CompuPro stack with Disk 1 only able to read double-sided diskettes

[MxArgent]

So, I've been working on getting myself a CompuPro stack set up. Disk 1 FDC, FD50to34 in the middle, Gotek for my boot media. I'm currently having a strange issue here - My system can read double-sided disks fine, but not single-sided disks. I suspect this may be an issue with my adapter config - can anyone post theirs for me to compare with?

Thanks!

 

[hmb]

So, I've been working on getting myself a CompuPro stack set up. Disk 1 FDC, FD50to34 in the middle, Gotek for my boot media. I'm currently having a strange issue here - My system can read double-sided disks fine, but not single-sided disks. I suspect this may be an issue with my adapter config - can anyone post theirs for me to compare with?

Thanks!

You need to remove the jumper labeled 2SIDE* on your FD50to34 adapter. Removing that jumper tells the floppy controller that there is a single-sided disk (or in the case of the Gotek - disk image) in the drive. You need to remember to manually set this jumper depending on whether the Gotek has a single- or double-sided disk image. I know its a pain, but the Gotek does not have an output that emulates an 8" drive's "two sided" output signal.

 

[MxArgent]

Ah, that'd do it! I've been wanting to try to upgrade from a Disk 1 to a Disk 1A so I can just use 34p drives directly, and this is some more reason to do so.

Narrows some things down. Next up: Trying to get to a point where I can boot both CP/M-80 and CP/M-86. Got my GO 86 ROM written out, but there's still work to be done here evidently.

The stack right now: CPU8085-88, two RAM21, a Disk 1, a Interfacer 3, and a Support 1. I also have a CPU-Z that'll theoretically be paired with a CPU8086/87 down the line, but that's all for later.

 

[hmb]

Ah, that'd do it! I've been wanting to try to upgrade from a Disk 1 to a Disk 1A so I can just use 34p drives directly, and this is some more reason to do so.

Narrows some things down. Next up: Trying to get to a point where I can boot both CP/M-80 and CP/M-86. Got my GO 86 ROM written out, but there's still work to be done here evidently.

The stack right now: CPU8085-88, two RAM21, a Disk 1, a Interfacer 3, and a Support 1. I also have a CPU-Z that'll theoretically be paired with a CPU8086/87 down the line, but that's all for later.

Have you gotten either CP/M-80 or CP/M-86 to boot? If not, what are you seeing happening?

What is your plan with "a CPU-Z that'll theoretically be paired with a CPU8086/87" ?

 

[MxArgent]

Have you gotten either CP/M-80 or CP/M-86 to boot? If not, what are you seeing happening?

What is your plan with "a CPU-Z that'll theoretically be paired with a CPU8086/87" ?

I’ve gotten CP/M-86 to boot in the past, though with the stock configuration described in the System 8-16 and MP/M manuals I can only get CP/M-80 to boot. That runs fine; I’ve had it running memory tests using the Sorcim utility diagnostic diskette and hashing diskettes using CRCK without issue.

My plan is to migrate from the CPU8085-88 to the two board stack long term, if possible. It seems like they offer some higher end features, and I’d like to have a full 8086 here. This is supposed to be a “period” late S-100 to compare and contrast with some of the stuff I’m doing with my S100computers stack, which uses the 8086 CPU board for the i86 side.I think exhibiting a multiuser setup at Midwest could be fun, especially if I can snag another RAM21 board or two.

 

[hmb]

I’ve gotten CP/M-86 to boot in the past, though with the stock configuration described in the System 8-16 and MP/M manuals I can only get CP/M-80 to boot. That runs fine; I’ve had it running memory tests using the Sorcim utility diagnostic diskette and hashing diskettes using CRCK without issue.

My plan is to migrate from the CPU8085-88 to the two board stack long term, if possible. It seems like they offer some higher end features, and I’d like to have a full 8086 here. This is supposed to be a “period” late S-100 to compare and contrast with some of the stuff I’m doing with my S100computers stack, which uses the 8086 CPU board for the i86 side.I think exhibiting a multiuser setup at Midwest could be fun, especially if I can snag another RAM21 board or two.

You could also try booting one of the versions of CompuPro CP/M 8-16, which should also run on your board set that includes the CPU8085-88.

Do you have a CPU-Z or an SPUZ?
The CPU-Z and the CPU86-87 are both designed to be an S-100 bus master, therefore only one of these boards can be installed in a system.
The SPUZ was designed to be an S-100 bus slave in a multiuser/multiprocessor system, and requires the software support provided by Concurrent DOS 8-16 v4.1 or higher.

 

[MxArgent]

Ah! So it sounds like sticking to the 8085-88 might actually be my best bet, then. Makes me wonder how the NSC800 would do here - I know from my experience with the Model 100 that it's a viable way of opening up Z80 instructions on a board designed for 8085. Looks like there was a interposer board intended for CompuPro CPU boards, too. If I ever get a shot at a SPU-Z, though, I'll have to keep that in mind. In that case I'm assuming the CPU8086/87 would be my master, then?

First and foremost, I want to upgrade from a Disk 1 to a Disk 1A, I think. Getting that 50-34 adapter out of the picture would be a big help.

As for what I'm working with in terms of reference material, I'm using the 11/1983 service guide and the MP/M manual for a sane set of defaults. During the period where I had CP/M-86 booting, I was configuring boards piecemeal using their respective manuals.

I should also note that I'm using a N8VEM backplane, fully terminated. (Leftover from my S100computers stack)

 

[hmb]

Ah! So it sounds like sticking to the 8085-88 might actually be my best bet, then. If I ever get a shot at a SPU-Z, though, I'll have to keep that in mind. In that case I'm assuming the CPU8086/87 would be my master, then?

First and foremost, I want to upgrade from a Disk 1 to a Disk 1A, I think. Getting that 50-34 adapter out of the picture would be a big help.

As for what I'm working with in terms of reference material, I'm using the 11/1983 service guide and the MP/M manual for a sane set of defaults. I should also note that I'm using a N8VEM backplane, fully terminated. (Leftover from my S100computers stack)

CompuPro Concurrent DOS v4.1 will run with either a CPU8085/88 or a CPU86/87 as the bus master. CDOS v4.1 included a pretty good 8080 software emulator, which allowed running of both CP/M-80 and CP/M-86 software if the bus master was a CPU86/87.

CompuPro's CP/M-80, CP/M-86, and CP/M8-16 system software was never released in versions that would boot from a 5.25" floppy disk. Sure you could use a 5.25" HD drive as an 8" drive replacement - but that drive would still need to be connected via an adapter to the 8" drive controller port on either a DISK1 or DISK1A. Therefore, there is no escaping the fact you have to use the 8" drive controller port if you want to run these versions of CompuPro's system software. CompuPro did not begin to support booting from 5.25" drives until the release of CDOS v4.1 - and even then, their default 5.25" drive was a DSQD drive.

The definitive guide to board configuration should be CompuPro's installation manual specific to the system software version you are using - these manuals are easy to find on internet. It might be okay, but I'd avoid the generic configuration advice provided in the 1983 Xerox service center guide, or the advice provided in the MP/M 8-16 manual unless you are trying to boot that specific system.

 

[MxArgent]

I see! I'll have to keep an eye out, it's hard to match some of these diskette images to an appropriate manual. Right now I'm using Dave Dunfield's images with a Gotek running FlashFloppy; expected to remain the basic arrangement throughout the machine's life. I do want to work in a second drive eventually, but I'm taking things one at a time here.

Makes me wonder if I should replace the 2.54mm jumpers on 2SIDE* with a pushbutton or a switch!

 

[hmb]

I see! I'll have to keep an eye out, it's hard to match some of these diskette images to an appropriate manual. Right now I'm using Dave Dunfield's images with a Gotek running FlashFloppy; expected to remain the basic arrangement throughout the machine's life. I do want to work in a second drive eventually, but I'm taking things one at a time here.

Makes me wonder if I should replace the 2.54mm jumpers on 2SIDE* with a pushbutton or a switch!

As I mentioned - having to switch out a jumper to select single- vs double-sided disks is a pain.

The obvious solution is to limit your use to double-sided disks. Just copy the distribution software (like CompuPro's system masters) to formatted and bootable double-sided disks, and thereafter stick to use of double-sided disks.

 

[MxArgent]

Yeah, I think that'll be the way to do it once I'm ready to introduce a second diskette drive. I kind of wish there were some mature tools for just editing images on the PC side, but CP/M stuff kind of has to be handled on a per-machine basis from my experience.