[Coco] Determining OS-9 Floppy Type

[Andrew]

As you all know, I am doing a floppy disk conversion project for Carey, 
to rescue a bunch of data from some old floppies, and convert it into 
images which can be read under emulation. I have already completed the 
DECB subset of floppies, and I am beginning to tackle the OS-9 subset.

However, I am running into a snag. When I worked on the DECB subset, I 
was able to determine what kind of disks the OS-9 floppy sides were 
(some of the floppies were "mixed" - one side being DECB, the other 
OS-9) by inference:

Since under OS-9 there are only 35 track SSDD device descriptors and 40 
track DSDD descriptors (but no 40 track SSDD descriptors), if there was 
readable OS-9 data on one side of a floppy and the other was DECB 
formatted (and there were two index holes punched in the floppy jacket), 
then it could only be a 35 track SSDD floppy side.

However, I can't make that inference now since a 35 track SSDD floppy 
(with a single index hole) looks the same physically as a 40 track DSDD 
floppy (which also has a single index hole). Unless it is labeled as a 
certain format, I am not sure how to tell which is which.

Can anyone tell me what the best way of determining whether an OS-9 
formatted floppy is a 35 track SSDD floppy or a 40 track DSDD floppy? 
Whether the method uses DECB, OS-9, or DOS, it doesn't matter. However, 
I don't have access to a Windows machine with a 5.25 floppy drive, so 
that method is out.

I need to know this information so I can make a proper backup and 
recovery image of the floppy (btw - what would be the best way for me to 
create a DSK image of a 40 track DSDD OS-9 floppy under DOS?). Is there 
a way to take an image with each side using RETRIEVE.EXE and then 
combining them somehow? Or, is there something like RETRIEVE.EXE, that 
runs on DOS, that will do this?

Or - could I run a program under DECB in the emulator that took each 
side image and then directly wrote it to a third image using DSKI$ and 
DSKO$? Or perhaps in a similar manner use OS-9 on the emulator to pull 
and combine each image?

Hmm - this conversion effort for the OS-9 floppies has gotten hairy 
quickly. Any and all answers will be appreciated - I don't plan on doing 
anything until I have a working answer from someone(s) out there, or no 
answer is forthcoming and I have to cobble something together myself.

Thank you in advance...

-- Andrew L. Ayers
    Glendale, Arizona