结构以提高生产率,简化程序设计,获得可复用
性和提高软件的可靠性。所有的面向对象的程序设计语言都具有对象、多态
和继承的特点。 让我们来看一下这几个概念。
对象是一种数据结构。 它既含有结构化的信息又含有相关的操作。一个
对象可以含有另外一个对象。通过这种方式,对象被赋予数据特征和行为,
因此,使用面向对象程序能够更好地反映程序欲模拟的现实世界。多态本质
上就是使用一个名字来描述几个相关但又有所区别的目的。继承就是一个对
象获得另一个对象的特征的过程。这一点非常重要,因为它支持分类的概念。
例如,一个美味可口的红苹果是苹果类的一员,而苹果又是水果类的一部分,
再进一步,水果又是食物这更高一级类的一部分。
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