Dual Boot 7 / XP different drives both as C:?

#1
I have looked thru all the various resources, but excuse me if I have missed a key item that explains this:

I have a Dell 9150 with 4 SATA drives, and now with Win7 eval installed on SAT drive 0, which boots up as drive C: .
I also have SATA 2 and 3 as data drives.
What I would like to do is dual-boot XP on SATA 1, and for it to come up as drive C: - as there are some app installs that really don't like the OS to be on anything but C:.

I'm hoping that EasyBCD Beta2 may help - the only way I can see to effect an XP install (after the W7 is already installed) as C: is to disable all the other drives during installation, then turning them back on again... But what to do to get them to boot properly and to not argue?

Or is this an idealised situation that can not be made to work?

Thanks....

Addendum:

Hah. Just as soon as I sent the message, I find the solution.
And just in case others were wondering:
-Install W7 from scratch on SATA 0, comes up as C: then install EBCD in W7.
-Disable W7 (and other) drives and install XP as though it were on C:
-Re-enable all drives and boot into W7.
-Copy BOOT.INI, NTLDR and NTDETECT from the XP root to W7 root.
-Modify BOOT.INI in W7 root to point to the hardware location of XP boot drive ( in my case multi(0)disk(0)rdisk(1)partition(1) instead of multi(0)disk(0)rdisk(0)partition(1) )
-Add entry in EBCD for WinXP to boot from C:.
Hey presto!
Thanks to LoveBug and replies for extra info.
 
Last edited:

Terry60

Knows where his towel is.
Staff member
#2
Hi Ali, welcome to NST.

Change the blue line to "Use EasyBCD 2.0 latest build to add an entry for XP"
and all of the stuff in red will happen automatically.

-Install W7 from scratch on SATA 0, comes up as C: then install EBCD in W7.
-Disable W7 (and other) drives and install XP as though it were on C:
-Re-enable all drives and boot into W7.
-Copy BOOT.INI, NTLDR and NTDETECT from the XP root to W7 root.
-Modify BOOT.INI in W7 root to point to the hardware location of XP boot drive ( in my case multi(0)disk(0)rdisk(1)partition(1) instead of multi(0)disk(0)rdisk(0)partition(1) )
-Add entry in EBCD for WinXP to boot from C:.
 
#3
I after the same result e.g. Dual Boot XP 32bit / Win 7 64bit on different drives both as C: but in my case I already have XP installed on the primary partition of one drive.
I have a second drive with a Primary partition already created for the second OS.

Following the steps laid out above can I disconnect my XP drive and then install Win 7 on the other drive.
Then reconnect the XP drive but change the boot order in my bios to make the Win 7 drive the boot disk?
Then install EasyBCD 2.0 in Win7 and add the XP installation.
Would that work and give me both drives as C: when they are running?
 
#5
I have another question concerning the drive letter of the partition that the second (unused) OS is sitting on.

Should I do anything with my current drive letters prior to installing the second OS? I read somewhere that it is assigned D: but currently D: is assigned. Can I change the drive letter of the partition from within each OS so that its well down the list in Explorer without causing any problems? e.g Z: should this be done prior to installing EasyBCD?
 
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Terry60

Knows where his towel is.
Staff member
#6
EasyBCD is just a tool in your toolbox for managing the Vista /W7 BCD. It's not part of the system and will have no effect on disk lettering whenever it's installed.
Windows will assign letters to devices in the order it detects them, which will normally be indentical boot to boot unless you change the hardware in some way (add or remove a USB device, switch HDD channels, move a PCI card to a different slot etc).
To keep your letter assignments fixed, set them yourself.
If you reassign your CD/DVD drive from D: to Z: that's fine (as long as you haven't already installed software that might look for application files on D:\app lib which will obviously not be there any more)
Once you assign a letter to a device, it becomes an entry in the registry tied to the UID of the device, and every time the OS detects that particular UID, it will assign the letter you chose, regardless of which order devices are detected.
Obviously though, if you chose to call a flash drive D: and you don't have it permanently plugged in, there's no chance that D: will still be available when you do insert it, unless every other device that you could conceivably plug in has a letter assigned too. Windows will still use the next available letter when it encounters an "unknown" device, and so it will steal D: which won't then be available for your flashdrive.
It's good practice therefore to permanently letter all of your removable devices, and use the letters from further up the alphabet. Use the identical lettering on every version of Windows you multi-boot, and you'll never be confused about what's what or where.
My camera is O: (for Olympus) whether I connect it on Vista XP or W7,
my DVD drives have been U: and V: since Windows95 (when the lettering algorithm was different and much more restricting), my USB devices N P Q R, my card reader W X Y Z and my HD partitions B: to I: identically across all systems except where the OS recognizes itself as C: and its opposite number as I:
You can rename anything to what you want unless it has a "system" "boot" or "page" flag.