CP/M development environment setup (opens in new tab)

Speaking of weird chips from that era, Amstrad CPC464's sold in Spain came with an extra 8KB RAM on board that was not connected to anywhere. It was put there only to avoid import tax for computers with 64KB RAM or less.

I've rarely used the C128 mode in VICE, but according to the manual[1], x128 emulates a z80 too. It would be kind of cool to develop in linux and then "deploy" the code to x128's z80 emulator as a "production" environment.

[1] http://www.cs.cmu.edu/~dsladic/vice/doc/html/vice_2.html#SEC...

IIRC the Z80 would be the first processor to wake up, too, and would retain control CP/M were being used but would shift control over to the other processor if either native or C64 mode were being used.

Microsoft's first hardware product was a Z80 add on board for the Apple II, which served the same purpose.

Apple ][ with a Z80 card was a similar setup I used, mainly for Turbo Pascal and dBase.

Cool, good luck. Blog about it :) It'll be a lot of fun indeed and it gives you incredible magic powers of actually understanding computers.

I am currently reading Uzix[0] and the disassembly of Symbos[1] to do some OS dev on Z80 machines which, in the end, will hopefully run on my own homebrew hardware.

[0] https://github.com/marioaugustorama/uzix-kernel [1] http://symbos.de/

Edit: forgot; https://github.com/EtchedPixels/FUZIX

Well, back in the day, when Z80 systems were still a thing, I actually built a soundcard for one such system. Wavetable synthesis, DAC-controlled envelope, did the whole nine yards from scratch, starting with circuit diagrams drawn on the proverbial napkin. Ended up using it to make theremin-like sounds. I was still in school and it was a fun project.

Sounds like you're gonna have some huge fun time :) Same here, software developer turned hardware tinkerer.

I used to develop apps in dBase II on CP/M back in the early to mid 80's. We used to have these lovely NEC computers (PC 8800 and APC) with dual 8" and 5.25" drives running CP/M. Later the boss bought me a Torch Z80 [0] co-processor, which ran a clone of CP/M called CPN, for my BBC Micro so I could fiddle about and work from home. We used to use WordStar as our code editor and would patch its printer drivers by hand to get them working with certain NEC and Juki printers. Then once day we bought an early PC clone (a Ferranti box) and things moved on.

Amazingly some semblance of Torch is still around [1]

[0]: https://en.wikipedia.org/wiki/Torch_Computers

[1]: http://www.torchcomputers.co.uk/

DataFlex :) it's still around, but nowadays it supports less platforms. There's still a unix/linux version (3.2) but that hasn't been updated in many years.

The Windows version however is still going strong -version 18.2- and also supports web.

I used to program in dBase and Turbo Pascal around that time, but mostly skipped CP/M and started with that Microsoft clone albeit the IBM version.

What hardware did they typically use?

My first computer was an Amstrad 8256, also known as the Joyce. It ran a custom word processing program straight on the metal, but also came with CP/M. I used it for Protext, later added a 3 1/2 floppy and a serial interface so I could connect to bbs's, and got a 16 bit dot matrix printer. I still kind of like CLI, you feel in more direct control of the computer.

I had these machine, however, I never saw CP/M running it. As far I read, was weird, as not had a 80 column mode and the CP/M for it, had a weird trick of panning the screen so the user could see the right half of the 80 column screen.

>I still have the floppies, though I very much doubt if they'd read any more

I think you might be surprised. Those low-density floppies were remarkably DURABLE.

I have a whole pile of 8" and 5.25" floppies from the late 1970s / early 80s and even after decades of storage in less-than-ideal circumstances nearly all of them worked the last time I fed them to a TRS80 or my old Apple ][ about 5 years ago. (I was just as surprised the computer power supplies were still functional after this time, as electrolytic caps aren't exactly known for their longevity).

Looking at code written when I was 12 is equal parts bemusement and cringe. Text adventures, BBS (bulletin board systems), Video game copies of arcade hits (space invaders in Basic. Donkey Kong in 6502 Assembly, A half-written tempest clone...) all are terrible judged by today's standards, but I thought they were amazing at the time.

Speaking of amazement, I have no idea how I was able to accomplish anything without a search function, autocomplete, or google search. Just a blinking block in a text editor.

Those 5.25 drives makes me pine for slot load optical drives and discs formated for packet writing.

Acorn's master plan for the BBC Micro series of computers was that they'd really just be the I/O terminals for another, much faster computer attached via a high-speed bus; there was an RPC interface to allow the second processor unit to make system calls on the I/O computer and use its peripherals.

The only second processor unit they released in bulk was a 6502 unit (3MHz with 62kB of free RAM and no interrupt overhead, so it was blisteringly fast by 8-bit standards). But there was also a Z80 unit, which would run CP/M.

http://chrisacorns.computinghistory.org.uk/8bit_Upgrades/Aco...

The plan was evenutally scrapped in favour of the BBC Master, but they produced limited quantities of a 10MHz 32016 unit (running Panos) and was used to develop the original 8MHz ARM1.

I seem to recall that the C64 floppy drive had as powerful internals as the C64 itself.

This is where I worked (link below), they gave me my first job coding when I was 17. On the first page of the brochure, the card in the lower left was what we called the dpc-816. It had a Z80 and an 80186 chip on it. The silver heat sink covers the 80186 and the Z80 is just to the left, vertically oriented. I worked on parts of the BIOS for it. Both the 8 and 16 bit BIOSes scanned for a sequence, ESC Ctrl-\, which would switch the terminal from one CPU to the other. Both CPUs could execute simultaneously on the same bus, with shared RAM. They solved the arbitration problem very simply; they inverted the clock from the 80186 and fed the inverted clock into the Z80. This way whichever CPU was going for the bus first would pull the HLT pin on the other via some TTL logic, so on the next rising edge of the clock, the other chip would stop. When the bus cycle was complete, some TTL would drop the HLT pin.

http://www.vintagecomputer.net/ace/ACEDiscovery500Ads.pdf