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Anyone got some spares?
I need to write some TRS-80 discs...
Also a 3.5" drive would be great too, as I want to write amiga & archi discs.


100 posts! woot!

What kind of 5.25 inch drive Matt? They are not all created equal. Single sided, double sided? 40 track, 80 track? 300 rpm or 360 rpm?

Are the disks for use in a TRS-80 Model III?

Yes, for the model III...
I'm guessing I'm about to hear some bad news.
I thought I could just get a double sided 80 track and it'd all be go?

I'm not an expert on the Model III, but I'm pretty sure it's not as easy as just hooking up any old 5.25 inch drive.

I know for the Model 1 you could mix drives of track number and heads (single sided vrs double sided) but the DOS usually had to be told what type of drive was occupying that particular drive number. Some DOSes could only handle a particular type of drive.

The stock Model III came with 40 track, single sided drives. You MAY have to tweak the DOS for it to recognise anything else. I say MAY because I don't know too much about LDOS or some of the Model III DOSes. They may detect what you've got. I guess what I'm saying is it would be worth doing some research on it. I suspect it's not just plug-and-play.

To my knowledge, half-height 80 track, double sided drives can be used on a Model I/III but only at 300 rpm. At 360 rpm they become 1.2 MB PC drives. Some of these drives have a jumper allowing a speed change, but many are just set at 360.

What track number and head number (one side or two) are your existing Model III drives?

When I do a CAT, it says Type: Double, Cylinders: 40.
Definitely single sided.

I have read you can format 80 track as 40 by just writing each cylinder twice.

Yes, that CAT info is typical of a Model III drive.

I'm not sure if you can format an 80 track as 40 by just writing each cylinder twice? Perhaps you can but you'd need to have a drive which can run at 300 rpm. Ordinary PC D/S 80 track 1.2 MB 5.25 drives run at 360 rpm by default.

I take it only one of your Model III drives are working?

tezza wrote:I take it only one of your Model III drives are working?

LOL, no they both work, I just have to hold one closed (or jam a block in to hold it closed)