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Sunday, March 2, 2008

Classification & Generation of Computers

We are going to represent a paper presentation on classification & generation of computers. The term “computer generation” is widely used particularly by the sales personnel of computer manufacturers. Most often it is used in relation to the hardware of computers. We will take a broader view and examine the developments in software and applications besides hardware.
Computers were classified as supercomputers, mainframe computers, microcomputers. Technology, however, has changed and this classification is no more relevant. Today all computers use microprocessors as their CPU. Thus classification is possible only through their mode of use. Based on interconnected computers we can classify them as distributed computers and parallel computers.

Computers History and Development Overview

Nothing symbolized modern life better than the computer. Computers do much more than simply compute.
For example - In shopping malls they can calculate our grocery bill while keeping store inventory.
computerized telephone switching centers play handle millions of calls and keep lines of communication well connected .With Automatic Teller Machines (ATM)we can do banking activities from anywhere in the world.

Where did all this technology come from and where is it heading?

To fully understand and appreciate the impact computers have on our lives and promises they hold for the future, it is important to understand their evolution.

Early Computing Machines and Inventors
In 1642, Blaise Pascal at the age of 18 , invented a numerical wheel calculator, also called as Pascaline. The drawback to the Pascaline:It was limited to only addition of numbers.
In 1694, a German mathematician Leibniz improved the Pascaline by creating a machine that could also multiply.Charles Colmar, a Frenchman, invented a machine that could perform the four basic arithmetic functions, called as the arithometer. It could add, subtract, multiply and divide. The arithometer was widely used up until the First World War.
English mathematics professor, Charles Babbage: The real beginnings of computers as Babbage's first attempt at solving this problem was in 1822 when he proposed a machine to perform differential equations, called a Difference Engine. Powered by steam and large as a locomotive, the machine would have a stored program and could perform calculations and print the results automatically. After working on the Difference Engine for 10 years, Babbage was suddenly inspired to begin work on the first general-purpose computer, which he called the Analytical Engine.
Classification of computers

There are four types of computers: -
1) Super Computer. 2) Mainframe Computers.
3) Mini Computers. 4) Micro Computers.

2.1 Supercomputers: -

Supercomputers are the most powerful type of computer. These machines are high-capacity computers, used by very large organizations.
For example: - NASA uses supercomputers to track and control space explorations.

2.2 Mainframe computers: -

Mainframe computers occupy specially wired , air-conditioned rooms. Although not nearly as powerful as supercomputers, mainframe computers are capable of great processing speed and data storage.
For example: - Insurance companies use mainframe computers to process information about millions of policyholders. They require computers with very large disks to store several Tera bytes of data and transfer data from disk to main memory to several hundred Megabytes/sec.

2.3 Minicomputers: -

Minicomputers ,also known as midrange computers ,are desk-sized machines .Medium-sized companies or departments of large companies typically use them for specific purposes.
For example: -Production departments use minicomputers to monitor certain manufacturing processes and assembly line operations.

2.4 Microcomputers: -

Microcomputers are least powerful ,yet are the most widely used and fastest –growing type of computer .
In categories of microcomputers include Desktop, Ntebook ,Personal Digital Assistants.(PDAs) .
-Desktop computers are small enough to fit on top of or alongside a desk yet aare too big to carry around.
-Notebook computers are protable,weight between 4&10 pounds, and fit into big briefcase.
-Personal Digital Assistants (PDAs) are also known as palmtop computers or handheld computers.

· Distributed Computer System

A configuration in which several workstation / PCs are interconnected by a communication network is called a distributed computer system .
3 Parallel Computers

A set of computers connected together by a high speed communication network and programmed in such away that they cooperate to solve a single large problem is called parallel computer

Generations of Computer

1) First generation (1945-1956)
2) Second generation (1956-1963)
3) Third generation (1964-1971)
4) Fourth generation (1971-present)
5) Fifth generation

3.1 First Generation Of Computer (1945 –1956)
With the onset of the Second World War. In1941 by German engineer Konrad Zuse had developed a computer, the Z3, to design airplanes and missiles. American efforts produced a broader achievement. Howard H. Aiken (1900-1973), A Harware engineer working with IBM, succeeded in producing an all-electronic calculator by 1944. It was about half as long as a cricket ground and contained about 1000 kilometers of wiring. The Harvard-IBM Automatic Sequence Controlled Calculator, or Mark I for short, was a electronic relay computer. It could perform basic arithmetic as well as more complex equations. Electronic Numerical Integrator and Computer (ENIAC), Developed by John Presper Eckert and John W. Mauchly Consisting of 18,000 vacuum tubes, 70,000 resistors and 5 million soldered joints, the computer was such a massive piece of machinery that it consumed 160 kilowatts of electrical power, enough energy to dim the lights in an entire city Von Neumann designed the Electronic Discrete Variable Automatic Computer (EDVAC) in 1945 with a memory to hold both a stored program as well as data. The key element to the von Neumann architecture was the central processing unit, which allowed all computer functions to be coordinated through a single source. In 1951, the UNIVAC I (Universal Automatic Computer), built by Remington Rand, became one of the first commercially available computers to take advantage of these advances.
Characteristics of First Generation Computers:
Operating instructions were made-to-order for the specific task for which the computer was to be used. Each computer had a different binary-coded program called a machine language that told it how to operate. Difficult to program and limited its versatility and speed Other distinctive features of first generation computers were the use of vacuum tubes and magnetic drums for data storage.
3.2 Second Generation Computers (1956-1963)
By 1948, the invention of the transistor greatly changed the computer's development. The transistor replaced the large, cumbersome vacuum tube in televisions, radios and computers. As a result, the size of electronic machinery has been shrinking ever since.
Transistors led to second generation computers that were smaller, faster, more reliable and more energy-efficient than their predecessors. The first large-scale machines to take advantage of this transistor technology were early supercomputers, Stretch by IBM and LARC by Sperry-Rand. These computers, both developed for atomic energy laboratories, could handle an enormous amount of data, a capability much in demand by atomic scientists. The machines were costly, so limited to business needs only. Second generation computers replaced machine language with assembly language, allowing abbreviated programming codes to replace long, difficult binary codes. Throughout the early 1960's, there were a number of commercially successful. Second generation computers used in business, universities, These second generation computers were also of solid state design, and contained transistors in place of vacuum tubes. They also contained all the components we associate with the modern day computer: printers, tape storage, disk storage, memory, operating systems, and stored programs. One important example was the IBM 1401, which was universally accepted throughout industry. . By 1965, most large business routinely processed financial information using second generation computers. It was the stored program and programming language that gave computers the flexibility to finally be cost effective and productive for business use. The stored program concept meant that instructions to run a computer for a specific function(known as a program) were held inside the computer's memory, and could quickly be replaced by a different set of instructions for a different function. A computer could print customer invoices and minutes later design products or calculate paychecks. More sophisticated high-level languages such as COBOL (Common Business-Oriented Language) and FORTRAN (Formula Translator) came into common use during this time, and have expanded to the current day. These languages replaced cryptic binary machine code with words, sentences, and mathematical formulas, making it much easier to program a computer.
New types of careers (programmer, analyst, and computer systems expert) and the entire software industry began with second generation computers.
3.3 Third Generation Computers (1964-1971)
Though transistors were clearly an improvement over the vacuum tube, they still generated a great deal of heat, which damaged the computer's sensitive internal parts. The quartz rock eliminated this problem. Jack Kilby, an engineer with Texas Instruments, developed the integrated circuit (IC) in 1958. The IC combined three electronic components onto a small silicon disc, which was made from quartz. Scientists later managed to fit even more components on a single chip, called a semiconductor. As a result, computers became ever smaller as more components were squeezed onto the chip. Another third-generation development included the use of an operating system that allowed machines to run many different programs at once with a central program that monitored and coordinated the computer's memory.
3.4 Fourth Generation (1971-Present)
After the integrated circuits, the only place to go was down - in size, that is, Large scale integration (LSI) could fit hundreds of components onto one chip In the 1980's, very large scale integration (VLSI) squeezed hundreds of thousands of components onto a chip. Ultra-large scale integration (ULSI) increased that number into the millions.
It also increased their power, efficiency and reliability. The Intel 4004 chip, developed in 1971, took the integrated circuit one step further by locating all the components of a computer (central processing unit, memory, and input and output controls) on a minuscule chip.
Previously the integrated circuit had to be manufactured to fit a special purpose, now one microprocessor could be manufactured and then programmed to meet any number of demands. Soon everyday household items such as microwave ovens, television sets and automobiles with electronic fuel injection incorporated microprocessors. Such condensed power allowed everyday people to harness a computer's power. They were no longer developed exclusively for large business or government contracts. By the mid-1970's, computer manufacturers sought to bring computers to general consumers .These minicomputers came complete with user-friendly software packages that offered even non-technical users an array of applications, most popularly word processing and spreadsheet programs.
Pioneers in this field were Commodore, Radio Shack and Apple Computers. In the early 1980's, arcade video games such as Pac Man and home video game systems such as the Atari 2600 ignited consumer interest for more sophisticated, programmable home computers.
In 1981, IBM introduced its personal computer (PC) for use in the home, office and schools. The number of personal computers in use more than doubled from 2 million in 1981 to 5.5 million in 1982. Ten years later, 65 million PCs were being used. Computers continued their trend toward a smaller size, working their way down from desktop to laptop computers (which could fit inside a briefcase) to palmtop (able to fit inside a breast pocket). In direct competition with IBM's PC was Apple's Macintosh line, introduced in 1984. Notable for its user-friendly design, the Macintosh offered an operating system that allowed users to move screen icons instead of typing instructions. Users controlled the screen cursor using a mouse, a device that mimicked the movement of one's hand on the computer screen.
As computers became more widespread in the workplace, new ways to harness their potential developed. As smaller computers became more powerful, they could be linked together, or networked, to share memory space, software, information and communicate with each other. As opposed to a mainframe computer, which was one powerful computer that shared time with many terminals for many applications, networked computers allowed individual computers to form electronic co-ops. Using either direct wiring, called a Local Area Network (LAN), or telephone lines, these networks could reach enormous proportions. A global web of computer circuitry, the Internet, for example, links computers worldwide into a single network of information. The most popular use today for computer networks such as the Internet is electronic mail, or E-mail, which allows users to type in a computer address and send messages through networked terminals across the office or across the world
3.5 Fifth Generation
Using recent engineering advances, computers are able to accept spoken word instructions (voice recognition) and imitate human reasoning. The ability to translate a foreign language is also moderately possible with fifth generation computers. Many advances in the science of computer design and technology are coming together to enable the creation of fifth-generation computers.
Two such engineering advances are parallel processing, which replaces von Neumann's single central processing unit design with a system harnessing the power of many CPUs to work as one. Another advance is superconductor technology, which allows the flow of electricity with little or no resistance, greatly improving the speed of information flow. Computers today have some attributes of fifth generation computers. For example, expert systems assist doctors in making diagnoses by applying the problem-solving steps a doctor might use in assessing a patient's needs. It will take several more years of development before expert systems are in widespread use.

Computer are classified into a number of generation based on the electronic technology used in constructing the computer, the associated system software and applications. Computers may be classified based on their mode of use and the way individual computers are interconnected.
Fundamental of computers – P. K. Sinha


Namrata D. Balkawade
Deepali B.Jagtap

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