The Electronic Revolution: Part 1

Question 1

What is the difference between electronic and mechanical/electro mechanical computing devices

Answer 1

electronic computing devices derive results using electronics, any mechanical parts are not part of key calculations. In contrast, mechanical/electro-mechanical use mechanical parts for key calculations.

Question 2

What were the three main categories of electronic computers

Answer 2

• The ABC
• The ENIAC
• The British code breaking machines

Question 3

What was the first electronic computer (partially and fully completed)

Answer 3

partially: ABC
fully: ENIAC

Question 4

The technical specifications of the first electronic computers

Answer 4

ABC:
• Arithmetic unit: – 300 vacuum tubes (addition and subtraction)
• Control and memory – 300 vacuum tubes

Question 5

The general appearance and cost/resources used in the building of the first electronic computers

Answer 5

ABC: Cost 6000
ENIAC: Cost over 486 000

Question 6

The history behind the names of the first electronic computers

Answer 6

ABC: Atanasoff-Berry Computer named after creators

Question 7

Who were the people behind these computers and what were some of the major events in their lives

Answer 7

ABC: John Atanasoff, Clifford Berry
ENIAC: John Mauchly and J. Presper Eckert

Question 8

What were the approximate dates/time frames of significant

developments in the mechanical monsters

Answer 8

weg

Question 9

What was the motivation behind the ABC’s development?

Answer 9

Atanasoff was researching methods of solving complex physics equations.
The drudgery of using the calculators of the day motivated him to find something better.

Question 10

What were the circumstances behind the ABC’s conception?

Answer 10

Atanasoff was building the machine by himself until he decided he needed the help from Berry. Cost almost 6000.

Question 11

How did the regenerative memory work?

Answer 11

Used a drum and capacitors. Drum rotates around and each time capacitors reached a certain spot in the rotation they would receive an electrical charge.

Question 12

What were The major events in the history of the Moore school with regards to the ENIAC?

Answer 12

wage

Question 13

What was The type of research work was done at the Moore school with regards to the ENIAC?

Answer 13

aweg

Question 14

What was the major computational bottleneck with regards to the ENIAC?

Answer 14

The accumulators were frequently the limiting speed factor of the machine.
Sometimes the 20 accumulators could not store all the partial results.
– The results would then have to be printed and fed back into the machine as a new calculation.

Question 15

Why multiplication and division operations were theoretically fast but in practice slow and what alternatives were employed with regards to the ENIAC?

Answer 15

Multiplication and division would so resource intensive (partial values) that although the machine could perform them quickly if all the results could be stored they were usually avoided whenever possible:
– Multiple adds/subtractions
– Bit shifting
– Using the principle of constant differences between functions (Babbage)

Question 16

What was a ‘unit’ in the ENIAC and what did it consist of?

Answer 16

A unit would contain it’s own memory and control (vacuum tubes and relays).

Question 17

How was numerical information stored in memory in the ENIAC?

Answer 17

As 10 digit signed numbers(decimal) in accumulators

Question 18

How did the cooling system work in the ENIAC?

Answer 18

• The computer was air cooled
– Two 12 horse power motors pumped 600 cubic feet of air per minute through each panel
• Each panel had it’s own thermometer
– The temperature for each panel could be individually regulated
– There was fail safe that would shut down the entire machine if any panel exceeded 120 F/49C.
• During servicing the panels had to be opened (air leak) and the fail safe disabled.
– A floor fan could be used to cool a panel during this time.

Question 19

What was The method of programming the ENIAC?

Answer 19

re-wiring cables going to/from different sockets.
bus wires determine:
- which units are activated
- which units to send data to
- whether instructions should be repeated
- if a memory accumulator should be reset to 0
numerical buses:
- send number and complement
- used 12 wires, 10 for digit, 1 for sign , 1 for grounding connection

Question 20

What were some of the later enhancements of the ENIAC?

Answer 20

• A magnetic drum to store intermediate results.
• More (core) memory added:
– Store intermediate results
– Act as an input/output buffer
– 100 words (digits) in a cabinet
• the ENIAC became programmable

Question 21

What was the eventual fate of the ENIAC?

Answer 21

It was shut off for the final time on October 2, 1955
• Parts of the machines are on display at the National Museum of American History (Smithsonian) and other locations (e.g., School of Engineering and Applied Science at the University of Pennsylvania).