Mylex DAC960 RAID Controller Causes "Missing Operating System" (143141)
The information in this article applies to:
- Microsoft Windows NT Server 3.1
- Microsoft Windows NT Server 3.5
- Microsoft Windows NT Server 3.51
- Microsoft Windows NT Server 4.0
- Microsoft Windows NT Workstation 3.1
- Microsoft Windows NT Workstation 3.5
- Microsoft Windows NT Workstation 3.51
- Microsoft Windows NT Workstation 4.0
- Microsoft Windows NT Advanced Server 3.1
This article was previously published under Q143141 SYMPTOMS
When you try to install Windows NT on a system that is using the Mylex
DAC960 RAID controller or an OEM version of this controller, NT will under
some circumstances complete the first phase of setup but fail when
rebooting into GUI mode, displaying the following error message:
Missing Operating System.
When formatting the partition, prior to the initial file copy operation,
Windows NT might also have warned you that the partition you were creating
contained more than 1024 cylinders.
CAUSE
This error occurs because the RAID controller misrepresents the geometry
of the logical drives it presents to Windows NT. (When there is only one
logical drive of less than 2 gigabytes (GB), or if a formatted partition
already exists, Windows NT is able to correctly determine the geometry.)
WORKAROUND
There are two ways to avoid this problem:
- Prior to installing Windows NT, create and format a partition on the
boot logical drive using Microsoft MS-DOS or another operating system
-or-
- Create only one logical drive of a size smaller than 2 GB on the RAID
array, using the configuration software that was supplied with the
controller. After NT is installed, you may create additional logical
drives.
STATUS
Microsoft has confirmed this to be a problem in Windows NT versions 3.5
and 3.51. We are researching this problem and will post new information
here in the Microsoft Knowledge Base as it becomes available.
MORE INFORMATION
This problem has been reproduced on the Mylex DAC960 RAID controller and
the IBM RAID controller.
| Modification Type: | Major | Last Reviewed: | 5/7/2003 |
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| Keywords: | KB143141 |
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