William Donzelli wrote:
Well the 1620
was a variable length machine ... A sign/flag bit made
more sence at the time since
you only had as many BCD digits as you needed.
It is still very inefficient, with lots of wasted bits. It would not
matter with a small machine like a 1620, but it does when the system gets
larger. Even a small S/360 dwarfs a 1620. All those wasted bits add up.
The 1620 is BCD serial ... slow but then lots less $$$ than a 360.
Since I only got to know small computers like a PDP 8 and a IBM1130
I never had to deal with the bigger stuff.
Going back a few days to a previous thread about books,
I suggest you read
pages 148 and 149 of *IBMs System 360 and Early 370 Computers*. You may
then see that there was no conspiracy against sixbit.
I never said a word about 6 bits ... I grumble about 11111111 base 0 bits.
There is a lot of good reasions why we have 8 bits mostly because 4 bits
work
nice for MSI like alu's and shift registers.
William Donzelli
aw288 at
osfn.org