ST-238R and ST-225, likely controller?

[Jim Leonard]

Ryan Underwood wrote:

Hi Ryan!

> A friend has a ST-238R and ST-225 that came out of his XT long ago.
> We're trying to figure out what the most likely controller that was
> being used in the original machine so we can recover the data.  It must
> have been 8-bit and support RLL.  The best guess I can come up with is
> the WD 27X (which I used to have).  Anyone else have a good guess?

An ST-255 is MFM and probably used an WD1002* controller (although any MFM 
controller should work).  It's a 20MB drive; check web for the cyl/hd/sec count.

The ST-238R is an RLL drive -- I'm only casually familiar with RLL so I can't 
help you there.  I do know that matching drive+controller is more important 
with RLL than MFM, though.

> I think the ST-225 came with the machine and then the ST-238R was
> installed as part of a kit.  

It is very possible to use an RLL drive with an MFM controller, but you won't 
get the rated size out of the drive due to the MFM encoding method.  Maybe he 
just slapped the drive on?
-- 
Jim Leonard (trixter at oldskool.org)                    http://www.oldskool.org/
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