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8 inch disks with different sector sizes

Posted: Sat Oct 26, 2019 10:33 pm
by Zorix
Hi,

Got my Kryoflux reading 8 inch disks now. However, the disks I have are interesting. Track 0 is 128 bytes and the other tracks are 512 bytes. Was able to figure that out by looking at the ui for the raw tracks. How do I handle this properly?

./dtc -fimages/disk/disk -i0 -fimages/disk/disk.img -v360 -z0 -i3 -t5 -l8
00.0 : FM: OK*, trk: 000, sec: 26, *H
00.1 : FM: OK*, trk: 000, sec: 26, *HS
01.0 : FM: <mismatch>, *N
01.1 : FM: <mismatch>, *NS
02.0 : FM: <mismatch>, *N

/dtc -fimages/disk/disk -i0 -fimages/disk/disk.img -v360 -z2 -i3 -t5 -l8
00.0 : FM: <mismatch>, *N
00.1 : FM: <mismatch>, *NS
01.0 : FM: OK*, trk: 001, sec: 8, *H
01.1 : FM: OK*, trk: 001, sec: 8, *HS
02.0 : FM: OK*, trk: 002, sec: 8, *H
02.1 : FM: OK*, trk: 002, sec: 8, *HS

Also, I thought 00.0 was side 0 and 00.1 was side one. These disks don't have a second side and the drive itself only has a single head. What's the deal with that?

Thanks!

Re: 8 inch disks with different sector sizes

Posted: Sat Oct 26, 2019 10:59 pm
by ZrX
You can only generate two different imagefiles of such disks and manually splice together a single imagefile from the used tracks. If such imagefile would work for something is anyones guess.

KryoFlux doesn't know how many heads a diskdrive might have, so it sends the electronic signal to select which side to read, but as the drive has only one head the same track data is returned for both head selections. That's why the report shows error *S for xx.1 meaning the side number reported from the decoded track data seems incorrect.

By using the switch -g0 somewhere between *.img and -i3 you can force to use only the first side.

dtc -fblah -i0 -fblah1.img -v360 -z0 -g0 -i3 -fblah2.img -v360 -z2 -g0 -i3 -t5 -l8

Re: 8 inch disks with different sector sizes

Posted: Sun Oct 27, 2019 12:10 am
by Zorix
Thank you! That worked for me. Just have to figure out how to make these images useful. Apparently its an IBM 33FD Type 1, 303KB image according to Wikipedia.

https://en.wikipedia.org/wiki/List_of_f ... sk_formats