Today’s Topics Lecture 10: Wartime Development Konrad Zuse 1910-95 Zuse Z1 The Coming Digital Electronics: Main Steps ABC of Eniac The Eniac based on Williams Chapter 7 Cradle of Invention Eckert & Mauchly A Vital Meeting The Machine Analysis of Eniac John Von Neumann Delay Line Memory
The ENIAC Slide 1
History of Computing Wartime Developments
Electronics development was increased by the war:
•Radar
•Atomic energy (bomb) calculations
•Coding and deciphering machines
•Electronic calculators.
15 Seconds after test detonation
The ENIAC Slide 2
History of Computing Konrad Zuse 1910-95
Konrad Zuse is popularly recognized in Germany as the inventor of the computer.
He built a mechanical device, which he (much later) called ``Z1'', in the living room of his parents' apartment in Berlin.
The construction of the Z1, the first programmable binary computing machine in the world, began in 1936 and finished in 1938. Konrad Zuseworking on a Z4 Computer (1942).
The ENIAC Slide 3
1 History of Computing Zuse Z1
In many ways the Z1 was a remarkable machine.
Z1 used punched tape memory, had a binary floating point unit, a control unit and binary-decimal-binary converters.
The Z1 was the first programmable, binary based machine in the world!
The building blocks of the Z1 The Z1 computer in the living room of Zuse's parents in 1936 were thin metal sheets.
The ENIAC Slide 4
History of Computing Digital Electronics: Main Steps
There were three main steps to the development of digital electronics:
Atanasoff-Berry Computer (ABC)
Colossus
ENIAC (Electronic Numerical Integrator and Computer)
15 Seconds after test detonation
The ENIAC Slide 5
History of Computing ABC
Atanasoff (1903-95) was of Bulgarian origin.
He wanted a better calculator for his mathematical calculations and produced an electronic calculator with a regenerative memory.
He was helped by his assistant Clifford Berry. Berry later committed suicide and Atanasoff was publicity-shy.
This didn’t help when there was a controversy about Mauchly (ENIAC) stealing Atanasoff’s ideas in 1940.
15 Seconds after test detonation
The ENIAC Slide 6
2 History of Computing
The ENIAC Slide 7
History of Computing The ABC in 1942
Clifford Berry with the actual ABC
The ENIAC Slide 8
History of Computing
Berry 1962
Atanasoff 1983
The ENIAC Slide 9
3 History of Computing The Eniac
Although NOT the first electronic computer, Eniac was a very important machine as it signalled a huge advance in electronic computing.
President Truman in front of ENIAC (U.S. Army photo, from archives of ARL/SLAD/BVLD, courtesy of Mike Muuss ).
The ENIAC Slide 10
History of Computing Cradle of Invention
The Moore School of Electrical Engineering, University of Pennsylvania collaborated on research with the U.S. Army Ordnance Department Ballistic Research Laboratory at the Aberdeen Proving Ground in Maryland.
The Ordnance department had to create complicated ballistic firing tables so that soldiers could aim guns etc. accurately. A collage depicting the Moore School during WWII, showing Mauchly in classroom.
The ENIAC Slide 11
History of Computing Eckert & Mauchly
John Mauchly and J. Presper (Pres) Eckert were the main driving force.
Eckert was the electronics expert and was a laboratory instructor.
Mauchly was professor of physics at Ursinus College, Philadelphia.
They met at the Moore school on a training course for the war. They chatted whilst others toiled.
Mauchly then joined the staff. He was interested in weather forecasting.
The ENIAC Slide 12
4 History of Computing A Vital Meeting
Mauchly met Atanasoff in 1940 and visited him during summer 1941. This led to discussions with Eckert on electronic calculations.
He wrote a paper on the subject in August 1942 and showed a huge increase in the number of calculations per second.
Early 1943 ballistics tables had fallen behind schedule.
Ballistics lab and Moore school decided to build ENIAC based on Eckert’s report.
The ENIAC Slide 13
History of Computing The Machine
The design was criticised by other engineers for its complexity.
Eckert was experienced in radar development and drew on for the ENIAC project management.
He allowed for component failure and carefully designed his circuits with this in mind (worse case scenario).
He also used cheap components, even if less reliable, in preference to paying for ultra-reliable, but more, expensive ones.
The complete machine consisted of a large number of individual units set out in a horseshoe shape. The ENIAC Slide 14
History of Computing The Units (1) 20 Accumulators.
They acted as a memory for a single 10 digit signed number; and also an arithmetic unit which could add or subtract a number from the one currently stored. They were an electronic copy of the mechanical register used for the Harvard Mark I.
A Multiplication Unit. These circuits worked by carrying out repeated single-digit multiplication.
A combined division and square root unit.
Three function tables, which stored tables of values, by means of switches (Harvard Mark I).
The ENIAC Slide 15
1 History of Computing The Units (2) An input unit connected to a card reader (120 cards per minute).
An output unit connected to a card punch (100 cards per minute).
The master programmer to control the sequence of operations.
There were 40 front panels, each 2 ft wide.
Each unit was made up of rows of electronic vacuum tubes and relays behind front panels containing •switches •indicator lights •plug sockets to interconnect units.
The ENIAC Slide 16
History of Computing Facts and Figures
Dimensions ENIAC was 8 ft high, 3 ft wide, 100 ft long, weighed 30 tons and used 140 KW of power.
Components 18,000 vacuum tubes of 16 basic types; 1,500 relays; 70,000 resistors; 10,000 capacitors
Cost Original estimate $150,000 dollars. Final cost $486,804.22
The ENIAC Slide 17
History of Computing Hot Stuff! With all this power consumption, ENIAC needed cooling and this was achieved by forcing air over the components (doors shut).
ENIAC up and running in Spring 1945.
Fire! A technician left a door open and the safety switch disabled and two units caught fire.
Reliability One vacuum tube out of 150 would fail every week or so. 18,000 logic tubes – one failed every two or three days.
Buses The units were connected via two bus lines which ran the entire length of the machine. One line carried data, the other instructions, the switches determining the precise details.
The ENIAC Slide 18
2 History of Computing Working with the Eniac
The machine carried out a calculation by plugging a large number of cables between the bus wires and the panels to ensure the data and instructions reach the correct units.
ENIAC programming Exercise
The ENIAC Slide 19
History of Computing Analysis of Eniac
Not enough accumulators;
Multiplication and division were time-consuming – repeated addition;
For a few years it was the only large-scale digital electronic computer in daily use.
Vacuum tubes reliable once warmed-up. Problem with night fire guard. Once solved, ran for next 10 years.
It had neither memory nor stored program (although memory was added later).
The ENIAC Slide 20
History of Computing John von Neumann (1)
Hungarian, brilliant mathematician;
1993 youngest member of Institute of Advanced Study, Princeton;
Worked on development of atom bomb during World War 2;
Good at report writing;
Science consultant;
Met Goldstine on train platform and found out about ENIAC;
The ENIAC Slide 21
3 History of Computing John von Neumann (2)
January 1944 Eckert considered storing programs electronically, and wrote document on magnetic storage;
September 1944, von Neumann regular visitor and entered into discussions on a new machine EDVAC, which, would store its instructions in its memory and issue these at the same speed as other components.
Von Neumann wrote up a report on EDSAC in June 1945 and he was credited with inventing the stored program and his name is in all the books (von Neumann architecture).
Bitter disputes!
The ENIAC Slide 22
History of Computing Delay Line Memory Exercise
Used in EDSAC, EDVAC, LEO and Pilot ACE.
A series of electrical pulses were converted into sound waves using piezoelectric quartz crystal.
These waves would then travel slowly down the tube, which was filled with mercury.
At the other end, they would be detected by another quartz crystal, amplified and reshaped and sent back to the front of the delay line again.
The ENIAC Slide 23
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