Transcript A sophisticated mechanical calculator

Some 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. building
where 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 computers
Only material base has been changed.
ABC Replica
Berry with the ABC
Card punch and reader
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.
From ENIAC to …
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.
ENIAC (1946) weighed 30 tons,
occupied 1800 square feet and
had 19,000 vacuum tubes.
It could make 5000 additions per
second
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.
Smaller, Denser, Cheaper
Moore’s Law (1965): every 2 years
the number of transistors on a chip is
doubled