Epson Endeavor 468C - Manual (Page 59)

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 it or delete
any files it contains.
On a 3.5-inch 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 3.5-inch diskette, slide the switch
toward the edge of the diskette until it clicks into position,
exposing a hole in the corner.
To remove the write protection, slide the switch toward the
center of the diskette until it clicks into position and the hole is
covered.
Using Your Computer 3-7