Specifications

Default Drive
MS-DOS will only look at one disk drive at a time. Normally,
this is the “default” drive. You can tell which disk drive is the
current default drive by looking at the system prompt.
For example:
indicates that the “A” drive is currently the default drive.
Unless you specify otherwise, MS-DOS will direct any disk
activity to the “A” floppy disk drive.
You can easily change the default drive with an internal DOS
command. For instance, to change from the “A” drive (floppy
disk), to the C d rive
(hard disk), enter:
The computer will respond:
As you can see, the system prompt has changed to show the
new default drive letter.
Note
If the computer responds:
Invalid Drive Specification
it may mean that either there is no hard disk system
installed, or your hard disk drive has not been configured
yet. See Chapter 6, “Using Your Hard Disk,” for
instructions.
4-10 Using MS-DOS With Your Computer