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Old 08-15-2007, 08:51 PM   #1
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Default Let's All Bow Our Heads

To what started it all..................


Eniac


Programmers operate the ENIAC's main control panel at the Moore School of Electrical Engineering. "U.S. Army Photo" from the archives of the ARL Technical Library


Detail of the back of a section of ENIAC, showing vacuum tubes.

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ENIAC, short for Electronic Numerical Integrator And Computer,[1] was the first large-scale, electronic, digital computer capable of being reprogrammed to solve a full range of computing problems,[2] although earlier computers had been built with some of these properties. ENIAC was designed and built to calculate artillery firing tables for the U.S. Army's Ballistics Research Laboratory. The first problems run on the ENIAC however, were related to the design of the hydrogen bomb.

The contract was signed on June 5, 1943 and Project PX was constructed by the University of Pennsylvania's Moore School of Electrical Engineering from July, 1943. It was unveiled on February 14, 1946 at Penn, having cost almost $500,000. ENIAC was shut down on November 9, 1946 for a refurbishment and a memory upgrade, and was transferred to Aberdeen Proving Ground, Maryland in 1947. There, on July 29 of that year, it was turned on and would be in continuous operation until 11:45 p.m. on October 2, 1955.

Description
Physically, ENIAC was massive compared to modern PC standards. It contained 17,468 vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5 million hand-soldered joints. It weighed 30 short tons (27 t), was roughly 8 feet (2.4 m) by 3 feet (0.9 m) by 100 feet (30 m), took up 1800 cubic feet (167 cubic meters), and consumed 150 kW of power. Input was possible from an IBM card reader, while an IBM card punch was used for output. These cards could be used to produce printed output offline using an IBM accounting machine, probably the IBM 405.

ENIAC used ten-position ring counters to store digits; each digit used 36 tubes, 10 of which were the dual triodes making up the flip-flops of the ring counter. Arithmetic was performed by "counting" pulses with the ring counters and generating carry pulses if the counter "wrapped around", the idea being to emulate in electronics the operation of the digit wheels of a mechanical adding machine. ENIAC had twenty ten-digit signed accumulators that used ten's complement representation and could perform 5,000 simple addition or subtraction operations between any of them and a source (e.g., another accumulator, constant transmitter) every second (Note: It was possible to connect several accumulators to run simultaneously, so the peak speed of operation was potentially much higher due to parallel operation). It was possible to wire the carry of one accumulator into another to perform double precision arithmetic but the accumulator carry circuit timing prevented the wiring of three or more for higher precision. The ENIAC used four of the accumulators controlled by a special Multiplier unit and could perform 385 multiplication operations per second. The ENIAC used five of the accumulators controlled by a special Divider/Square-Rooter unit and could perform forty division operations per second or three square root operations per second. The other nine units in ENIAC were the Initiating Unit (started and stopped the machine), the Cycling Unit (synchronized the other units), the Master Programmer (controlled "loop" sequencing), the Reader (controlled an IBM punch card reader), the Printer (controlled an IBM punch card punch), the Constant Transmitter, and three Function Tables.
The reference by Rojas and Hashagen gives more details about the times for operations, which differ somewhat from those above. The basic machine cycle was 200 microseconds (20 cycles of the 100 kHz clock in the cycling unit), or 5,000 cycles per second for operations on the 10-digit numbers. In one of these cycles, ENIAC could write a number to a register, read a number from a register, or add/subtract two numbers. A multiplication of a 10-digit number by a d-digit number (for d up to 10) took d+4 cycles, so a 10- by 10-digit multiplication took 14 cycles, or 2800 microseconds—a rate of 357 per second. If one of the numbers had fewer than 10 digits, the operation was faster. Division and square roots took 13(d+1) cycles, where d is the number of digits in the result (quotient or square root). So a division or square root took up to 143 cycles, or 28,600 microseconds—a rate of 35 per second. If the result had fewer than ten digits, it was obtained faster.

Reliability
ENIAC used common octal-base radio tubes of the day; the decimal accumulators were made of 6SN7 flip-flops, while 6L7s, 6SJ7s, 6SA7s and 6AC7s were used in logic functions. Numerous 6L6s and 6V6s served as line drivers to drive pulses through cables between rack assemblies. Some electronics experts predicted that tube failures would occur so frequently that the machine would never be useful. This prediction turned out to be partially correct: several tubes burned out almost every day, leaving it nonfunctional about half the time. Special high-reliability tubes were not available until 1948. Most of these failures, however, occurred during the warm-up and cool-down periods, when the tube heaters and cathodes were under the most thermal stress. By the simple (if expensive) expedient of never turning the machine off, the engineers reduced ENIAC's tube failures to the more acceptable rate of one tube every two days. According to a 1989 interview with Eckert the continuously failing tubes story was therefore mostly a myth: "We had a tube fail about every two days and we could locate the problem within 15 minutes."

In 1954, the longest continuous period of operation without a failure was 116 hours (close to five days). This failure rate was remarkably low, and stands as a tribute to the precise engineering of ENIAC

Programmability
The six women who did most of the programming of ENIAC by manipulating its switches and cables were inducted in 1997 into the Women in Technology International Hall of Fame ([1]). As they were called by each other in 1946, they were Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas and Ruth Lichterman.

Eckert and Mauchly took the experience they gained and founded the Eckert-Mauchly Computer Corporation, producing their first computer, BINAC, in 1949 before being acquired by Remington Rand in 1950 and renamed as their UNIVAC division.

ENIAC was a one-of-a-kind design and was never repeated. The freeze on design in 1943 meant that the computer had a number of shortcomings which were not solved, notably the inability to store a program. But the ideas generated from the work and the impact it had on people such as John von Neumann were profoundly influential in the development of later computers, initially EDVAC, EDSAC and SEAC.

A number of improvements were also made to ENIAC from 1948, including a primitive read-only stored programming mechanism [2] using the Function Tables as program ROM, an idea proposed by John von Neumann. Three digits of one accumulator (6) was used as the program counter, another accumulator (15) was used as the main accumulator, another accumulator (8) was used as the address pointer for reading data from the function tables, and most of the other accumulators (1-5,7,9-14,17-19) were just used for data memory. It was first demonstrated as a stored-program computer on September 16, 1948, running a program by Adele Goldstine for John von Neumann. This modification reduced the speed of ENIAC by a factor of six and eliminated the ability of parallel computation, but as it also reduced the reprogramming time to hours instead of days, it was considered well worth the loss of performance. Also analysis had shown that due to differences between the electronic speed of computation and the electromechanical speed of input/output, almost any practical real world problem was completely I/O bound even without making use of the original machine's parallelism and most would still be I/O bound even after the speed reduction from this modification. Early in 1952, a high speed shifter was added, which improved the speed for shifting by a factor of five. In July 1953, a 100-word expansion core memory was added to the system, using binary coded decimal, excess-3 number representation. To support this expansion memory, the ENIAC was equipped with a new Function Table selector, a memory address selector, pulse-shaping circuits, and three new orders were added to the programming mechanism
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Old 08-15-2007, 09:16 PM   #2
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Default Re: Let's All Bow Our Heads

to wat started it all!
lol i dont think my p3 is that under powered any more.......
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Old 08-15-2007, 10:05 PM   #3
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Default Re: Let's All Bow Our Heads

the VERY first computer was built in like 1944 and was used to guide battleships guns to hit targets at sea durning WWII
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Old 08-15-2007, 10:06 PM   #4
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Default Re: Let's All Bow Our Heads

This thread belongs in the Social Lounge. Although it has material that has to do with Hardware and Software, this is not discussion of a problem.

Moved.
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Old 08-15-2007, 10:09 PM   #5
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Default Re: Let's All Bow Our Heads

Wow, thats one fast computer, lol. Not to mention a power saver.
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Old 08-15-2007, 10:10 PM   #6
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Default Re: Let's All Bow Our Heads

Yo! Dave needs to get himself one of these. Then the server would run puuuurfectly.
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Old 08-15-2007, 10:17 PM   #7
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Default Re: Let's All Bow Our Heads

lets see... time to compute 10 + 10 on one of those? probably a few seconds. Time to compute 10 times 10.... a few minutes...

today... instant calculation of almost any sequence of numbers regardless of the amount, yet you can fit something that can do that in the palm of your hand. back then, you would need a pretty good sized building and still not get the same results.

i still love old computers though..
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Old 08-15-2007, 10:30 PM   #8
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Originally Posted by Thelis View Post
Yo! Dave needs to get himself one of these. Then the server would run puuuurfectly.
he did and running pretty good expect for it lagged reciving the word purfectly

BTW i know its not spelled right
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Old 08-16-2007, 09:30 AM   #9
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Originally Posted by Thelis View Post
This thread belongs in the Social Lounge. Although it has material that has to do with Hardware and Software, this is not discussion of a problem.

Moved.
Just where in the description does it say there has to be a problem to list it in the general forum?
Seems like a much better fit in the "General Computer Hardware And Software" forum than to lump it into a "social" forum where people can talk about a bunch of garbage like food, movies, girl friends, etc.
Computer talk in the social forum........seems backwards doesn't it?
Bad call IMHO.............maybe a little bored with nothing to do?

Sorry I wasted my time posting something I thought would be quite informative............

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General Computer Hardware And Software
General personal computer discussion and troubleshooting help goes here. Talk about your experience with computer products good or bad. Post pictures of your modified computer case, cards or new water or general cooling systems.
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Old 08-16-2007, 09:36 AM   #10
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New mod didnt read rules.
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