· System/Partition Commander does not assign drive letters.
· The booting Operating System assigns drive letters. OS/2 is a rare exception, when it is installed to a logical partition.
· The various Unix Operating Systems, do not use drive letters.
· Operating Systems that use drive letters assign the letters based on a standard scheme adopted by DOS/Windows Operating Systems.
The drive letter C does not refer exclusively to the first partition on the first physical hard drive. The rule for assigning the drive letter C is that C is reserved for the active (the booted or bootable) primary partition on the first physical hard drive at boot time.
For instance, this means that if you boot into the third primary partition on the first hard drive the OS will see the third primary as C. If it sees no second hard drive, it will call the first logical partition, D. All logical partitions will be assigned drive letters before the next primary partition is assigned a drive letter. (The logical partitions are contained within the extended partition.)
Example 1: A Single Hard Drive with 3 Primary Partitions and one Extended Partition, which contains 3 Logical Partitions.
C: The active primary partition.
D: The first logical partition.
E: The second logical partition.
F: The third logical partition.
G: The lowest numbered primary partition that has not yet been assigned a drive letter.
H: The lowest numbered primary partition that has not yet been assigned a drive letter.
Example 2: A system with two hard drives. Each hard drive has two primary partitions and an extended partition which contains three logical partitions. Drive letters are assigned in the following manner:
C: The active primary on the first physical hard drive.
D: The first primary on the second drive.
E: The OS will return to the first hard drive. The first logical on the first drive.
F: The second logical on the first drive.
G: The third logical on the first drive.
H: The OS will go to the second drive. The first logical on the second drive..
I: The second logical on the second drive.
J: The third logical on the second drive.
K: The OS will return to the first drive. The second primary on the first drive.
L: The OS will go to the second drive. The second primary on the second drive.
Notes:
1. Adding a partition or booting into another OS may cause the drive letter to change.
2. Multiple hard drives change the drive letter assignment.
3. A hidden drive will not be assigned a drive letter.
To be certain that you are booting into the correct partition, you should check volume labels and partition sizes: do not rely upon drive letters alone.