bit slice chips (was Re: Harris H800 Computer)
elson at pico-systems.com
Sat Apr 23 10:33:59 CDT 2016
On 04/22/2016 11:10 PM, Jon Elson wrote:
Yikes, too many typos, let me try over!
> I built a 32-bit micro-engine for a project that was
> eventually going to be an IBM 360-like CPU.
> I picked the 360, not because it was the greatest design,
> but it was VERY well laid-out and would be easy to write
> efficient microcode for. I used the 2903 with 2910
> controller. I was able to get it to run at 8 MHz, with
> 3-address operations running at 6 MHz.
> But, the project got bogged down, at a certain point, I
> realized HOW MUCH more work lay ahead of me to get a
> working system. I had to add 2 more features to the
> micro-engine - a 256-way branch from the op-code, and some
> OR gates to OR in the register address fields. Then, I
> had to build a system bus and memory interface.
> (I was going to make the I/O architecture much more like a
> PDP-11 than the 360 channel architecture.) Then, I had to
> design a general-purpose peripheral controller. I had a
> VERY rough sketch for about a 20-chip micro-machine using
> (probably) 3X byte-wide EPROMS for instructions) that
> would hopefully run at 4 MHz. Then, I had to build a SCSI
> controller (I already had a SASI disk on my S-100 system),
> a serial mux and a tape controller.
> Finally, I had to write at least a primitive OS and figure
> out how to come up with compilers for it. Had I known
> that UNIX-360 existed, I might have tried to make some
> kind of port of that. But, obviously, YEARS of work would
> have been needed to make it usable.
> See http://pico-systems.com/stories/1982.html for some
> pics and description of it.
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