hardware - Is this machine the EDVAC, MANIAC, or IAS? - Retrocomputing Stack Exchange
ENIAC was amongst the earliest electronic general-purpose computers made. It was Turing-complete, digital and able to solve "a large class of numerical problems" through reprogramming. Although ENIAC was designed and primarily used to calculate artillery firing From ENIAC to UNIVAC: An Appraisal of the Eckert-Mauchly Computers. Your image is a crop of an image used in George Dyson's book a play on where the machine was located. After ENIAC came: EDVAC IAS. Only the left half of ENIAC is visible in the first picture, the right half was After ENIAC and EDVAC came other computers with humorous names such as ILLIAC .
ENIAC had 20 ten-digit signed accumulatorswhich used ten's complement representation and could perform simple addition or subtraction operations between any of them and a source e.Who Invented the Modern Computer? The Triumphs and Tragedies of the World's First Computer (1999)
It was possible to connect several accumulators to run simultaneously, so the peak speed of operation was potentially much higher, due to parallel operation. Army photo  It was possible to wire the carry of one accumulator into another accumulator to perform double precision arithmetic, but the accumulator carry circuit timing prevented the wiring of three or more for even higher precision. The other nine units in ENIAC were the initiating unit started and stopped the machinethe cycling unit used for synchronizing the other unitsthe master programmer controlled loop sequencingthe reader controlled an IBM punch-card readerthe printer controlled an IBM card punchthe constant transmitter, and three function tables.
If one of the numbers had fewer than 10 digits, the operation was faster. So a division or square root took up to cycles, or 28, microseconds—a rate of 35 per second. If the result had fewer than ten digits, it was obtained faster. Special high-reliability tubes were not available until 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.
According to an interview in with Eckert, "We had a tube fail about every two days and we could locate the problem within 15 minutes.
Programming[ edit ] ENIAC could be programmed to perform complex sequences of operations, including loops, branches, and subroutines.
However, instead of the stored program computers that exist today, ENIAC was just a large collection of arithmetic machines, which originally had programs hard coded into the machines  by a combination of plugboard wiring and three portable function tables containing ten-way switches each.
Due to the complexity of mapping programs onto the machine, programs were only changed after huge numbers of tests of the current program.
This was followed by a period of verification and debugging, aided by the ability to execute the program step by step. Historians had at first mistaken them for "Refrigerator Ladies", i.
The job of computers was to produce the numeric result of mathematical formulas needed for a scientific study, or an engineering project. They usually did so with a mechanical calculator. This was one of the few technical job categories available to women at that time. Though contemporaries considered programming a clerical task and did not publicly recognize the programmers' impact on the successful operation and announcement of ENIAC,  McNulty, Jennings, Snyder, Wescoff, Bilas, and Lichterman have since been recognized for their contributions to computing.
The labor shortage created by World War II helped enable the entry of women into the field. For example, the National Advisory Committee for Aeronautics said in"It is felt that enough greater return is obtained by freeing the engineers from calculating detail to overcome any increased expenses in the computers' salaries.
The engineers admit themselves that the girl computers do the work more rapidly and accurately than they would. This is due in large measure to the feeling among the engineers that their college and industrial experience is being wasted and thwarted by mere repetitive calculation". Among these were several women, including Gloria Ruth Gordon. Scientists involved in the original nuclear bomb development used massive groups of people doing huge numbers of calculations "computers" in the terminology of the time to investigate the distance that neutrons would likely travel through various materials.
The success of this project showed the value of Monte Carlo methods in science. Elizabeth Snyder and Betty Jean Jennings were responsible for developing the demonstration trajectory program, although Herman and Adele Goldstine took credit for it.
None of the women involved in programming the machine or creating the demonstration were invited to the formal dedication nor to the celebratory dinner held afterwards.
It was formally accepted by the U. Army Ordnance Corps in July There, on July 29,it was turned on and was in continuous operation until The freeze on design in meant that the computer design would lack some innovations that soon became well-developed, notably the ability to store a program. Eckert and Mauchly started work on a new design, to be later called the EDVACwhich would be both simpler and more powerful.
Von Neumann is perhaps most famous infamous? Once the computer's program was represented electronically, modifications to that program could happen as fast as the computer could compute.
EDVAC Image taken originally from The Image Server ( Javier Vega ppt video online download
In fact, computer programs could now modify themselves while they ran such programs are called self-modifying programs. This introduced a new way for a program to fail: Today, one of the most notable characteristics of a computer is the fact that its ability to be reprogrammed allows it to contribute to a wide variety of endeavors, such as the following completely unrelated fields: By the end of the 's computers were no longer one-of-a-kind hand built devices owned only by universities and government research labs.
Eckert and Mauchly left the University of Pennsylvania over a dispute about who owned the patents for their invention. They decided to set up their own company.
Many people still confuse a picture of a reel-to-reel tape recorder with a picture of a mainframe computer. IBM grew so dominant that the federal government pursued anti-trust proceedings against them from to notice the pace of our country's legal system. You might wonder what type of event is required to dislodge an industry heavyweight. In IBM's case it was their own decision to hire an unknown but aggressive firm called Microsoft to provide the software for their personal computer PC.
This lucrative contract allowed Microsoft to grow so dominant that by the year their market capitalization the total value of their stock was twice that of IBM and they were convicted in Federal Court of running an illegal monopoly. The first was called time sharing because the computer gave each user a tiny sliver of time in a round-robin fashion. Perhaps users would be simultaneously logged on, each typing on a teletype such as the following: The Teletype was the standard mechanism used to interact with a time-sharing computer A teletype was a motorized typewriter that could transmit your keystrokes to the mainframe and then print the computer's response on its roll of paper.
You typed a single line of text, hit the carriage return button, and waited for the teletype to begin noisily printing the computer's response at a whopping 10 characters per second.
On the left-hand side of the teletype in the prior picture you can observe a paper tape reader and writer i. Here's a close-up of paper tape: Three views of paper tape After observing the holes in paper tape it is perhaps obvious why all computers use binary numbers to represent data: Something which can only take two states is very easy to manufacture, control, and sense.
In the case of paper tape, the hole has either been punched or it has not. Electro-mechanical computers such as the Mark I used relays to represent data because a relay which is just a motor driven switch can only be open or closed. The earliest all-electronic computers used vacuum tubes as switches: Transistors replaced vacuum tubes because they too could act as switches but were smaller, cheaper, and consumed less power.
Paper tape has a long history as well. It was first used as an information storage medium by Sir Charles Wheatstone, who used it to store Morse code that was arriving via the newly invented telegraph incidentally, Wheatstone was also the inventor of the accordion. The alternative to time sharing was batch mode processing, where the computer gives its full attention to your program. In exchange for getting the computer's full attention at run-time, you had to agree to prepare your program off-line on a key punch machine which generated punch cards.
An IBM Key Punch machine which operates like a typewriter except it produces punched cards rather than a printed sheet of paper University students in the 's bought blank cards a linear foot at a time from the university bookstore.
Each card could hold only 1 program statement. To submit your program to the mainframe, you placed your stack of cards in the hopper of a card reader. Your program would be run whenever the computer made it that far. You often submitted your deck and then went to dinner or to bed and came back later hoping to see a successful printout showing your results.
Obviously, a program run in batch mode could not be interactive. But things changed fast. By the 's a university student would typically own his own computer and have exclusive use of it in his dorm room. A microprocessor uP is a computer that is fabricated on an integrated circuit IC. Computers had been around for 20 years before the first microprocessor was developed at Intel in The micro in the name microprocessor refers to the physical size.
Intel didn't invent the electronic computer. But they were the first to succeed in cramming an entire computer on a single chip IC. In they were approached by Busicom, a Japanese manufacturer of high performance calculators these were typewriter sized units, the first shirt-pocket sized scientific calculator was the Hewlett-Packard HP35 introduced in Busicom wanted Intel to produce 12 custom calculator chips: But integrated circuits were and are expensive to design and this approach would have required Busicom to bear the full expense of developing 12 new chips since these 12 chips would only be of use to them.
A typical Busicom desk calculator But a new Intel employee Ted Hoff convinced Busicom to instead accept a general purpose computer chip which, like all computers, could be reprogrammed for many different tasks like controlling a keyboard, a display, a printer, etc.
Intel argued that since the chip could be reprogrammed for alternative purposes, the cost of developing it could be spread out over more users and hence would be less expensive to each user. The general purpose computer is adapted to each new purpose by writing a program which is a sequence of instructions stored in memory which happened to be Intel's forte.
Busicom agreed to pay Intel to design a general purpose chip and to get a price break since it would allow Intel to sell the resulting chip to others. But development of the chip took longer than expected and Busicom pulled out of the project. Intel knew it had a winner by that point and gladly refunded all of Busicom's investment just to gain sole rights to the device which they finished on their own. Thus became the Intelthe first microprocessor uP.