The Hard disk
|
|
The hard disk drive (HDD) is the most important storage device in PCs.
It saves data non-volatile by magnetizing and demagnetizing sections
of rotating magnetical platters.
|
|
A hard disk is multiple times faster than CD drives, tape drives or
anything like that (not to mention the incredible slow floppy drives)
without being too expensive. Its only disadvantage is that the medium
is not removeable - you cannot extend the capacity by using
different media.
|
|
|
Fujitsu hard drive, top view
|
|
Hard disks differ in speed and capacity. While for the capacity the
the thumb rule "the more the better" is more or less valid, this is
not neccesarily the case with the speed: A hard disk with ten- or even
fifteen thousand revolutions per minute (as it is available for
servers today) makes so loud noises when it is busy that no one would
like to work on that computer anymore. Typical hard disks for desktop
computers perform 4800 or 7200 revolutions per minute (rpm).
|
|
When deciding on the amount of capacity needed the only good advice is
to buy it as large as one can afford. Though it is still possible to run
an up-to-date operating system from a 250 MB hard disk (Linux for
instance), generally for all purposes much more memory is needed than
it was estimated in beforehand. Windows alone takes 1 GB disk space,
office solutions easily consume 2 - 3 GB, and if only a few hundred MP3's
are to be saved several GB are occupied just like that. Also keep in mind
that an almost full hard disk's performance will go down rapidly, as it
has to search much longer for free sectors.
|