Santa delivered a C128 and an Indus GT. Can I boot CP/M?

[towmater]

I read somewhere that a 1571 can boot CP/M on the Commodore 128, bit not a 1541? So I wonder if anyone has experience booting CP/M from this new Indus drive?  Also any hints as to how to make a boot disk for CP/M, (assuming it the Indus GT can start it?)

[+OLD CS1]

The Indus can only read GCR-formatted disks.  Thus, the only CP/M disks you will be able to boot will be in the 1541 format.  I am pretty certain you will be able to find one somewhere.

 

It has been a while since I used CP/M on my 128D.  IIRC, the CP/M 3+ boot disk is a GCR-formatted disk, but formatted double-side (1571.)

 

I might have a chance to check that for certain this week.  I have all my CP/M stuff in its own disk box as I used to use it a lot back in my early college days.

 

Otherwise, that Indus is a really nice drive.  It is as fast as it can be on the CBM serial buss, and you can (and would be a great benefit to) get JiffyDOS for it and your 128.

[Casey]

If I remember right (from years ago) - the CP/M system disk is a flippy disk - not a double sided disk (i.e. you turn it over to use the back side).  It should boot in a 1541 but it certainly would not be fast.  The 1541 can’t use any of the MFM formatted CP/M disks that the 1571 can read however.  May or may not be an issue in your case.  

 

I think to make a system disk, you use the FORMAT.COM utility in CP/M to format the disk first, and then you just need to PIP the CPM+.SYS and CCP.COM to the new disk and it will be bootable.

 

Some good information here:

https://www.commodore.ca/manuals/128_system_guide/sect-11.htm#11.4.1

[+OLD CS1]

1 hour ago, Casey said:

If I remember right (from years ago) - the CP/M system disk is a flippy disk - not a double sided disk (i.e. you turn it over to use the back side).  It should boot in a 1541 but it certainly would not be fast.

Thanks.  I could not recall this for certain.

 

1 hour ago, Casey said:

The 1541 can’t use any of the MFM formatted CP/M disks that the 1571 can read however.  May or may not be an issue in your case.  

The Indus GT can only read GCR-formatted disks, so any of the other CP/M formats will be unreadable.  For the most part, though, if he is only working with C128 CP/M stuff he should be fine.  It will be slow, for certain.  A 1581 is fantastic for CP/M, and I recommend an REU as the system gets built up.

[towmater]

4 hours ago, OLD CS1 said:

The Indus GT can only read GCR-formatted disks, so any of the other CP/M formats will be unreadable.  For the most part, though, if he is only working with C128 CP/M stuff he should be fine.  It will be slow, for certain.  A 1581 is fantastic for CP/M, and I recommend an REU as the system gets built up.

 

5 hours ago, Casey said:

If I remember right (from years ago) - the CP/M system disk is a flippy disk - not a double sided disk (i.e. you turn it over to use the back side).  It should boot in a 1541 but it certainly would not be fast.  The 1541 can’t use any of the MFM formatted CP/M disks that the 1571 can read however.  May or may not be an issue in your case.  

 

I think to make a system disk, you use the FORMAT.COM utility in CP/M to format the disk first, and then you just need to PIP the CPM+.SYS and CCP.COM to the new disk and it will be bootable.

 

Thanks for this. Is there an REU clone design? I should also mention that I have an IEC2SD device, and wonder if D128IT or D64IT can be used to transfer the necessary CP/M data to a floppy. (Or could I boot CP/M from the SD?) I'm not sure how one would use the CP/M format command without booting... unless this can be done on another machine such as a PC first.

[+OLD CS1]

I believe GG Labs has created a REU clone.  As for copying, you are really going to make me pull out my CP/M stuff... or Google, whichever I get to first.  I believe the CP/M directory is different than the CBM directory.  I have no idea if D128/64IT will handle them.

 

I am pretty certain creating a CP/M boot disk would need to be done within CP/M, or a program which understands the CP/M format.  That said, remembering that I have used ZipCode to transfer 1541-format CP/M disks before, I suspected that you should be able to get them in D64 and I was not disappointed.

 

Check out Zimmers for CP/M system disks in D64 format.  They are GZipped for space, but 7-Zip in Windows handles that just fine.  Put the resultant D64 on your SD2IEC and you can mount the D64 or use your favorite program to write the D64 to a real disk.

[+OLD CS1]

The GG Labs REUs are geoRAM clones.  These do not work like standard CBM REUs, which use DMA to move data into and out of memory.  The geoRAM expansions use banked memory-mapped RAM.

 

Digging around for a little bit, it appears your only hope for an REU is to find a old CBM unit or get something like the Chameleon64 or the Ultimate 1541.  It helps with a CP/M system as you can use it as a drive for temporary or data space or copy your frequently-used utilities into it.  It is not an absolute requirement.

[motrucker]

I can completely agree that an REU helps running CP/M on a C-128. It speeds up disk access except the initial boot. As far as I know, the original Commodore REU is what you will need. They can made larger though - I use a 2Mb REU.

The Indus GT is a great drive, but is still a 1541 clone, and has the same limitations.

 

 

[towmater]

11 hours ago, OLD CS1 said:

I believe GG Labs has created a REU clone.  As for copying, you are really going to make me pull out my CP/M stuff... or Google, whichever I get to first.  I believe the CP/M directory is different than the CBM directory.  I have no idea if D128/64IT will handle them.

 

 

Many thanks. We Retroists seem to forget that Google stopped working as an easy search tool a decade or more ago. 

 

Eating my words, Google led to this:

https://sites.google.com/site/h2obsession/CBM/C128/cp-m

 

And the same search engine confirms that SD2IEC will read a D71 format.

 

There, now was that so hard? I think perhaps Google has cataloged more info on the Commodore machines than some other devices for which I've searched lately. "XTIDE in an AMSTRAD PPC640" anyone?

[+OLD CS1]

Oh, yeah.  The SD2IEC is pretty flexible.  It can mount D71, D64, G64, D81, native CMD partitions.  What it cannot do, so far as I know, is mount images of MFM disks.  Now, that would be pretty cool, to take a DSK image and mount it in 1571 MFM mode.

[Casey]

I was going to say something similar.  You should be able to create a .d64 or .d81 and format it within CP/M.  I was able to play with CP/M on Vice using a .d81 boot disk image.  Those can be found I think pretty easily and I would think it would work.

 

OLD CS1 has given me something to try this weekend though.  I’m curious also if you can insert a MFM disk image into the emulated 1571 in Vice and see if CP/M can access it.

[towmater]

Well it was a valiant effort, nevertheless it was merely an effort.

 

[towmater]

I can't help but let anyone within earshot know that a 1581 is on ShopGoodwill at this moment.

 

Edited December 28, 2019 by towmater

[R.Cade]

CPM on the C128 works fine on the SD2IEC. It does not work with burst-mode disk access, but it works fine nonetheless.

 

[carlsson]

@towmater Is that an SD2IEC device you are using? That is not how you mount disk images.

 

Using old school C64 syntax, you would use this:

 

OPEN 1,9,15

PRINT#1,"CD:CPM.D71"

CLOSE 1 (optional)

LOAD"*",9,1 (or LOAD"$",9 if you want to get the listing)

 

I think the C128 has commands for DIRECTORY and sending commands directly to the drive, but since I never was a C128 person I don't know exactly which ones are available.

[Casey]

If it's an actual CP/M boot disk image, after you mount it in the SD2IEC, you'll have to use this command:  BOOT,D0,U9

 

[towmater]

16 hours ago, Casey said:

If it's an actual CP/M boot disk image, after you mount it in the SD2IEC, you'll have to use this command:  BOOT,D0,U9

 

I guess BOOT D0,U9. This almost worked, but halfway through decided it wanted to use the Indus and offered up a "READ ERROR". I'll play with giving it a blank floppy in unit 8.

[carlsson]

It could also be that some part of the boot routine is hard coded to address device 8, which would mean that you need to flip around the device numbers (possibly detaching the Indus in the mean time) for it to work. The SD2IEC has reasonably simple commands to change device number and store it, in case you'd prefer it to permanently become 8. Unfortunately quite a lot of software are hardcoded for device 8 instead of reading the system variable for which device was last used.

[+OLD CS1]

I found a hack somewhere the other night which details how to get CP/M to boot off devices other than 8.  You have to hex-edit the disk.

[motrucker]

While there are newer storage options, I would highly recommend getting a real 1571 to use with your "new" C-128. The 1571 is one of the best disk drives Commodore ever made, and makes a great partner for the C-128!

You can speed up disk functions even more with Jiffy DOS, or Warp Speed or Mach 128 cartridges.

I believe the C-128 is the best eight bit computer made, period.

 

 

[towmater]

On 12/31/2019 at 8:08 AM, motrucker said:

 I would highly recommend getting a real 1571 to use with your "new" C-128.

I've been watching auctions. For $75-ish I can buy a questionable drive, for $125-ish a tested drive. 

[+OLD CS1]

1 hour ago, towmater said:

I've been watching auctions. For $75-ish I can buy a questionable drive, for $125-ish a tested drive. 

That seems about the going rate on eBay.  There is a guy who sells them for around the $125 mark with JiffyDOS.  You might be able to snag one here in AA for a better price if you post in the Wanted sub of the Marketplace.

[towmater]

2 hours ago, OLD CS1 said:

You might be able to snag one here in AA for a better price if you post in the Wanted sub of the Marketplace.

I should get around to offering up some trades. I have an Atari 1200XL that needs a new home, etc.

I'm just finding out that the Indus itself may be capable of running CP/M. Not loading it... it runs on the drive's internal Z80 CPU, apparently.  (It may only work on the Atari version, I'm not certain.)

[R.Cade]

The CP/M inside the drive is only on the Atari version. The C64 version is completely different.

 

[carlsson]

Yeah. A while ago I came across a site going through various Commodore clone drives and how their ROMs differ. I was a little surprised by the fact that even the Indus drive for the Commodore systems is just yet another 1541 clone using 6502 + 6522 with a few instructions swapped around to avoid getting caught by 1:1 copying. Supposedly the path to court to sue manufacturers for copying ROM when they swapped order of instructions and routines, sometimes data areas, was too long and windling for Commodore to go forth about it. While swapping order of routines usually breaks some of the low level compatibility (e.g. JiffyDOS), it also meant that Blue Chip, Excelerator, Indus and all the others didn't have to invent the ROM themselves, just hack Commodore's one. In the other end, it also means that Indus drives for Atari and Commodore may look similar on the outside but are different designs on the inside. When you think about it, there is no strict requirement for a Commodore floppy drive to be powered by a 6502 chip, as long as it responds to commands and outputs the data the computer expects, yet almost all of them are designed exactly like Commodore's own ones.

Edited January 2, 2020 by carlsson