-------Original Message: Date: Sun, 02 Dec 2007 23:06:02 -0800 From: "Chuck Guzis" <cclist at sydex.com> Subject: Re: Mechanical calculators (was: Re: *updating* 8088's) On 3 Dec 2007 at 1:46, M H Stein wrote: ----- Well, the Burroughs F styling was a _little_ more modern and the Sensimatic program panels were a Burroughs trademark, but yes, that's the idea (even the flip-up table for the ledger tray on the left). The one in the eBay ad that Arno mentioned is a fairly late model F with the beige and blue colour scheme; the older ones were dark brown. Some nice pictures on that Portuguese site; even the 517 interpreter that got that other thread going. Incidentally, Sensimatic referred to the way the program pins were "sensed;" the pins were different lengths which determined the operation to be performed (add/subtract/print/etc.) and different pin locations determined the register number or the accumulator (sound familiar?). A set of sensing pins would rise up to measure the length of the program pins, and the keyboard also had "function keys" (called OCKs - Operator Control Keys) for different options (normal entry, error correction, etc.) A program would consist of steps like "Load A (from keyboard) (INP 01), "LD R1, 2 and 3 from A," "SUB A from R5&6," "Punch A (OUT 2)," "IF OCK3 then SKIP (JMP) to Step12," etc., all done mechanically with gears, levers and springs of course. Programming was done with a nibbling tool, a tray of numbered different length pins and a screwdriver. Wouldn't you love to have 20 registers today, and the ability to load/store more than one simultaneously? Mind you, that was also the entire memory until electronic versions came along... And of course they usually had colour printers ;-) (Red & black ribbons). BTW, AFAIK some Teletypes used the same type "box" as the typing Sensimatic that Arno is talking about. Think I still have one of those somewhere as well. m