Some HistorySome History

Computer

• First, there were mechanical calculators …

Antikythera Mechanism decoded?!

• Found in 1901 near the Antikythera island in a Roman shipwreck dated 80 BC• Remained a puzzle for over 100 years • Recently deciphered using X-ray tomography, optical imaging, texture mapping

Nature, 30 November 2006 (page 587)

A sophisticated mechanical calculator

Predicts:• Lunar and solar cycles, taking into account ellipticity of the moon’s orbit• Lunar and solar eclipses• Accurate positions of the sun, moon, and planets• Luni-solar calendar

Next time when much simpler mechanisms of this kind appeared was in Islamic countries in 1300 AD (Al Biruni)Later they were imported to Europe and became clock mechanisms

Invention of Computer

• The first digital electronic computer was invented by Theoretical Physics Prof. John Vincent Atanasoff in 1937. It was built by Atanasoff and his graduate student Clifford Berry at Iowa State College in 1939 ($650 research grant).

Basement of the Physics Dept. buildingwhere the Atanasoff-Berry Computer

(ABC) was built.

ABC•Used base-two numbers (the binary system) - all other experimental systems at the time used base-ten •Used electricity and electronics as it's principal media •Used condensers for memory and used a regenerative process to avoid lapses that could occur from leakage of power •Computed by direct logical action rather than by the enumeration methods used in analog calculators

Implemented principles of modern computersOnly material base has been changed.

ABC Replica

The drum – the only surviving fragment of ABC. It holds 30 numbers of 50 bits each. They are operated on in parallel. It is the first use of the idea we now call "DRAM" -- use of capacitors to store 0s and 1s, refreshing their state periodically.

Card punch and reader

Berry with the ABC

From ENIAC to …

ENIAC (1946) weighed 30 tons, occupied 1800 square feet and had 19,000 vacuum tubes.It could make 5000 additions per second

Computers in the future may weigh no more than 1.5 tons. (Popular Mechanics, 1949)

1940's - IBM Chairman Thomas Watson predicts that "there is a world market for maybe five computers".

1950's - There are 10 computers in the U.S. in 1951. The first commercial magnetic hard-disk drive and the first microchip are introduced. Transistors are first used in radios.

1960's-70's - K. Olson, president, chairman and founder of DEC, maintains that "there is no reason why anyone would want a computer in their home." The first microprocessor, 'floppy' disks, and personal computers are all introduced. Integrated circuits are used in watches.

Moore’s Law (1965): every 2 years the number of transistors on a chip is doubled

Smaller, Denser, Cheaper