A hard drive, also referred to as a hard disk drive (HDD), is a mechanical device that stores digital information. Hard drives are the primary method that Macs use for storing data.
All Macs come with at least one hard drive, which holds a pre-installed version of the Mac operating system. The hard drive will also have ample room for installing applications and user data.
A sealed enclosure in a hard drive holds one or more magnetic platters whose surface magnetic properties can be altered to represent the ones and zeros of computer data. The faster the magnetic platter spins, the faster the drive's data can be accessed. A platter's speed is referred to as its rotation rate, and is measured in RPMs.
The amount of data that can be stored on a particular hard drive is referred to as its capacity, such as 80 GB (gigabytes). The speed at which data can be written or read is referred to as the drive's native transfer rate.
There are a few things you should know before shopping for a hard drive. The specification most commonly cited is the drive's storage capacity, measured in gigabytes. The larger the drive, the more data it can store, an important consideration if you work with digital video, or have a large collection of digital photos or digital music.It's also important to check the type of interface the hard drive uses, to ensure that it will work with your computer. The two most common interfaces are PATA and SATA. The SATA interface has been standard on Macs since the Mac G5.
