View Full Version : Help writing CP/M programs to disk on a PC

December 29th, 2017, 04:02 PM

I'm finishing a restoration on an Intertec Superbrain and am now looking to get some software on it. Just as an example, I'm trying to write Zork to a disk from this archive: http://www.retroarchive.org/cpm/games/games.htm

My setup is a mid-2000s machine with a good floppy controller. I've got a 360K 5.25" drive installed, and I'm booting to FreeDOS. I'm using new double density disks. I was able to use Dave Dunfield's excellent ImageDisk software to write a boot disk for the machine, which works perfectly. The trouble I'm having is I seem to be unable to get any software to write individual files to a formatted disk. I've used this site as a guide: http://www.z80.eu/transfercpm.html and tried Uniform, PC Alien, and 22DISK. None of them seem to be able to write a disk. I get a seek error or similar. I've tried formatting the disk in the Superbrain itself, as well as in the tools listed. Even if I take a new disk out of the box, format it in 22DISK for instance, then try to write a file it will error out.

Does anyone have any experience with this? I suspect my hardware setup is good as it wrote the boot image flawlessly. Maybe FreeDOS is the problem?

December 29th, 2017, 06:37 PM
What is the exact Model of SuperBrain that you have? There are several versions of hardware (floppy Drives, etc.) and there are
five types (typical) of floppy formats.
1 Superbrain JR - SSDD 48 tpi 5.25" - 512 x 10
2 Superbrain 40 track - SSDD 48 tpi 5.25" - 512 x 10
3 Superbrain QD - DSDD 48 tpi 5.25" - 512 x 10
4 Superbrain II - DSDD 96 tpi 5.25" - 512 x 10
5 Superbrain - SSDD 48 tpi 5.25" - 128 x 30

22DISK should work fine to copy the files to your floppy from FreeDos. I'm assuming you are a REGISTERED USER with SYDEX. If not, it's well
worth the price to be able to easiiy access your Floppy's. You can test the Floppy Disk controller with the Imagedisk Utility "TESTFDC.COM".
The Software will test the FDC and determine what formats you can write successfully.

If you happen to have a SuperBrain II QD with Bios 4.x, there are folks on this Forum looking for a Good Copy of the Boot Disk with
Configur.com and Format.com. An .IMD file would be great.

If you have cpmtools (built with libdsk) installed, then you can also use cpmtools to access your Floppy Images after converting them to a .RAW image.
There are ways to write those images back to Floppy.


December 30th, 2017, 06:36 PM
I have a tool that might help you get the files onto a disk image at least. The best way to go from there would probably be using a HxC FDD emulator, or a disk imager and hardware that can handle the specific floppy format.

You might also need to make an image of an empty disk first as well...

(having some issues dragging an dropping to re-attach the old upload using a smartphone, so I just link to the old thread instead.)

December 30th, 2017, 09:28 PM

I swapped motherboards to one of similar vintage with an almost identical FDC and was able to get Alien to format and write a CP/M disk for the Superbrain. I thought this was the solution, but after swapping back to the original motherboard I was able to get both Alien and 22DISK to work intermittently. At this point I'm assuming it's either sketchy floppies, or my drive isn't quite 100% At least I've got something to go on and know the rest of my setup is good.

One question about TESTFDC. My drive passes both single and double-density 250kb tests, but the program always skips the 300 and 500 tests. Does that indicate the the drive I'm using doesn't support those speeds?