Thinkpad 750Cs hard disk upgrade questions

["Alexander J. Annala" <a.annala@ucl.ac.uk>]

I found it interesting that although the IBM DBOA-2720 drive
is physically 1400CYL/16HD/63SECT it appears to be remapped
(by TP750 BIOS?) to be a virtual 699CYL/32HD/63SECT drive --
which is rather nice for DOS because this stays within the
1024 cylinder limit of what DOS can handle on its own.  Also
for anyone considering this upgrade, this drive is so thin
it does not fill the empty space in the caddy -- this may be
good for air circulation -- but I think it also results in a
bit more noise when the drive is running.

While 720 MB was a nice upgrade from 340 MB, I am considering
maybe spending a bit more (the store will take both the 720 MB
drive and the 340 MB drive in trade at 2/3 of retail price) on
1,350 MB Toshiba MK1301MAV drive.  This new disk would cost
me about $195.00 US -- so it seems worthwhile on the surface.
On the other hand, it is not an IBM drive.  Has anyone put the
MK1301MAV drive in a Thinkpad 750 notebook?  Do you find that
the drive is remapped so DOS thinks it is dealing with a drive
containing less than 1024 cylinders?

If you have 1,350 MB in a notebook, what do you do for backup?
I have a SCSI card which I could use to backup to DAT or 8 MM
at work, but it would be nice to have my own backup system.  I
really wonder what everyone else with large portable hard disk
does for reliable backup.  Road Warrier offers a $125.00 US
box which you could put another IDE disk into -- but it uses
the parallel port to do data transfers.  How fast is parallel
port on Thinkpads?  1.3 GB backup at low speed is not workable.
Does anyone make a similar SCSI to IDE/EIDE box?  Also, the
Road Warrier solution tries to suck power from the keyboard
port -- my previous experience with this kind of arrangement
was with the original black and white quick cam -- the camera
never saw enough power to function -- not a good indication of
the amount of power available to run an external disk drive.

Could someone tell me who sells empty IBM Thinkpad 750 caddys?
I don't think there is an official IBM source, but I recall an
advertisement some time ago about a company which makes them.
Also, there were 170 MB IBM caddys available cheap at one time
-- are they all gone?

Alexander J. Annala, Ph.D.
Laboratory for Molecular Pharmacology
University College London