The Demo Site

Every computer stores the information saved in its memory on its hard drive. A hard drive is a set of disks held up on a central spindle, and each disk is made up of many tiny magnetic bits. An antenna, called a read-write head, encodes information onto these disks by using an electromagnetic flux to change the magnetic polarity of the bits that make up the disk. The more disks a hard drive has, and the more bits on each disk, the more memory space is available in the hdd. Different computers are specialized for different uses, so there are also different kinds of hard drives that are compatible with different kinds of computers. The three types of hard drives that you are most likely to encounter are SATA hard drives, PATA hard drives, and SCSI hard drives.
SATA hard drives, otherwise known as Serial ATA drives, are the cheapest variety of hard drive on the market. They are the newer variety of Parallel ATA hard drives, or PATA drives, which used to be the most common type of hard drive. Within the past two years, the SATA drive has almost completely taken the PATA drive's place as the most common hdd. The SATA hdd was designed for high bandwidth applications, such as multiplayer video games and video editing, so it is much faster and performs more efficiently than the traditional PATA drive. Also, SATA hard drives are easier and less costly to manufacture than PATA drives, so SATA hard drives are much cheaper in stores. The cable used to plug in the SATA variety of hard drive is more advanced than that of the PATA hard drive. The plug the cable uses to connect to the motherboard is smaller and cheaper, and it is easier to plug in without damaging the connector pins on the motherboard. Some of the newer models of the SATA hard drive do not work with the older cable ports on a computer's motherboard, so you may have to buy a SATA adaptor cable.
SCSI hard drives are of an even older design than the PATA hard drives, but they are still used today because they function much faster. They cannot hold as much information, and they are far more expensive than their SATA counterparts, but if you spend a lot of time on fast-paced network servers, or use other high speed, high bandwidth applications, you may want to consider using a SCSI hard drive.
The most important thing to remember when you are buying a hard drive is to get one that is designed for the motherboard your computer uses. If your motherboard and your hard drive are designed to work with each other, they will be more efficient than if you use an adaptor cable.

Source: http://ezinearticles.com/