Hardware components of the PC
Storage devices
How information is stored on a magnetic spinning disk

Data is recorded onto magnetic media by writing a pattern of fluxes or pole changes that represent binary ones and zeros. Data is written to both sides of the disk, via a read/ write head in concentric rings or tracks. These tracks are divided up into sectors.

The data pattern written to each sector consists of control data to mark its physical position, called the sector address, and a 512-byte block of user data, called the data file. The sector address is made up from a physical surface number, track number and sector number. When requesting a data file to be read, the starting sector address of the data file is looked up from a reference table located in a reserved area on the disk known as the file allocation table (FAT). The FAT keeps track of the starting sector address and the number of sectors in each data file stored on the disk.

Disc Labelling

It is important to label disks if possible. Floppy disks always have enough labels to hand-write information. An unlabelled disc will be assumed to be unformatted with no data. The following are the essential items that should be on any disc label, whether Floppy, Zip, CD or any other type of removable media:

The Date and Time; what is on the disc; if a backup then the type of backup; if the disc if one of several then which disc it is, i.e. 1 of 4 etc.; if an application the name and version of the application; if a revision of a project - the name of the project and the revision number; a catalogue number for the disc, to ensure the information is documented in the catalogue and state where the original data is held.

Specific details will be found in the quality procedures for a company or project.

There are many programs and label types around nowadays to create labels for disks - there is no excuse for having a disc without a label.