FozzTexx
Member
- Joined
- Aug 4, 2013
- Messages
- 23
It seems like it's pretty common for CP/M systems that supported double density MFM to use FM encoding on the first two tracks, and then MFM encoding on the rest of the tracks. Or sometimes they use 128 byte sectors for some tracks, and larger sector sizes for other tracks.
As I'm trying to get my Altos 8000 working I'm finding a lot of the disk images archived online don't boot or have some other corruption. I think I might be able to repair some of them by working with an image made entirely of raw sectors, but then I have no way of converting the raw sector data back into an .IMD which describes how each track is encoded, so I can write it out to a real 8" floppy. It seems like the ImageDisk conversion tools only support having all tracks use the exact same number of sectors and encoding.
As an example, one of the disks I'm trying to repair needs to have the first 2 tracks replaced. The first two tracks contain the OS (seems to be not quite CP/M) and are 128 byte 26 sector FM encoding. But the rest of the tracks are 128 byte 48 sector MFM encoding. Some others use 512 byte 15 sector MFM encoding for the non-OS tracks.
Is there a way to construct an ImageDisk .IMD file from a raw sector image that uses different encodings on different tracks?
As I'm trying to get my Altos 8000 working I'm finding a lot of the disk images archived online don't boot or have some other corruption. I think I might be able to repair some of them by working with an image made entirely of raw sectors, but then I have no way of converting the raw sector data back into an .IMD which describes how each track is encoded, so I can write it out to a real 8" floppy. It seems like the ImageDisk conversion tools only support having all tracks use the exact same number of sectors and encoding.
As an example, one of the disks I'm trying to repair needs to have the first 2 tracks replaced. The first two tracks contain the OS (seems to be not quite CP/M) and are 128 byte 26 sector FM encoding. But the rest of the tracks are 128 byte 48 sector MFM encoding. Some others use 512 byte 15 sector MFM encoding for the non-OS tracks.
Is there a way to construct an ImageDisk .IMD file from a raw sector image that uses different encodings on different tracks?