Hardware Reference
In-Depth Information
Figure 8.11. Areal density, combining tracks per inch and bits per inch.
Drives record data in tracks, which are circular bands of data on the disk. Each track is divided into
sectors.
Figure 8.12
shows an actual floppy disk sprayed with magnetic developer (powdered iron)
such that an image of the actual tracks and sectors can be clearly seen. The disk shown is a 5 1/4-inch
360KB floppy, which has 40 tracks per side, with each track divided into nine sectors. Note that each
sector is delineated by gaps in the recording, which precede and follow the track and sector headers
(where ID and address information resides). You can clearly see the triple gap preceding the first
sector, which includes the track and sector headers. Then, following in a counterclockwise direction,
you see each subsequent sector, preceded by gaps delineating the header for that sector. The area
between the headers is where the sector data is written.
Figure 8.12. 360KB floppy disk media sprayed with magnetic developer (powdered iron)
showing the actual track and sector images.
