Hacker News Reader

Comment by II2II | Hacker News Reader

Sure, but if memory serves me correctly, many early workstations used a microprocessor with an external MMU. It is misleading in the sense that it is not part of the Z80, but it is in the character of the times. (And MMUs are not the only CPU feature that was originally external. The FPU is an example that more people will be familiar with since it was an upgrade path available on many personal computers.)

View on HN

I don't think MMUs were common on machines that ran on a Z80 however.

The home-brew pager (MMU) of the MIT-MC PDP-10 KL10 was appropriately called "KL-UDGE". (KL was the prefix of the PDP-10 model).

https://en.wikipedia.org/wiki/Kludge

It's on display at the Paul G. Allen Living Computer Museum.

https://sites.google.com/site/mthompsonorg/Home/pdp-10/pdp-1...

https://donhopkins.com/home/catalog/images/mc-console.jpg

Lars Brinkhoff has taken photos of the KL-UDGE blinken lights panel and naked wire wrap boards:

https://twitter.com/larsbrinkhoff/status/1128601896619524097

>Photo 6/7: KL-UDGE lights panel

>Photo 7/7: KL-UDGE boards. Real-time time of day clock?

Was on display. The LCM closed due to COVID and there's no indication that it's coming back, sadly.

The Commodore 128 had an 8502 CPU, a Z-80 CPU and an 8722 MMU.

Was a pretty popular machine - sold 5.7 units worldwide. But probably only a tiny fraction actually used the CP/M mode that used the Z80.

I don't know what's more concerning. The fact they only sold 5.7 units, or the fact someone managed to only buy .7 of a Commodore 128.

The sixth unit had CP/M disabled, so accountants wrote it down as 0.7 units.

Wow, I had no idea there was basically a second computer hiding inside of the C128. No wonder it cost so much.

Did you mean 5.7M?

For example a Programmable MMU was an optional add on for the Macintosh II (which wasn’t a z80 but serves to illustrate the time when they began to become available to home computers)

Reply on news.ycombinator.com