Rodime RO200 series

[Tony Duell]

> 
> I've recently acquired a TORCH-725 which has this RO200
> series hard drive in it, trouble is when I took everything
> out of the TORCH case for first inspection I heard something
> 'ting' off one of the platters in the drive. Opening it up
> to have a look, well a little dust can't be as bad as debris
> that goes 'ting', I found a 12mm long 2.7mm dia. roll pin
> lying in one corner. Anyone have a clue where this may have
> come from? Dare I power the drive without it? This may

No real idea.... Look for a hole that could have taken it, I guess. 
Obvious candidates would be an end stop for the head movement, part of a 
flexiprint guide, or part of the positioner itself (am I correct that 
this drive uses a stepper motor to position the heads?)

> eventually be the only option if I can't re-install the pin.
> 
> While this is an RO200 series I don't know which one. The
> series seems to run from 5MB to 40MB and I'd like to know
> which one this is likely to be.
> 
> Assuming this drive needs to be replaced can I use a 40MB
> SCSI drive on the Torch SCSI board and bypass the SCSI to
> ST506 interface? This would be the prefered eventual solution

I doubt it. Most Torch machines used an OMTI 5000 series board, I think 
(the XXX certainly did, I think the rare SCSI plinth for the Beeb did 
too). Said board certainly supports multiple 'units' at one SCSI address 
(do most SCSI drives fo that). There's also something about reading the 
drive geometry from the first (zeroth?) sector of the drive, then sending 
some commands to the OMTI board. I doubt that modern SCSI drives will 
handle that correctly.

-tony