Epson 10020 - Manual (Page 182)

Write, Read Check
This test checks the ability of the selected disk drive to read
and write data from a diskette. The test writes to and reads from
each cylinder on the diskette, starting at the center.
Select option 3 from the menu to start this test.
If you have only one diskette drive, you are prompted to
exchange the Diagnostics (Reference) Disk for a blank diskette
before running the test. You see these messages:
Use only a formatted blank diskette for this test.
Any data present may be erased.
If using drive A, remove your Diagnostics Disk.
Enter Y to start this check.
Enter N to return to the menu.
Make sure the blank, formatted diskette you prepared is in
drive A, then press Y and Enter.
The program displays the current track number as each cylinder
is tested. For example, with a 360KB diskette, the first message
you see is:
Current track is 39
Speed Check
This test checks the revolution speed of the specified disk drive.
Select option 4 from the menu to start this test. You see a
message similar to this:
The disk rotation speed should be more
than 294.0 rpm and less than 306.0 rpm.
Performing System Diagnostics D-25