Epson 386SX - Manual (Page 101)

Specifying the drive designator
If you want to access a program or file on another drive without
first changing the current drive, type the drive designator along
with the filename. For example, if you are logged onto drive A
and want to use a file named PROGRAM on drive B, type
B : PROGRAM
and press Enter. MS-DOS loads and executes
the file named PROGRAM from drive B but stays logged onto
drive A.
Types of MS-DOS Commands
Each MS-DOS command is either internal or external. Internal
commands are built into MS-DOS; so you can use them any
time after MS-DOS has been loaded into memory. External
commands are separate files which MS-DOS must be able to
find before it can execute the command. If it cannot find the
file, MS-DOS displays an error message.
If you installed MS-DOS according to the instructions in your
MS-DOS Installation Guide, most external commands are
stored in a subdirectory named DOS on the hard disk (unless
you specified a different name when you installed MS-DOS).
The external commands CONFIG.SYS, AUTOEXEC.BAT,
and COMMAND.COM are stored in the root directory. (For
information on directories, see “Using Directories,” later in this
chapter.) MS-DOS automatically finds any external commands
you use in the DOS subdirectory or the root directory because
the installation process has set a path to them. (For information
on setting paths, see “Using Pathnames,” later in this chapter.)
Using MS-DOS with Your Equity 386SX 4-5