Problem With CP/M Plus Diskettes
#1
I can usually use SCP to convert DMK or DSK images into bootable floppies but the Tandy Model 4 CP/M Plus diskettes I create with SCP are not bootable. I use a two-step approach.
 
First I use the HxC Floppy Emulator software in Windows 10 to convert from DMK or DSK format to SCP format.
 
Then I use the SCP software/hardware to write the physical floppy diskette.
 
As I said, this works fine for most MFM-encoded formats (Kaypro, TRS-80, Color Computer, TI-99/4A. etc.) but after going through the entire writing process with no error messages, the SCP-created CP/M Plus diskettes are not bootable on a TRS-80 Model 4.
 
Finally I tried using HxC to create an IMD image which ImageDisk was able to use to create bootable floppies from DOS.
 
According to ImageDisk, Tandy CP/M Plus uses a dual-format. Track 0 is 18 sectors of 256 bytes but the other 39 tracks are 8 sectors of 512 bytes. I believe SCP software could be modified to write these disks successfully. If you’re interested in tackling the job, I can provide either DSK or DMK images of the Tandy software.
 
Let me know if you’d like copies of the diskette images.
 
Tom Lake
Malone, NY
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#2
SuperCard Pro knows absolutely nothing about disk formats.  It is a flux imager/copier, so it "handles" every type of disk possible.  I responded to your email.  Send me a disk image and I can tell you what the issue is.  Since you are using HxC to convert the disk and other non-CP/M disks work this way, I would think that the issue is that HxC is not doing the conversion correctly.  It would have to know that it is a CP/M variable sector format when doing the conversion and I am not sure if Jeff supports that.  I do know that .dsk and .dmk formats are not variable sector formats.

SuperCard Pro writes entire tracks of flux data.  It doesn't write any disk "format" because it doesn't handle data that way.  You should be able to take an original CP/M disk, dump it as an image file (.scp) and then write it back out to another disk, and boot that disk.  I don't have any control of what any conversion software does.  SuperCard Pro accepts only flux transitions and those have to be right in order to have a working disk.
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#3
(03-07-2019, 03:25 AM)admin Wrote: SuperCard Pro knows absolutely nothing about disk formats.  It is a flux imager/copier, so it "handles" every type of disk possible.  I responded to your email.  Send me a disk image and I can tell you what the issue is.  Since you are using HxC to convert the disk and other non-CP/M disks work this way, I would think that the issue is that HxC is not doing the conversion correctly.  It would have to know that it is a CP/M variable sector format when doing the conversion and I am not sure if Jeff supports that.  I do know that .dsk and .dmk formats are not variable sector formats.

SuperCard Pro writes entire tracks of flux data.  It doesn't write any disk "format" because it doesn't handle data that way.  You should be able to take an original CP/M disk, dump it as an image file (.scp) and then write it back out to another disk, and boot that disk.  I don't have any control of what any conversion software does.  SuperCard Pro accepts only flux transitions and those have to be right in order to have a working disk.

It turns out that HxC is the software that can't handle the CP/M Plus format. DMK and DSK are only supposed to handle uniform sector counts and sizes. The HxC team is working on the problem. Of course SCP can't create good diskettes from a bad SCP file.
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