Epson Equity 320SX PLUS - Manual (Page 132)

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
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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” drive and which is the “slave” 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 both of your hard disk drives.
7-4 Installing and Removing Disk Drives