The American astronauts calculated critical course-correction maneuvers on their HP-65 programmable hand-held during the rendezvous of the U.S. In September 1975, an advertisement in Scientific American read: AdvertisementsĪn HP brochure from 1974 proclaimed "This man is holding the smallest programmable computer ever". It was also the first to directly perform degrees.minutes seconds arithmetic (D.MS+ and D.MS-). The HP-65 was the first HP pocket calculator with base conversions (but only octal and decimal). (See the programming page detailed information.) Other features
Hp calculator emulator pc 42c manual#
In fact, the manual suggested that deleting lines and reinserting them, was often the quickest way to back up in a program. When displaying programs, only the keycodes (no line numbers) were shown and there was no BST (backstep) key. There were also operations to split numbers: INT truncated after the decimal and f -1 INT preserved only the fractional part. (0-9 could be used as the targets of gotos.) Two flags were provided as well as four conditional tests: x≠y, x≤y, x=y and x>y. "A" called a function labeled "A".) Valid label names were A-F and 0-9 but since 0-9 by themselves were interpreted as numbers rather than function calls, you could only use A-F as function/subroutines. On the HP-65, a function was called simply by invoking its name: (i.e. Some, but not all, multi-keystroke commands were merged into one line. Each instruction word was 6 bits long allowing for 64 distinct operations. The HP-65 had 100 lines of space and used label addressing. (e.g., f -1 LN gave you e x.) This allowed HP to get four functions per key without a lot of clutter. (This was the first appearance of the "tall" HP keys which continued to be used for years.) The fourth function was accessed using the f -1 key which produced the inverse of the f key. The normal function, a function printed in gold on the keypad above and a function printed in blue on the slanted front key surface. This little change kept HP-65's from looking prematurely old due to silver rubbing off when the calculator was switched on. If you look at the picture, notice how the silver band now goes around the display rather than below it.
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The HP-65 was housed in a case that looked much like the HP-35, but it was really slightly larger and very different to accommodate the card reader. After passing a card through the calculator, the card could be slid into a slot just above the top row of keys where the writable side of the card served as key labels for the calculator's five program-defined keys.
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These tiny cards (see pictures) had magnetic media on one side and a writable surface on the other. Users could write programs up to 100 lines in length and record them on blank cards, or they could buy pre-programmed cards.