Tatung Computer Forum

arcadesy wrote: ↑Mon Jan 30, 2023 11:54 am https://www.tatung-forum.co.uk/viewtopic.php?f=3&t=83 << interesting thread about getting 800k from a Gotek dsk image

The above link works with my 5.25" floppy drive (TEAC FD55FV-30-U) and is able to read a few 700KB discs and show the file index. Some discs show no files at all, even though there is writing on the disc labels It could be right but I doubt it.

Drive 0 set to single sided 40 track
Drive 1 set to double sided 80 track
Drive 2 and 3 set to same as Drive 0 (I dont have anything connected so just configured as standard)

Not sure if my drive is busted or not, as there is a lot of squeaking and whirring going onwhen reading discs. It is very old and I cannot remember where I aquired it from.

When trying to run a program off the floppy, the heads just move back and forth and I get a Bad Data 1: or No Sector 1: error message.

What external 5.25" drives are other people using (Make and model with jumper settings)?

I have 6 boxes of 5.23" discs that I need to test and check, but that project has hit a brick wall

Maybe the drive (In it's current configuration) will work with Grease Weazle and allow me to image the discs and use them in Mame or on my Gotek?

Thanks

Mike.

Sounds like the drive is either out of alignment or the discs are corrupt (or both!).

Or the discs are not 80 track double-sided discs. They may have been originally formatted as 40 or 80 track single sided, perhaps? You could try the other formats to rule this out.

Without dedicated equipment, trying to fix the alignment by trial and error is not impossible but I doubt it’d be successful. There are some videos showing this process on YouTube. It’s easier to try an alternative drive that is calibrated correctly. Unfortunately I’ve not used a 5.25” drive in years so can’t help in offering an alternative working drive.

If you’ve a spare disc you can format and verify successfully with the 5.25” drive that would at least rule out a major problem with the drive itself. Even if the alignment is out, then your formatted disc should be readable and run programs, etc.

Data on corrupt discs can sometimes be salvaged, but if the directory sectors are unreadable then it’s highly likely that other areas of the disc are also corrupted.

If Greaseweasel doesn’t work, then I’m tempted to think the drive is faulty if your newly formatted disc also doesn’t work.

I’d use DISCMOD to look at the directory entries on the Discs that appear to be empty. If you see entries not showing with a DIR, then the DOS is set to the wrong format. If you see entries, the discs may have deleted programs that can be restored, even if a DIR shows no files. If you can’t access the sectors using a drive you know is working, then it looks like the discs are corrupt.

You can’t really check disc corruption on the Einstein as there are no available software tools. I’ve used an Amstrad CPC to more thoroughly check for the number of tracks, the sector numbers that vary by format and for missing address marks that make the disc unreadable.

Be interesting to see if DISCMOD throws any light on your project.

If you manage to convert the disc to an DSK image using Greaseweasel but you find it still doesn’t work as expected, then there are a few things you can try to determine the extent of the disc corruption.

Using DISCMOD on your Einstein with your DSK copy is much safer in ensuring you don’t inadvertently further corrupt the original disc.

HxC Floppy Emulator software on your PC has a track analyser that’ll reveal the exact extent of any corruption.

Check your disks for signs of mold too. I find 5.25" disks very prone to it.