Re: Thinkpad 750Cs hard disk upgrade questions

[Michael Redmond <redmond@engr.wisc.edu>]

I put an MK1301MAV into my TP 755CD. It went very smoothly. I was worried
that some jumper settings might mess up when using the original TP drive
carrier, but it plugged right in and started working fine. 

I partitioned into two drives using standard FAT. One drive is right below
512M so the allocation units are 8K. The other is about 700+Meg, and the
allocation units are 16K. I put my base system on the 512M partition, and I
use the second partition for various work and archives. When I start
running into problems with wasted space from big allocation units, and when
I start running out of archive room on the second partition, I will
compress it. That should remove any problems with allocation units, since
it will turn the disk into one big file. At least that's the theory. 

Sometime, I will probably upgrade to the FAT32 to solve parts of this problem.

I bought one of the Road Warrior bullet cases. I put my old 540M IBM drive
into it. There were some initial glitches with setting up the parallel port
interface (needed to use LPT2 rather than LPT1 in setup). But now it
basically works. It is very slow.

I use the 540M in the Bullet as my backup system. Using MS Backup with
compression, I'm able to put all my info from my 2 partitions (now
totalling about 450M of useful stuff) into a full backup file of about
230M. This takes about an hour to back up using the parallel port
connection. It's faster than most tape drives but still pretty excruciating.

My keyboard port (and in fact just about any of the PC keyboard ports I
tried) doesn't supply enough for the Bullet drive. I found other 5V
supplies around to do the job.

I tried a third party caddy from a company called PS Solutions, but I found
it didn't hold in tight enough to the TP connector, and that caused
problems. I eventually returned it. The IBM caddy has the locking wire that
holds it firmly in place.

Thanks
Mike Redmond
------------
At 08:35 AM 12/25/96 +0000, Alexander J. Annala wrote:
>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
>
>
>