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Hard Drive Glossary

by Staff Writer

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Slim black external hard drive on a table

Your computer's hard drive is one of the most basic and vital components. It holds all of your data and entirely determines how many files you can store. This hard drive glossary will help expand your knowledge of hard drive features and options for your computer.

Hard Drive Glossary:

  1. Hard disk: A "hard disk" refers to the magnetic disk on which your hard drive actually stores data. The hard disk spins at thousands of RPMs while a tiny, magnetic "head" reads and writes data to the disk.

  2. Byte: A byte is a basic unit of measure used to describe computer memory. A kilobyte (KB) is 1,000 bytes. Megabytes and gigabytes are one million and one billion bytes, respectively. Hard drives usually have capacities in the hundreds of gigabytes, with hard-drive size increasing with each passing year.

  3. External hard drive: Not all hard drives actually need to be inside your computer case. An external hard drive usually has its own case and can connect to your computer through either a USB or Firewire connection. Your internal hard drive can back itself up to the external hard drive to help preserve your data in case the internal hard drive fails.

  4. USB hard drive: Portable or external hard drives that connect to your computer via a USB cable are known as USB hard drives.

  5. RAM and ROM: All computers, including external hard drives, have RAM and ROM. RAM is the active memory, and ROM is the archive. RAM is temporary and erases whenever a drive is turned off. When your computer saves information in a file, the active data in RAM copies to ROM on the drive and stays there until it is changed, even if you turn off your computer.

  6. Spindle speed: The spindle refers to a spinning hard-drive disk. A hard drive's rotational speed is a good measure of the drive's performance, the higher numbers usually being the better performers. Some are as slow as 3,600 RPM, but the most common spindle speed is 7,200 RPM, which is fast enough for most applications. High-performance models are as fast as 10,000 RPM.

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