计算机专业文档资料整理英文Word文件下载.docx

1、 The first automatic calculator was invented in 1642 by Blaise Pascal. However, none of devises should be compared to a computer because they could be programmed. A computer must not only calculate automatically, but it should also be possible to programme it. The first step in this direction was ta

2、ken in 1801 when Joseph Marie Jacquard invented a punch card that could be used for weaving. The card made sure that the threads went through in the right order. This is important, because computers use codes in order to work. By 1883, Charles Babbage invented the major parts of the mechanical compu

3、ter. DIFFERENT TYPES OF COMPUTERS;Past, Present, Future COLOSSUS COMPUTER The Colossus was a giant computer build by British Secret Service during World War II. It was build by an engineer called Tommy Flowers, and used vacuum tubes to perform the calculations. Colossus computers were used by the Br

4、itish to break the German codes. They were the worlds first programmable, digital, electronic, computing devices. Z3 COMPUTERS The Z3 computer was build by Konrad Zuse, between 1936 and 1941, in Germany. It was first reliable, freely programmable, working computer in the world, and was completely co

5、nstructed from 2000 relays. The Z3 contained almost all of the features of modern computer. The success of Zuses Z3is often attributed to its use of the simple binary system that is, all the data is stored in the form of just 2 numbers, 0 and 1. HARVARD MARK - I Many consider that the modern compute

6、r era commenced with the first large - scale automatic digital computer, which was developed between 1939 and 1944. This device, the brain child of Harvard graduate Howard. H. Aiken, was commonly referred to as the Harvard Mark I was constructed out of switches, relays, rotating shafts, and clutches

7、, and was described as sounding like a roomful of ladies knitting. The machine contained more than 750,000 components, was 15 meter long, 2.4 meter tall, and weighed approximately 5 tons. ATANASOFF BERRY COMPUTERS The Atanasoff Berry Computer was the worlds first electronic digital computer. It was

8、build by John Vincent Atanasoff and Clifford Berry at lova state university during 1937 42. It incorporated several major innovations in computing. The machine was capable of solving up to 29 simultaneous linear equations. The machine was, however, the implement three critical ideas that are still p

9、art of every modern computer. It used binary digits, it performed all calculations using electronics rather than wheels or mechanical switches, and it organized MICRO COMPUTERS Micro computers have a micro processor as their central processing unit, and are therefore relatively small in size. When t

10、hey have a key board and monitor, they are used as personal computers, which is type of computer that you have in your home. LAP TOP COMPUTERS A lap top computer or note book computer is a small lightweight computer that you can carry around easily. It can perform all the functions of a regular comp

11、uter, and has build in key board, pointing devise and a lightweight, non bulky screen. Lap top computers can run both on batteries and from an external adaptor that charges the battery while supping power. If you have a lap top computer, you can work on it while traveling or even you are outdoors. D

12、ESKTOP COMPUTERS A desktop computer is a small computer that you can use from a fixed power source. It gets its name from a fact that it is small enough to fit on a table or desk. Desktop computers have separate key boards and screens, and come in a variety of styles and models. POCKET PC A pocket P

13、C is a scaled down version of a full sized computer that you use in home or office. Although they are the size of a small diary, pocket PCs are proper computers. They have many of capabilities of full size computers, and can run sophisticated software applications. They are compact enough to fit in

14、your shirt pocket hence the clever name. TABLET PC A tablet PC is cross between a note book PC, and a handheld computer. It is a flat panel portable PC in a form of a slate. You can enter information by typing the screen with a stylus, or electronic pen. You can use the pen directly on the screen ju

15、st as you would a mouse to do things like select, drag, and open files. You can also use it a place of a key board to hand write notes and communications. Unlike a touch screen, the tablet PC screen only receives information from this special pen. HANDHELD COMPUTER A handheld computer is a portable

16、computer that is small enough to be held one hand. They are about the size of spectacle case, and a capable of storing thousands of address, appointment and memos. So, they are also called Personal Digital Assistants or PDAs. Handheld computers have extremely small screens and key boards. Today, the

17、 key board has been replaced with an electronic pen in some handheld computers. You can connect a handheld computer to a desk top computer to exchange information between the two. ULTRA MOBILE PC The ultra - mobile PC or UMPC is a small, mobile computer that runs on the Windows Vista operating syste

18、m. The UMPC goes anywhere, and can be used any time, just like a mobile PC. The UMPC has many advantages. It is smaller and lighter than traditional lap top computers and has multiple input methods like tough screen, tablet pen, the USB key board and others. It can also operate on different systems.

19、 SUPER COMPUTERS The fastest and most powerful computers available at a particular time are called super computers. Super computers are very expensive and employed for specialized tasks that required immense amount of mathematical calculations. The New York World, referring to tabulators manufacture

20、d by IBM, coined the term super computer in 1929. To modern computer users, these tabulators would probably appear awkward and slow. In the constantly changing the world of computing, it should come as no surprise to learn that most super computers are considered to be super only few years, in fact,

21、 todays super computer will become tomorrows ordinary computer! MINISUPER AND SUPERMINI COMPUTERS A minisuper computer is super computer that is about a quarter to a half as fast as the most powerful super computers, but cost much less. A minisuper computer a mini computer with high performance comp

22、ared to ordinary mini computers. BIOLOGICAL COMPUTER Biological computers are special types of micro computers that are specifically designed to be used for medical applications. The biological computer is planted inside the body and is mainly used for tasks like monitoring the bodys activities, or

23、diagnosing and treating diseases. Biological computers are important because they enable a doctor to focus on, find a treat only damaged or diseased cells. QUANTUM COMPUTERS We already know that a bit is a fundamental unit of information which is represented as a 0 or 1 in digital computer. Ordinary

24、 computers interrupt information according to the well understood laws of classical physics. In quantum computer, fundamental unit of information is called quantum bit or qubit. A quantum computer obeys the laws of quantum mechanics which are very different from classical physics. Scientists have al

25、ready built basic quantum computers that can perform certain calculations, but a practical quantum computer is still years away. DNA COMPUTERS DNA or deoxyribonucleic acid molecules, material our genes are made of, have the potential to perform calculations many times faster than the worlds most pow

26、erful human built computers. A computer that uses DNA to store information and perform complex calculations is called a DNA computer. It was in 1994 that University of Southern California computer scientist Leonard Adelman suggested that DNA could be used to solve complex mathematical problems. Whil

27、e still in their infancy, DNA computers will be capable of storing billons of times more data than your personal computer. OPTICAL COMPUTER An optical computer is a computer that uses light instead of electricity. An optical computer uses photons to manipulate, store and transmit data. You also know

28、 the modern electric computer use transistors. In optical computers electronic components are replaced with optical ones and optical transistors must be used. Optical computer technology is still in early stages. CHEMICAL COMPUTERS A chemical computer is an unconventional computer based on a semi so

29、lid chemical soup, where data is represented by varying concentration of chemicals. The computations are performed by naturally occurring chemical reactions. So far, it still in very early experimental stage, but may have great potential for the computer industry. NANO COMPUTER A nano computer is a

30、computer that is microscopic size. It is smaller than micro computer, which is smaller than mini computer. We can also say it is a computer whose fundamental parts are no bigger than a few nanometers. It is commonly used nano technology which is the building of extremely small machines. WETWARE COMP

31、UTERS A wetware computer is an organic computer. Organic refers any thing that is derived from living organisms. A wetware computer is from living neurons, which are cells found in brain, spinal column and nerves. A wetware computer is some times called an artificial organic brain or a neurocomputer. A wetware computer has already been constructed from leech neurons. SHOE COMPUTERS A shoe computer is a type of computer that uses law level electrical impulses emitte