Epson Equity 320SX PLUS - Manual (Page 130)

Your computer has two horizontal drive bays and one
vertical mounting position to hold up to three drives, as
shown below.
Using the Correct Drive Bay
Your computer may have come with a hard disk drive already
installed in the vertical mounting position. If not, you can
install one 31/2-inch hard disk drive in this position.
If you are installing your first hard disk drive, it is best to
install it in the vertical mounting position. If you add a
second hard disk drive or diskette drive, use the lower
horizontal drive bay.
7-2 Installing and Removing Disk Drives