HD enumeration errors

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HD enumeration errors

Postby skipro » Sun Nov 06, 2011 5:27 am

This thread refers to previous thread in BIBM but I felt it should be here
and my query is somewhat in a different direction, thus the new thread.

Can anyone shed light how or why a Window's OS system correctly determines
which of 2 HDs is the primary HD for booting, but when booted [correctly]
into Windows then sees it [50% of the time] as HD1, while BIBM sees it
always correctly as HD0? The HDs are standard SATA on SATA 1 [HD0] & SATA 2
[HD1]. This occurs across XP, Win 7 and Win 8, which leads me to believe it
is a BIOS issue, not a Windows issue. I have not gotten any response from
mobo support.
It would seem if the system sees which HD to boot, which for Windows must be
HD0, how does Windows then see it as HD1 after booted?
It is this that confuses me. Obviously 2 different means of detection or
passing of information must be involved that results in different results.
I do not know the methods this information is passed from BIOS to Windows
and how Windows then interprets it. In previous thread, TB remarked,
"windows tries to determine the drives via the BIOS EDD information". I can
except a miscommunication or error in reporting between BIOS and Windows but
I cannot understand how/why it sees it correctly to boot, then incorrectly
later in Windows.

Restated, if BIOS passes info to Windows indicating the correct booting HD,
which for Windows must be HD0, why then does Windows see it as HD1?

Thanks for any illumination anyone can provide.

Posts: 41
Joined: Tue Aug 16, 2011 2:57 pm

Re: HD enumeration errors

Postby TeraByte Support(PP) » Sun Nov 06, 2011 9:45 am

This Microsoft KB article has some information on the problem as it pertains to setup, but it seems to be the same type of problem. Specifically:
The disk-assignment numbers may not necessarily match the corresponding SATA or RAID channel numbers. There is no assurance of a consistent relationship between PnP enumeration and the order of the hard disks that are detected during setup. Devices are presented in the order in which they are enumerated. Therefore, the disk-assignment numbers may change between startups.
Paul Purviance
TeraByte Support
TeraByte Support(PP)
Posts: 1089
Joined: Thu Aug 11, 2011 5:51 pm

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