计算机专业英语.doc

Unit 1 Computer OverviewText AFoundation of ComputersComputer is electronic equipment which can make arithmetic and logical calculation, process information rapidly and automatically.It was in 1946 that the first computer of the world was invented in America, it is named ENIAC. Though it was very huge and without high performance, it made basis for the development of computers.Since the first computer was born, the development of computer science technique has been quite surprising. Take the speed of calculation for instance, ENIAC could only make calculations 5,000 times per second; but today, the fastest computer can do 100,000,000,000 times. Computers can process various tasks in a variety of areas, such as industry, agriculture, finance, transportation, culture and education, national, defense and family use. In summary, applications of computers may be classified as follows.Science CalculationThe purpose of inventing and developing computer is to make arithmetic calculation rapidly and accurately. Computers can be used for all kinds of science calculation, which have become one of the most important fields of computer application, for example, calculations in the process of launching satellites and missiles, etc.Data ProcessingWith the development of science and technology, more and more information including numerical data and non- numerical data comes out. At present, data processing is the widest field of computer application. Production management, data counting, office automation, traffic dispatching, information retrieval all belong to this field. Especially in recent years, with the development of the database and computer network technique, computer users in different districts and countries can share many valuable information resources through the network.Real-Time ControlReal-time control is the control of procedure in the process of practical productions where computers are applied. Real-time means that the time of computers calculating and controlling may match the time of controlled objects practical running or working.Adjuvant DesignWith its strong ability in calculating and mapping, we can use the computer to improve the quality and efficiency when doing engineering designs in the matter of architecture, machinery and electron. At present, as CAM, CAD and CAI being used very widely, complete automation from design to production has been achieved in many fields.Artificial IntelligenceComputers can simulate peoples feelings and thoughts, replacing part labors of human beings.Text BThe History of Computers While computers are now an important part of the lives of human beings, there was a time when computers did not exist. Knowing the history of computers and how much progress has been made can help you understand just how complicated and innovative the creation of computers really is. Unlike most devices, the computer is one of the few inventions that do not have one specific inventor. Throughout the development of the computer, many people have added their creations to the list required to make a computer work. Some of the inventions extend the types of computers, while others help computers to be further developed. oJ. The Beginning Perhaps the most significant date in the history of computers is the year 1936. It was in this year that the first computer was developed. It was created by Konrad Zuse and dubbed the Z1 Computer. This computer stands as the first as it was the first system to be fully programmable. There were devices prior to this, but none had the computing power that sets it apart from other electronics. It wasnt until 1942 that any business saw profit and opportunity in computers. This first company was called ABC computers, owned and operated by John Atanasoff and Clifford Berry. Two years later, the Harvard Mark I computer was developed, furthering the science of computing. Over the course of the next few years, inventors all over the world began to search more into the study of computers, and how to improve upon them. Those next ten years say the introduction of the transistor, which would become a vital part of the inner workings of the computer, the ENIAC I computer, as well as many other types of systems. The ENIAC I is perhaps one of the most interesting, as it required 20 000 vacuum tubes to operate. It was a massive machine, and started the revolution to build smaller and faster computers. The age of computers was forever altered by the introduction of International Business Machines, or IBM, into the computing industry in 1953. This company, over the course of computer history, has been a major player in the development of new systems and servers for public and private use. This introduction brought about the first real signs of competition within computing history, which helped to spur faster and better development of computers. Their first contribution was the IBM 701 EDPM Computer . .J. A Programming Language Evolves A year later, the first successful high level programming language - FORTRAN was created. This was a programming language not written in assembly or binary, which are considered as very low level languages. FORTRAN was written so that more people could begin to program computers easily. The year 1955, the Bank of America, coupled with Stanford Research Institute and General Electric, saw the creation of the first computers for use in banks. The MICR, or Magnetic Ink Character Recognition, coupled with the actual computer, the ERMA, was a breakthrough for the banking industry. It wasnt until 1959 that the pair of systems was put into use in actual banks. In 1958, one of the most important breakthroughs in computer history occurred, the creation of the integrated circuit. This device, also known as the chip, is one of the base requirements for modern computer systems. On every motherboard and card within a computer system, are many chips that contain information on what the boards and cards do. Without these chips, the systems as we know them today cannot function . .J. Gaming, Mice & the Internet For many computer users now, games are a vital part of the computing experience. 1962 saw the creation of the first computer game, which was created by Steve Russel and MIT, which was dubbed Spacewar. The mouse, one of the most basic components of modern computers, was created in 1964 by Douglass Engelbart. It obtained its name from the tail leading out of the device. One of the most important aspects of computers today was invented in 1969. ARPA net was the original Internet, which provided the foundation for the Internet that we know today. This development would result in the evolution of knowledge and business across the entire planet. It wasnt until 1970 that Intel entered the scene with the first dynamic RAM chip, which resulted in an explosion of computer science innovation. On the heels of the RAM chip was the first microprocessor, which was also designed by Intel. These two components, in addition to the chip developed in 1958, would number among the core components of modern computers. A year later, the floppy disk was created, gaining its name from the flexibility of the storage unit. This was the first step in allowing most people to transfer bits of data between unconnected computers. The first networking card was created in 1973, allowing data transfer between connected computers. This is similar to the Internet, but allows for the computers to connect without use of the Internet. -J. Household PCs Emerging The next three years were very important for computers. This is the time when companies began to develop systems for the average consumers. The Scelbi, Mark-8 Altair, IBM 5100, Apple I and II, TRS-80, and the Commodore Pet computers were the forerunners in this area. While expensive, these machines started the trend for computers within common households. One of the most major breakthroughs in computer software occurred in 1978 with the release of the VisiCalc Spreadsheet program. All development costs were paid for within a two-week period of time, which makes this one of the most successful programs in computer history. 1979 was perhaps one of the most important years for the home computer users. This is the year that WordStar, the first word processing program, was released to the public for sale. This drastically altered the usefulness of computers for the everyday users. The IBM home computer quickly helped revolutionize the consumer market in 1981, as it was affordable for home owners and standard consumers. 1981 also saw the megagiant Microsoft enter the scene with the MS-DOS operating system. This operating system utterly changed computing forever, as it was easy enough for everyone to learn. -J. The Competition Begins: Apple vs Microsoft Computers saw yet another vital change during the year of 1983. The Apple Lisa computer was the first with a graphical user interface, or a GUI. Most modern programs contain a GUI, which allows them to be easy to use and pleasing for the eyes. This marked the beginning of the out-dating of most text-based only programs. Beyond this point in computer history, many changes and alterations have occurred, from the Apple-Microsoft wars, to the developing of microcomputers and a variety of computer breakthroughs that have become an accepted part of our daily lives. Without the initial first steps of computer history, none of those would have been possible. Unit 2 Text AMicroprocessor Progression: IntelThe following table (Table2-1) helps you to understand the differences between the different processors that Intel has introduced over the years.Table 2-1Information about this table: The date is the year that the processor was first introduced. Many processors are re- introduced at higher clock speeds for many years after the original release date. Transistors is the number of transistors on the chip. You can see the number of transistors on a single chip has risen steadily over the years. Microns is the width, in microns, of the smallest wire on the chip. For comparison, a human hair is 100 microns thick. As the feature size on the chip goes down, the number of transistors rises. Clock speed is the maximum rate that the chip can be clocked at, Clock speed will make more sense in the next section. Date Width is the width of the AUL. An 8-bit AUL can add/subtract/multiply etc. Two 8-bit numbers, while a 32-bit AUL can manipulate 32-bit numbers. An 8-bit AUL world have to execute four instructions to add two 32-bit numbers, while a 32-bit AUL can do it in one instruction. In many cases, the external data bus is the same width as the AUL, but not always. The 8 088 had a 16-bit AUL and 8-bit bus, while the modern Pentiums fetch data 64 bits at a time for their 32-bit AULs. MIPS stands for “Millions of Instructions Per Second” and is a rough measure of the performance of a CPU. Modern CPUs can do so many different things the MIPS ratings lose a lot of their meaning, but you can get a general sense of the relative power of the CPUs from this column. From table 2-1 you can see that, in general, there is a relationship between clock speed and MIPS. The maximum clock speed is a function of the manufacturing process and delays within the chip. There is also a relationship between the number of transistors and MIPS. For example, the 8 088 clocked at 5 MHz but only executed at 0.33 MIPS (about one instruction per 15 clock cycles). Modern processors can often execute at a rate of two instructions per clock cycle. The improvement is directly related to the number of transistors on the chip and will make more sense in the next section.Text B Memory The memory is that part of a computer in which programs and data are stored. The term memory is usually used to refer to the internal storage locations of computer. It is also called real storage or primary storage, and is measured as quantities of K. Each K is equal to 1,024 bytes, and each byte is equal to 8 bits. The principal function of the main memory is to act as an intermediary between the CPU and the rest of the computer system components. It functions as a sort of desktop on which you place the things needed when you begin to work. The CPU can only utilize those software instructions and data that are stored in main memory. As you know, the main memory is a random access memory, or RAM. The name derives from the fact that data can be stored and retrieved at random from anywhere in the electronic main memory chips in approximately the same amount of time, no matter where the data is. The main memory is in an electronic, or volatile state. When the computer is off, the main memory is empty; when it is on, the main memory is capable of receiving and holding a copy of the software instructions and data necessary for processing. Since main memory is a volatile form of storage that depends on electric power and the power can go off during processing, users often save their work frequently onto nonvolatile secondary storage devices such as diskettes or hard disks. In general, the main memory is used for the following purposes: Storage of a copy of the main software program that controls the general operation of the computer. This copy is loaded into the main memory when the computer is turned on (you will find out how later) , and it stays there as long as the computer is on. Temporary storage of a copy of application program instructions (the specific software you are using in your business) to be retrieved by the CPU for interpretation and execution. Temporary storage of data that was input from the keyboard or other input device until instructions call for the data to be transferred into the CPU for processing . Temporary storage of data that has been produced as a result of processing until instructions call for the data to be used again in subsequent processing or to be transferred to an output device such as the screen, a printer, or a disk storage device. Several kinds of semiconductor memory chips are used in primary storage. Each serves a different purpose . .J. Random-Access-Memory Random-Access-Memory (RAM) is used for short-term storage of data or program instructions. The contents of RAM can be read and changed when required. RAM is volatile, which means that if the computer s electricity supply is disrupted or the computer is turned off, its contents will be lost. Thus, RAM can be used only as a temporary storage . .J. Read-Only Memory Because of the advantages in small semiconductor memories, there is a trend in recent years to build some software functions directly into computer chips. Like RAM, these electronic chips are mounted on boards inside the system unit. Once placed on these chips, programs can be accessed very rapidly. On many microcomputers for example, the operating system is built onto a chip rather than being stored on a floppy disk. This kind of software in hardware is called firmware. Several kinds of firmware are available. Read-only Memory (ROM) is by far the most common form of firmware. A ROM module contains a program supplied by the manufacture. The program can be read from the module, but it is impossible for a user to destroy the contents of the module by accidentally writing over them (hence read-only ) . .J. Programmable ROM ( PROM) Like ROM, the Programmable ROM (PROM) is nonvolatile and may be written into only once. For the PROM, the written process is performed electrically by a supplier or customer later than the original chip fabrication. Special equipment is required for the writing or programming process. PROM can provide flexibility and convenience . .J. Erasable Programmable Read-Only Memory (EPROM) EPROM can be read and written electrically, as with PROM. However, before the writing operation, all the storage cells of the chip must be erased to the same initial state by exposure to ultraviolet radiation. This erasure process can be performed repeatedly; each erasure can take as much as 20 minutes to perform. Thus, the EPROM can be rewritten multiple times, and like the ROM and PROM, holds its data indefinitely. For comparable amounts of storage, the EPROM is more expensive than PROM, but it has the advantage of multiple-update capability. .J. Electrically Erasable Programmable Read-Only Memory (EEPROM) EEPROM can be written at any time without erasing prior contents, only the byte or bytes addressed are updated. The writing operation takes considerably longer than the reading operation, about several hundred microseconds per byte. The EEPROM combines the advantage of nonvolatile with the flexibility of being updateable in place, using ordinary bus control, address, and data lines. EEPROM is more expensive than EPROM and is also less dense, supporting fewer bits per chip . .J. Flash Memory The newest form of semiconductor memory is the flash memory (so named because of the speed with which it can be reprogrammed). First introduced in the mid1980s, flash memory is an intermediate between EPROM and EEPROM in both its cost and functionality. Like EEPROM, flash memory uses an electrical erasing technology. An entire flash memory can be erased in one or a few seconds, which is much faster than EPROM. In addition, it is possible to erase just blocks of memory rather than an entire chip. However, flash memory does not provide byte-level erasure. Like EPROM, flash memory uses only one transistor per bit, and so achieves the same density (compared with EEPROM) with EPROM . .J. Cache Memory Some computers are designed with cache memory to increase the speed of transfer of instructions and data from secondary storage to the processor. Like RAM, cache memory is essentially a high-speed temporary storage,