We are really drawing plans onto a comet, but that's fine; lurker, don't
build on that until you save your data first, though...
In Folkert Rienstra va escriure:
I'd say, with basic disks, there is no way to "remember" the letter assigned
when the disk travels from a box to another (or even between OS setups on
the same box, as when one is doing multiboot).
There is some form of persistency, but the information is kept inside the
registry, which is private to one OS setup and not exported normally (I
exclude the MIGRATE.INF or ASR.SIF or $DRVLTR$ tricks used while
installing).
According to the article it is used by Logical Disk Manager that
on it's part advices Mount manager for a drive letter to be used.
Yes, that's my reasonning.
By changing back to Basic that LDM (extra) database would have been
taken out of commission.
Yes. However, if this decommission happened *after* the recording inside the
registry, its effect will be effectively nullified (case 1. in the KB text
you quoted).
This suggests that the other system must have changed this drive's
Windows registry settings. That's obviously not the case.
Let's remember in order (and imagine a bit about what is still unclear).
1. volume is alone in case A, named C:
2. computer A fails, drive is moved to case B; obviously there is yet a C:
disk there, so drive gets now D: in case B (in
{caseB}\WINDOWS\system32\SYSTEM). The (inactive)
{caseA}\WINDOWS\system32\SYSTEM, now in D:\WINDOWS\system32\SYSTEM, is left
intact
3. disk is turned to dynamic: Windows adds the LDM database at the end of
the drive, and it records there the fact this drive is named D:.
I assume there is some other change in the MBR which voided the signature
(or perhaps a bit later, when Ed "ran chkdsk which repaired some
problems"...)
4. drive is turned to case A. Windows (MountMgr.sys) boots, does not find
the letter inside the registry because the signatures do not match, finds
the LDM database, finds it matches, finds the letter should be D:, so it
assigns D: as letter for this disk, and... can't boot.
Where I am not clear about is what is then written in the registry
5. dynamic disk is canceled with Eric's (good) trick, so the LDM database is
now decommissioned. Ed said he then successfully booted, so I assume either
the registry was kept safe from the D: "infection" someway, or the signature
was reset again (and then MountMgr.sys will give the "natural" C: letter to
the unassigned volume); Ed could probably disambiguate here, looking at
HKLM\System\MountedDevices, if he sees \DosDevices\D: then it is probably
the second case.
I am not affirmative, it is my best idea of what could have occurred.
Another possibility is that the format to designate a volume inside
HKLM\System\MountedDevices could be different for basic or dynamic disks. In
fact, I guess this is even more possible (but I cannot confirm it right
now). If it is correct, the D: assignation was "forgotten" when the
partition has been reset to 07, creating the same effect as resetting the
signature. Of course, MS does not describe this in its KB, since they do not
support Eric's trick.
Antoine