Epson Apex 20020 - Manual (Page 187)

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.
Note
This test destroys all data on the diskette in the selected
drive.
Select option 3 from the menu to start this test. If you have
only one diskette drive, you see a prompt to remove the
diagnostics (Reference) diskette and insert 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 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 1.2MB diskette, the first message
you see is:
Current track is 79
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
352.8 rpm and less than 367.2 rpm.
Performing System Diagnostics C-23