I don't have a completely clear understanding of this problem, but I'll relate what I think I know. I've seen three different limits 4GB, 8GB and 32GB. I've seen a fix for this by using a different ATAPI driver. I believe that can be swapped in to installed systems.
I was able to install Warp 4 on a larger drive by using WARP4UI, which I got here:
You replace Disks 1 and 2 of the three installation diskettes with two new diskettes that are configured with the right drivers to allow you to access large drives. Also on the above page are some interesting articles about OS/2 and large drives, the problems, the causes, and the solutions.
That's all EIDE. What about SCSI? Did the same limitations apply? I found this explanation on a page accessible from a link on the above page:
The 1 Gigabyte Barrier
(Note: The above limit is based on the Adaptec 2940W adapter. It may be different with your adapter. )
SCSI disk drives are handled somewhat differently from IDE, but the basic results are the same. Here is a summary of the main differences:
1. There is no LBA option in the CMOS; the disk settings under Basic CMOS Setup are for IDE drives only;
2. Instead of an LBA in the CMOS there is an option in your SCSI adapter to enable large drives. On the Adaptec 2940W I have the setting is labelled "Extended BIOS translation for DOS drives > 1 GB." The wording is likely to vary from one manufacturer to another, but you should be able to recognize it easily.
This is from an explanation by Walter Metcalf at the WarpDoctor site: