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

Eric J Korpela korpela at
Thu Mar 10 18:16:13 CST 2005

> > 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.

ST-225.  The 255 is a 40MB drive.  Despite the price difference
between the 225 and the 238R they were pretty much identical drives
(since a 225R == 238).  I've never found a late model 225 that
wouldn't work with an RLL controller.  I won't claim they all will,
but I'd guess any manufactured after the 238R hit the lines are really
a 238R rebranded as a 225.

As far as controllers go when I was first shopping for an 8-bit RLL
adapter, the Adaptec cards were significantly less expensive than the
Seagate cards.  Unfortunately, I think the cards are incompatible in
their encoding, so you can't expect an Adaptec formated disk to be
readable with the Seagate card.
These disks were also very suseptible to head creep over time.  I'd be
surprised if they don't need a low level format.  You might be able to
reformat (somewhat) non-destructively with an old copy of Norton
Utilities or SpinRite.


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