Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Captain Zilog Crushed: The Story of the Z8000

thechipletter.substack.com

Post reply on HN
Print view View original

41–50 of 70 posts

Re: Captain Zilog Crushed: The Story of the Z8000

#41

Post by dboreham »

Someone wrote: post #16

FTA: “One cheaper version would fit into a 40-pin package. This version would have its memory address sizes limited to 16-bits and so would only be able to use 64 KB of memory. A more expensive 48-pin version would have access to a 23-bit or 8 MB address space. To support this approach, the architecture would be based on segmented addresses.” I don’t see how that follows, given the example of the 6507. https://en.wik…

> depending on how much the 6507 internals differ from that of the 6502

6502 and 6507 are the same die with some metal layer patches to tie unused pins to their inactive state: http://blog.visual6502.org/2010/09/6502-vs-6507.html

Re: Captain Zilog Crushed: The Story of the Z8000

#42

Post by jacquesm »

systems_glitch wrote: post #36
jacquesm wrote: post #29

Earlier quoted context omitted.

Ah, memory lane, I love you. The S100 was a great architecture, so incredibly versatile, every component was designed around a standard so solid that it lived for 20 years and likely there are still systems in industrial control in service today (though those would be pretty hard to keep running). Is anybody on HN aware of S100 systems used in production today?

Aside from the systems we use directly in maintaining other S-100 boxes? Yes! There are many Dahlgren engraving systems running with S-100 control crates. The boards are mostly Solid State Music whitelabels, except for the actual tool driving boards. They don't break often, but we do sometimes get requests to fix them. Other S-100 boxes still exist, mostly being used by small old companies who are, frankly, in the "o…

Heh, I knew it :)

Thank you for confirming my hunch. Besides being clever from a technical perspective those systems were also designed in ways that make your average kitchen appliance look flimsy. You could probably drop one from a first floor, end up with a damaged pavement, a fine and and working system ;)

Re: Captain Zilog Crushed: The Story of the Z8000

#43

Post by shrubble »

jacquesm wrote: post #29
ChuckMcM wrote: post #7

There was an earlier, and to my way of thinking, much better idea at Zilog than the Z8000. That was the Z280 (later christened the Z800) it was a 16 bit machine akin to the 8086 but with upward compatibility with the Z80 and a much nicer architecture. I believe that Godbout made and S-100 card with this processor at one time. I wanted one so badly and yet the 8088 and the IBM-PC steamrolled the industry because "big…

Ah, memory lane, I love you. The S100 was a great architecture, so incredibly versatile, every component was designed around a standard so solid that it lived for 20 years and likely there are still systems in industrial control in service today (though those would be pretty hard to keep running). Is anybody on HN aware of S100 systems used in production today?

The s100computers Google Group is pretty active and there are new designs for boards that have compact flash etc.

As far as production use? Not sure since the S100 bus is less compact and more expensive than many newer designs.

Re: Captain Zilog Crushed: The Story of the Z8000

#44

Post by systems_glitch »

jacquesm wrote: post #42
systems_glitch wrote: post #36

Earlier quoted context omitted.

Aside from the systems we use directly in maintaining other S-100 boxes? Yes! There are many Dahlgren engraving systems running with S-100 control crates. The boards are mostly Solid State Music whitelabels, except for the actual tool driving boards. They don't break often, but we do sometimes get requests to fix them. Other S-100 boxes still exist, mostly being used by small old companies who are, frankly, in the "o…

Heh, I knew it :) Thank you for confirming my hunch. Besides being clever from a technical perspective those systems were also designed in ways that make your average kitchen appliance look flimsy. You could probably drop one from a first floor, end up with a damaged pavement, a fine and and working system ;)

Some of them! Some S-100 stuff is definitely cheese grade construction. We end up repairing a fair number of Altair 8800s of various models for hobbyists and collectors, and they are...not well-designed systems. It's pretty amazing how well S-100 progressed from the initial MITS design, given how slapdash it was.

Re: Captain Zilog Crushed: The Story of the Z8000

#45

Post by krylon »

MichaelZuo wrote: post #34

> One key implementation decision was that the Z8000 would not make use of microcode. Microcode would have broken down the Z8000’s instructions into a series of simpler instructions, hidden from the outside world, which the processor would execute. Instead, all instructions would be ‘hard-wired’ into the logic of the CPU, a more challenging approach for the designer. Shima would later discuss how much more difficult…

I was under the impression RISC architectures usually(?) don't use microcode. Or am I mistaken?

Re: Captain Zilog Crushed: The Story of the Z8000

#46

Post by jacquesm »

systems_glitch wrote: post #44
jacquesm wrote: post #42

Earlier quoted context omitted.

Heh, I knew it :) Thank you for confirming my hunch. Besides being clever from a technical perspective those systems were also designed in ways that make your average kitchen appliance look flimsy. You could probably drop one from a first floor, end up with a damaged pavement, a fine and and working system ;)

Some of them! Some S-100 stuff is definitely cheese grade construction. We end up repairing a fair number of Altair 8800s of various models for hobbyists and collectors, and they are...not well-designed systems. It's pretty amazing how well S-100 progressed from the initial MITS design, given how slapdash it was.

I used some pretty beefy boxes for industrial systems in the 80's and what struck me about them - and of the PCs of that era - is that they were all built to last for decades. Modern stuff is built to last for a couple of years at best in most cases, with some rare exceptions. Flimsy cases, plastic instead of steel. Unserviceable, non-standard and proprietary instead of standardized and repairable. Miniaturized as much as possible instead of open frame. And finally, undocumented versus documented right down to the component level and the software source code.

From a longevity perspective that stuff absolutely rocks, much like I'd much rather have a car from the 90's than one built today. The 90's one will outlive me, the one built today will need at least one replacement.

Re: Captain Zilog Crushed: The Story of the Z8000

#47

Post by [deleted] »

rjsw wrote: post #25
rob74 wrote: post #13

Earlier quoted context omitted.

Thanks for mentioning that! I had an Amiga in the early nineties and consider myself pretty knowledgeable when it comes to Commodore history, but wasn't aware of this machine either. The article doesn't mention why the C900 was cancelled, but I guess Commodore was afraid to go up against IBM with a purely business-oriented machine? So they did what many other big companies have done since: bought up a startup to get…

> The article doesn't mention why the C900 was cancelled My guess would be that it was caused by Commodore and Atari swapping senior people.

[deleted]

Re: Captain Zilog Crushed: The Story of the Z8000

#48

Post by monocasa »

krylon wrote: post #45
MichaelZuo wrote: post #34

> One key implementation decision was that the Z8000 would not make use of microcode. Microcode would have broken down the Z8000’s instructions into a series of simpler instructions, hidden from the outside world, which the processor would execute. Instead, all instructions would be ‘hard-wired’ into the logic of the CPU, a more challenging approach for the designer. Shima would later discuss how much more difficult…

I was under the impression RISC architectures usually(?) don't use microcode. Or am I mistaken?

Correct, true RISCs tend to not use microcode. ARM historically has, but it's also always been a bit of a RISC/CISC hybrid.

Re: Captain Zilog Crushed: The Story of the Z8000

#49

Post by kens »

MichaelZuo wrote: post #34

> One key implementation decision was that the Z8000 would not make use of microcode. Microcode would have broken down the Z8000’s instructions into a series of simpler instructions, hidden from the outside world, which the processor would execute. Instead, all instructions would be ‘hard-wired’ into the logic of the CPU, a more challenging approach for the designer. Shima would later discuss how much more difficult…

The NEC V33 (1988) was a hardwired (not microcoded) version of the 286. The decision not to use microcode might be related to the long lawsuit between Intel and NEC over microcode.

Also, as krylon points out, RISC chips generally don't use microcode.

Re: Captain Zilog Crushed: The Story of the Z8000

#50

Post by systems_glitch »

jacquesm wrote: post #46
systems_glitch wrote: post #44

Earlier quoted context omitted.

Some of them! Some S-100 stuff is definitely cheese grade construction. We end up repairing a fair number of Altair 8800s of various models for hobbyists and collectors, and they are...not well-designed systems. It's pretty amazing how well S-100 progressed from the initial MITS design, given how slapdash it was.

I used some pretty beefy boxes for industrial systems in the 80's and what struck me about them - and of the PCs of that era - is that they were all built to last for decades. Modern stuff is built to last for a couple of years at best in most cases, with some rare exceptions. Flimsy cases, plastic instead of steel. Unserviceable, non-standard and proprietary instead of standardized and repairable. Miniaturized as mu…

Yeah, add on top of that you usually got full schematics, and logic tables if there were programmable logic devices! That's how we're able to continue offering service on these systems.

There's a pretty good hobbyist community around S-100, a fair number of folks are designing hobbyist-level new boards and such. A lot of that is centered around the following site:

s100computers.com

Some of their designs are...weird...and often "that's not a bug, we like it like that" is what you'll get for pointing out actual design issues...but! it's still cool to see people hacking on it.

Post reply on HN