If it wasnt some mostly custom system it was probably an HP 64000 Logic Development System. Which used Z80s to run user facing software and control the actual mainframe. I doubt it was a pure Z80 "mainframe". Loved to be proved wrong though!

Nice! This one is also being produced: https://retrogamecoders.com/agon-light-first-impressions/

RC2014 is the real deal: https://rc2014.co.uk

Why I have not picked one up yet… I think I just have a sweet spot for the 6502 and keep putting together KIM-1 kits.

(EDIT: Finally after years, I just pulled the trigger on their Classic II kit.)

(emulated)

Woah that’s cool! I love the case!

"Simple" is really not a word I would associate with the Z80 ;)

The ISA is quite messy because of the backward compatibility requirement with the Intel 8080 (e.g. the Z80 had to fill undocumented gaps in the 8080 opcode encoding map with new instructions, four of which were prefix instructions to unlock additional instruction 'subsets' (DD/FD for replacing instructions involving the HL register pair with indexed addressing modes via the IX/IY registers, and ED/CB prefixes for adding two entirely new opcode blocks).

If the Zilog engineers would have been free to design their own ISA I'm sure they would have been able to come up with a much more elegant design.

Also the Z80 had more than twice as many transistors as the 6502 (8500 for the Z80 vs 3500 for 6502).

I still prefer programming the Z80 over the 6502 though :)

I cut my teeth writing assembly on a ZX Spectrum (mostly hacking games for infinite lives, etc).

Over the past couple of years I've gone back to the Z80, working on CP/M emulation, testing, and similar things. It's fun to play the old infocom games, and mess around with BIOSes when all you have is 64k.

There's a lot of good CP/M reference material out there, and numerous emulators to run it on modern systems

We still have the venerable 8051 for anyone who likes old architectures!!

I'm sure clones are still being made.

> so 17 million 8080 equivalents

At, ballpark, 1000 times the clock frequency. It’s a pity we do not how to connect such a large number of tiny cores in a way so that it can perform meaningful work. One hurdle is that, even ignoring the insane amount of connections needed, it would not be possible to connect each of those cores to each other one because their address spaces are so tiny.

This is understandable, considering that the M5 is the Ultimate Computer, powered by Dr. Richard Daystrom's very own engrams

The ARM 1 only had 25,000 or so.

Yup and Moore's law about transistors doubling every 18 to 24 months did basically hold, which is even more impressive.

Foreseen it was.

Nitpicking, but since the M5 includes cache and GPU a more realistic comparision would probably be to count all transistors in an entire 8-bit home computer system against a modern integrated GCPU (e.g. from googling around a C64 might have around 0.75 million transistors, most in the memory chips).

And in a way, those old 8-bit home computers also worked like a single integrated 'super-chip', because the whole system was driven by a single clock and entirely 'hard realtime', while modern computers are much more asynchronous (and I guess this asynchronous design is what enabled most performance improvements that go beyond pure transistor count scaling).

Z80 also powered the whole MSX line of home computers, how could have he missed that?!?

Slop from the article