1970 · Programmable Desktop Terminal · Work 882 of 1,871
A desk-top computer terminal in the accounts office of a food company in Minneapolis on a spring morning, a low wide box about half a metre across in near-black anthracite with a cream-white rim around its face, on the left a wide low screen in a thin pale frame with a soft even green-grey glow, on the right a round orange button and a round white switch on a plain smooth dark panel, in front a row of cream-white keys with plain smooth tops, a hand in a white shirt cuff sliding a plain grey tape cassette into a slot in the top of the case, a grey steel desk, cool fluorescent light.
What it was used for
A programmable desk-top data station from Computer Terminal Corporation (CTC) of San Antonio, built for one user working directly. The IEEE Milestone proposal names General Mills (first sale 25 May 1970), Pillsbury (payroll), Levi Strauss (data entry), insurance firms and the University of Kansas as customers, and lists the CTOS cassette operating system, terminal emulators, an editor, an assembler, BASIC and the Databus business language as software. The screen showed 80 characters by 12 lines on a tube the size of an IBM punched card; 2 built-in cassette drives held 130 KB each; the machine weighed 25 kg. oldcomputers.net gives 7,800 USD for the 8K Version I and about 2,500 units sold by mid-1973; the proposal counts over 200 installations in the 3 months after the first sale.
What was new
Not "the first desktop computer", but: a machine with the footprint of a typewriter (18.5 by 9.6 inches) that ran programs itself instead of sending characters to a mainframe. Its processor was bit-serial, built from TTL parts, with 8 registers of 8 bits, a 16-bit address space formed from 2 combined 8-bit words and, in Version 1, 31 basic instructions; working store was recirculating shift registers, not core. Because the TTL processor needed about 100 packages, CTC gave functional specifications to Intel and to Texas Instruments to put the processor on one chip; Intel's version became the 8008. CTC never fitted that chip, but the proposal says the instruction set carried on through the 8008 and 8080.
What the sources leave open: The dates are of different kinds: the IEEE proposal gives a showing in April 1970, first sale 25 May 1970 and first installation invoice 7 April 1971; oldcomputers.net gives an announcement in June 1970 and release in November 1970. The proposal contradicts itself on memory size (128/256 bits versus 256/512 bits), so that figure is left out. Price and total unit numbers come only from oldcomputers.net.