The IBM DASD ReadMe I have here (October 7, 2005) has the following couple of paragraphs:
...
1 Introduction
_________________
FixPak 35 (FP35) for Warp 3 and FixPak 6 (FP6) for Warp 4 extended support
for fixed Enhanced IDE drives to sizes up to 8.4GB and added new caching
HPFS and FAT file system support for removable media drives such as SCSI
Syquest Syjet 1.5GB portable hard drive and the Iomega jaz 1GB and 2GB
personal hard drives.
This package contains updates to the support in FP35 and FP6, extending
support to fixed Enhanced IDE drives first past the 8.4GB boundary and
second past the 512 Gb boundary. It also fixes some other problems, and
adding additional documentation on removable media support. Beginning with
FP40 and FP10 OS/2 base device drivers were separated into a Base Device
Driver FixPak.
...
Further on, under section #3 (Large Hard Drive Support) the following can be found:
...
3.2 Cannot Mark a Partition Installable
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There is a BIOS restriction for most older (typically pre-2001 manufacture)
computers that installable (startable) or bootable partitions must be
contained within the first 1024 logical cylinders of the disk. This is true
for both EIDE and SCSI hard disk drives. If FDISK fails to allow a
partition to be marked installable, the partition is either above 1024
cylinders or the partition spans the first 1024 logical cylinders of the
disk. Use FDISK to reduce the size of the startable or bootable partition
by sufficient MBytes. One way to calculate the correct partition size is to
do the following:
1. Edit your CONFIG.SYS and add the parameter /W or /V to the
BASEDEV=IBM1S506.ADD statement.
2. Save this change and reboot the system.
3. At initialization, record the far left hand column of numbers of the
geometry information under the OS2:log heading; for example, where
C=cylinder, H=head, and S=sector:
OS2:log
C 1027
H 63
S 128
4. Calculate the 1024 cylinder size in MBytes as ( H x S ) / 2. (round
down).
All bootable partitions must be contained within this size. In this
example the bootable partition must be contained in the first 4032
MBbytes of the disk and cannot exceed a single partition size of 4032
MBytes within this area. No bootable partition may extend beyond the
first 4032 MBytes.
5. Use FDISK to resize the partitions and reboot.
...
Worth a read, as there are numerous other mentions of Hard Drive Size limitations, etc.
I've attached to this post.