A kitchen table in Albuquerque on a winter afternoon, a desk calculator kit half assembled, the lower half of a beige plastic case thirty centimetres deep holding a green circuit board, at its front two blocks of black, red and white keys, all plain smooth and unmarked, at the back a row of eight small glass tubes, the wedge-shaped beige cover with its wide dark window lying beside, a hand pressing a black chip into an empty socket, five more plain unmarked chips on grey foam, a muffin tin of resistors and capacitors, a soldering iron in its stand, a roll of solder, desert light on an adobe wall outside the window.
What it was used for
A desktop calculator the buyer soldered together himself. MITS (Micro Instrumentation and Telemetry Systems) announced the 816 in November 1971, with an article in Popular Electronics and a note in the newsletter of the Amateur Computer Society. It calculated with the 6-chip MOS-LSI set S-80 from Electronic Arrays, a slightly altered version of the S-100 set that set the decimal point by another method. Ready-assembled units were also sold, at a higher price. In the account of the Old Calculator Web Museum, the 816 was the first electronic calculator offered as a kit.
What was new
What marked it was not the calculating technique but the form of delivery: 6 LSI devices and a board the buyer populated himself, while competitors put finished machines on the shelves. The road ended within a few years. Against the single-chip calculators of Texas Instruments, Mostek and others MITS could not match prices; Ed Roberts turned to microprocessors such as the Intel 8080, presented the Altair 8800 in January 1975, left the calculator business in 1976 and sold MITS, debts included, to Pertec in the summer of 1977. He later studied medicine, graduated in 1986 and became a doctor in the small town of Cochran, Georgia.
What the sources leave open: The day's plan gives only title, year and technique; the identification as the MITS 816 rests on the year (1971) and the form (a desktop calculator sold as a kit). The source gives no prices, only that assembled units cost more. The November 1971 issue of Popular Electronics could not be consulted. The museum says Roberts was a doctor before MITS; according to Mercer University he only completed medical school in 1986.