Epson 3865X Plus - Manual (Page 196)

If you are installing your first hard disk drive, the jumpers
should already be set in the correct positions. If they are, follow
the instructions under “Installing a Hard Disk in the Vertical
Position,” on page B-8, to install the drive.
If the jumpers are not in the correct positions, you need to
change their settings. See “Changing the Jumper Settings,” on
page B-6, for instructions.
If you’ll be using two hard disk drives, see “Setting the Jumpers
for Two Hard Disk Drives,” below.
Setting the Jumpers for Two Hard Disk Drives
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.
The Setup and System diagnostics programs on the Reference
diskette recognize your master drive as drive 1 and your slave
drive as drive 2. The power-on diagnostics programs refer to
your master drive as drive 0 and your slave drive as drive 1. Just
remember that the master drive is always the lower number.
Follow the instructions in the next section to change the
jumper settings on both of your hard disk drives.
Installing and Removing Disk Drives B-5