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The UNIVAC

A Complete History Of Mainframe Computing
By
The UNIVAC

As mentioned, Eckert and Mauchly left the University of Pennsylvania in 1946 to form the Electronic Control Co. They incorporated their company in 1947, calling it the Eckert-Mauchly Computer Corp., or EMCC. Their departure delayed the completion the EDVAC to the extent that the EDSAC, based on the EDVAC design, was actually completed before it. The dynamic duo, however, wanted to explore the commercial opportunities that this new technology offered, which was not possible with university-sponsored research, so they developed a computer based on their ideas for the EDVAC and even superseded them. Along the way, they created the BINAC for financial purposes, but the Universal Automatic Computer (UNIVAC) is really the more interesting machine.

The UNIVAC was the first-ever commercial computer, 46 units of which were sold to businesses and government after its 1951 introduction. All machines before it were unique, meaning they only made one of them. The difference for the UNIVAC was there were multiple UNIVACS (meaning many of the same design). Eckert and Mauchly correctly concluded that a computer could be used not only for computations, but also for data processing, while many of their contemporaries found the idea of using the same machine for solving differential equations and paying bills to be absurd. At any rate, this observation was critical in the design and success of the UNIVAC.

On a lower level, the UNIVAC consisted of 5,200 vacuum tubes (almost all in the processor), weighed 29,000 pounds, consumed 125 KW, and ran at a whopping 2.25 MHz clock speed. It was capable of doing 455 multiplications per second and could hold 1,000 words in its mercury delay-line memory. Each word of memory could contain two instructions, an 11-digit number and sign, or 12 alphabetical characters. The processing speed was roughly equivalent to the amount of time it took the ENIAC to complete the tasks that it could perform. But in virtually every other way, it was better.

Perhaps most importantly, the UNIVAC was much more reliable (mainly due to its use of much fewer vacuum tubes) than the ENIAC. On top of this, the "Automatic" in its name alluded to how it required no human effort to run. All the data was stored and read from a metal tape drive (as opposed to having to manually load the programs each time they were to be run with paper tapes or punched cards). Using tapes made actual processing much faster than the ENIAC, since the I/O bottleneck was mitigated. And of course, setup time re-wiring the ENIAC for the next "program" was eliminated. There were other niceties that made their appearance on the UNIVAC as well, like buffers (similar to a cache) between the relatively fast delay lines and relatively slow tape drives, extra bits for data checking, and the aforementioned ability to operate on both numbers and alphabetical characters.

The UNIVAC gained additional fame by correctly predicting the landslide presidential victory of Dwight Eisenhower in 1952 on national TV. This and the fact it was the first commercially available computer gave Remington Rand (which had bought EMCC) a very strong position in the burgeoning electronic computer industry. They had thrown down the gauntlet with UNIVAC. But what was IBM doing at this time?

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