88 Part 2 The instruction-set processor: main-line computers
instructions of the operator-operand variety; the use of the word as an information unit, within the range of 12 to 64 bits; and a processor state of less than 100 words. Alternative organizations are conceivable, though they have clearly riot seemed practical to computer designers. For instance, in the early fifties there was an at tempt to construct an electronic plugboard machine, after the fashion of the ENIAC and the IBM CPC (Card Programmed Calculator). And we see in the new programmed desk calculators (Part 3, Sec. 4) yet another organization that is rather far from the main line (but because of low cost may yet be a part of the future main line). These desk calculators, by the way, are decimal, rather than binary.