The letter used to denote the first disk drive on the PC. A PC has two or three disk drives. One floppy disk, called A: and one hard disk called C:. If you have a second floppy disk, this is called B: and a CD-ROM drive is D:. When talking about the different disk drives, you say "drive A" for the floppy drive, but normally write "A:". When your PC starts up it will show what's called the C-prompt (which looks like C:\> on your screen). This means you are looking at the hard disk. If you want to change to drive A: to read data from a floppy disk, enter A: and press Return. (See also C:, floppy disk, hard disk.)
