On a 3 ‘/z-inch diskette, the write-protect device is a small switch on the back of the diskette in the lower right comer, shown below. To write-protect a 3 ½-inch 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 and the hole is covered.
Using a Single Diskette Drive System
MS-DOS expects the computer to have at least two diskette drives and displays prompts and messages accordingly. Usually, MS-DOS recognizes the first diskette drive (the top drive on your computer) as A and a second diskette drive as B. If you have only one diskette drive, MS-DOS can treat it as both A and B when you need to perform operations that normally require two diskette drives.
