Epson EQUITY 386/33 PLUS - Manual (Page 92)

Setting the Hard Disk Drive Jumpers
You may need to change the hard disk drive jumper settings if
you install or remove a hard disk drive. The jumpers tell the
computer whether you are using one hard disk drive or two.
Note
You do not need to set these jumpers if you are removing
your only hard disk drive.
If you are installing just one hard disk drive, see “Changing the
Jumper Settings,” below, to check the jumpers on your drive.
If you are removing one hard disk drive and leaving another in
your computer, you need to change the jumper settings on the
remaining drive to indicate that it will be the only hard disk
drive installed.
If you install two hard disk drives in your system, you must
change the jumper settings on each drive to indicate which
drive is the master (primary) drive and which is the slave
(secondary) drive.
A master drive is the drive on which you’ll install the operating
system that the computer loads into its memory each time you
turn it on. You can run application programs and store data on
both the master drive and the slave drive, but the operating
system must be contained on the master drive.
Follow the instructions below to change the jumper settings on
your hard disk drives.
5-4 Installing and Removing Drives