Apple IIe - Page 178

178 Apple lie Users Handbook
Single and Double Sided Diskettes
Some floppy diskettes are designed to be written on only one
side. These are known as single sided (SS) diskettes.
Diskettes
which are designed to be written on both sides are
known as double sided (DS) diskettes.
Single, Double, and Quad Density Diskettes
Density refers to a diskette's recording format , which in turn
affects its capacity. Double density diskettes generally have a
greater recording capacity than single density diskettes, while
quad density diskettes generally have a greater capacity than
either single or double .
The
Apple lie Disk Drive uses double-density diskettes with a
capacity
of 143 , 250 bytes.
Diskette Write Protection.
Diskettes have a notch on the side of their protective envelope
which determines whether or not data can be written onto that
diskette. On 8 inch diskettes, this notch is known as a write-
protect notch. On 51/.i in~h diskettes, it is known as a write-
enable notch .
On a 8 inch diskette, information cannot be written onto the
diskette unless this notch has been covered . On 51/.i inch
diskettes, information cannot be written onto the diskette unless
the notch is left uncovered.
Some 51/.i inch diskettes (especially system' diskettes) may be
permanently write protected if their protective envelope does
not contain a notch . Any 51/.i inch diskette with a notch can be
write protected by merely covering the notch with a piece of
tape as shown in Illustration 5-6.