Rod Coleman's personal history of founding, building & running SAGE

Boris Gimbarzevsky boris at
Sat Jan 2 20:38:37 CST 2021

Probably read about this machine in Byte back 
then but was programming PDP-11's. Was very 
disappointed in IBM PC as IMO was far inferior to 
PDP-11 which was was easier to interface to data 
acquisition hardware and had a much nicer 
instruction set.  Ran into 68000 processor for 
first time in 1986 when my father bought a 512 K 
Mac and couldn't believe performance of this CPU 
compared to PDP-11 - 24 bit addressing! and 
inferior memory access to what Sage had.  Also, 
found 68000 instruction set very similar to 
PDP-11 and had no trouble writing assembly code 
for it a few years later and also really liked 
Apple's debug switch which was best 
implementation of a debugging system I've thus 
far run into.  Weird that Rod Coleman had 68000 
instruction set associated with IBM 370 whereas 
to me it was very PDP-11 like and 24 bit 
addressing was a very nice feature (that was one similarity to IBM 360)

Other interesting aspect to SAGE history was the 
influence of September 1966 issue of Scientific 
American computer issue on Rod Coleman and lots 
of other people I've talked to.  Was so glad that 
had this issue to read in 1966 and spent most of 
my time in boring school classes designing logic 
circuits and then building them at home using 
discrete DTL logic with parts salvaged from surplus IBM boards.

Thanks for the link as didn't realize 68000 was 
used for home systems before I ran into Mac.

>This may be old news -- it was new to me, though.
>I'm not really familiar with SAGE machines. They were not as
>well-known in the UK, I think, being upmarket from the Apple ][ and
>IBM PC, both of which were eye-wateringly expensive by UK standards of
>the time.
>Also, they were terminal-based things and even back then I was
>interested in boxes with graphics. :-)
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