Hard Disk Drives
Hard disks consist of one or more
magnetic disks contained in a box. They are used as storage media in the PC,
where you store programs and other digital data.
Overview of Hard Drives
The hard disk (or hard drive) is
the permanent storage area of your computer. It stores information whether the
computer is on or off. A hard drive is a mass storage device found in all PCs
(with some exclusions) that is used to store permanent data such as the
operating system, programs and user files.
The data on hard drives can be
erased and/or overwritten, the hard drive is classed as a non-volatile storage
device which means it doesn't require a constant power supply in order to
retain the information stored on it (unlike RAM).
Inside every hard drive are small
round disk-like objects made of either an aluminum/alloy or a glass/ceramic
composite, these are called platters, each platter is coated with a special
magnetic coating enabling them to store data magnetically. Hovering above these
platters are read/write heads that transfer data to and from the platters.
Hard drives come with many
different storage capacities, hard drive capacity is measured in bytes, with
common capacities being stated in MB (Megabytes) and GB (Gigabytes).
How to Choose a Hard Drive
When you are choosing one Hard
Drive you have to consider:
ATA and SCSI
In the hard drive world, there are
two data access standards, ATA and SCSI (pronounced 'Scar-Zee'). Most of normal
hard drives we're used to rely on the PATA standard. Some newer hard drives use
the SATA standard.
SATA allows transfer speeds of up
to 150 MBs while PATA gives up to 133 MBs. However, to use SATA, you'll need a
Serial ATA controller, a SATA drive and a SATA power cable. The speed
difference between PATA and SATA is also not significant unless you have a
high-end SATA drive.
The SCSI standard is a very fast
hard drive standard used for professional computer systems which demand
extremely fast data access. SCSI drives provide an access time of about 9.5ms -
which I feel is really not needed for average home use.
Disk Space vs. Price
An important factor to consider is
the disk space versus price ratio. When you look at the 30 GB, 40 GB and 80
GBPATA hard drives, you'll find they are very close in price. For the average
home user, however, 40 GB to 80 GB of disk space is plenty.
Drive Speed
If data access speed is important
to you, you can go for faster SATA drives or SCSI drives. But remember that
these drives come at a price premium and may not be necessary for average home
use.
No comments:
Post a Comment