Western Digital FD1797 Floppy Disk controller

[steffenspies]

Hello around,
CP/M trouble... what else.

I try to read my old CP/M disks but fail massively and I've no idea what else can be done.
Maybe someone has a good hint where to start.

What I know:
5 1/4" Teac FD-55B is used from the original system (which still works, so I know the disk is working).
Floppy Disk Controller is Western Digital FD1797
A formated disk has 320kB free, is double sided, 40 Tracks/side, 48tpi, MFM, 300 RPM
The WD document mentions a "IBM System 34 Double Density (MFM)" format.

I tried almost any possible settings, different drives, diskettes and had the chance to try a kryflux too beside my Greaseweazlke V4 with no luck at all.

Track 00 can't be found seems to me the biggest problem.

Thanks for time and brain crunching!
Steffen

[keirf]

What type of greaseweazle? Tried another 5.25 drive?

[keirf]

From where do you get the 360kB raw figure?

[keirf]

Most of the disk is empty so you could truncate the IMG to 360kB if you think it might help the image be recognised. Actually only the first 126kB of the disk image contains any data at all.

[keirf]

Okay, mystery solved. You can decode your files using cpmtools and the format is ampdsdd (also pmc101, amp3 and amp5 all work too):

cpmls -f ampdsdd mydisk.img
cpmcp -f ampdsdd mydisk.img 0:* mydisk/

[steffenspies]

Thank you, that was very kind and very helpful.
Now that I have a solution and I'm very happy that there is way now to read all my old Floppies, I still want to find out why my informations are wrong (360kB, sector numbers, sector size). Since my CP/M computer is a homebrew project based on a publication in a German magazine, some informations seem to come from wrong sources.

And I'm sorry that you had to spend so much time for my problem. Need to dive deeper into this. Thank you again, @keirf

[steffenspies]

OK, what a mess...
I found out, that my old documentation simply was wrong. Had have a look into the format tool I used back in the days and now all you, @keirf found out was correct. An formated disk has 390kB free and 1024kB/sector is also correct(obvisly).
Meanwhile all 59 disks are read, stored and are now converted to use with the IMSAI clone. Found only very few bad sectors, which I find amazing after so many years.