UNIVAC I
| UNIVAC I | |
| Manufacturer: | Remington Rand |
|---|---|
| Year Design Started: | Early 1947 |
| Year First Shipped: | March. 1951 |
| Form Factor: | mainframe |
| Word Size: | 72 bits |
| Logic Type: | vacuum tubes |
| Design Type: | serial asynchronous |
| Clock Speed: | 2.25 Mhz (basic - serial machine; add - 120 μsec for operation, 525 μsec for complete instruction) |
| Memory Speed: | 400 μ sec (maximum) |
| Physical Address Size: | 3 digits (decimal) |
| Predecessor(s): | EDVAC |
| Successor(s): | UNIVAC II |
| Price: | US$1250-1500K (system) |
The UNIVAC I ('UNIVersal Automatic Computer'; originally, just plain 'UNIVAC', until later models appeared) was the first commercially-available computer in the US.
It was a vacuum tube machine, using mercury delay lines for main memory, with 1000 words organized as 100 lines of 10 words each (to reduce access times). The CPU operated in digit-serial mode (i.e. a digit at a time), to match the memory. Its word size was 72 bits, with two instructions per word, with 12 digits/characters per word; it stored numbers with a form of packed decimal, digits being represented as their character equivalents.
The only input/output devices were magnetic tape units, the 'UNISERVO'. Data could be tranferred to and from tape with offline peripherals which allowed use of printing, keyboard input, and punched cards.
A careful, slow power-on procedure, in which the filaments in the tubes were slowly warmed up, produced very reliable operation. (No doubt prior experience with tubes in the ENIAC had educated the UNIVAC's builders.)
