计算机专业英语相关素材.doc

“计算机专业英语”课程教学相关素材阅读材料1Computer and MicrocomputerA computer is a machine with an intricate network of electronic circuits that operate switches or magnetized tiny metal cores. A total computer system includes both hardware and software. Hardware consists of the physical components and all associated equipment. Software refers to the programs that are written for the computers.It is possible to be familiar with various aspects of computer software without being concerned with details of how the computer hardware operates. It is also possible to design parts of the hardware without a knowledge of its software capabilities. However those concerned with computer architecture should have a knowledge of both hardware and software because the two branches influence each other.A program written by a user may be either dependent or independent of the physical computer that runs his program. For example, a program written in standard FORTRAN is machine independent.A computer can solve a series of problems and make hundreds, even thousands, of logical decisions without becoming tired or bored. It can find the solution to a problem in a fraction of the time it takes a human being to do the job. A computer can replace people in dull, routine tasks, but it has no originality; it works according to the instructions given to it and cannot exercise any value judgements. But a computer can carry out vast numbers of arithmetic logical operations almost instantaneously.Microcomputers, or micro for short, is a kind of computers. It was born in the early 1970s. The central processor of the micro, called the microprocessor, is built as a single semiconductor device; that is, the thousands of individual circuit elements necessary to perform all the logical and arithmetic functions of a computer are manufactured as a single chip. A complete microcomputer system is composed of a microprocessor, a memory and some peripheral equipment. The processor, memory and electronic controls for the peripheral equipment are usually put together on a single or on a few printed circuit boards. Systems using microprocessors can be hooked up together to do the work that until recently only minicomputer systems were capable of doing. Micros generally have somewhat simpler and less flexible instruction sets than minis, and are typically much slower. Different micros are available with 4-, 8-, 12-, 16-bit word lengths. Similarly, minis are available with much larger primary memory sizes. Micros are becoming more powerful and converging with minicomputer technology.翻译1计算机和微型计算机计算机是一种具有复杂电路网络的机器，其电路可控制开关或磁化微小的金属磁心。一个完整的计算机系统应包括硬件和软件两部分，硬件由物理元件和所有相关设备组成；软件则是为计算机所写的程序。即使不了解计算机硬件的工作细节，也可以通晓计算机软件的各种特性；同样，不懂计算机软件也可以设计硬件部分。但是，一旦涉及计算机体系结构，就必须同时具有硬件和软件两方面的知识，因为这两个分支是相互影响的。用户所写的程序，可以依赖，也可以独立于运行这个程序的具体计算机。例如，用标准FORTRAN语言所编写的程序就是独立于机器的。计算机能够解决一系列问题，作出成百甚至上千个逻辑判定而不感到疲劳和厌烦。计算机能够在人类做这项工作所需的一小部分时间内，就找到问题的答案。计算机可以代替人们做那些单调的日常工作，但是它没有创造力；计算机根据给它的指令工作，而不能行使任何意义的判断。但是计算机几乎在瞬间就可以处理大量的算术逻辑运算。微型计算机或简称微型机是计算机的一种。它诞生于70年代初期。称为微处理器的微机中央处理器是单片半导体装置。也就是说，实现计算机所有逻辑和算术功能所必不可少的成千上万个单独的电路元件都制造在一块芯片上。完整的微机系统由微处理器、存储器和外围设备组成。处理器、存储器和外围设备的电子控制装置通常一起放在一块或几块印刷电路板上。使用微处理器的系统可以在一起来做迄今为止只有小型计算机系统才能够做的工作。一般来说，微机的指令系统比小型机略为简单，灵活度稍低，而且特别是比小型机慢得多。微型机的字长不同，有4位、8位、12位和16位的。同样，小型机字长可达32位。尽管小型机可以装上较大的主存，但是微型机变得功能越来越强，并与小型机技术结合起来了。阅读材料2Types of MemoryThe memory unit is an essential component in any digit computer since it is needed for storing the programs that are executed by the CPU. A very small computer with a limited application may be able to fulfill its intended ask without the need of additional storage capability. However, most computers would run more efficiently if they are supplied with additional storage beyond the capacity of the main memory.There is just not enough space in one memory unit to accommodate all the systems programs written for a typical computer. Moreover, most computer installations accumulate and continue to accumulate large amounts of information.Not all computers have the same type of memory. The memory of the first computers was made up of a kind of grid of fine vertical and horizontal wires. At each intersection where the wires crossed, there was a small ferrite ring called a core (hence the name core memory) which was capable of being either magnetized or demagnetized. Every intersection had its unique address; consequently, when an electrical current was passed through the wires, the magnetized as well as the demagnetized cores were identified by their respective address. Each core represented a binary digit of either 0 or 1, depending on its state. Early computers had a capacity of around 80000 bits; whereas now, it is not surprising to hear about computers with a memory capacity of millions of bits. This has been made possible by the advent of transistors and by the advances in the manufacture of miniaturized circuitry. As a result, mainframes have been reduced in both size and cost. Throughout the 1950s, 1960s and up to the mid-1970s, core memory dominated the market.In the 1970s, there was a further development which revolutionized the computer field. This was the ability to etch thousands of integrated circuits onto a tiny piece (chip) of silicon, which is a non-metallic element with semiconductor characteristics. Chips have thousands of identical circuits, each one capable of storing one bit. Because of the very small size of the chip, and consequently of the circuits etched on it, electrical signals do not have to travel far; hence, they are transmitted faster. Moreover, the size of the components containing the circuitry can be considerably reduced, a step which has led to the introduction of both minis and micros. As a result, computers have become smaller, faster, and cheaper. There is one problem with semiconductor memory, however, when power is removed, information in the memory is lost, unlike core memory, which is capable of retaining information during a power failure.Another development in the field of computer memories is bubble memory. The concept consists of creating a thin film of metallic alloys over the memory board. When this film is magnetized, it produces magnetic bubbles, the presence or absence of which represents one bit of information. These bubbles are extremely tiny, about 0.1 micrometer in diameter. Therefore, a magnetic bubble memory can store information at a greater density than existing memories, which makes it suitable for micros. Bubble memories are not expensive, consume little power, are small in size, and are highly reliable.Magnetic disk storage looks rather like a juke-box but instead of records, which have only one track on each side, the disks are metal and coated on each side with magnetic material and have as many as 500 concentric tracks per side, each track usually stores one block.The disks are mounted on a vertical shaft with spaces between them to allow the insertion of an arm with two read / write heads, one for the upper disk and the other for the lower. The shaft and disks rotate at about forty revolutions per second. 翻译2存储器的种类任何一台数字计算机都需要存储CPU（中央处理器）所执行的程序，因此，存储器是计算机最重要的部件之一。一台应用于有限范围的很小的计算机，不扩充其存储容量，也可以满足进一步的请求。但是，大多数计算机在扩充原有主存储容量后，运行效率更高。对一台典型的计算机而言，一个存储器的空间不足以容纳其全部系统程序。而且，大多数计算机越来越聚集了大量的信息。并不是所有的计算机都有同样类型的存储器。最初的计算机存储器是由纤细的横竖导线组成的格栅构成。每两根导线的交叉点处有一个称为磁心的小铁氧环（所以取名为磁心存储器）。磁心能够被磁化或去磁。每一个交叉点有自己特定的地址。因而当电流通过导线时，被磁化以及被去磁的磁心根据它们自己的地址而被识别出来。每个磁心代表一个二进制数，不是0就是1，依它的状态而定。早期计算机的存储量大约为80000位。而现在，听到计算机的存储量为上百万位是不足为奇的。晶体管的出现和小型化电路生产的改进已使之成为可能。其结果是主机的体积减小且成本降低了。在整个50年代、60年代一直到70年代中叶，磁心存储器的销路占很大优势。在70年代，计算机有了进一步的发展，使计算机领域发生了一场革命。这就是将上万个集成电路蚀刻在一小块硅（芯）片上的能力。硅片是具有半导体特性的非金属元件。芯片上具有成千上万个相同的电路。每个电路能存储一位。由于芯片很小，且电路蚀刻在芯片上，电信号无需行进很远，因此它们传输得较快。此外，装有电路的部件体积可以大大减小，这一进步已导致了小型机和微型机的引入。其结果是计算机体积变小，速度加快，价格更便宜。可是半导体存储器有一个问题。当电源切断时，存储器里的信息就丢失了，而不像磁心存储器，在断电时还能保留信息。计算机存储器领域里的另一发展是磁泡存储器，它的原理是在存储板上形成一层金属合金薄膜。当这层膜被磁化时，就生成磁泡。磁泡的出现和消失代表一位信息的状态，这些磁泡非常小，直径大约为0。1微米。所以，磁泡存储器能以比现在的存储器更大的密度常常信息，这使它适用于微型机。磁泡存储器造价不高，电能消耗小，体积小，可靠性高。磁盘存储器看起来很像一个投币式的自动点唱机，但它装的不是唱片。唱片每面只有一道唱纹，而磁盘则是用金属制成的，两面都涂有磁性材料，每面的同心磁道多达500道，而一道通常存储一个字块。这些磁盘片安装在一个竖轴上，盘片与盘片之间留有间隙，以便一个取数臂伸入其间。每一取数臂上装有两个读/写头，一个用于上面盘，一个用于下面盘。竖轴和磁盘每秒钟大约旋转40转。阅读材料3Buses: Connecting I/O Devices to Processor and MemoryIn a computer system, the various subsystems must have interfaces to one another. For example, the memory and processor need to communicate, as do the processor and the I/O devices. This is commonly done with a bus. A bus is a shared communication link, which uses one set of wires to connect multiple subsystems. The two major advantages of the bus organization are versatility and low cost. By defining a single connection scheme, new devices can easily be added, and peripherals can even be moved between computer systems that use the same kind of bus. Furthermore, buses are cost effective, because a single set of wires is shared in multiple ways.The major disadvantage of a bus is that it creates a communication bottleneck, possibly limiting the maximum I/O throughput. When I/O must pass through a single bus, the bandwidth of that bus limits the maximum I/O throughput. In commercial systems, where I/O is very frequent, and in supercomputers, where the I/O rates must be very high because the processor performance is high. Designing a bus system capable of meeting the demands of the processor as well as connecting large numbers of I/O devices to the machine presents a major challenge.One reason bus design is so difficult is that the maximum bus speed is largely limited by physical factors: the length of the bus and the number of devices. These physical limits prevent us from running the bus arbitrarily fast. Within these limits, there are a variety of techniques we can use to increase the performance of the bus; however, these techniques may adversely affect other performance metrics. For example, to obtain fast response time for I/O operations, we must minimize the bus latency by streamlining the communication path. On the other hand, to sustain high I/O data rates, we must maximize the bus bandwidth. The bus bandwidth can be increased by using more buffering and by communicating larger blocks of data, both of which increase the bus latency! Clearly, these two goals, low latency and high bandwidth can lead to conflicting design requirements. Finally, the need to support a range of devices with widely varying latencies and data transfer rates also makes bus design challenging.A bus generally contains a set of control lines and a set of data lines. The control lines are used to signal requests and acknowledgments, and to indicate what type of information is on the data lines. The data lines of the bus carry information between the source and the destination. This information may consist of data, complex commands, or addresses. For example, if a disk wants to write some data into memory from a disk sector, the data lines will be used to indicate the address in memory in which to place the data as well as to carry the actual data from the disk. The control lines will be used to indicate what type of information is contained on the data lines of the bus at each point in the transfer, some buses have two sets of signal lines to separately communicate both data and address in a single bus transmission. In either case, the control lines are used to indicate what the bus contains and to implement the bus protocol.翻译3总线：连接I/O设备到处理器和存储器在一个计算机系统中，各种各样的子系统必须有接口相互连接。例如，存储器和处理器间需要通信，处理器和I/O设备间也一样。这通常由一条“总线”来完成。总线是共享的通信链路，它用一束通信线来连接多个子系统。总线结构的两个最主要的优点是：灵活性和廉价性。通过定义一种连接方式，可以很容易地增加新设备，甚至也可将外围设备在两个使用同种总线的计算机系统间搬动。此外，总线能被有效地使用，因为一条总线可以多种方式共享。总线的最大缺点是它产生通信瓶颈，可能限制最大的I/O流量。当I/O必须经过一条总线时，总线带宽限制了最大I/O流量。在I/O很频繁的商用系统中和因处理器的高性能而要求I/O速率也很高的超级计算机中，设计一个既能满足处理器要求、又能连接大量I/O设备的总线系统是一个重要的课题。总线设计如此困难的一个原因是，总线的速度很大程度上受物理因素限制：总线长度和设备数量。这些物理因素使我们不能以任意高速使用总线。在这些限制下，尽管我们可用许多技术来提高总线的性能，但是，这些技术也会相反地影响其它性能。例如，为获得较快的I/O响应时间，我们必须用流水线化通信路径来最小化总线延时。另一方面，为维持高速I/O数据速率，我们必须最大化总线宽度。使用更多的缓冲和用更大的数据块通信能增加总线宽度，但两者都增加总线的延时。显然，这两个目标，低延时和高带宽，会导致设计要求的冲突。最后，支持具有不同延时和数据传送速率的一定范围的设备的需要，也使总线设计成为困难。一条总线一般包括一束控制线和一束数据线。控制线被用于标记请求和应答，并且指出数据线上信息的种类。总线的数据线在源地和目的地间运送信息。这种信息可以包括数据、复杂命令和地址。比如，磁盘想要从某个扇区往内存中写数据，数据线就用于指明内存中的哪个地址用于存放数据，并且在实际上将数据从磁盘运输到内存，控制线用于指出传送的每一时刻数据线上都包括哪种类型的信息。一些总线有两束信号线，在一个总线传送中独立地传送数据和地址。在任何一种情况下，控制线都用于指出总线包括什么并且执行总线协议。阅读材料4MonitorMonitors maybe are one of the most important output devices. Computers only use monitors to show you exciting operation results or marvelous and vivid pictures. Monitors also are the best windows for conversation between users and computers. So, many users select monitors carefully. Which parameters or indexes ought be paid attention to when you select a monitor? We provide some here for your reference.Element DistanceThe distance between two picture elements in horizontal direction is called element distance here and its current value in most PC monitors is 0.28mm. if the value is smaller, the screen is more distinct.Video BandwidthIt is an important concept in monitor technology. It is related to the highest work frequency of the monitor. It is from tens MHz to hundreds MHz. Here is a formula for you to calculate the video bandwidth:Video bandwidth = row number column number frame-refreshed rateHere, row number = picture element number in one column; column number = picture element number in one row; frame-refreshed rate = frame change times per second.Example: let row number = 768, column number = =1024, frame-refreshed rate = 85 then video bandwidth = 768102485=66.85MHz.Vertical Scan Rate and Horizontal Scan FrequencyVertical scan sate is equal to frame-refreshed rate; horizontal scan frequency is what its name tells. The relationships between vertical scan rate, horizontal scan frequency and video bandwidth in non-interlace monitors are as follows:Vertical scan rate = video bandwidth / column number / row numberHorizontal scan frequency = video bandwidth / column number.So, only horizontal scan frequency is enough to measure the property of a monitor and it is between 50KHz and 90KHz.SolutionIt is an another important parameter of a monitor. Its higher, the view on a screen is clearer. Solution means the sum of all picture elements on a screen. The solution is 640 480 for 14inch monitors and 1024 768 for 17 inch monitors commonly.Scan StyleThe scan style of a electron gun in a tube is divided into two styles: interlace and non-interlace. In interlace style, electron-beam sweeps elements in odd rows first time and does elements in even rows second time. A frame to be renewed needs sweeping two times. In non-interlace style, electron-beam sweeps all elements only in one time. In non-interlace work style, the monitor works better and gives clear pictures without flash.翻译4显示器显示器可能是最重要的输出设备之一。计算机只能用它们来显示有趣的结果和神奇生动的画面。显示器也是人机对话的最好窗口，所以很多用户选择显示器时非常小心。当选择显示器时应该注意哪些参数和指标呢？这儿我们给出一些参数供你参考。像素距离两个像素水平方向的距离称为像素距离。目前大多数PC的流行像素距离是0.28毫米。这个值越小、屏幕越清晰。视频带宽它是监视器技术中一个很重要的概念，它关系到监视器的最高工作频率。它的范围从几十兆赫兹到几百兆赫兹。这里有个用来计算视频带宽的公式：视频带宽 = 行数 列数 刷新率其中，行数等于每列中像素的个数，列数等于每行中像素的个数，刷新率等于每秒钟画面的变化次数。例：设列数=768，行数=1024，刷新率=85，则视频带宽 = 768 1024 85 = 66.85MHz垂直扫描和水平扫描频率垂直扫描频率等于刷新率，水平扫描频率就是它名字所提示的。二者与视频带宽的关系在非隔行监视器下如下：垂直扫描频率=视频带宽 / 列数 / 行数水平扫描频率=视频带宽 / 列数所以，仅用水平扫描频率就足以度量监视器的性能，它的范围从50KHz到90KHz分辨率它是监视器的另一个重要参数，它的值越高，屏幕上的图像越清晰。分辨率表示一个屏幕上全部像素的总和。一般而言，14英寸的监视器的分辨率为640480，17英寸的监视器的分辨率为1024768。扫描方式显像管中的电子枪的扫描方式有两种：隔行和非隔行。在隔行方式中，电子射枪首先扫描奇数项中的像素，第二次再扫描偶数项中的像素。一帧画面的更新需扫描两次。在非隔行的方式中，电子射枪一次完成扫描全部像素。在这种工作方式中，监视器工作得更好而且图像清晰、不闪光。阅读材料5Hard DiskEvery user has used hard disks and liked them very much since they have gigantic storage capacity and work fast, especially since operating systems grow larger and larger. One example is Win98, with its full installation needing 300MB memory, long application programs and multimedia development need more and more storage space, etc. All of these spur the development of hard disks. The hard disk storage capacity almost is doubled every year and the hard disk works faster and faster.Ultra DSP is great advance in hard disk technology. Ultra DSP means Ultra Digital Signal Processor, the working speed of which is 1050 times as fast as the speed of CPU. It ameliorates hard disk functions and promotes hard disk speed and reliability much more.Cache technology is another advanced technology applied in hard disks. The CPU can read data directly from the cache and improved the access speed tremendously. The cache storage capacity is now between 512KB to 2MB.The average seek times is another significant index. The shorter it is, the better the hard disk. Users should prefer those with an index generally below 10 ms. The internal data transfer rate should also be paid attention to. The rate will affect the whole hard disk working speed.翻译5硬盘每个用户都用过硬盘而且很喜欢它，因为它有巨大的存储容量和快速的工作速度，特别是在操作系统愈来愈大的时代。如Windows 98，它的全部安装需要300MB存储空间，长的应用程序和多媒体的发展需要的存储空间愈来愈大等，所有这些都刺激了硬盘的发展。硬盘存储容量几乎每年都加倍增长而且工作速度越来越快。Ultra DSP是硬盘技术中很先进的技术。Ultra Digital Signal Processor的意思是超级数字处理器。它的工作速度510倍于CPU的工作速度。它改进了硬盘的性能且大大提高了硬盘的速度和可靠性。硬盘的另一个先进技术是高速缓冲技术。CPU能直接从高速缓冲器中读取数据并大大提高访问速度。现在的高速缓冲的存储量为512KB到2MB。平均寻道时间是另一个重要指标，它愈短，硬盘愈好。用户应选择该指标低于10ms的产品。也应注意内部数据传输率，它直接关系到硬盘的工作速度。阅读材料6Keyboard and DisplayThe basic input device on most microcomputer systems is a keyboard. As characters are typed, they are stored in main memory, and then copied from the memory to the basic output device - a display screen. The screen, often called a monitor, serves as a window on main memory, allowing the user to view its contents.Through the keyboard you “talk” to a computer. That is, it allows you to input information, instructions, or data to the computer. Keyboards vary considerably from system to system, but most look a lot like a standard typewriter keyboard. Many also have a numeric keypad on the right, which looks like the keypad on a 10-key adding machine. The keypad makes it easy to input large amounts of numerical data into the computer