When OS/2 version 4 came out hard disk sizes were still well below the 8Gb maximum size that the OS/2 hard disk drivers could handle. Since then hard drive sizes have increased enormously. It is now no longer possible to install OS/2 to the large hard drives in use today using the original install disks.
Don't throw OS/2 out yet because there is a solution. You could obtain the updated drivers that IBM created to resolve this problem but the site where they provided the update no longer exists.
An alternative is to download the danis506 substitute drivers (which support a much larger range of hardware). This too has disappeared from the web but I have managed to locate a copy you can use. Simply unzip to a temporary directory, then create an updated copy of disk one of your install disks (the second disk not the install disk). You need to place SET COPYFROMFLOPPY=1 in the first line of the CONFIG.SYS file. Do not delete the IBM drivers as the install process will still expect to find this later. Instead delete some of the drivers that you know that you don't have to make space for the DANIS driver. You will also need to update the CONFIG.SYS to change the IDE driver reference to point to the new driver and to comment out references to the drivers you deleted.
You can use SET INSTALLDRIVE=X in your CONFIG.SYS to install OS/2 to your X drive (substitute the appropriate drive letter). This will bypass the FDISKPM selection of where to install OS/2 but if Boot Manager is not already installed you will get a swapping error and will be unable to proceed with the install. OS/2 requires boot manager to be on the drive during an install to a logical partition or second disk even if you have an alternate boot manager already installed.
With the DANIS driver installed you should have no further problems with installing OS/2 and having it able to see your entire hard drive (or at least that part formatted in ways OS/2 recognises). Still having problems with a multi-boot install then read on.
If you are setting up OS/2 to run on a computer that will also be running Windows 98 (or later) then you have a problem regarding the partition identifier for your extended partition. OS/2 (and most operating systems) expect the logical partition to be of type 05 whereas Windows 98 expects an extended partition that crosses the 8Gb boundary to be of type 0f.
If you installed windows 98 first then OS/2 will not be able to see your extended partition and hence will not be able to install there or access any programs or files stored there. To fix this you need to change the extended partition back to type 05. One way that you can do this using Ranish Partition Manager. Just run part, select your extended partition, press the insert key, select type 05 from the list, press enter, press F2, and finally esc. OS/2 should now be able to see your extended partition properly. Windows 98 will report one extra partition that it is unable to access but all FAT partitions will still be accessible to windows.
If you installed OS/2 first then you need to be very careful when installing Windows 98. First set the appropriate C drive active and change your extended partition to type 0F. Now you can run the Windows install. Reply NO when Windows asks if it can delete the non-windows partitions from your drive. Ignore messages about inaccessible partitions and complete the install. Finally change the extended partition type back to 05. See the previous paragraph for the effect of this on Windows.
Note that not converting the partition to type 0f before installing Windows will result in Windows reporting your extended partition as unformatted and you will be able to proceed with the install without wiping your extended partition.
Worth noting is that FAT16 partitions have a maximum size of 2Gb and HPFS partitions must be no bigger than 4Gb if you intend to access them from Windows 98/ME or Windows NT 4. If you only require OS/2 and Linux to access your HPFS partitions then this limit doesn't apply.
You can use Partition Magic 4 or later to partition your hard drive before starting your OS/2 install but you need to watch out for the windows version creating a 0f extended partition - see above on how to resolve this. Earlier versions of Partition Magic cannot partition beyond the first 8Gb.
This article written by Stephen Chapman, Felgall Pty Ltd.