Choosing a Hard Drive

What, Exactly, is a Hard Drive?

A hard drive is a stack of magnetic disks that spin at very high rates of speed (7200 RPM for a modern EIDE or SATA drive) and are used to store your computer's data.

Unlike 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 were 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.

The disks are enclosed in a protective casing that also contains the drive motor, servos, actuator arms, read/write heads, and the logic circuitry necessary to interface with the system and read from and write to the magnetic disks. Hard drives also contain their own ROM, RAM cache, and controller circuitry. (Image courtesy of Maxtor Corporation.)

 

Types of Hard Drives

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

• Very high-end computers often use SCSI (pronounced "skuzzy" and standing for "Small Computer Simplified Interface") drives, which are capable of higher data transfer rates. But for most home computer users, SCSI drives are prohibitively expensive. They also require special controllers and are a bit complicated for most beginners to configure.

• Until recently, most home and small office computers used EIDE (Enhanced Integrated Drive Electronics) drives, which were commonly known as ATA (short for ATAPI) drives. Nowadays they're called PATA (Parallel ATA) drives, to distinguish them from SATA (Serial ATA) drives.

• The designation ATA is followed by a number (33, 66, 100, or 133) that gives the drive's maximum data transfer rate in MB/second. ATA-33 and ATA-66 hard drives are now obsolete. ATA-100 drives are still available, but most new EIDE hard drives are ATA-133.

• Most new computers are now built using Serial ATA (SATA) drives. SATA replaced the EIDE hardware interface while maintaining the ATA command set, enabling much faster data transfer rates than EIDE drives, but with fewer compatibility and configuration issues than SCSI drives. SATA drives also are less expensive than SCSI drives of comparable capacity.

 

How Big a Hard Drive do I Need?

Well, that depends.

An 80 GB drive is probably plenty for a single user who mainly uses standard office applications and doesn't store a lot of graphic, video, or music files. Chances are that the drive will wear out before you fill it up. But 80 GB drives are about as small as hard drives come at the time of this writing, so you'll probably find that you can buy a much larger drive for about the same price.

If you're into digital photography, music, or video, then you'll want a much bigger drive for your homebuilt computer -- probably something in the 300 GB range or bigger. The same holds true for a computer that will be used by multiple users.

It's a lot easier and more economical to install a larger drive to begin with, then to have to install a larger drive later on when you have run out of drive space. So when pondering whether it's worth an extra ten bucks to step up to that bigger drive, the answer is probably yes.

Next Page -> ATA Hard Drive Configuration

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• Getting Started
  • Components
    • Hard Drives
      • The Hard Drive (This Page)
      • ATA Drive Configuration
      • ATA Drive Jumper Settings
    • Other Storage Devices