Today computers have become part of our life. Usage of computers in different fields has become a necessity in the present competitive world. Lot of work and evolutions has transpired from the initial computer systems to the present day computer systems. Computers are made up of Electrical, Electronic and Mechanical components. Computers are just the machines and you must specify the work that is to be carried out by the computer. Thus to carry out a specific task series of instructions must be given to the Computer in a particular order. In this unit, we are going to study the computer structure, evolution of computers, characteristics of computer & organization of the computer.
After studying this unit, you should be able to:
explain the evolution of the Computers
explain the Characteristics of computers
explain Organization of a Computer and its units
Computer – Definitions
A computer is a device that receives information (in the form of digitalized data) and manipulates it for some result based on a program or sequence of instructions on how the data is to be processed. Complex computers also include the means for storing data (including the program, which is also a form of data) for some necessary duration. A program may be invariable and built into the computer (and called logic circuitry as it is on microprocessors) or different programs may be provided to the computer (loaded into its storage and then started by an administrator or user).
Ultimate histories of the modern computer begin with the Analytical Engine envisioned by Charles Babbage following the mathematical ideas of George Boole, the mathematician who first stated the principles of logic inherent in today’s digital computer. Babbage’s assistant and collaborator, Ada Lovelace, is said to have introduced the ideas of program loops and subroutines and is sometimes considered the first programmer. Apart from mechanical calculators, the first really useable computers began with the vacuum tube, accelerated with the invention of the transistor, which then became embedded in large numbers in integrated circuits, ultimately making possible the relatively low-cost personal computer. Modern computers inherently follow the ideas of the stored program laid out by John von Neumann in 1945. Essentially, the program is read by the computer one instruction at a time, an operation is performed, and the
computer then reads in the next instruction, and so on. Recently, computers and programs have been devised that allow multiple programs (and computers) to work on the same problem at the same time in parallel. With the advent of the Internet and higher bandwidth data transmission, programs and data that are part of the same overall project can be distributed over a network and embody the Sun Microsystems slogan: “The network is the computer.” Technically, a computer is a programmable machine. This means it can execute a programmed list of instructions and respond to new instructions that it is given. Today, however, the term is most often used to refer to the desktop and laptop computers that most people use. When referring to a desktop model, the term “computer” technically only refers to the computer itself – not the monitor, keyboard, and mouse. Still, it is acceptable to refer to everything together as the computer. If you want to be really technical, the box that holds the computer is called the “system unit.” Some of the major parts of a personal computer (or PC) include the motherboard, CPU, memory (or RAM), hard drive, and video card. While personal computers are by far the most common type of computers today, there are several other types of computers. For example, a “minicomputer” is a powerful computer that can support many users at once. A “mainframe” is a large, high-powered computer that can perform billions of calculations from multiple sources at one time. Finally, a “supercomputer” is a machine that can process billions of instructions a second and is used to calculate extremely complex calculations.
The evolution of computers
Since civilizations began, many of the advances made by science and technology have depended upon the ability to process large amounts of data and perform complex mathematical calculations. For thousands of years, mathematicians, scientists and businessmen have searched for
computing machines that could perform calculations and analyze data quickly and efficiently. One such device was the abacus.
The abacus was an important counting machine in ancient Babylon, China, and throughout Europe where it was used until the late middle ages. It was followed by a series of improvements in mechanical counting machines that led up to the development of accurate mechanical adding machines in the 1930’s. These machines used a complicated assortment of gears and levers to perform the calculations but they were far to slow to be of much use to scientists. Also, a machine capable of making simple decisions such as
which number is larger was needed. A machine capable of making decisions is called a computer. The first computer like machine was the Mark I developed by a team from IBM and Harvard University. It used mechanical telephone relays to store information and it processed data entered on punch cards. This machine was not a true computer since it could not make decisions. In June 1943, work began on the world’s first electronic computer. It was built at the University of Pennsylvania as a secret military project during World War II and was to be used to calculate the trajectory of artillery shells. It covered 1500 square feet and weighed 30 tons. The project was not completed until 1946 but the effort was not wasted. In one of its first demonstrations, the computer solved a problem in 20 seconds that took a
team of mathematicians three days. This machine was a vast improvement over the mechanical calculating machines of the past because it used vacuum tubes instead of relay switches. It contained over 17,000 of these tubes, which were the same type tubes used in radios at that time. The invention of the transistor made smaller and less expensive computers possible. Although computers shrank in size, they were still huge by today’s standards. Another innovation to computers in the 60’s was storing data on tape instead of punch cards. This gave computers the ability to store and retrieve data quickly and reliably. This series covers many of the major milestones in computer history with a concentration on the history of personal home computers. See table 1.1, which shows the evolution of Computers.
Description of Event
|1936||Konrad Zuse – Z1 Computer||First freely programmable|
|1942||John Atanasoff & Clifford|
|Who was first in the computing|
biz is not always as easy as
|1944||Howard Aiken & Grace|
Harvard Mark I Computer
|The Harvard Mark 1 computer.|
|1946||John Presper Eckert & John|
ENIAC 1 Computer
|20,000 vacuum tubes later…|
|1948||Frederic Williams & Tom|
Manchester Baby Computer
& The Williams Tube
|Baby and the Williams Tube|
turn on the memories.
|1947/48||John Bardeen, Walter|
Brattain & Wiliam Shockley
|No, a transistor is not a|
computer, but this invention
greatly affected the history of
|1951||John Presper Eckert & John|
|First commercial computer &|
able to pick presidential
IBM 701 EDPM Computer
|IBM enters into ‘The History of|
|1954||John Backus & IBM|
|The first successful high level|
(In Use 1959)
|Stanford Research Institute,|
Bank of America, and
ERMA and MICR
|The first bank industry|
computer – also MICR
(magnetic ink character
recognition) for reading checks.
|1958||Jack Kilby & Robert Noyce|
The Integrated Circuit
|Otherwise known as ‘The Chip’|
|1962||Steve Russell & MIT|
Spacewar Computer Game
|The first computer game|
Computer Mouse & Windows
|Nicknamed the mouse because|
the tail came out the end.
|1969||ARPAnet||The original Internet.|
|1970||Intel 1103 Computer Memory||The world’s first available|
dynamic RAM chip.
|1971||Faggin, Hoff & Mazor|
Intel 4004 Computer
|The first microprocessor|
|1971||Alan Shugart &IBM|
The “Floppy” Disk
|Nicknamed the “Floppy” for its|
|1973||Robert Metcalfe & Xerox|
The Ethernet Computer
|1974/75||Scelbi & Mark-8 Altair & IBM|
|The first consumer computers.|
|1976/77||Apple I, II & TRS-80 &|
Commodore Pet Computers
|More first consumer computers.|
|1978||Dan Bricklin & Bob Frankston|
|Any product that pays for itself|
in two weeks is a surefire
|1979||Seymour Rubenstein & Rob|
The IBM PC – Home
|From an “Acorn” grows a|
personal computer revolution
|From “Quick And Dirty” comes|
the operating system of the
|1983||Apple Lisa Computer||The first home computer with a|
GUI, graphical user interface.
|1984||Apple Macintosh Computer||The more affordable home|
computer with a GUI.
|1985||Microsoft Windows||Microsoft begins the friendly|
war with Apple.