Character width; was: these RTL or what?
ard at p850ug1.demon.co.uk
Sun Oct 7 15:21:08 CDT 2007
> > 6 bits was miserably crowded when numbers and punctuation were added.
> Six bits also is VERY inefficient for numeric data - all that stuff
Curiously, the HP9100 _calculator_ used 6 bit words. This made sesne for
user programs (and keycodes), but numbers were stored with one BCD digit,
a sign bit and a blanking bit in each word (I think). The main processor
register was 6 bits wide too.
The HP9810 that replaced it used 6 bit (logical width) memory, but I
think only for the user programs (which again were lists of 6-bit
keycodes). I think nunmbers were stoed in 16-bit-wide memory. Actually,
since this machine had phyical memeory that was half the width of the
logical memory (and circuitry to automaitcally do 2 memory cycles), this
must be one of the few machines to have 3-bit-wide memory boards.
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