The Hard Drive

What is a Hard Drive, Anyway?

The hard drive is a set of magnetic disks that hold your computer's data until it is needed. Data on the hard drive remains there until it is deleted or changed, either by a program or by the user (either accidentally or intentionally).

Isn't that the Same Thing as Memory?

No, they are different. Unlike memory (or RAM), the hard drive is a semi-permanent storage device. It is non-volatile. That means it continues to hold data even when power to the drive is turned off (or even if the drive is removed from the computer, for that matter). A properly functioning hard drive will retain data until the user or a program instructs it to delete or modify that data.

Types of Hard Drives

There are several different types of hard drives available for desktop computers. They are distinguished mainly by type of connection between the drive and the rest of the computer.

• SCSI (pronounced "skuzzy" and standing for Small Computer Simplified Interface) drives are capable of very high data transfer rates. But they are very expensive and are rarely used in home or small office computers.

• As of this writing (in early 2004), EIDE (Enhanced Integrated Drive Electronics) drives still are the most commonly used drives in computers built for home and small office users. EIDE drives are also known as ATA or ATAPI drives. An ATA-133 drive spins at 7200 RPM and is capable of data transfer at up to 133 MB per second. It is likely that this will be as far as EIDE drives progress, as they are rapidly being eclipsed by...

• SATA (Serial ATA) drives, which are capable of much faster data transfer than EIDE drives. SATA drives are only slightly more expensive than EIDE drives, and are much less expensive than SCSI drives. We expect SATA to become the new standard for desktop computers within a year or two -- probably sooner.

How Big a Hard Drive do I Need?

Well, that depends.

For most people who use their computers for browsing the Web, writing the occasional letter, and sending and receiving email, a 40 GB drive is probably enough.

But if you use your computer for digital photograpy or video, music, gaming, running a business, or heavy-duty word processing, you'll probably want a much bigger hard drive. Hard drives in excess of 200 GB are now economically available, so you may as well buy a big enough drive now, rather than have to replace it and transfer all your data later when you run out of space.