Transcript Pre-mechanical computers

A Brief History of Computers
Bernard John Poole
University of Pittsburgh
Pre-Mechanical Computing:
From Counting on fingers
to pebbles
to hash marks on walls
to hash marks on bone
to hash marks in sand
Interesting thought:
Do any species, other than homo sapiens, count?
Mechanical computers
From
The Abacus
c. 4000 BCE
to
Charles Babbage
and his Difference Engine (1812)
Mechanical computers:
The Abacus (c. 3000 BCE)
Napier’s Bones and
Logarithms (1617)
Picture courtesy IBM
Oughtred’s (1621) and
Schickard‘s (1623]
slide rule
Blaise Pascal’s
Pascaline (1645)
Gottfried Wilhelm von Leibnitz’s
Stepped Reckoner (1674)
Joseph-Marie Jacquard and his punched
card controlled looms (1804)
Charles Babbage (1791-1871)
The Father of Computers
Inventor:
• cowcatcher, standard
railroad gauge,
• dynamometer,
• uniform postal rates,
• occulting lights for
lighthouses,
•Greenwich time signals,
• heliograph
opthalmoscope.
Charles Babbage’s Difference
Engine
Charles Babbage’s Analytical Engine
Lady Augusta Ada
Countess of Lovelace
- Documented Babbage’s discoveries
- programmed his machines
Electro-mechanical computers
From
Herman Hollerith’s
1890
Census Counting Machine
to
Howard Aiken
and the Harvard Mark I (1944)
Herman Hollerith and his
Census Tabulating Machine (1884)
A closer look at the Census
Tabulating Machine
The Harvard Mark I (1944)
aka IBM’s Automatic Sequence
Controlled Calculator (ASCC)
• Howard Aiken Physics at Harvard
• supported by IBM
• mechanical relays (switches)
• 35 tons with 500 miles of wiring
The first computer bug
Rear Admiral Dr. Grace
Murray Hopper
Electronic digital computers
From
John Vincent Atanasoff’s
1939
Atanasoff-Berry Computer (ABC)
to
the present day
Alan Turing
1912-1954
The Turing Machine
Aka
The Universal Machine
1936
John Vincent Atanasoff (1903-1995)
Physics Prof
At
Iowa State
University
1937: idea of
the first
modern
computer
Clifford Berry (1918-1963)
PhD student
of
Dr. Atanasoff’s
1939: paper
documenting
their design
1939
The Atanasoff-Berry Computer (ABC)
The ABC was the first electronic digital computer, invented
by John Vincent Atanasoff
1943
Bletchley Park’s Colossus
The Enigma
Machine
1946
The ENIAC
John Presper Eckert
(1919-1995)
and
John Mauchly
(1907-1980)
of the
University of
Pennsylvania Moore
School of Engineering
The ENIAC:
Electronic Numerical Integrator and
Computer
• 30 tons
• 18000
vacuum tubes
Programming the ENIAC
• programming
= rewiring
ENIAC’s Wiring!
John Von Neumann
John Von Neumann came up with the
bright idea of using part of the computer’s
internal memory (called Primary Memory)
to “store” the program inside the computer
and have the computer go get the
instructions from its own memory, just as
we do with our human brain.
1951
Univac
Typical 1968 prices—excluding maintenance & support!
Vacuum Tubes (1941 – 1956)
First Generation Electronic Computers
 ABC and ENIAC used Vacuum Tubes,
invented by Lee de Forrest in 1907
 Vacuum tubes are glass tubes with
circuits inside.
 Vacuum tubes have no air inside of
them, which protects the circuitry.
Transistors (1956-1963)
Second Generation Computers
 Uses Silicon
 developed in 1948 by William
Shockley and his team at Bell Labs
(Nobel prize)
 on-off switch
 Speed, in electronic terms, is
essentially a function of space. The
transistor was a fraction the size of a
vacuum tube and thus enabled
significant advances in computing
speed.
Integrated Circuits (1963-1971)
 Third Generation Computers used Integrated
Circuits (chips).
 Integrated Circuits are transistors, resistors, and
capacitors integrated together into a single “chip”
Very Large Scale Integrated Circuit
(VLSI), 1971-today

Kilby and Noyce, who founded Intel
Corporation, invented the
semiconductor in 1958. They are the
equivalent of a transistor, but layered
onto a thin sliver of silicon using
photomasking techniques

INTEL 4004 Microprocessor (by Hoff)
2,250 transistors
four-bit chunks (four 1’s or 0’s)
108Khz
Called “Microchip”
Personal Computers (1)
MITS Altair - 1975
 256 byte memory
 2 MHz Intel 8080 chips
 Just a box with flashing lights
 cost $395 kit, $495 assembled
PCs (2)
IBM PC – 1981
 IBM-Intel-Microsoft joint venture
 First wide-selling personal
computer used in business
 8088 Microchip - 29,000
transistors
4.77 Mhz processing speed
256 K RAM standard
 One or two floppy disk drives

PCs (3)
Apple II released 1977
widely used in schools
Macintosh (left)
released in 1984, Motorola
68000 Microchip processor
first commercial computer with
graphical user interface (GUI)
and pointing device (mouse)
Summary: Evolution of modern computers
UNIVAC
(1951-1970)
(1968 vers.)
Mits
IBM PC Macintosh
Pentium
Altair
(1981)
(1984)
IV
(1975)
2 Intel
Intel 8088 Motorola
Intel P-IV
8080
Microchip 68000
Microchip
29,000
- 7.5 million
Microchip Transistors
transistors
Circuits
Integrated
Circuits
RAM
Memory
Speed
512 K
265 Bytes 256 KB
256 MB
1.3 MHz
2 KHz
Storage
100 MB
Hard Drive
8” Floppy Floppy
Drive
Drive
Size
Whole
Room
Briefcase
3200 MHz
= 3.2 GHz
Hard
Drive,
Floppy,
CD-Rom
Small
Tower
(no monitor)
4.77 MHz
Floppy
Drives
Briefcase Two
+ Monitor shoeboxes
(integrated
monitor)
Cost
$1.6 million $750
$1595
~$4000
$1000 $2000