Epson 386SX - Manual (Page 218)

If you have only one diskette drive, you see a prompt to remove
the the Reference diskette and insert a blank diskette before
running the test. You see these messages:
If using drive 1, remove your Reference Disk.
Insert a formatted blank disk in the drive
before starting the check.
Any data present may be erased.
Start the check ? (Y/N)
Make sure the blank diskette you prepared is in drive A (l),
then select
Y.
The program displays the current track number as
each cylinder is tested. For example, with a 1.44MB diskette,
the first message you see is:
Current track is 79
After the test is over, be sure to replace the Reference diskette
in drive A before you select another device from the Device List
or exit System diagnostics.
Disk Change Check
This option tests the ability of a diskette drive to detect
whether a diskette has been inserted or removed. Disk changes
cannot be detected by a 360KB diskette drive.
Select option 4 from the menu to start this test. The program
checks the selected drive type; if it is a 360KB drive, you see
these messages:
Drive d is a 360 KB drive.
DISK CHANGE is not allowed with this type of
drive.
Press ENTER to return to the menu.
C-26 Performing System Diagnostics