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Data Storage Devices > Hard Drives - Pg. 176

Digital Lifestyle Hardware: Digital Rules, Analog Drools Table 7.2. Storage Device Technologies Technol- ogy Internal ATA External FireWire External USB Internal or External SCSI Size Description 176 The AT Attachment interface is used for the internal hard drives in most modern Macs. ATA hard drives are plentiful and inexpensive and their performance is adequate for all but the most demanding applications. You can add one or more internal ATA hard drives to Power Mac computers. Other models include a single ATA hard drive. External FireWire data storage devices come in different types, including hard drives, CD-RW drives, DVD-R drives, tape drives, and so on. FireWire drives offer excellent performance, and they are easy to connect to Macs (just connect to the drive to the Mac with a FireWire cable). USB data storage devices include CD-RW drives, Zip drives, and so on. USB data storage devices are easy to use, but their performance is not as good as that of FireWire devices (not surprisingly, USB devices tend to be less expensive than FireWire devices). The Small Computer Serial Interface was standard on previous generations of Macs. SCSI provides very high per- formance, but its cost made Mac hardware more expensive than it needed to be--once ATA drives performed well enough to be useful for Mac users. SCSI is still available, but it is typically used only when the fastest speed is needed. All data devices can store an amount of data, which is the drive's size. Hard drives are limited to their size, such as 60GB, but drives that use removable media, such as CD-RW drives, have an unlimited capacity because you can always use additional media. The size parameter of such drives refers to the size of the media to which they write. For example, a CD-RW drive can write 700MB to a disc while a tape drive can often store 20GB on a single tape. Speed is critical to those storage devices that you use for active projects, which are typically hard drives. The speed at which the drive turns, the speed at which data can be read from or written to the drive, and the speed at which the device communicates, determine how "fast" the drive is. For other devices, such as CD-RW or tape drives, speed is not quite as important because you don't use those devices while you are working on a project. However, faster devices are still better. Recordable drives can write to recordable media. Recordable media, such as a CD-R disc, can't be erased. Once it is written to, the disc is no longer recordable. Rewritable drives can also write to rewritable media, which means it can be erased and used again. Recordable media is less expensive than rewritable media is. All recordable CD drives today are CD-RW drives so that you can use either type of media in them. However, there are DVD-R drives, such as the Apple SuperDrive, and DVD-RW drives, which enable you to erase DVD-RW discs. Speed R vs. RW