1966 · Capacitor-Memory Desk Calculator · Work 928 of 1,871
A repair workshop for office machines in Tokyo at midday, on a steel workbench a light grey calculator forty-six centimetres wide with the back of its case opened, a hand in a white shirt cuff drawing out of it a brown circuit board, on its left half twelve dense rows of small red capacitors, on its right half small transistors with coloured caps, a row of gold contacts along its lower edge, every part plain, smooth and unmarked, beyond it in the long dark front window of the machine a row of fourteen small glass tubes glowing soft orange and out of focus, a soldering iron in its stand, cool fluorescent light.
What it was used for
The Toscal BC-1411 was an electronic desk calculator made by Tokyo Shibaura Electric (Toshiba); production began in November 1966; it had 14 Nixie digits of type CD-66, the 4 basic operations with direct percentage, one memory and a decimal point settable to 0, 3 or 6 places; it weighed 37.5 pounds, drew 25 W, and its clock ran at 40 kHz. Of the earlier BC-1001 the Old Calculator Museum writes that it may only have been sold in Japan, because Tokyo Shibaura Electric was at the time still establishing a marketing presence in the United States.
What was new
Working memory consisted of discrete capacitors: 15 by 12 of them, 180 bits in all, soldered onto a circuit board; the whole logic had 286 transistors, nearly all germanium PNP type 2SA50 of Toshiba's own making. Other calculators of the period used core memory, delay lines, flip-flop registers or rotating magnetic storage. The comparison with the later DRAM suggests itself and yet does not concern the same object: Robert Dennard's patent US 3,387,286 was filed on 14 July 1967 and granted on 4 June 1968, and claim 7 claims a cell consisting only of a field-effect transistor and a capacitor, that is, the monolithically integrated cell, whereas the Toscal had wired components in a matrix.
What the sources leave open: Use is not documented; the only detailed technical account comes from Rick Bensene after opening the machine. Company records are missing: Bensene writes that Toshiba left the calculator business in the early 1980s and kept nothing. The $1,695 price is marked there as an estimate; a yen price and a diode count are missing. Bonhams calls the memory "a unique form of dynamic random access memory (DRAM)", not the first DRAM.