Magnetic Storage
Permanent or semipermanent computer data storage works by either optical or magnetic principles—or, in some cases, a combination of the two. In the case of magnetic storage, a stream of binary computer data bits (0s and 1s) is stored by magnetizing tiny pieces of metal embedded on the surface of a disk or tape in a pattern that represents the data. Later this magnetic pattern can be read and converted back into the exact same stream of bits you started with. This is the principle of magnetic storage and the subject of this chapter.
Magnetic storage is often difficult for people to understand because magnetic fields can't be seen by the human eye. This chapter explains the principles, concepts, and techniques behind modern computer magnetic storage, enabling you to understand what happens behind the scenes. This information is designed for those who have an insatiable curiosity about how these things work; it is not absolutely necessary to know this to use a PC or perform routine troubleshooting, maintenance, or upgrades. Because the data I store on my hard drives, tape drives, floppy drives, and other magnetic storage devices happens to be far more important to me than the devices themselves, knowing how my data is handled makes me feel much more comfortable with the system in general. Having an understanding of the underlying technology does help when it comes to dealing with problems that might arise.
This chapter covers magnetic storage principles and technology and can be considered an introduction to several other chapters in the book, including the following:
Consult these chapters for more specific information on various types of magnetic and optical storage, as well as drive installation and configuration.
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