CP/M for the ZX81 / TS1000

[Bill H]

I have been wondering what is the posibility of recompiling CP/M 2.2 to run on a ZX81 / TS1000 emulator? Using an emulator you could hook the disk i/o in CP/M to the emulators disk i/o, you may have to make changes to the emulator to get this to happen. You would still be limited to the smaller screen dimensions but it could be a nifty project? Wouldn't it be a hoot to have an unmodified copy of WordStar or VisiCalc run on a ZX81/ TS1000, even if it is in an emulator? If you could get it to work you could always then look at how to put it on a real system and use a real disc or other storage device.

Bill H

[Paul]

If this thing would be using ZXPAND and the CPM files would be in a subdirectory like "CPM"
EO could work with this fine, and also real machines which do not easily connect to disc drives "other than ZXPAND" in the real world.
I just don't see who would have enough time to do it.
There are Spectrum version, is that right?
No ZX81 Version?
What about sponzy? Capable of running CPM?

[1024MAK]

CP/M on a Zeddy?
I think the best method for use on real machines is to use two Zeddies.

The first Zeddy has 32k bytes of internal RAM and a ZXpand (32k internal RAM plus the 32k of ZXpand RAM making a total of 64k). The custom "boot" ROM can be "bank" switched out leaving the whole 64k free for CP/M (the ZXpand overlay ROM would need to also be switched out). This Zeddy runs in FAST mode and does not generate any display. Instead, it transfers the "ASCII" data (inc. control codes) to a second Zeddy.

The second Zeddy receives the ASCII data from the first ZX81 and displays it on a high resolution display (say 64 columns by 24 lines or maybe even 80 columns is possible?). This Zeddy functions as a display only. It is equipped with a custom ROM and 16k or 32k RAM.

The communication link between the machines can be a simple one way 8 bit parallel port (8 bit latch/register plus a flip-flop to indicate when new data has been written into the latch/register).

Anyway, that's my thoughts

Mark

[Paul]

This Zeddy runs in FAST mode and does not generate any display

I thought the idea was to create the slowest CP/M machine.
Anyway, using a standard ZX81 with ZXPAND would result in nearly no compatible software.
Minimum would be having wordstar and Turbo pascal running.
Any serial Terminal would do. Like a PC running a terminal program.
Maybe the ZX2000 would be a good base for development as it has full (more than) 64K inside, ROM disabling works fine and offers mefisdos as a "harddisk" base in the flash memory.
Then it would be nice to have ZX2000 added to EightyOne
ZX97 is already there and could be extended a "little".