Running with two C drives

  • Thread starter Thread starter Jim Walker
  • Start date Start date
J

Jim Walker

I have cloned my C drive by going into DOS and removing the clone before
going into Windows. What would happen if I went into Windows with both the
original and the clone and therefore two C drives?
 
Well, only one drive is going to be designated your master boot up drive.
Windows will automatically reassign drive letters to other drives, including
partitions.
 
That is what I thought. If a drive is reassigned a drive letter, can it be
changed back to C in any way, obviously with the other C drive removed.
 
Jim Walker said:
That is what I thought. If a drive is reassigned a drive letter, can it be
changed back to C in any way, obviously with the other C drive removed.
Click to expand...

Drive letter assignment is done by the operating system "on the
fly" during startup, depending on partition type and cable position;
nothing is written internally to a relocated drive that would give it a
fixed new letter. As long as the drive has a primary partition defined
and set "active," and is set as master on the first controller cable, the
operating system will see that as partition C:, even if it had been
reassigned D: when temporarily made the slave of a new C:.
 
Donald G. Davis said:
Drive letter assignment is done by the operating system "on the
fly" during startup, depending on partition type and cable position;
nothing is written internally to a relocated drive that would give it a
fixed new letter. As long as the drive has a primary partition defined
and set "active," and is set as master on the first controller cable, the
operating system will see that as partition C:, even if it had been
reassigned D: when temporarily made the slave of a new C:.
Click to expand...


True in the "vanilla" case. Assuming WinXP (and Win2K, maybe
WinNT as well), the boot loader will go to the 1st HD in the boot
sequence - whether it is a Master or Slave makes no difference -
and it will go then to the "active" partition on that HD to start ntldr
which will look in boot.ini to see where to go to find the OS. If the
OS selected by default or by keyboard input is on another partition,
even on another partition on another HD, it will go there to get the
OS to load. The point is that the boot sequence and the boot.ini file
determine from which partition the OS ultimately comes, and Master/
Slave modes of the HDs and their positions on the IDE cable are
arbitrary. (Yes, a Slave can be at the end position on the cable, and
a Slave can contain the booted OS. I've tried it.)

*TimDaniels*
 
Previously Jim Walker said:
I have cloned my C drive by going into DOS and removing the clone before
going into Windows. What would happen if I went into Windows with both the
original and the clone and therefore two C drives?
Click to expand...

The second "c" gets moved to "d" and all your other partitions
are shifted. An unfortunate consequence of the not well-designed
drive-letter concept.

Arno
 
True in the "vanilla" case. Assuming WinXP (and Win2K, maybe
WinNT as well), the boot loader will go to the 1st HD in the boot
sequence - whether it is a Master or Slave makes no difference -
and it will go then to the "active" partition on that HD to start ntldr
which will look in boot.ini to see where to go to find the OS. If the
OS selected by default or by keyboard input is on another partition,
even on another partition on another HD, it will go there to get the
OS to load. The point is that the boot sequence and the boot.ini file
determine from which partition the OS ultimately comes, and Master/
Slave modes of the HDs and their positions on the IDE cable are
arbitrary. (Yes, a Slave can be at the end position on the cable, and
a Slave can contain the booted OS. I've tried it.)
Click to expand...

Thanks for this comment; I have never used the WinNT-based
operating systems and was not familiar with their boot procedure. Can
something other than the first active primary partition be designated as
drive C: on NT-based systems? Win9x can also boot from a partition above
C:, but it still designates the first active primary partition as drive
C:, from which its underlying MS-DOS will boot. Returning to the original
poster's question as I understood it: under either the DOS/Win9x or WinNT
systems, drive lettering is determined dynamically by the OS during
startup; relocating a drive when cloning it does not "brand" it with a
new fixed letter that could cause any future relocation difficulty.
 
Donald G. Davis said:
:

[.....] Assuming WinXP (and Win2K, maybe
WinNT as well), the boot loader will go to the 1st HD in the boot
sequence - whether it is a Master or Slave makes no difference -
and it will go then to the "active" partition on that HD to start ntldr
which will look in boot.ini to see where to go to find the OS. If the
OS selected by default or by keyboard input is on another partition,
even on another partition on another HD, it will go there to get the
OS to load. The point is that the boot sequence and the boot.ini file
determine from which partition the OS ultimately comes, and Master/
Slave modes of the HDs and their positions on the IDE cable are
arbitrary. (Yes, a Slave can be at the end position on the cable, and
a Slave can contain the booted OS. I've tried it.)
Click to expand...

Thanks for this comment; I have never used the WinNT-based
operating systems and was not familiar with their boot procedure. Can
something other than the first active primary partition be designated as
drive C: on NT-based systems? Win9x can also boot from a partition above
C:, but it still designates the first active primary partition as drive
C:, from which its underlying MS-DOS will boot.
Click to expand...


I'm not sure what you mean by "FIRST active primary partition".
AFAIK, there can be only one partition marked "active" on a
HD, but that partition need not be the 1st one on the drive. And,
as I pointed out, the boot.ini file in that partition can designate
another partition as being the source of the OS, and that OS
will designate itself as the C: drive. Then it will designate other
partitions as being other drives, i.e. "Local Disks", with other
drive letters.

Returning to the original poster's question as I understood it
under either the DOS/Win9x or WinNT systems, drive lettering
is determined dynamically by the OS during startup; relocating
a drive when cloning it does not "brand" it with a new fixed letter
that could cause any future relocation difficulty.
Click to expand...


That has been my experience, although it hasn't been
exhaustive (just exhausting). :-)

*TimDaniels*
 
Back
Top