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CP/M on XT?

offensive_Jerk

offensive_Jerk

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Does CP/M run Natively on an XT, or do you need some special card?
I thought I remembered it being able to run natively, but it appears I am getting mixed information.

I see that it's free to download.

I am guessing I need CP/M-86.
I found this site http://www.cpm.z80.de/binary.html#operating but it looks like only 720k and 1.2M floppy versions. Would like version to try out on an XT. I see the CP/M-86 for the PC 1.1, but no HD support.
 
There are also emulators (that can take advantage of a V20) that will run x80 CP/M on your XT.

So it all depends on what you want to run. There are far more programs for CP/M-80 available than for CP/M-86.
 
Chuck(G) said:
There are also emulators (that can take advantage of a V20) that will run x80 CP/M on your XT.

So it all depends on what you want to run. There are far more programs for CP/M-80 available than for CP/M-86.
Click to expand...

Would the emulation cause any speed/performance issues?

(Speed on a 4mhz... :p)
 
offensive_Jerk said:
Would the emulation cause any speed/performance issues?

(Speed on a 4mhz... :p)
Click to expand...

If you can run only 8080 code and you have a V20 installed, it'll run pretty much like a 4MHz 8080 (well, a bit faster because it uses the CPU prefetch queue and internal bus structure). Z80 will require software emulation or a Z80 card (there were several brands, some with Z80H or better). Z80 software emulation on a stock XT isn't wonderful (think a 1MHz Z80), but it can fill a need in a pinch.
 
Please forgive my ignorance, but I am fairly new to the 80's Computer hardware. What is a V20?

I purchased an XT from a member here, and it should be arriving next week.
Was curious to play around with CP/M only because I never have.

I never had any old IBM hardware before, the oldest I had was a Commodore PC with a 20MB hdd. Think an 8088 was in there. I sold it on ebay a few years ago to make some ends meet.
 
offensive_Jerk said:
Please forgive my ignorance, but I am fairly new to the 80's Computer hardware. What is a V20?
Click to expand...

NEC V20 - uPD70108 CPU, pin-compatible with the 8088, but uses an improved internal architecture to deliver a speedup on ordinary 8088 code, plus has an 8080 emulation mode built in. It also supports many of the 80286 non-protected mode instructions, so some things that don't run on an 8088-equipped system will run on the V20.

Get it from Jameco.
 
I've been using the 22nice program on my XT with the NEC v20 installed to run cp/m programs. 22nice can use the v20's ability to run 8080 instructions. In this mode, I'd say the speed is very usable. 22nice also has the ability to run 8080 code and cp/m using software emualtion only (slower). This is necessary for a few programs that don't seem to work using the v20's 8080 emulation mode. There are a handful of programs out there that do the same thing as 22nice. This one seems pretty good and I like the documention. I was a bit concerned about losing any normal compatabilty with PC software by installing the v20 CPU because you will read a few mentions of it not being 100% compatable. But I can't say that I have run into any compatability problems yet.

You can also check out this thread where I was asking questions about the v20 as well. I ran into a RESET problem that I resolved also when using this CPU.

http://www.vintage-computer.com/vcforum/showthread.php?t=17421
 
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There IS also a PC-compatible version of CP/M. I think that would run natively without the need of replacing the CPU or adding a special Z80/8080 card.

BTW, the PC version of CP/M is for sale under the "for sale or trade" topic just now, so if you were interested in that, you should check it out.
 
per said:
There IS also a PC-compatible version of CP/M. I think that would run natively without the need of replacing the CPU or adding a special Z80/8080 card.

BTW, the PC version of CP/M is for sale under the "for sale or trade" topic just now, so if you were interested in that, you should check it out.
Click to expand...

Yes, but that's CP/M-86, not binary compatible with the CP/M-80 versions that most people think of when you say "CP/M". While there was a fair amount of third-party CP/M-86 software released, it was mostly in the form of an alternate product to MS-DOS, so those programs are almost always available in MS-DOS form.

What put the nail in the coffin for CP/M-86 was DRI's abandoning of the platform and reworking it to 'Concurrent CP/M" and then "Concurrent DOS". I seem to recall that early (not later) versions of Concurrent DOS could run CP/M-86 programs also. The IBM-branded CP/M-86 was very short-lived.

I saw CP/M-86 run on a few clones (e.g. DEC Rainbow) and in some industrial CNC stuff (e.g. Siemens PG-685), but it basically died because of a lack of interest. CP/M 68K for the Motorola CPUs seemed to find a spot in industrial controllers and lab equipment for a time.

It's worth noting that DRI GEM for the 68K (e.g. on the Atari ST) is much closer internally to MS-DOS than CP/M, mimicking MS-DOS's system calls and filesystem structure. GEM for the PC was an interesting product that received virtually no third-party interest, so you install it, play with a couple of the bundled apps and say "Okay, now what?"
 
Chuck(G) said:
It also supports many of the 80286 non-protected mode instructions, so some things that don't run on an 8088-equipped system will run on the V20.
Click to expand...

Basically you can run any 286 software that doesn't require protected mode (most games for example).

Chuck(G) said:
While there was a fair amount of third-party CP/M-86 software released, it was mostly in the form of an alternate product to MS-DOS, so those programs are almost always available in MS-DOS form.
Click to expand...

The CP/M trio of WordStar, dBase, and Supercalc were all ported to DOS very early. CP/M-86 and DOS were also not compatible with each other, and the latter was much cheaper.

Chuck(G) said:
What put the nail in the coffin for CP/M-86 was DRI's abandoning of the platform and reworking it to 'Concurrent CP/M" and then "Concurrent DOS". I seem to recall that early (not later) versions of Concurrent DOS could run CP/M-86 programs also. The IBM-branded CP/M-86 was very short-lived.
Click to expand...

Most of the non-IBM 80x86 machines at that time had CP/M-86, but they invariably also had DOS as well.

Chuck(G) said:
CP/M 68K for the Motorola CPUs seemed to find a spot in industrial controllers and lab equipment for a time.
Click to expand...

CP/M 68k for the Mac would have been amusing.

I one saw a discussion somewhere where people asked why CP/M was never ported to the 6502, and the answer was that it really couldn't be adapted well to the 6502's architecture.
 
Fallo said:
I one saw a discussion somewhere where people asked why CP/M was never ported to the 6502, and the answer was that it really couldn't be adapted well to the 6502's architecture.
Click to expand...

I don't think that's true and "porting" would be the wrong word in any case. You'd essentially rewrite the thing from the ground up in 6502 code. Since CP/M uses registers to pass arguments, you'd have to use something like the zero page cells instead. But I think it wouldn't be hard to come up with something that had the "look and feel" of 8-bit CP/M.

But what would you run on it?

Consider that a lot of 6502 systems are graphically oriented. CP/M is pretty much a text-based OS. While running CP/M 68K on a (68K) Mac probably could be done, what would you do with it?
 
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Interesting. Curious that he doesn't support file "user numbers" at all as far as I can tell. It looks as if there are more than a few issues with zero page memory. He tried to save it and then restore it over a system call, but apparently things can occasionally get scrambled.

Okay, how about CP/M for the TMS9900?
 
Chuck(G) said:
I don't think that's true and "porting" would be the wrong word in any case. You'd essentially rewrite the thing from the ground up in 6502 code. Since CP/M uses registers to pass arguments, you'd have to use something like the zero page cells instead. But I think it wouldn't be hard to come up with something that had the "look and feel" of 8-bit CP/M.
Click to expand...

Software would have to be totally rewritten. And I mean really rewritten from scratch, as trying to convert Z80 code directly to the 6502 (and it has been done) will kill you performance-wise.

Chuck(G) said:
Consider that a lot of 6502 systems are graphically oriented. CP/M is pretty much a text-based OS. While running CP/M 68K on a (68K) Mac probably could be done, what would you do with it?
Click to expand...

Yes, most CP/M boxes just had monochrome text with no graphics capability.

What software was there for CP/M 68K, anyway? WordStar and friends were certainly never ported to it.

CP/M 68K could be done for the Amiga and Atari ST as well, although again it would be pretty useless.

I also read a post once where a guy said that he found a bunch of computer magazines from 1982. A number of machines were reviewed in one of them, but the writer of the article pretty much trashed everything except CP/M boxes with detachable keyboards. The Apple II, VIC-20, TRS-80 CoCo, etc., all got a thumbs down from this guy. Needlessly harsh, if you ask me.
 
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