Ask A Scientist© Computer Science Archive

Index Key:   COM036
Author:      dutch minott
Subject:     Hard drive operation.
How does a computers hard drive work...store and send data?  Please be as
technical as possible.

Response #:  1 of 1
Author:      gregory r bradburn
For details on this you should visit the library.  There are many magazines
devoted to computers and most will have introductory articles that would
cover this type of information -- use the Reader's Guide or some other index
(ask your local librarian for help) to locate specific articles of use to
you.
Basically, the hard drive works the same as a cassette tape.  The surface of
a flat disk (a platter) is coated with a magnetic material (just like a
cassette tape).  A reading and/or writing head senses or creates a magnetic
field over a very small part of the platter.  Let us just discuss reading. 
The reading head moves over the platter in a specific pattern.  If it senses
a magnetic field it sends a "1" to the computer.  If it does not sense a
magnetic field it sends a "0".  The pattern of "1"s and "0"s contains the
information that the computer needs to do its work.