Epson Apex 20020 - Manual (Page 196)

2. Re-format the disk using option 2, Format hard disk, on the
OPERATION MENU. See Appendix D for instructions.
3.
Prepare the hard disk for use with FDISK and SELECT. See
Appendix E for instructions.
Head Select Check
This test checks whether each head of the hard disk can be
selected correctly. If both heads are checked without error, the
program returns to the main menu. Select option 3 from the
menu to start this test.
Error Detection and Correction Check
This test checks the ability of the hard disk drive to detect a
read/write error and to correct the data accordingly.
Select option 3 from the menu to start this test. You see these
messages:
The data on the highest physical cylinder
may be destroyed by this check.
Enter Y to start this check.
Enter N to return to the menu.
Press
Y
and then
Enter to
continue with the test. If no errors
occur, the program returns to the menu.
An error occurs only if the drive is malfunctioning. In this case,
back up all your files, and have the drive serviced immediately.
(The drive may be corrupting your data.)