26 Oct
2010
26 Oct
'10
1:48 a.m.
From: William Donzelli <wdonzelli at gmail.com>
True
For production the plan was for bare silicon mounted on hybrids but the silicon itself was
large. Of course as production progressed die sizes would have been shrunk but not fast
enough.
We also used up to 22 layer PCBs! IIRC, samples when they became available would have
been DIPs, they were for the Z8001 for sure. We used our own Elliott 920ATC computers to
load code into shared RAM before the microprocessor was released from reset. I also wrote
a simulator (for the Z8001) for compiler, high level assembler and other utility software
development.
Unfortunately working at a technical level on the leading edge does not pay very well in
the UK. I was told I would not be able to progress to a higher grade without becoming a
manager, so I left and became a major shareholder and director of a tiny company and have
remained technical to this day. Somewhat to my surprise I found I can still out-program
every other programmer we have ever employed despite now being 57 years old.
There was talk of the VAX design being the
inspiration for the Motorola 68k. Isn't it more likely that the PDP11 influenced the
design of both the VAX and the 68k?
Big microcoded CISC was the dominant thinking in computer architecture
at the time, so it is really hard to say that X influenced Y. The engineers did not believe the Motorola design
was practical and we worried about a large 64 pin chip in the environment of a military
helicopter's avionics bay (G forces, vibration, expansion, cooling etc) and it was
decided to go with the 48pin Zilog Z8001 instead.
Why not use PGA or Flatpack?