Transcript Quick Overview of the History of Computers

A Brief Tour
of
The History of Computers
Presented by
Kevin Nichols
KA7OFR
The History of Computers
► About
me
► What I’ll be talking about
 Primarily information on selected computers
from the 1930s - 1950s
 A few details of how specific computers worked
 Such a vast field, I can do no more than touch
briefly on what’s out there
Preliminaries
► What
is a computer?
 A computer is “a machine that manipulates data
according to a list of instructions” – Wikipedia
 A program historically distinguished computers from
calculators, but not always
 Distinction is also made between devices that have
conditional instructions and those that do not
 Early computers came in two flavors: Analog & Digital,
And three methods of implementation: Mechanical,
Electric & Electronic
Early Calculating Devices
► Many
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examples of early calculating devices
Abacus / Soroban
Astrolabe
Napier’s Bones
Slide Rules
Early Calculating Devices
► But
none of these are computers if we
adopt the definition that a computer is a
device that contains a program, a list of
instructions to carry out automatically
► What I will discuss today are early
mechanical and electronic computers that
have the ability to be programmed
“Computer”
►
Side Note: The term “computer”, a term in use from the
mid 17th century, meant a person who performed
mathematical calculations (“computors”)
First Computer
► Which
was the “first” computer?
 Highly controversial
 Depends on specific terms and precise qualifications
► “First
electronic computer with stored program memory” vs
“First stored program computer” vs “First electronic computer”
 Not my intent to try to pin it down here
 I’ll just present several of the more “interesting” and
historical computers, and leave it to you to research
which you think was the “first”
Computer Categories
► Categorizing
computers
 Initially computers were human, then mechanical, then
electric, and finally electronic
 Differentiated by the calculating “medium” used
► Mechanical
 Gears, shafts, pulleys
► Electrically
 Relays
operated
► Electronic
 Vacuum tubes, Transistors, ICs
 Differentiated by the method of computing
► Analog
was initially faster, but less accurate
► Digital was initially slower but more precise
Computer Categories
Mechanical
Electrical
Analog
•Vannevar Bush’s
Differential
Analyzer
•Instructional
computers (GE
EF-140)
Digital
•Babbage’s
Difference &
Analytical
Engines
•Zuse Z1
•Bell Labs Relay
Computers
(Complex
Number
Calculator)
•Zuse Z3
Electronic (tube)
•Op-Amp Based
Computers
(Heathkit ES
Serias)
•Eniac
•Edvac
•Manchester “Baby”
•Edsac
Electronic
(transistor/IC)
•Op-Amp based
“plugboard”
computers
•Modern
Computers
Digital / Mechanical
Computers
1800’s & 1930’s
Digital / Mechanical
Babbage Difference & Analytical Engines
► Charles Babbage, 1791 - 1871
► Work included design of two
classes of machines
 Difference Engines
► Used
method of finite differences
► Uses only addition & subtraction
 Analytical Engines
► Mechanized
true “computer”
► Would have allowed decisions to be
made based on previous results
 Decimal based machines
 None of his machines were ever
completed in his lifetime
Image courtesy Computer History museum, Mountain View CA
Digital / Mechanical
Babbage Difference & Analytical Engines
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In 1800’s, mathematical
tables were used
extensively for Astronomy,
Engineering, Finance,
insurance
Tables were generated by
hand and prone to errors
These are what prompted
Babbage to work on his
mechanical devices
Image courtesy Computer History museum, Mountain View CA
Digital / Mechanical
Babbage Difference & Analytical Engines
► Babbage
utilized the method of “finite
differences” to create the mathematical
tables
► Eliminated the need for more complicated
operations (multiplication, division)
► Easier to implement using mechanical
devices
Digital / Mechanical
Babbage Difference & Analytical Engines
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Say we want to calculate the
function F(x) = X^2 + 4
The first several values of the
function are calculated (by
hand)
Columns of differences are
calculated until they are
constant
The rest of the values of the
function can then be calculated
(without multiplication!)
Any nth degree polynomial can
be calculated starting with the
nth difference
That is what Babbage was
trying to “mechanize”
Image courtesy Computer History museum, Mountain View CA
Digital / Mechanical
Babbage Difference & Analytical Engines
► Difference
Engine #1, 1821
25,000 parts
Est. 15 tons
8 ft high
Designed to calculate
polynomial tables using
method of finite differences
 Work was halted in 1832 due
to dispute with a co-worker
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Image courtesy Computer History museum, Mountain View CA
Portion of Difference Engine #1, 1832
Digital / Mechanical
Babbage Difference & Analytical Engines
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Difference Engine #2,
1847 - 1849
 8,000 parts (3x less than
#1)
 5 tons
 7ft high, 11 ft long, 18”
deep
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Could compute 31 digit
results
Up to 7th order polynomial
(could hold 7 differences)
Included a paper printing
press with mold for type
Video…
Image courtesy Computer History museum, Mountain View CA
Working reproduction of Difference Engine #2
Built from 1985 - 2002, using Babbage’s original designs
Digital / Mechanical
Babbage Difference & Analytical Engines
Video courtesy: Computer History Museum, Mountain View CA
Digital / Mechanical
Babbage Difference & Analytical Engines
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Babbage also designed a
much more ambitious
calculating device: The
Analytical Engine
Contained a memory (the
“store”) and an
arithmetical unit (the
“mill”)
Could add, subtract,
multiply & divide
Was programmable using
punched cards
Capable of conditional
branches and loops
Image courtesy Science Museum, London England
Portion of the “mill” of the Analytical Engine, 1871
Digital / Mechanical
Zuse Z1
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Konrad Zuse, Germany, 1910
- 1995
Z1 built 1936 – 1938 in
apartment of his parents
Binary computer using metal
plates as logic elements
Programmed via punched
tape
2 registers of 22 bits each
Floating point numbers(!)
Clock frequency of 1 Hz
Destroyed in Dec. 1943
during WW II Berlin
bombardment
Reconstructed Z1, 1986 - 1989
Digital / Mechanical
Zuse Z1
► Metal
sheets
function as logic
gates
NOT
 AND
 OR
 NOT
OR
Part of original metal plates, Z1
Digital / Mechanical
Zuse Z1
Input
Output
Clock
Digital / Mechanical
Zuse Z1
Input
Output
Clock
Digital / Mechanical
Zuse Z1
Input
Output
Clock
Digital / Mechanical
Zuse Z1
Input
Output
Clock
Digital / Mechanical
Zuse Z1
Input
Output
Clock
Digital / Mechanical
Zuse Z1
Input
Output
Clock
Analog / Mechanical
Computers
Early 1900s
Analog / Mechanical
Bush Differential Analyzer
Vannevar Bush, 1890 – 1974
► Engineering professor at MIT
► Built the Differential Analyzer, 1928
– 1931 to solve electric power
transmission problems
► Used metal rods, gears, wheels
► Designed to solve up to 6th order
differential equations & calculate up
to 18 independent variables
► Solves differential equations by
integration, 2% accuracy
► 150 motors
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Analog / Mechanical
Bush Differential Analyzer
► The
Differential Analyzer consists of several
interconnected parts
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Disk & Plate Integrators
Torque Amplifiers
Input/Output tables
All the connecting gearing, rods, etc.
► Great
effort required to set up the computer
for different problems
Analog / Mechanical
Bush Differential Analyzer
Analog / Mechanical
Bush Differential Analyzer
► Integration
performed
with glass disk
integrators
► Uses knife edge wheel
rolling on glass disk
► Rotation of output shaft
depends on rotation of
input glass disk, and
distance of wheel from
center of disk
Analog / Mechanical
Bush Differential Analyzer
► Torq
Amplifier
 Required due to the very
low torque output
available from the
integrator wheel
 Wheel must not be
allowed to slip on glass
disk
► Output
rotates at same
velocity as input, but
with greatly increased
torque
Analog / Mechanical
Bush Differential Analyzer
► Input/Output
Tables
 Input table
► Provide
arbitrary input as
computer runs
► Computer drives ‘X’
direction, human turns
knob to make pen follow
curve
 Output table
► Computer
drives pen in
‘X’ and ‘Y’ coordinates to
draw curve on paper
Analog / Mechanical
Bush Differential Analyzer
► Examples
of use
 Calculation of firing tables for artillery used in WWII
 “Bouncing Bomb” by Barnes Wallis for attack on Ruhr
Valley Hydro dams in WWII
► Height,
length, number of bounces calculated based on
changing parameters of:
 Bomb initial spin, Speed & height of aircraft, Weight of bomb
 Bomb shape influencing ballistic characteristics, Buoyancy in water
 River control studies
► Calculation
of soil erosion based in changing parameters of
 Rate at which water falls on surfaces, resistance to flow by surface
 Speed of flow of water, Volume of water
Analog / Mechanical
Bush Differential Analyzer
►A
“home made” differential analyzer was
built in 1934 by Hartree & Porter
► Built at the University of Manchester
► Made primarily of Meccano parts
 Was actually used for military purposes
 Cost 20 pounds
 Said to have Achieved 2% accuracy
Analog / Mechanical
Bush Differential Analyzer
Analog / Mechanical
Bush Differential Analyzer
►A
modern version of the Meccano
Differential Analyzer was recently built
 Designed, assembled and operated by Tim
Robinson
 Shown at the Vintage Computer Festival in
California
 Contains 4 wheel & disk integrators
 Video…
Digital / Electric (Relay)
Computers
1930s - 1940s
Digital / Electric - Relay
Bell Relay Computers
► Bell
Labs / George Stibitz
 1937 – Demonstrate relays
used as a binary adder
 1939 - Complex Number
Calculator (Model 1 Relay
Computer) Demonstrated
► Cost
$20,000
► 450 telephone relays
► Calculated quotient of two 8place complex numbers in 30
seconds
 A calculator Not truly a
computer
 First demonstration of remote
access
Digital / Electric - Relay
Zuse Z3
►
Konrad Zuse created many
other relay-based ‘Z’
machines beyond the Z1,
Z3 probably the most
famous
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Operational May 12, 1941
64 numbers of 22 bits each
Floating point math
“+”, “-”, “*”, “/” and square
root
5.3 Hz, Addition 0.8 seconds,
multiplication 3 seconds
2600 relays, 4kW, 1 ton
I/O using punched tape
No conditional jump
Reconstructed Z3, 1960
Digital / Electric - Relay
Reconstructed Z3, 1960
Zuse Z3
Digital / Electric - Relay
IBM Relay Computers
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IBM / Harvard Mark I (Automatic
Sequence Controlled Calculator)
Development lead by Howard
Aiken
1944 – Installed at Harvard
University
 51 ft long, weighed 5 tons
 750,000 parts
 72 accumulators, 60 sets of rotary
switches
►
Addition: 1/3 second,
multiplication 1 second
Digital / Electric - Relay
IBM Relay Computers
 Automatic Sequence Controlled Calculator
Digital / Electric - Relay
IBM Relay Computers
►
IBMs Selective Sequence
Electronic Calculator
 1948 – 1952
 21,400 relays, 12,500
vacuum tubes
 50 14 digit x 14 digit
multiplications / sec
 Reportedly produced the
moon position tables used
for plotting the course of
the 1969 Apollo moon
flight
Digital / Electric - Relay
IBM Relay Computers
► Operator
console
 Lots of blinking
lights
 Machines of this
era responsible for
Hollywoods early
fascination with
blinking lights on
computers
Digital / Electronic (Tube)
Computers
1940s - 1950s
Digital / Electronic (Tube)
ENIAC
► At
start of WWII, the Army’s Ballistics Research
Lab trained about 100 human computers to
calculate ballistics tables
Digital / Electronic (Tube)
ENIAC
► The
Differential Analyzer & mechanical desktop
calculators were used to solve the differential
equations of motion
► A skilled operator took about 3 days to calculate a
single trajectory
► As the war progressed, the BRL couldn’t keep up
and fell way behind
► No firing table = useless guns!
► This crisis lead to the Army investing in two men
with an idea of how to calculate much faster
Digital / Electronic -Tube
ENIAC
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Electronic Numerical Integrator And Computer
Probably most well known of the early computers
Started in April 1943 finished Nov 1945 (after the war!)
Digital / Electronic (Tube)
ENIAC
► Developed
by John Mauchly and J. Presper Eckert
► Built at the Moore School of Electrical Engineering
at the University of Pennsylvania
Digital / Electronic (Tube)
ENIAC
► The
complete computer consisted of several
interconnected modules
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Initiating Unit
Master Programmer
Cycling unit
Multiplier
Divider/Square Rooter
20 accumulators
Input/Output
Constant transmitters
Function Tables
Digital / Electronic (Tube)
ENIAC
► Eniac used approx. 18,000 radio tubes
► Experts questioned reliability of tubes
► Eckert’s design for low power, modular
worked well
design
Digital / Electronic (Tube)
ENIAC
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ENIAC Statistics
 17,468 tubes
 70,000 resistors, 10,000 capacitors
 1,500 relays
 6,000 manual switches
 8’ high x 80’ long, weighed 30 tons
 Consumed 174,000 watts
► Performance
 Could do 5,000 10-digit additions / sec
 333 multiplications / sec
 Calculate trajectory in 20 seconds (D.A. took 15-30
minutes)
Digital / Electronic (Tube)
ENIAC
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Computed by counting pulses using base-10 rather than base-2
Eniac’s primary calculating modules were the 20 Accumulators
Each accumulator consisted of 10 ring counters of 10 digits each
Digital / Electronic (Tube)
ENIAC
► Function
tables were (laboriously) entered using
rotary switches
Digital / Electronic (Tube)
ENIAC
► Programming
consisted of connecting together the
various units with cables
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ENIAC could not
store programs
electronically
A program was
defined by the state
of patch cords and
switches
“Reprogramming”
required days of
configuring cables
Digital / Electronic -Tube
ENIAC
► Eniac
was even
used as a
recruiting tool
► Army’s 1940’s
version of “Be all
you can be” ad!
Video…
Digital / Electronic (Tube)
ENIAC
Digital / Electronic (Tube)
EDVAC
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Electronic Discrete Variable Automatic Computer
Mauchly & Eckert proposed & started
before Eniac was fully complete
First designed computer for Stored
Program concept
Built for US Army Ballistics Research
Lab. Contract signed April 1946,
completed 1953
Contract for $100,000. Final cost
$500,000
Capability
 16 instructions
 1,024 44-bit binary words
 Add (864 us), Subtract, Multiply (2.9
ms) Divide
 “RAM” was ultrasonic delay line
 6,000 tubes, 12,000 diodes
 56 kW power
 8.5 tons
Digital / Electronic (Tube)
EDVAC
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Mercury delay lines used
as “RAM” memory
Leveraged research in
RADAR during WWII
2 sets of 64 delay lines of
8 words capacity each
Each tube was 384 us
“long”
Representative Univac delay line memory
Digital / Electronic (Tube)
EDVAC
► One
of the first machine to which the “von
Neumann Architecture” applies
Digital / Electronic (Tube)
EDVAC
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Eckert & Mauchly left the EDVAC project prior to completion, so it
was not the first computer to operate with a stored program
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The Manchester “Baby” computer (above) therefore was the first
computer to operate with the stored-program concept in June 1948
Digital / Electronic (Tube)
Manchester Baby
Developed by Tom
Kilburn at the University
of Manchester
► Utilized a “Williams Tube”
CRT for memory
► Stored 2048 bits of “RAM”
► 32 bit word length
► 3 bits for instructions
► Serial binary operation
► Solved finding the largest
factor of 2^18 in 52
minutes
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Digital / Electronic (Tube)
Manchester Baby
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RAM Memory was Williams
Tube stores bits as charge
on the face of the 6” CRT
Digital / Electronic (Tube)
Manchester Baby
►7
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Instructions
A = -S (010)
A = A – S (101)
S = A (110)
If A < 0, CI = CI + 1 (011)
CI = S (000)
CI = CI + S (100)
Halt (111)
Later added: A=S, A=A + S,
A=A&S
Where A is the accumulator
S address of a memory location
CI is the address of the current instruction
Tom Kilburn’s First Program, find the
highest proper factor of any number
Digital / Electronic (Tube)
EDSAC
Electronic Delay Storage Automatic Calculator
EDSAC was developed
by Maurice Wilkes at
Cambridge University
► Work started in 1947
after Wilkes attended
the 1946 Moore School
lectures
► Patterned after EDVAC
► Contained 3000 tubes,
600 operations / sec
► First program executed
May 1949
►
Digital / Electronic (Tube)
EDSAC
► EDSAC
Memory
 EDSAC utilized
ultrasonic mercury
delay line tubes for its
memory
 32 tanks, each of which
contained 32 numbers
of 17 bits each (1024
storage locations)
 Two can be combined
to handle a number 35
bits long
Digital / Electronic (Tube)
EDSAC
► Control
Desk
 Contained 6 CRTs
used to monitor the
contents of memory
 5-hole punched tape
for input
 Output was to a
teleprinter
 Used a telephonetype dial to input
single decimal digits
Digital / Electronic (Tube)
EDSAC
A very good Windows
simulator is available
for the EDSAC
► Written at Warwick
university
► Complete instructions
on use and sample
programs are included
► Demonstration?
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Analog / Electronic
(Transistor)
Computers
1950s - 1960s
Analog / Electronic (Transistor / IC)
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In the 50s and
60s (even 70’s)
electronic versions
of the analog
computer were
available
Generally
consisted of Op
Amps with the
ability to connect
them to add,
subtract, multiply
integrate, etc.
Hobby / Training
Computers
1950s - 1960s
Hobby / Training computers
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Heathkit produced several analog
computer kits in the 50’s
One shown is the ES series
Tube operated, amplifier based
15 amplifiers, 3 I.C. power supplies,
30 coefficient potentiometers
Full kit listed for $945 in 1956 (about
$7,400 today)
Hobby / Training computers
GE produced a simple
educational analog computer
► Model EF-140 shown
► Used potentiometers and
cardboard dials with scale
markings
► Solved equations like Y = 3X,
or Z = X / Y
► $29.29, used 4 ‘D’ batteries
► Used transistors for amplifier
/ oscillator / null indicator
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Hobby / Training computers
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Digicomp 1
Produced in 1965 by ESR
Inc. for $5.95 (about $40
today)
Taught basics of boolean
algebra, writing
“programs”, binary addition
Possible to play game of
“nim”
50 page instruction manual
included
Hobby / Training computers
► Bell
Labs “Cardiac”
probably the least
expensive of any
“computer”
► Manually operated
► Designed to teach
the basics of digital
computer operation
The End
Thanks!
Resources
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Websites
 Computer History Museum
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http://www.computerhistory.org
Mountain View, CA
 London Science Museum
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http://www.sciencemuseum.org.uk/
 Tim Robinson’s Differential Analyzer Meccano
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Books
http://www.meccano.us/differential_analyzers
/robinson_da/
 “Bit by Bit an Illustrated History of
Computers” by Stan Augarten
 “The Moore School Lectures” Vol 9, The MIT
Press, © 1985
 “The Origins of Digital Computers” Selected
Papers, Springer Verlag, 2nd ed © 1970