Flash floppy gotek and 5.25” drive

[ThomasBrysonOwen]

Hello Everyone,
I have a gotek on an old s100 computer system as D0 that boots the (cp/m) software just fine. I want to add a 5.25” drive as D1.
When I add the 5.25 drive the gotek no longer boots. The controller polls each drive normally, but no boot.
There should be no issues with the flat cable and drive addressing, but I am stumped.
Any suggestion?

[Dietrich-L]

Does the 5.25 boot as D0 alone?
Dietrich

[ThomasBrysonOwen]

Yes it will also work fine by itself. Here is a bit more info:

1. with a straight cable and gotek as DS0 by itself system boots
2. with gotek as DS0 and a DD drive (Teac 55B with no termination) as DS1, the gotek will boot. it will try to format the disk as well, but not correct for my cp/m system.
3. with gotek as DS0 and HD drive (Teac 55gfr with soldered in termination) the gotek will not boot. .
   And this is the drive I need to have working.
   Something in the termination or interface is slightly different with the HD drive and I cannot figure it out.

[Dietrich-L]

Ah, a HD drive reqires a HD capable controller, which your S100 most probably does not have, because HD didn‘t exist at the time.

Dietrich

[ThomasBrysonOwen]

No, the hd drive ‘appears’ to the controller as a 8” drive. Again, it functions fine by itself, just not on the same cable with the gotek.

*** Further troubleshooting today I found that it is pin 30, Read Data, that causes the problem. If that pin is taped over on the floppy connector, the gotek will boot.
Why then would this be causing the trouble?

[Dietrich-L]

Ok, the HD 5.25 inch format is identical to the DD 8 inch format - 360 rpm and 500 kHz data rate. 5.25 inch DD would be 300 rpm and 250 kHz data rate. Are you sure, the S100 controller can handle 500 kHz data rate?

Dietrich