| gerard46 2004-04-22, 2:30 am |
| | Charles A. Crayne wrote:
|> George Weiss wrote:
|> Speaking of the 1620 - is that the model that was nicknamed the CADET? It
|> stood for "Can't Add - Doesn't Even Try" because it had no math processor
|> and used table lookup instead.
| That is, indeed, the story which I always heard.
The IBM 1620 (later renamed to the 1620 I) used a table lookup for adding and
multipling (and also for subtraction and division in a fashion).
The IBM 1620 II didn't require a table for either. Saying that the earlier
model didn't have a math processor is assuming a very narrow definition of
what a math processor is. There was a floating point (optional) feature,
and all arithmetic was in decimal (not binary). The IBM 1620 was a BCD
machine (binary-coding decimal).
By modifying the addition/multiplication table, one could do arithmetic in
any base <= 10 (on the model I). __________________________________Gerard
S.
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