Epson 386SX - Manual (Page 99)

Note
Before you turn off the computer, be sure to exit any
application program you are using. The screen should display
the Shell Start Programs Menu or the MS-DOS command
prompt. Then remove your diskettes (if any), turn off the
computer, and turn off any peripherals.
Using Drive Designators
MS-DOS uses letters known as drive designators to identify the
disk drives in your computer. If you have one diskette drive, it is
known as drive A. If you have two diskette drives, the top drive
is A and the bottom drive is B.
If you have one hard disk drive, MS-DOS identifies its primary
partition as drive C (even if you have only one diskette drive).
If you have a second hard disk drive, MS-DOS identifies its
primary partition as drive D.
If you created one or more extended partitions on your hard
disk when you installed MS-DOS, the logical drives that make
up the extended partition(s) are identified by drive letters. For
example, if you have one hard disk (one physical drive)
partitioned into three logical drives, the logical drives are C, D,
and E. If you have two hard disk drives partitioned into a total
of five logical drives (three on the first physical drive and two
on the second), the first physical drive is divided into logical
drives C, E, and F, and the second physical drive is divided into
logical drives D and G, as shown here:
drive 1
C: (primary)
E:
F:
drive 2
D: (primary)
G:
Using MS-DOS with Your Equity 386SX 4-3