Friday, October 10, 2014


The word ‘Computer’ was first recorded as being used to describe a Human who performed Computations or Calculations during 1613.
Human Computers

As the time past, people realized that machine can do calculations more accurately and more faster and never get tired like humans.

In 1822, Charles Babbage began developing Difference Engine which was considered as first automatic computing engine.
Difference Engine

In 1837, Charles Babbage proposed first general mechanical computer called the Analytical Engine, which contained an Arithmatic Logical Unit (ALU), basic flow control, Integrated memory.

But he could not build it due to funding issues till he was alive. In 1910, Henry Babbage, Charles Babbage’s son, complete a portion of this machine and able to perform basic calculations.

Hollerith's invention, known as the Hollerith desk, consisted of a card reader which sensed the holes in the cards, a gear driven mechanism which could count (using Pascal's mechanism which we still see in car odometers), and a large wall of dial indicators (a car speedometer is a dial indicator) to display the results of the count.
Hollerith Desk

Z1 was the first electromechanical binary programmable computer created by Zuse in 1936-38.

Turing Machine was proposed by Alan Turing in 1936. It was theoretical generalised computer, composed of a tape on which symbols representing instructions are imprinted. The tape can move forward and backward in the machine, which can read the instructions and write the result output back onto the tape.

Turing Machine

ABC (Atanasoff Berry Computer) was developed by Professor Atanasoff and Graduate student Berry in 1937 till 1942 at Iowa State University. It was the first electrical computer used vacuum tubes for digital computations and had no CPU.
Atanasoff Berry Computer (ABC)

Colossus, also called Mark I, was the first programmable computer developed by Tommy Flowers in 1945 during world war II in England. It was created to help british code breakers to read encrypted German messages.
Colossus Computer

Electromechanical computer Mark I used relays to represent data. Ist calculation was done on May 6, 1949 on Mark I and also it ran the first graphical computer game nicknamed as ‘Baby’.
Earliest all computers used vacuum tubes as switches.

During 1943-1945, ENIAC (Electronic numerical Integrator And Calculator) was built by Professors J.Presper Eckert and John Mauchly at University of Pennsylvania. It occupied about 1800 sq feet of space, weighted 30 tons and used about 18,000 vacuum tubes.

But when ENIAC was ON, 18,000 vacuum tubes generated about 174,000 watts of heat. So it was operated in a specially designed room with heavy duty air conditioning system.
ENIAC could hold 20 numbers at a time. A multiplication that required 6 seconds on Mark I could be performed in 2.8 thousandth of a second on ENIAC.
ENIAC (Electronic numerical Integrator And Calculator)

ENIAC first task was to compute whether it was posiible to build a hydrogen bomb and after using half a million punch cards for 6 weeks, ENIAC declared hydrogen bomb feasible.
But In ENIAC, physical modification of all patch words and switches was required for reprogramming the system. It generally took several days.

Eckert and Mauchly along with mathematician John Von Neumann designed EDVAC (Electronic Discrete Variable Automatic Computer)which pioneered the stored program. Neumann realized program could be represented electronically  just like data.
EDVAC(Electronic Discrete Variable Automatic Computer)

 Ist computer company was Electronic Controls Company founded in 1949 by J. Presper Eckert and John Mauchly and later on it became Eckert-Mauchly Computer Cooperation.
But Mauchly and Eckert’s company fall into financial problems and was sold at loss.

UNIVAC I (Universal Automatic Computer) was the first computer for commercial use in public.

In 1953, Ist Electronic computer was launched by IBM (International Business Machines) named as “IBM 701”.  By 1955 IBM was selling more computers than UNIVAC.
IBM 7090, IBM 360, IBM 370 are mainframe computers.
IBM 7094 Computers

Bell Laborataries invented transistors. Transistors replaced vacuum tubes because of small size, cheaper, less power consumption, fast switching speed.

Assembly language was used like COBOL, ALGOL, SNOBOL, FORTRAN. Around 100 programming languages were developed at that time.

Microprocessor is a computer fabricated on Integrated circuits. 1st microprocessor was developed at Intel in 1971.

It was not Intel company which invented the electronic computer but they firstly succeed in cramming an entire computer on a single chip.

Intel 4004 was the first microprocessor consisted of 2300 transistors and was clocked at 108 MHz.

Intel followed the 4004 with 8008 and 8080 microprocessor.

Intel priced 8080 microprocessor at $360 dollars in competition with IBM’s famous mainframe computer IBM 360 which costs million of dollars.
Altair8800 Computer was the world’s 1st personal computer.
Altair8800 computer

Intel Pentium 4 used in today’s PC is still compatible with Intel 8088 used in IBM’s 1st PC.
In 1981, IBM introduced its 1st Personal Computer.
The computer was code named and referred to as ‘Acorn’ and had 8088 processor, 16 KB of memory, utilized MS-DOS.

The IBM 5100 is the first portable computer, which was released on September 1975. The computer weighed 55 pounds and had a five inch CRT display, tape drive, 1.9MHz PALM processor, and 64KB of RAM.
IBM 5100 Computer

Compaq - In March 1983, Compaq released its first computer and the first 100% IBM compatible computer the "Compaq Portable."
Compaq Portable PC

Dell - In 1985, Dell introduced its first computer, the "Turbo PC."

Hewlett Packard - In 1966, Hewlett Packard released its first general computer, the "HP-2115."

NEC - In 1958, NEC builds its first computer the "NEAC 1101."

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