maxtherabbit
Veteran Member
I have two floppy controllers in my 286. Primary is part of some generic Taiwanese IDE/IO card managed by the system BIOS with 2 high density drives. I also have an Adaptec 1542B SCSI controller which contains a NI DP8473V FDC (similar to the one on the CC IV) jumpered to the secondary FDC address.
As per TESTFDC, this FDC will support single density and 128B sectors. I am able to read and write disk images to/from drives connected to the secondary controller in IMD with no issues. I can then quit IMD and perform DOS file accesses to the primary FDC's drives. I'm interpreting this to mean that the two FDCs are able to "share" the IRQ/DMA without issue.
So far I have not been able to locate any software which will assign a drive letter to any drive on the secondary FDC and allow file level access.
Tried:
SDRIVE.SYS - says secondary controller not operational, tried hex editing it to not reset FDC, no effect
WONDER34.SYS - does not appear to support secondary FDC in any capacity
Uniform-PC - only allows selecting Compaticard products as Secondary FDC. Selecting the Compaticard 4 requires the CC4 device driver be loaded. Trying to load the CC4BIOS.SYS to facilitate the CC4 driver's loading is balking at the secondary FDC.
Really struggling to believe that after 40 years+ of using floppies in DOS no one ever wrote a DOS driver to access a secondary FDC, but that is seeming more and more like the case. Would it be possible to use 22disk to read DOS formats? Or would that require changing the code? I guess the other thing would be modifying the CC4 BIOS image to work with a different FDC but that's beyond my capability.
As per TESTFDC, this FDC will support single density and 128B sectors. I am able to read and write disk images to/from drives connected to the secondary controller in IMD with no issues. I can then quit IMD and perform DOS file accesses to the primary FDC's drives. I'm interpreting this to mean that the two FDCs are able to "share" the IRQ/DMA without issue.
So far I have not been able to locate any software which will assign a drive letter to any drive on the secondary FDC and allow file level access.
Tried:
SDRIVE.SYS - says secondary controller not operational, tried hex editing it to not reset FDC, no effect
WONDER34.SYS - does not appear to support secondary FDC in any capacity
Uniform-PC - only allows selecting Compaticard products as Secondary FDC. Selecting the Compaticard 4 requires the CC4 device driver be loaded. Trying to load the CC4BIOS.SYS to facilitate the CC4 driver's loading is balking at the secondary FDC.
Really struggling to believe that after 40 years+ of using floppies in DOS no one ever wrote a DOS driver to access a secondary FDC, but that is seeming more and more like the case. Would it be possible to use 22disk to read DOS formats? Or would that require changing the code? I guess the other thing would be modifying the CC4 BIOS image to work with a different FDC but that's beyond my capability.