Partition shift w Dual boot XP/Win7


E

Eric

I've installed Win7 to D: on a machine that already had XP on C:. I
was sSurprised to find that when the machine rebooted to Win7, the
Win7 partition was now C: and XP was reassigned to D:

That's not the case when setting up two XP partitions on one
machine--the 2nd will boot from, and stay on, drive D:

Initially I didn't like the partition shift, but I realized that there
are places where I need that to happen. Does anyone know if Win7
always does the partition shift, or was that the result of the way it
was installed? Any way to force that to happen?

Also, do the two bootable partitions just exchange drive letters
(bootable E->C, D->D, C->E), or are they going to sort of rotate?
(bootable E->C, C->D, D->E)

I ask because one system has XP on C:, with immovable data on D:. I'd
like to install Win7, but need to make sure the D: partition doesn't
shift. If I install Win7 to E:, if the above holds, I presume that it
will 'rotate' the D: drive to E: (as above). I'd like to keep D:
stationary.
 
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C

c_atiel

Drive letter assignments are generated by the OS, they are not hardwired
into the hard drive.
When you boot into XP it should see itself as the C drive because otherwise
programs installed in XP will not work as they are looking for files
scattered on the C drive-dlls and the like. The Win 7 partition/hard drive
will be assigned another letter by XP. When you boot back to Win 7 it will
again see itself as the C drive, or whatever drive letter Win 7 assigned
itself at installation, which does not have to be C.
When you are working in Win7 you cannot use programs installed on XP unless
you have also installed them in Win 7. Therefore it does not matter what
drive letter Win 7 assigns the XP hard drive/partition when you are working
in Win 7.
Win 7 installs a different boot loader than XP and installs it on whichever
drive your BIOS recognizes as the first hard drive to look to for an
operating system, presumably the hard drive that held XP in your case.
Dual boot installations, as long as you installed XP first, are pretty
reliably set up correctly automatically when you then install Win 7.
 
E

Eric

Drive letter assignments are generated by the OS, they are not hardwired
into the hard drive.
Yes, I know.
When you boot into XP it should see itself as the C drive because otherwise
programs installed in XP will not work as they are looking for files
scattered on the C drive-dlls and the like. The Win 7 partition/hard drive
will be assigned another letter by XP. When you boot back to Win 7 it will
again see itself as the C drive, or whatever drive letter Win 7 assigned
itself at installation, which does not have to be C.
Well, that is the main question. I've installed lots of dual boots
with XP on both partitions. In that case, as I mentioned, the XP on D:
stays on D: when it's booted.

By contrast, the recent XP/Win7 dual does indeed shift the partitions.
XP was installed on C:. I later installed Win7 to D:.

When I boot to Win7, which I expected to be on D:, it was actually on
C: (and the XP partition was shifted to D:). That's the difference in
behavior.

My question: Is that always going to occur when Win7 is installed to a
machine previously running XP? How to you assure that it does happen?

(BTW, the q is in regard to a laptop. Just one large drive, with 3
partitions. XP already installed on C:)
 
E

Eric

I've installed Win7 to D: on a machine that already had XP on C:. I
was sSurprised to find that when the machine rebooted to Win7, the
Win7 partition was now C: and XP was reassigned to D:

That's not the case when setting up two XP partitions on one
machine--the 2nd will boot from, and stay on, drive D:

Initially I didn't like the partition shift, but I realized that there
are places where I need that to happen. Does anyone know if Win7
always does the partition shift, or was that the result of the way it
was installed? Any way to force that to happen?

Also, do the two bootable partitions just exchange drive letters
(bootable E->C, D->D, C->E), or are they going to sort of rotate?
(bootable E->C, C->D, D->E)

I ask because one system has XP on C:, with immovable data on D:. I'd
like to install Win7, but need to make sure the D: partition doesn't
shift. If I install Win7 to E:, if the above holds, I presume that it
will 'rotate' the D: drive to E: (as above). I'd like to keep D:
stationary.
Now that I think about it, it only matters that the Win7 partition
shifts to C: when Win7 is booted. I can change the drive letters of
the non-active partitions via DiskManager.

So I'm hoping to install Win7 to E:, and get that partition to shift
to C: when it's booted.

As noted, this is for a laptop, with 3 partitions on one large drive.
 
P

peter

So your aiming to run 1 installation of XP and 2 Installations of W7???
Do you have 2 copies of W7? if not what you are propsosing is against the
EULA and you might not be able to activate that 2nd install of W7.

peter
 
E

Eric

So your aiming to run 1 installation of XP and 2 Installations of W7???
Do you have 2 copies of W7? if not what you are propsosing is against the
EULA and you might not be able to activate that 2nd install of W7.

peter
Nope, only one of each. And I have multiple licenses for both anyway,
so that's not the issue.

Any ideas about the original question?
 
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A

Andy

The rule is, when you boot from the DVD to install, the partition in
which you install Windows 7 is set to C:, and the system partition,
which would be C: in XP, is set to D:. If you install Windows 7 from a
running Windows XP, then the drive letters for Win7 will be the same
as XP's. This behavior started with Vista.
 
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E

Eric

The rule is, when you boot from the DVD to install, the partition in
which you install Windows 7 is set to C:, and the system partition,
which would be C: in XP, is set to D:. If you install Windows 7 from a
running Windows XP, then the drive letters for Win7 will be the same
as XP's. This behavior started with Vista.
Excellent! That answers that.

On the first system, I could have sworn that I installed Win7 via XP
rather than booting the DVD, but I must have misremembered. Good
thing I asked.

Thanks, Andy.
 

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