Change boot drive

#1
Not as simple as post implies. I have an SSD, with WXP as the C drive, and W7 as the D drive. I have set EasyBCD to boot W7 from the D drive, and all is well. I will not be using WXP anymore, but would like to hang on to it for a while.
Can I use EasyBCD to change the W7 drive to C and to change the XP drive to D? It just seems to me that booting from the C drive is the more natural way to do things. If I delete or format the C drive, with XP on it, will the D drive change to C.

This is a minor matter, and I can live with it.
 

Terry60

Knows where his towel is.
Staff member
#2
Is W7 "D" when it's booted or just as seen from XP ?
W7 will install itself as "C" if you booted the installation DVD.
The only way it will be anything other than "C" is if you executed the setup.exe on the DVD from a running OS (not the booted DVD).
If that is what you did, you're stuck with it.
(Disk letters don't "really" exist. They're just entries in the registry of the running OS, and as such have no connection with what any other OS calls them)
 

Terry60

Knows where his towel is.
Staff member
#4
OK, then I'm afraid you're stuck with it.
There's nothing EasyBCD can do about it.
As a matter of fact, there are no disk letters in the BCD.
The BCD addresses a partition using UID, a combination of the unique disk signature and the partition offset from the disk start.
Because that is an unintelligible string to the human brain, EasyBCD "translates" it for you by looking up in the registry of the running OS, which disk letter the system uses to describe the partition. Similarly, when you point EasyBCD to a disk letter, it will translate that back to the unintelligible form for you.
That's why, when you "view settings" from EasyBCD from two different OSs, the letters might appear to change.
The UIDs are just being translated into the "local" language of the running OS (using its registry map)
The letters in EasyBCD will simply match the letters you see in Explorer, which is doing the same thing.
You might be able to use a partition manager "copy partition" function to change a disk letter, or even find an online utility to do it for you, I have even done it manually (laboriously) once in the past.
It requires not only hacking the partition table in the registry, but scanning the entire registry for every reference the OS contains to itself (the location of each driver e.g.), and altering all of those too. (miss one, and the system won't boot - there are hundreds of them)
 

Terry60

Knows where his towel is.
Staff member
#6
Nothing except tradition (from the old IBM DOS days) says the OS has to be C.
The floppy drive got labelled A, and then expensive machines got a second floppy drive (guess what - B).
When they invented the amazing miniature HDD with scores of Mb available running several times faster than the floppy drives, and unsurprisingly called it C,
of course people chose to put the OS on the biggest fastest device and a tradition was born.
Sadly, third party coders started to assume that C=OS and hard-code it into some software which would cause problems on non-compliant machines, but those days seem to be fading into history, so nowadays it has no ramifications.