Epson 10020 - Manual (Page 114)

When you finish installing an option card and reconfiguring
the system, you should test the option if possible. Some option
cards come with their own diagnostics programs, and you can
test others with the diagnostics programs on your Reference
diskette. The options you can test with the Reference diskette
include the following:
Expansion memory
8087-1 math coprocessor
Serial and parallel ports
Monitors and display adapters
Disk drives.
See Appendix D for instructions.
Optional Disk Drive Controllers
The built-in disk drive controller in your computer can control
two 360KB (5 1/4”) or 720KB (3 1/2”) diskette drives. If you
install an optional disk drive controller card in your computer
to control the diskette drives, you must connect the drives to
the option card, and disable the computer’s built-in controller
by changing a jumper setting.
4-10 Installing Option Cards