The C128 and Z80 CPU ...or Intel 8088?

[glitch]

The C128 and Z80 CPU ...or Intel 8088?

So as I sit here testing CP/M on a TRS-80 Model 4P, I began thinking about the Commodore 128 and CP/M mode.  I had a few instances to play with it, but never really gave it a fair shake.  To me, the C128 was always best used in C64 mode and occasionally in C128 mode.  I would boot up in CP/M mode more to test disks and CP/M compatibility than to ever use it for anything serious.  Has anyone here actually used the C128 and CP/M?  CP/M seemed to me to be past its prime when the C128 rolled out.

That got me thinking.

What if noticing that, CBM had instead made the C128 with an Intel 8088 (or preferrably an 8086) instead of the Zilog Z80 CPU?  

To me, I think this would definitely encouraged more sales.  More parents buying ONE machine instead of two - C64/C128 mode for the kids and PC mode for "serious" work.  Perhaps this would have launched the company in a completely different direction.  It could have seriously hurt the Amigas sales too, or the development of the bridgeboards at least.

In hindsight I know there are about a thousand things we could have wished CBM management had done differently, but this one got me going today...

Thoughts?

[trekiej]

I wish I knew what to add.
I did not use CPM much on the 128 either.
I wonder if Vice 128 uses CPM.

[danbeaver]

IMHO,

Well the 8086 required 16 data lines, that makes no sense in an 8-bit computer.
Commodore already had a CP/M cartridge for the C64, so they had a history of hardware development there (disk formats did suck).
While CP/M could run on an 8088, the 8088 was far more expensive than a Z80 that was there to run CP/M -- also the CP/M OS and software was proven.  Commodores implementation of CP/M was always tertiary behind the C64 and C128 -- no one bought a C128 to run a non-graphical OS. I believe they just threw in the Z80 and CP/M as a publicity gimick to give weak justification to productivity on the C128 to people who did not know the C128 has such software.

[trekiej]

I believe a C65 would have been better.

[Iggy]

I believe a C65 would have been better.

Obviously.
I never really got the idea of including the Z-80 either.
CP/M was pretty dated and lacked graphics support.
So what was the point?

[Blizz1220]

Maybe they bought them for something else and had nowhere to use them knowing how things were run

I had C128 , it should have had built in disk drive (that would probably need another CPU) at that point and a mouse.

Only good thing is that case looked much better and more professional.

[mongo]

CP/M 3.0 was only 2 years old when the 128 came out and there was a huge library of software available for it including business and productivity software that was seriously lacking on the C64.

[mechy]

Maybe they bought them for something else and had nowhere to use them knowing how things were run

I had C128 , it should have had built in disk drive (that would probably need another CPU) at that point and a mouse.

Only good thing is that case looked much better and more professional.

The c128dcr had a built in 71, Both commodore and CMD made mice for the c64/128
Lt Kernel(SP?) and CMD made hard drives.

The z80 was chosen on purpose not for just cpm, but it was a necessary chip to make all 3 modes live together,iirc it used the z80 for its early startup.

[Rob]

I read that there were a load of Timex Sinclair TS1000s at Commodore after people bought the $49 systems to get a $100 rebate on a C64.  I think they had shipping containers full of them onsite and they were also used as doorstops.  

I guess you could clarify with Bill or Dave but I understand that one of the doorstops donated it's CPU when they were designing the C128.  Had it not been for the doorstops they probably wouldn't have considered adding CP/M mode but it was concenieent and probably sounded like a good idea when presented to mangement and the marketing people.

No Idea if any of the CPUs from the thousands of TS1000s they had were recycled for use in productions C128s or if they just used brand new chips.

[LoadWB]

CP/M 3.0 was only 2 years old when the 128 came out and there was a huge library of software available for it including business and productivity software that was seriously lacking on the C64.

This.  I used CP/M 3+ on my 128D frequently, but mostly for my first programming classes.  Small C, some COBOL and Pascal compilers.  It worked great, and I could write to floppies which my instructor could read with her computer.

I used a bunch of other software for various things.  I downloaded a lot of software, some from Q-Link's CP/M area but almost everything else from GEnie, and some things from BBSes.

I have discussed various CP/M ports on and to other CPUs, like 68000 and 9900.  But the prevalence of Z80 software almost negates native ports and rather encourages good Z80 emulation.

[RobertB]

What if noticing that, CBM had instead made the C128 with an Intel 8088 (or preferrably an 8086) instead of the Zilog Z80 CPU?

CBM did make the desktops, like the Commodore Colt, PC-10, PC-20, PC-30, (and more), and 286, 386, and 486 laptops.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

[RobertB]

I guess you could clarify with Bill or Dave but I understand that one of the doorstops donated it's CPU when they were designing the C128.

I've never heard that story from either Bil or Dave.

No Idea if any of the CPUs from the thousands of TS1000s they had were recycled for use in productions C128s or if they just used brand new chips.

Since 4 to 5 million C128's were produced, having a few thousand chips from TS1000's would not fulfill production needs.  Anyways, nothing has been said about how many TS1000's were exactly turned in.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

[RobertB]

...no one bought a C128 to run a non-graphical OS.

There were those who bought the C128 so that they could run the graphical OS, GEOS, in 80-column mode.

Instead of the 40-column C64 GEOS,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

[RobertB]

I believe a C65 would have been better.

FYI, C128 development began in 1984 with the release of the C128 in 1985.  C65 development began and stopped in 1989-1990, due to the fact that 8-bit development was a dead-end in those later years.

The C64 lasting in production until 1992,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

[psxphill]

I've never heard that story from either Bil or Dave.

From On The Edge:

To fix the problem, Herd required the C128 to start at memory address zero, but the 8502 started elsewhere. "One night, everybody left and it was broken," says Herd. "During the night, I said, 'I have no way to fix this, unless we startup by not starting at that address.' I said, 'Hey, Von. The Z80 chip starts from zero, doesn't it?' He said, 'Yup.' I said, 'Cool. I need somebody wire wrapping tonight.'"
The hour was too late to purchase a Z80 chip, so Herd looked elsewhere. "Everybody had doorstops that were actually Sinclairs," he recalls. "I went and tore open my doorstop because we didn't own a Z80 chip in the place."


I don't believe they re-used the Z80's in production models though. After hearing about how the C64 was put into production for Christmas however, nothing would surprise me

Putting in an 8088 would likely have not helped much as making the computer MSDOS compatible to any real degree would have been impossible. An NEC V20 would have been better as it could run CPM in it's 8080 mode, but you can also run 8086 software. It lacks the extra Z80 instructions but most CPM software is compatible with 8080 anyway (Z80 is an 8080 clone with added instructions). It might not add much, but you also wouldn't really lose anything.

The C128 was like the A3000. Both were based on custom chips from a previous design, but with extra glue around them because there was no time/money/inclination to improve them. If the C128 had an 80 column VIC that could work when the CPU was running at 2mhz then it would have been a worthwhile upgrade & much closer to the C65 but still C64 compatible.

The C65 was designed during the time when AAA was in development hell, I can understand why in that environment the C65 project would have made some sort of sense and it probably would have sold if it was cheap enough. Another couple of engineers also went off and pushed through the Pandora project, which turned into AGA.