Floppy formats used with Memotech ?

[Crazyboss]

Hi.

Saw the list on Andys homepage. I seems like only 5.25" 40 tracks Double Sided DD was used. For FDX

Dave knows I have a SDX in a FDX box, which only have 3 slots. Wonder if it used the same disk format, its a Qumetrack 142 drive.

By the way when I google Qumetrack 142, it said its a 80track drive wonder if its forced to 40track mode with a jumper?

Anyway Andys page also mention 3.5" 40 track format, its a bit weird how they did that. Did they only use half of the disk? I never saw a 40 track 3.5" drive. I seen 80 tracks single sided (which was used at the MSX) and the 80 track double sided also used at MSX, which was compatible with the PC standard.

It would be more logical if they used 3.5" 80 tracks single sided then? as the MSX did.

Later versions of SDX seems to run 3.5" 80 tracks double sided.

[Dave]

DS/DD (Memotech Type 03) was the most common drive for FDX

Qumetrak 142 are not 80 track drives - they are 40 tracks (per side, so you could say 80 in total)
(The Maintenance Manual is on my site)

Yes, your SDX is probably the same drive (or the Epson SD-521 equivalent)

regards
Dave

[1024MAK]

3.5 inch 40 track drives did exist. The Opus Discovery disk drive system for the ZX Spectrum used them.

Mark

[Crazyboss]

3.5 inch 40 track drives did exist. The Opus Discovery disk drive system for the ZX Spectrum used them.

Mark

wonder how it was done, maybe they only used the first 40 tracks on the diskette or maybe it had double steps ?

Actually I remember I modified a amstrad cpc diskdrive with a 3.5" drive and i added a switch to force side select, but amstrad diskettes was also only 40 tracks so actually only half of the diskette was used, so if there was a way to make the offset of track 0 to be 40, then i could actually format 4 amstrad disks on one 3.5" diskette.

[1024MAK]

I don't know if they had larger heads and mechanisms that stepped across the useable disk surface in 40 steps. Or if they used the same size heads as 80 track drives and stepped twice for every "step command". I think it unlikely that they only used the first half of the disk. Someone, somewhere would have discovered this and come up with a hack (to get more data storage) if this was the case. Just like on the Atari ST it was found that custom formatter programs could get 82, 83 or even 84 tracks from the 80 track 3.5 inch drives...

The Opus could be upgraded to 80 track drives.

Mark