1. University of Utah 1 ENIAC First fully-electronic, general-purpose programmable computer Built 1943-1946

2. University of Utah 2 Background History Artillery gun "firing tables" Computed by hand "Computers" were people

3. University of Utah 3 Background History Herman Goldstine -Army lieutenant in charge of firing tables John Mauchly and Presper Eckert -Professors at U. of Pennsylvania -Idea for electronic calculating machines

4. University of Utah 4 Background History Army accepts proposal! -Why? Wartime desperation? Humiliation from atom bomb experience? New application of existing technology?

5. University of Utah 5 Background History Built it in-place on first floor of engineering building on U.Penn campus University assigns 12 people to project -no senior faculty

6. University of Utah 6 ENIAC Design Three main parts: -Math units -Memory units -“Master programmer” Wired together via cables

7. University of Utah 7 ENIAC Design Twenty "accumulators" -Base 10, not base 2 -Each could hold a 10-digit signed number -Each digit had its own circuit

8. University of Utah 8 ENIAC Design Counters -Vacuum tubes, not electromechanical relays -10 flip-flops per digit each flip-flop consists of 2 vacuum tubes -Converted electronic "pulses" to numbers -"Carry pulse" if sum > 9

9. University of Utah 9 ENIAC Design Speed -5000 additions per second -Multiplication: 2.6 milleseconds -Square root: 25 milleseconds

10. University of Utah 10 10 ENIAC Design Hackery -Multiplication = lots of additions "Multiplication table" had hard-coded answers to many multiplications -Division & square roots = lots of subtractions and additions -Constants: entered via "function tables" or punched cards

11. University of Utah 11 11 ENIAC Design Output -Punched cards -Neon lightbulbs

12. University of Utah 12 12 ENIAC Design Physical dimensions -40 "panels" -each panel 8.5 feet tall (2.6 m) -17,468 vacuum tubes -30 tons

13. University of Utah 13 13 ENIAC Design Quality standards -Used best vacuum tubes available < 10% recommended voltage Always powered on Broken tubes once every 2 days -"Least appetizing" wires -Custom-designed knobs

14. University of Utah 14 14 Pictures

15. University of Utah 15 15 Pictures

16. University of Utah 16 16 Pictures

17. University of Utah 17 17 Pictures

18. University of Utah 18 18 Programming No "programming" in the modern sense of the word. Manually set dials and plug in cables

19. University of Utah 19 19 Programming Time to program -Month to prepare a program -2 days to set up a program -1 week to debug “Usability” was an afterthought!

20. University of Utah 20 20 Timeline Finally finished in 1946 -(World War II was already over!) -Dismantled and sent to Aberdeen Proving Ground (Maryland) Used for hydrogen bomb calculations Retired in 1955

21. University of Utah 21 21 Demo

22. University of Utah 22 22 Other Early Computers Konrad Zuse -Another early pioneer -Z1 (mechanical) -Z3 (electromechanical) -Z4 (electronic)

23. University of Utah 23 23 Other Early Computers Atanasoff-Berry Computer (ABC) -1937 -All-electronic -Not general-purpose Designed to solve linear equations

24. University of Utah 24 24 Patent Problems ENIAC patent 1964 Honeywell vs Sperry-Rand (1973) -invalidated patent -ABC declared first computer -computers are public domain

25. University of Utah 25 25 Please note... Today is last of "pre-history" Wednesday we start with the textbook

26. University of Utah 26 26 “Test Question” On a scrap of paper, write a question that encapsulates one of the points from today's class, and turn it in. (Put your name on it!)