Installing Windows NT On a Caching SCSI Controller

• Microsoft Windows NT Workstation version 3.5
• Microsoft Windows NT Server version 3.5

SYMPTOMS

When you install Windows NT 3.5 on a Windows NT file system (NTFS) partition using a SCSI Host Adapter with an onboard cache, Windows NT may not get installed correctly. After the initial installation completes the system reboots for the first time and then tries to convert the FAT partition to NTFS. The conversion appears to take place correctly and then reboots a second time. The system continually reboots itself.

CAUSE

When the conversion from FAT to NTFS takes place, the SCSI controller caches information about the converted partition (in this case NTFS). When the computer is rebooted, the SCSI controller is supposed to write status information to the disk, indicating that it is now an NTFS partition. Some computers, such as the Intel P90 PCI, issue a hard reset when the computer is rebooted. This flushes the partition status information from the controller's cache before it is written to the disk. Because the data in the cache is lost, the Windows NT continues to try to convert the FAT drive to NTFS after the computer is rebooted.

WORKAROUND

In some cases this problem can be avoided by either disabling the SCSI onboard cache or by physically removing it. The cache for some controllers may need to remain enabled. In particular, on some controllers that support hardware RAID, disabling cache is not possible. In that case, the only workaround is to install Windows NT as FAT on the boot drive.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 3.5. This problem was corrected in Windows NT version 3.51.