External Hard Drive
An external hard drive is a portable device used to store data. They are just like the hard drives already in a computer except, as the name implies, they are external. They can be disconnected and reconnected at will. Typical external hard drive sizes range from 500GB to 3TB with more expensive ones ranging from 3TB to 4TB. External hard drives are useful for backing up data and for the use of keeping data in two locations in case of unforeseen computer crashes.
For Mac users, it is very strongly recommended that you do not backup your data using Time Machine. File:TimeMachine Your external hard drive must be properly formatted before use.