http://www.pcguide.com/ref/hdd/bios/sizeMB504-c.html

Here is an article that may interest you.  I recall using larger drives with
at least one 386 pc, although it had some late generation features not
common to the 386.  What I did is pick a disk from the built-in table of
available disks in the CMOS setup.  If there is a user-defined entry, then
you can make one up.  The article explains what the cylinder, head, and
sector entries mean.  I don't remember if there were BIOS limits below 504
megabytes for IDE drives, so you may get away with the articles suggested
maximum settings (for each, respectively) 1024, 16, 63.  More likely, pick
something from the BIOS table of the PS/2 model 40 that gives you the
biggest size, keeping in mind that cylinders is the least relevant in terms
of accuracy as far as the drive is concerned.  the article explains how to
do the math from the 3 values to calculate the resulting formatted size.

If you do get a decent size, remember that some DOS versions will be
constrained to FAT16 partitions.  Optimum partition sizes give different
cluster sizes (the minimum space it takes to store a file to disk), and
these  are: 65 meg @ 1024 byte per cluster, 130 meg @ 2048 bytes, and 260
meg @ 4096 bytes.  A 504 meg partition results in 8192 bytes being used per
file cluster, which wastes a lot of storage and will slow all your disk
accesses.  If you get 504 useful MB from your 800 MB drive, I would suggest
a mininum of two partitions if you choose (or are forced to use) FAT16.

The drive should be able to interpret any values you have regardless of the
physical structure of the drive.  The article links to a page that explains
what happens if it won't, which is not physical damage to the drive (at
least I have never damaged a drive doing this.)
Tom Turak

-----Original Message-----
From: Kyle Elmblade [mailto:[log in to unmask]]
Sent: Wednesday, March 12, 2003 11:22 AM

Hi Joseph,
The only way to get the BIOS to recognize a larger drive is if there were an
update for it.  Given the age of the laptop there is very little chance of
this.  As much as I hate to say this, the best bet would be to purchase a
drive that you can put an overlay on, and this will "trick" the BIOS (and
the operating system) into seeing the whole drive.  This will affect the
performance a little bit, but given the age of the system and the fact that
you are using DOS, you shouldn't notice it too much.

The other option, of course, is to try and find a smaller drive on Ebay or
at some of the Internet classifieds sites.

Good luck!
Kyle Elmblade

From: "Joseph Rene C Hallare" <[log in to unmask]>
Sent: Wednesday, March 12, 2003 10:16 AM
> Mabuhay!
>
> I would like to know if any body on the list has any idea how large a hard
>disk I can use to replace the previous hard disk  of a IBM PS/2 Model 40 Sx
>Laptop which was 60 MB. Scrounging around the smallest one we can get right
>now is 800Mb. Sourcing a part overseas (I'm in the Philippines) is out of
>the question. I know it is a dinosaur being a 386Sx processor with 4MB of
>RAM. This laptop is for use in DOS. Is it possible to get the BIOS to
>recognize the bigger hard disk? Apparently it seems to shift to BASIC (I
>think) when no operating system is present.
>

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