Computing: Computer Administration

Disk size limits on Windows NT.

The original release of Windows NT 4.0 does not recognize the correct size of unallocated space on disk drives larger than 8 or 8.4 GB at installation time. On the screenshots below, you can see how the Windows NT installer reports 8,033 MB unallocated space on a new SCSI disk drive of 20 GB (left) resp, 7,554 MB on a new IDE disk drive of 20 GB (right). Also notice, that the total size of the IDE disk is reported being 7,555 MB instead of the real size of 20,474 MB (correctly recognized with SCSI disks).

Windows NT installation: Size of unallocated space not correctly recognized on SCSI disks
Windows NT installation: Size of unallocated space and size the disk itself not correctly recognized on IDE disks

Installing NT onto this unallocated space might fail, at the moment where you try to format the partition. Creating a (smaller) partition is the safest way to proceed. As 4 GB is largely enough for the Windows NT system files, I choose this size for the C: partition to be created (and NTFS formatted).

Windows NT installation: To avoid problems, create a 4 GB C: partition

After installation, the issue is resolved on SCSI disks: the unallocated space behind the C: partition is correctly reported as 16,457 MB (screenshot on the left) by Disk Administrator. On IDE disks, however, nothing has changed: the size of the disk is said to be 7,554 MB and the unallocated space behind the C: partition is reported as 3,459 MB. Also notice that the size of the C: partition is incorrectly recognized (screenshot on the right). The IDE disk issues issue is resolved by updating the ATAPI.SYS driver to the version included with SP4.

Windows NT Disk Administrator: Correct recognition of the disk size and the free space size on SCSI disks
Windows NT Disk Administrator: Incorrect recognition of the disk size and the free space size on IDE disks

Anyway, after the installation of Windows NT 4, the first thing to do should be the installation of Service Pack 6 (also required to install VMware tools on Windows NT) and doing so resolves all disk and partition size related problems.


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