COMPUTER HARDWARE BASICS: COMPUTER HISTORY

FIRST GENERATION (1940-1950) :: VACUUM TUBE


The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.

First generation computers relied on machine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. Input was based on punched cards and paper tape, and output was displayed on printouts.

The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.

ENIAC (ELECTRONIC INTEGRATED COMPUTER)

• The Electronic Numerical Integrator and Computer (ENIAC) was developed for the U.S. Army to calculate ballistic tables.
• ENIAC used 19,000 vacuum tubes and 1,500 mechanical relays.
• ENIAC consumed almost 200 KW of power.
• ENIAC performed decimal arithmetic, in contrast to the binary arithmetic performed by computers today.
• ENIAC did not run from a stored program, but was programmed using patch cords.
• ENIAC was completed in 1946, and was operated until 1955.
• ENIAC cost almost $500,000.

UNIVAC (UNIVERSAL AUTOMATIC COMPUTER) 

• The Universal Automatic Computer UNIVAC I design was begun in 1946, and the first working unit was finished in 1951.
• The UNIVAC was the first computer designed for commercial sale.
• The UNIVAC I had 5200 vacuum tubes, weighed 29,000 pounds, and consumed 125 kilowatts of electrical power.
• The memory of the UNIVAC I was mercury acoustic delay lines.
• Numbers were stored in excess-3 binary coded decimal form.

SECOND GENERATION (1950-1964) :: TRANSISTORS


     The transistor computer did not last as long as the vacuum tube computer lasted, but it was no less important in the advancement of computer technology.  In 1947 three scientists, John Bardeen,William Shockley, and Walter Brattain working at AT&T's Bell Labs invented what would replace the vacuum tube forever.  This invention was the transistor which functions like a vacuum tube in that it can be used to relay and switch electronic signals.

        There were obvious differences between the transisitor and the vacuum tube.  The transistor was faster, more reliable, smaller, and much cheaper to build than a vacuum tube.  One transistor replaced the equivalent of 40 vacuum tubes.  These transistors were made of solid material, some of which is silicon, an abundant element (second only to oxygen) found in beach sand and glass.  Therefore they were very cheap to produce.  Transistors were found to conduct electricity faster and better than vacuum tubes.  They were also much smaller and gave off virtually no heat compared to vacuum tubes.  Their use marked a new beginning for the computer.  Without this invention, space travel in the 1960's would not have been possible.  However, a new invention would even further advance our ability to use computers. 


THIRD GENERATION (1964-1974) :: INTEGRATED CIRCUITS (IC)


       

The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.

   Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory. Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.

FOURTH GENERATION (1974-PRESENT) :: VLSI / ULSI


  The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. The Intel 4004 chip, developed in 1971, located all the components of the computer—from the central processing unit and memory to input/output controls—on a single chip.

       In 1981 IBM introduced its first computer for the home user, and in 1984 Apple introduced the Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.

       As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. Fourth generation computers also saw the development of GUIs, the mouse and handheld devices. 


FIFTH GENERATION (NOW AND THE FUTURE) 

Fifth generations computers are only in the minds of advance research scientists and being tested out in the laboratories. These computers will be under Artificial Intelligence(AI), They will be able to take commands in a audio visual way and carry out instructions. Many of the operations which requires low human intelligence will be performed by these computers.

Parallel Processing is coming and showing the possibility that the power of many CPU's can be used side by side, and computers will be more powerful than those under central processing. Advances in Super Conductor technology will greatly improve the speed of information traffic. Future looks bright for the computers.