External Hard Drives

External Hard Drives

An external hard drive uses a standard 3.5-inch desktop or 2.5-inch portable drive mechanism to enable large amounts of data to be stored externally.

External drives based on standard desktop 3.5-inch drive mechanisms are larger but less expensive per megabyte and faster than those based on smaller 2.5-inch drive mechanisms originally developed for portable computers.

Interface Types Used by External Hard Drives

External hard drives based on the SCSI interface have been available for many years , but are not widespread in the PC environment. Most recent external hard drives have used the USB 1.1, USB 2.0, or IEEE-1394a interfaces.

Although a USB 2.0 external hard drive can be connected to a USB 1.1 port and function properly, its throughput would be much slower and this is not recommended.

Installing and Configuring External Hard Drives

Typical external drives using USB or IEEE-1394a interfaces are true PnP drives with Windows XP: Plug them in and they are ready for immediate use, because the drives are already formatted with a Windows-compatible file system (usually FAT32). See Chapter 15 for more details about file systems.

Older versions of Windows, particularly Windows 98, might require the user to load drivers from floppy disk or CD before the drive can be recognized.