first day

computer

English PC is a personal computer.

An object with computing power simulated by electronic components, the scientific name computer.

Originally invented by john von neumann (at that time, the computing power of computers was equivalent to today's calculators), it was as big as three warehouses, and then it gradually developed.

It is an electronic device that can automatically process and process all kinds of data and information according to instructions.

Generally speaking, a computer consists of two parts, namely hardware and software. Hardware includes: monitor, mouse, keyboard, chassis, power supply, motherboard, CPU, sound card, graphics card, optical drive (floppy drive has been eliminated), memory, hard disk, and some also include external devices such as network card, speaker, earphone, printer, scanner, camera and handwriting board. Software is divided into system software and application software.

The scientific name of computer is computer, which is developed from the early electronic calculator. 1946 February, the world's first electronic digital computer ENIAC was born. (Electronic digital integrator and calculator)

The original design scheme of "Eniac" computer was put forward by 36-year-old American engineer Mochri 1943. The main task of the computer is to analyze the trajectory of the projectile. The United States Ordnance Department allocated funds to support research and development, and set up a special research team, which was headed by Mochiri. The chief engineer is eckert, who is only 24 years old. Team member Geers is a mathematician and a logician Boxer. "Eniac”* * * uses 65,438+08,000 electron tubes, plus 65,438+0500 relays and other equipment. It has a total volume of about 90 cubic meters, weighs 30 tons, covers an area of 170 square meters, and needs a large room more than 30 meters long to store it. This is a complete monster. This computer with power consumption of 140 kW has an operation speed of 5000 additions or 400 multiplications per second, which is 1000 times faster than the mechanical relay computer. When "Eniac" is publicly displayed, the trajectory of a shell can be calculated in 20 seconds, which is faster than the flight speed of the shell. Eniac's memory is an electronic device, not a rotating "drum". It can complete tens of millions of multiplication operations a day, which is about 40 years' work for a person to operate a desktop computer. It runs in decimal instead of binary. However, there are also a few electron tubes that work in binary mode, so the machine has to convert decimal into binary in its work, and then back to decimal when data is input and output. "Eniac" was originally a special computer designed for ballistic calculation. But later, by changing the wiring mode inserted into the control panel to solve various problems, it became a universal machine. Its improved version was used in the development of hydrogen bombs. The "Eniac" program uses external plug-ins, and every time a new calculation is made, the line must be reconnected. Sometimes it takes several hours or 1~2 days to prepare a few minutes or dozens of calculated line connections, which is a fatal weakness. Its other weakness is that its storage capacity is too small, and it can only store 20 decimal numbers with 10 bits at most. General mountbatten of the British Society of Radio Engineers praised the emergence of "Eniac" as "the birth of electronic brain", from which the word "computer" came.

This is the latest stage of computer development since 1970s. By 1976, "Cray" made of LSI and VLSI made the computer enter the fourth generation. With the invention of VLSI, electronic computers are constantly upgrading to miniaturization, miniaturization, low power consumption, intelligence and systematization.

In the 1990s, computers developed in the direction of "intelligence", creating computers similar to human brains, which can do thinking, learning, memory and network communication.

In the 265,438+0th century, computers have become more notebook-oriented, miniaturized and specialized, with an operation speed of over 65,438,000 billion times per second. It is not only easy to operate and cheap, but also can replace part of people's mental work and even expand people's intelligence in some aspects. Therefore, today's microcomputers are vividly called computers.

The first personal computer in the world was launched by IBM in 198 1 year.

1 definition

According to the definition of the current Oxford English Dictionary (Second Edition), a computer is a device that performs or controls operations that can be represented by numbers or logic. This definition is really true and accurate. However, it contains too much content, just like other definitions of computer found in other dictionaries. These definitions cannot distinguish between historical, contemporary and future computers. More meaningful questions may include: What are the different types of computers? Or ask, what are the differences between the characteristics and capabilities of contemporary computers and those of other times?

Etymology of 1. 1

The meaning of the English word "computer" has been changing, but its meaning always lags behind the computer ability at that time. The word "computer" was originally used to mean a person who was hired to perform arithmetic calculations, that is, a calculator; This usage is still valid today. Oxford English Dictionary (Second Edition) thinks that it was first used in 1897 to represent a mechanical computing device. At 1946, the Oxford Dictionary has added several qualifiers to distinguish different types of computers. These qualifiers include analog, digital and electronic. However, from the reference context, these qualifiers were used before 1946.

2 the exponential growth of computer development

Due to the exponential growth of computer computing power, it is more complicated to divide different computers. Roughly estimated, from 1900 to now, the computing power of computing equipment (the number of computing instructions that can be bought at 1000 dollars per second) doubles every half to two years. Gordon e Moore, one of the founders of Intel Corporation, first described this characteristic of computer development in 1965 (refer to Moore's Law). The rapid development of computer manufacturing engineering technology has maintained this exponential productivity growth. Another process closely related to this capacity growth is the dramatic process of computer miniaturization. The first generation of electronic computers, such as ENIAC (appearing in 1946), are all giants weighing several tons, occupying several rooms and requiring multiple operators to maintain normal work. These things are so expensive that only the government and large institutions can afford them. They're really weird. At that time, people thought that a few or dozens of such machines could meet the needs of the whole world. In contrast, modern computers have several orders of magnitude more functions than their predecessors, and they are cheap, compact and ubiquitous.

3 the classification of computers

In order to define what a computer is, it is necessary to classify all computing devices. The following sections introduce several different classification methods. These classification methods must be combined to accurately describe a specific computer.

3. 1 Classification by purpose

This is the most obvious classification. Computer manufacturers usually describe their products like this; Users describe the machines they communicate with in the same way. For example:

super computer

Mini supercomputer

mainframe computer

Enterprise server

minicomputer

PC server

work station

Personal computer or desktop computer

Laptop or notebook computer

Personal digital assistant (PDA)

Wearable computer

embedded computer

Classification by purpose is very popular, but it also leads to its uncertainty, because it only includes the equipment that is widely used at present. The rapid development of computers means that new uses of computers emerge one after another, and the current definition will soon become outdated. Many types of computers that people no longer use, such as differential analyzers, are usually not included in the classification items. Therefore, other classification methods must be adopted to clearly define the word computer.

3.2 Classification by manufacturing technology

Mechanical type

Semielectronic-semimechanical

electronic formula

transistor

Semiconductor integrated circuit (SCIC)

optical computer

quantum computer

biocomputer

3.3 According to the classification of design features

Modern computers integrate many basic design features, which have been gradually developed by many contributors over the years. Design characteristics are usually independent of implementation technology. The comprehensive performance of modern computers comes from the way these features interact. Some important design features are listed below:

3.3. 1 digital and analog

There is a basic decision when designing a computer: should this computer be digital or analog? Digital computers deal with discrete numerical or symbolic values, while analog computers are still used in some special-purpose fields, such as the control of robots and cyclotrons. Other methods such as pulse calculation and quantum calculation are also possible; But they are either used for very special purposes or are still in the experimental stage.

Binary and decimal

In the development of digital computing, a major design progress is to introduce binary as an internal digital system. This method avoids the complicated carry mechanism necessary for computers based on other digital systems (such as decimal system). The advantage of binary system is that it simplifies the design of arithmetic function and logical operation.

3.4 Classification by ability

The best way to classify different computing devices may be to classify them according to their inherent capabilities, rather than according to their uses, implementation technologies or design features. Computers can be divided into three categories according to their capabilities: special equipment that can only calculate one function, special equipment that can calculate functions in a limited range, and general equipment that we use every day. In the past, the word computer was used to describe all these types of machines, but now the colloquial usage usually refers to general-purpose computers.

3.4. 1 general computer

By definition, a general-purpose computer can be used to solve any problem as long as it can be expressed by a program. But there are some practical limitations in running the program: the storage capacity of the computer, the size of the problem, and the speed of running. In 1934, alan turing proved that given the correct program, any general-purpose computer can imitate the behavior of any other computer. His mathematical proof was purely theoretical, because there was no general computer at that time. The significance of this proof is far-reaching: for example, in theory, today's general-purpose computer can simulate the behavior of any general-purpose computer made in the future, although the speed is very slow.

General-purpose computers, also known as complete Turing machines, are often used to define the upper limit of modern computer capabilities. However, this definition is problematic. Several simple computing devices have shown complete Turing machine characteristics. But they are all humorous expressions of "Turing asphalt trap" (? ) state, a kind of anything is possible, but it has nothing to do with practicality. Modern computer is not only a theoretical generalization, but also a practical general tool.

From the middle of 1930 to the late of 1940, many people were developing modern, digital, electronic and general-purpose computers. Many experimental machines have been built, which may be Turing-complete. These machines were declared as the first computers at that time, but their ability to deal with general problems was limited, so their designs were finally abandoned.

3.5 Classification by operation type

Computers can also be classified according to the way users operate. There are two modes of operation: batch processing and interactive processing.

4 Interpretation of old projects

Computer is an auxiliary tool for calculation, which can be divided into broad sense and narrow sense. Generalized computers include:

abacus

viper

slide rule

calculator

A computer in a narrow sense is an electronic computer, which is now called a computer.

Computers are divided into supercomputers, large computers, medium-sized computers, small computers and microcomputers (PCs). Computers have gradually entered all fields of society, especially families and individuals, which have greatly changed the daily appearance of society.

Looking back at the history of computer development, the birth of a new concept or a new product is undoubtedly the source of industrial transformation, and the energy emitted by personal computers (PCs) has made the whole industry leap to an unprecedented height in an instant. This massive PC revolution cannot be separated from the precise guidance of those great scientists, and Alan Kay is such a key leader. He is not only a prophet of PC revolution, but also a technical genius. His software Smalltalk (object-oriented programming language), Dynabook computer (predecessor of notebook computer) and the concept of Windows GUI (graphical user interface) laid an important foundation for the development of PC software, hardware and operating system.

When the National Institute of Engineering (NAE) awarded Kay the 2004 Draper Award, which is known as the Nobel Prize for Engineering, the chairman of NAE said: "Perhaps most people still don't understand why personal computers used in the network can affect us like fairy tales. In the process of redefining (computer) technology itself and its development direction, Kay played a vital role in this group. " Gary Chapman, director of the 2 1 century project at the University of Texas in the United States, also said that the concepts of Smalltalk and Dynabook have brought innovative inspiration to generations of technicians. His invention triggered a revolution in personal computers, from Apple's Macintosh to Microsoft's Windows.

Kay, 64, was born in America. His father is a physiologist and physician, his mother is an artist and musician, his grandmother is a professor and scholar, and his grandfather is a photographer and writer. In such a family environment, Kay has been versatile and smart since childhood. He was able to read by himself when he was three years old, and he had read hundreds of books in primary school. Because he often disobeyed management at school, he was ordered to suspend classes for many times, and even expelled from Bethany College in Virginia at 196 1. Soon, he took part in the voluntary service of the army. He has never touched a computer. In a computer aptitude test, he accidentally found himself gifted in this field and was recruited by the US Air Force to work in IBM 140 1 large computer project. Since then, he has formed an indissoluble bond with computers.

After leaving the US Air Force, Kay entered the University of Colorado to study mathematics and molecular biology. After receiving a double bachelor's degree from 65438 to 0966, Kay, who was gifted in music, medicine and philosophy, faced multiple choices, and finally he entered the University of Utah to study mechanical and electrical engineering. 1967, he cooperated with others and invented a machine called FLEX. This machine, which they call "personal computer", is equipped with a display and a control panel, uses a multi-window graphical user interface, and is implanted with an object-oriented operating system developed by Kay for the first time. Although this machine, which weighs 100 kilograms, basically has no practical function, let alone market value, it still excites Kay and his companions.

During a later visit to the artificial intelligence laboratory in Massachusetts, Kay was lucky enough to be exposed to the LOGO programming language for children. Inspired by the LOGO, he began to conceive and design a "laptop" suitable for children of all ages, that is, the KiddieKomp project. From 65438 to 0968, Kay received a master's degree and worked in the ARPA (Defense Advanced Research Projects Agency) laboratory of the University of Utah, developing 3D graphics systems and ARPA networks. 1969, he got his doctor's degree with a paper named Object-Oriented Graphics System. After two years as a professor in Stanford Artificial Intelligence Laboratory, Taylor, the technical predecessor of 1972, invited him to set up Xerox's Palo Alto Research Center (PARC), and Kay became one of the founders of the center.

During the ten years in PARC, many of Kay's ideas have come true. It took him only a few months to complete the Smalltalk program, and the first portable computer Dynabook based on it was also completed later. Although Dynabook computer is mainly designed for children's teaching, it contains the concept of the same size and weight as a book, as well as advanced technologies such as flat panel display, handwriting input, wireless network, local storage and graphical interface, which directly leads to the rooting and germination of the concept of personal computer in the world.

1983 After leaving PARC, Kay joined Atari, Apple and Disney successively, and set up a non-profit organization viewpoint research center. In 2002, he officially joined HP to continue software development. Dick Lampman, senior vice president of Hewlett-Packard's R&D department, said: "Kay's ability, creativity and observation have always had an unpredictable impact on the industry." HP hopes that Kay will trigger another technological revolution in the industry, just like Kay's own classic sentence: "The best way to predict the future is to create the future."

Computer upgrade can be divided into hardware upgrade and software upgrade. Software upgrade refers to a new program (mostly a driver), and hardware upgrade refers to adding new equipment or replacing parts to the computer to make it run faster.

But generally speaking, computer upgrades can be divided into host upgrades and other component upgrades (such as monitors, mice, speakers, etc. ), and most people refer to the host upgrade!

You can upgrade yourself, but you must have a certain understanding of computer hardware, as well as the latest computer accessories, performance and brand, so as to avoid not giving full play to the level after upgrading, or causing incompatibility, seriously affecting the service life of other computer parts, and even burning the computer!

Display: If the funds are insufficient, you can choose CRT (ordinary display), and if the funds allow, you can buy LCD (liquid crystal display), but you must pay attention to several characteristics of LCD: 1. High brightness 2. High contrast 3. Broad vision. Fast signal response time (less than 8ms) should not have any bad points that have passed TCO O3 certification.

Host: CPU, motherboard, memory, graphics card, sound card, hard disk, power supply and data cable.

However, how to upgrade depends on how much money you have and the original configuration. If the machine is new, it can be partially replaced. If it is old, it is recommended to replace it all. In short, it depends on the specific situation and personal wishes. It is suggested that if you don't know much about computers, please ask full-time computer personnel to help upgrade!

Computer is a general term for electronic computers. The world is undergoing a transition from A to B, that is, from the atomic age to the bit age, in which the progress of computer science and technology undoubtedly plays a key role. After more than 50 years of quantitative change, the application field of computer technology is almost everywhere, becoming an indispensable part of people's work, life and study, and thus forming a unique computer culture.

Li Yingdong provides the highest computer configuration since/info/jsj/3.htm.

CPU— Xeon 3.2 GHz× 2; Memory: 8192 MB (8g); Display CRT×3 sets of+17 LCD; Hard disk consists of 22 sets 180GXP, * * * 2 1 10GB; The power supply consists of 7 power supplies, with a total of 2740 watts; Graphics card Millennium 550+Millennium 450；; ; Sound card adopts Sound Blaster Audigy2 ZS fan and mute fan below 15dB.