机械工程英语part2所有单元翻译.docx
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机械工程英语part2所有单元翻译.docx
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Part02Unit01Computer Technologies
Introduction导言
The central and essential ingredient of CAD/CAM is the digital computer.
CAD/CAM最重要的组成部分是数字计算机。
Its inherent speed and storage capacity have made it possible to achieve the advances is image processing,realtime process control,and a multitude of other important functions that are simply too complex and time-consuming to perform manually.
数字计算机固有的速度及其存储能力使得CAD/CAM进行图像处理,实时控制以及其他许多重要功能若手工操作复杂又耗时能简单得进行成为可能。
To understand CAD/CAM,it is important to be familiar with the concepts and technoloty of the digital computer.
想要掌握CAD/CAM,熟悉数字计算机技术及理论是非常重要的。
The modern digital computer is an electronic machine that can perform mathematical and logical calculations and data processing functions in accordance with a predetermined program of instructions.
现代数字计算机是一种可以根据预先设定的程序指令进行逻辑数据运算以及数据处理功能的电子仪器。
The computer itself is referred to as hardware,whereas the various programs are referred to as software.
计算机本身称为硬件,而各种各样的程序都被称为软件。
There are three basic hardware components of a general-purpose digital computer:
通用的数字计算机有如下三个基本组成设备:
●Central processing unit (CPU)中央处理单元(CPU)
●Memory记忆单元
●Input/output (I/O) section输入/输出单元
The relationship of these three components is illustrate in Fig.1.1.The central processing unit is often considered to consist of two subsections:
a control unit and an arithmetic-logic unit (ALU).
三个设备的相关关系如图1.1所示。
中央处理单元往往被认为是由两个子单元组成:
控制单元和数据逻辑单元(ALU)。
The control unit coordinates the operations of all the other components.It controls the input and output of information between the computer and the outside world through the I/O section.
控制单元协调其他所有组件的操作,控制单元通过I/O部分控制计算机与外部环境信息的输入与输出。
Synchronizes the transference of the signals between the various sections of the computer,and command the other sections in the performance of their functions.The arithmetic-logic unit carries out the arithmetic and logic manipulations of data.It adds,substracts,multiplies,divides,and compares numbers according to programmed instructions.
指挥其他部分执行各自的功能。
数字逻辑单元控制数据的运算和逻辑操作。
根据程序指令进行加,减,乘,除以及数字的比较。
The memory of the computer is the storage unit.The data stored in this section are arranged in the form of words which can be conveniently transferred to the ALU or I/O section for processing.
计算机的记忆单元是计算机的存储单元,数据以方便传输至ALU单元或者I/O部分并进行处理的语音形式存储在这一部分。
Finally,the input/output provides the means for the computer to communicate with the external world.This communication is accomplished
through peripheral equipment such as
readers,printers,and process interface devices.
最后,输入/输出单元提供计算机与外部设备交互的方式。
这一交互是通过周边设备如读取器、打印机和过程控制接口设备实现的。
The computer may also connected to external storage units(e.g.tapes,didks,etc.) through the I/O section of the computer.
计算机也可以通过计算机的I/O部分连接外部存储单元(如磁带,磁盘等)。
The software consists of the program and instructions stored in memory and in external storage units.It is the software that assigns the various functions which the user desires the system to accomplish to the computer.The useful of the computer's memory can be easily changed.and therefore different programs can be placed into memory,the digital computer can be used for a wide variety of applications.
软件包括存储在内部和外部存储单元的程序和指令。
软件分配执行各种各样用户希望计算机去执行的功能。
有用的计算机内存可以很容易改变并且因此不同的程序可以放置进内存,数字计算机可以广泛应用于各种各样不同的场合。
Regardless of the application,the computer executes the program through its ability to manipulate data and numbers in their most elementary form.The data and numbers are represented in the computer by electrical signals which can take one of two alternative states.This form of representation is called the binary system.The more familiar decimal number system and a whole host of software languages can utilize the binary system to permit communication between computers and human beings.
不管应用于哪种场合,计算机总是通过计算机本身最基本的操作数据和编号形式执行程序。
在计算机中数据及编号是通过在两种不同状态的电信号中选择一种状态表示的。
这种形式的表现被称为二进制系统。
更熟悉的十进制系统和许多软件语言可以利用二进制允许计算机和人之间的交互。
Central Processing Unit(CPU)中央控制单元
The central processing unit(CPU) regulates the operation of all system components and performs the arithmetic and logical operations on the data.To accomplish these functions,the CPU consists of two operating units:
●Control unit
●Arithmetic-logic unit(ALU)
中央控制单元(CPU)的功能是控制所有系统部件的运行和对数据进行数字的或是逻辑的操作。
为了完成上述功能,CPU由以下两个单元组成:
●控制单元
●数字逻辑单元
The control unit coordinates the various operations specified by the program instructions.
These operations include receiving data which enter the computer and deciding how and when the data should be processed.The control unit directs the operation of the arithmetic-logic unit,It sends data to the ALU and tells the ALU what functions to perform on the data and where to store the results.The capability of the control unit to accomplish these operations is provided by a set of instructions called an executive program which is stored in memory.
控制单元通过程序指令来协调大量的特种操作,这些操作包括接受输入计算机的数据,并决定何时和以何种方法来处理这些数据。
控制单元能指挥数字逻辑单元的操作,他把数据发送给ALU来告诉ALU根据这些数据该运行什么功能,并且在哪里把结果存储下来。
控制单元完成上述操作的能力基于其安装了一个具有储存与记忆功能的总控程序机构。
The arithmetic-logic unit performs opertaions such as addition,substractions,and comparisons.These operations are carried out on data in binary form.The logic section can also be used to alter the sequence in which instructions are executed when certain conditions are indicated and to perform other functions,such as editing and masking data for arithmetic operations.
数字逻辑单元运行诸如加减比较之类的操作。
这些操作是根据数据以二进制的形式表现出来的。
在指示了确定的条件下,逻辑部也可以用来改变命令执行的次序。
此外,逻辑部分还具有在算术过程中编辑或清除数据等功能。
Both the control unit and the arithmetic-logic unit perform their functions by utilizing registers.Computer registers are small memory devices that can receive,hold,and transfer data.
Each register consists of binary cells to hold bits of data.The number of bits in the register establishes the word length with which the computer is capable of handling.The number of bits per word can be as few as4(early microcomputer) or as many as64(large scientific computers).
控制单元和数字逻辑单元都是得用寄存器来完成他们的功能的,计算机寄存器是一个可以接收短暂存储,转移数据的小记忆装置。
每个寄存器内包含有二进制小单元以来暂存二进制数据。
根据计算机能力的不同,寄存器能建立出相应的字节数的字长。
每个词的字节数从4(早期微型计算机)到64(大型科研计算机)不等。
Computer Programming Languages计算机程序语言
The binary number system could be used to represent any decimal number,alphabetic letter,or other common symblo.Data and instructions are communicated to the computer in the form of binary words.In executing a program.the computer interprets the configuration of bits as an instruction to perform electronic operations such as add,subtract,load into memory,and so forth.The sequence of these binary-coded instructions defines the set of calculations and data manipulations by which the computer executes program.
二进制数字系统可以用于表示任意的十进制数据,字,或者其他相类似的代表性数据并且指令是以二进制的形式与计算机进行连接。
在执行一个程序时,一个指令进行电子操作,如加、减、加载内存,等等时计算机就会翻译指令的字节结构。
这些二进制编码指令的序列定义了计算和数据操纵是由计算机的哪条程序执行。
The binary-coded instructions that computers can understand are called machine
language.Unfortunately,binary-coded instructions and data are very difficult for human programers to read or wirte.Also,different machines use different machine languages.To facilitate the task of computer programming,higer-level languages are available which can be learned with relative ease by human beings.In all there are three levels of computer programming languages:
●Machine languages
●Assembly languages
●Procedure-oriented(high-level) languages.
计算机能识别的二进制编码指令叫机器语言,不幸的是,二进制编码指令和数据,人类程序员是难以去读和写的。
另外,不同的机器应用不同的程序语言,为使计算机编程任务变得简单,高级语言可供选择,可以较容易地学习的人。
总共有三种不同计算机程序语言。
●机器语言
●汇编语言
●面象过程语言(高级语言)
Machine and Assembly languages机器与汇编语言
The language used by the computer is called machine language.It is written in binary,with each instruction containing an operation code and an operand.The operand might be a memory address,a device address,or data.In machine language programming,storage locations are designated for the program and data,and these are used throughout the programming to refer to specific data or program steps.In addition,the programmer must be familiar with the specific computer system since machine language instructions are different for each computer.
Programming in machine language is tedious,complicated,and time-consuming.To alleviate the difficulties in writing programs in binary,symbolic languages have been developed which substitute an English-like mnemonics for each binary instruction.Mnemonics are easier to be remembered than binary,so they help speeding up the programming the process.A language consisting of mnemonic instructions is called an assembly language.
计算机运用的语言叫机器语言。
运用二进制进行编写。
每个指令都包含有一个操作码和操作数。
操作数可以是一个内存地址,一个设备地址或者是数据。
在机械语言程序中,存储单元指定程序和数据,并且这种指定应用于整个程序以指向特定的数据或者程序步。
此外,每个程序员必须熟悉特定的计算机系统因为每种计算机的机器语言指令是彼此不同的。
机器语言编程是乏味的,复杂、而且耗费时间的。
为了减轻在编写二进制程序的困难,符号语言已经开发出一种每一个英语助记符代替二进制指令。
助记符比起二进制是比较容易记忆的,所以它们帮助提高程序的处理速度。
包含有助词符指令的语言叫做汇编语言。
Assembly languages are considered to be low-level languages.The programmer must be very knowledgeable about the computer and equipment being programmed.Low-level languages are the most efficient in terms of fast execution on the computer,but there are obvious difficulties for the programmer in writing large programs for various applications using different computers.
汇编语言也被认为是低级语言,程序员必须对计算机语言及被编制设备有相当的了解。
在计算机中低级语言能最有效的快速的执行。
但是让程序员运用不同的计算机为各种各样的场合编写大量的程序有明显的难度。
Assembly language programs must be converted into machine language before the
computer can execute them.The conversion is carried out by a program called an assembler.The assembler takes the assembly language program.performs the neccessary conversions,and produces two new programs;the machine language version and an assembly listing.The assembly listing shows mnemonic instructions and their associated machine laguage equivalents.and any erros the original assembly language program may have contained.
在计算机能运行汇编语言程序之前,汇编语言程序必须转换为相应的机器语言,一种叫汇编器的程序完成这一转换。
汇编器将汇编语言程序进行必要的转换,并产生两种新的程序:
机器语言版本和汇编列表。
汇编列表显示与机器语言相对应的助词符。
并且任何原始的汇编语言程序错误都会包含在其中。
High-level Language高级语言
Assembly languages are machine oriented.High-level languages,by constrast.are
procedure oriented.They are to a large exte
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