Epson 386SX - Manual (Page 88)

Write-protecting Diskettes
You can write-protect a diskette to prevent its data from being
altered. When a diskette is write-protected, you can read it and
copy data from it, but you cannot store new data on the diskette
or delete any files it contains. If you try to change data stored on
a write-protected diskette, MS-DOS displays an error message.
On a 3 diskette, the write-protect device is a small
switch on the back of the diskette in the lower right corner,
shown below. To write-protect a 3
diskette, slide the
switch toward the edge of the diskette until it clicks into
position, exposing a hole in the comer.
write-protect
switch
To remove the write protection, slide the switch toward the
center of the diskette until it clicks into position so the hole is
covered.
3-18 Using the Equity 386SX