电子信息类专业英语unit8computerbasics.ppt

Unit 8 Computer Basics,Text Key words Technical terms Expressions Notes to the text,Text We can define a computer as a device that accepts input, processes data, stores data, and produces output. According to the mode of processing, computers are either analog or digital. They can be classified as mainframes, minicomputers, workstations, or microcomputers. All else (for example, the age of the machine) being equal, this categorization provides some indication of the computer’s speed, size, cost, and abilities.,,,Ever since the advent of computers, there have been constant changes. First-generation computers of historic significance, such as UNIVAC, introduced in the early 1950s, were based on vacuum tubes. Second-generation computers, appearing in the early 1960s, were those in which transistors replaced vacuum tubes. In third-generation computers, dating from the 1960s, integrated circuits replaced transistors. In fourth-generation computers such as microcomputers, which first appeared in the mid-1970s, large-scale integration enabled thousands of circuits to be incorporated on one chip. Fifth-generation computers are expected to combine very-large-scale integration with sophisticated approaches to computing, including artificial intelligence and true distributed processing.,,Computer architecture, in computer science, is a general term referring to the structure of all or part of a computer system. The term also covers the design of system software, such as the operating system (the program that controls the computer), as well as referring to the combination of hardware and basic software that links the machines on a computer network. Thus, computer architecture covers computer systems, microprocessors, circuits, and system programs.,,There are five major elements that make up the system’s hardware: the arithmetic/logic unit, control unit, memory, input, and output. The arithmetic/logic unit performs arithmetic and compares numerical values. The control unit directs the operation of the computer by taking the user instructions and transforming them into electrical signals that the computer’s circuitry can understand. The combination of the arithmetic/logic unit and the control unit is called the central processing unit (CPU). The memory stores instructions and data. The input and output sections allow the computer to receive and send data, respectively.,,In addition to the hardware design, the architects must consider what software programs will operate the system. Software, such as programming languages and operating systems, makes the details of the hardware architecture invisible to the user.,,Operating systems for micro, mini, and mainframe computers perform many services. These services can be classified either as“external”or “internal.” The operating system provides external services that help users start programs, manage stored data, and maintain security. The operating system also provides internal services“behind the scenes”to ensure that the computer system functions efficiently. The operating system controls input and output, allocates system resources, manages the storage space for programs and data, and detects equipment failure without any direction from you.,,A programming language is a language used to write instructions for the computer. It lets the programmer express data processing in a symbolic manner without regard to machine-specific details. As programming languages became more powerful and abstract, building efficient compilers that create high-quality code in terms of execution speed and storage consumption became an interesting computer science problem in itself. A compiler, in computer science, is a computer program that translates source code into object code.,,,Key words classify vt. 分类, 分等 mainframe n. [计]主机；大型机 minicomputer n. 微机；小型机 workstation n. 工作站 categorize v. 分类 significance n. 意义，重要性 sophisticated adj. 诡辩的，久经世故的 artificial adj. 人造的，假的 intelligence n. 智力，聪明，智能 hardware n. (电脑的)硬件 software n. 软件,,microprocessor n. [计]微处理器 arithmetic n. 算术，算法 memory n. 存储器，内存 circuitry n. 电路，线路 architecture n. 体系结构，架构 invisible adj. 看不见的，无形的 allocate vt. 分派，分配 symbolic adj. 象征的，符号的 compiler n. [计] 编译器 execution n. 实行，完成，执行,,,Technical terms UNIVAC(universal automatic computer) 通用自动计算机 vacuum tube 真空管 artificial intelligence 人工智能 very-large-scale integration 超大规模集成 operating system 操作系统 the arithmetic/logic unit 算术逻辑单元 central processing unit (CPU) 中央处理器,,,Expressions be classified as. 分类为… ever since 自从 be based on 基于 referring to 参照；指的是 make up 构成 regard to 关注,,,Notes to the text 1. First-generation computers of historic significance, such as UNIVAC(通用自动计算机), introduced in the early 1950s, were based on vacuum tubes. 具有历史意义的第一代计算机，比如UNIVAC，发明于20世纪50年代，是基于真空管制造的。

句中“such as UNIVAC”为插入语，“introduced in the early 1950s”为非限制性定语从句，修饰前面的“UNIVAC”，省略引导词“which”2. The control unit directs the operation of the comput。