External hard drives are portable, easy to use, and can provide a large amount of storage whenever you need it. You can store the actual device any place you like, and carry a large number of files with you wherever you go. Another advantage of owning an external drive is that you can move them from computer to computer, making them great for sharing large files. Because of their usually large storage capacities (often in the terabytes), external hard drives are often used to store backed up files. It’s common to use a backup program to back up things like a music, video, or picture collection to an external drive for safe keeping, separate from the originals in case they’re accidentally changed or deleted.
Even if not used for backup purposes, external hard drives provide an easy way to expand your existing storage without having to open up your computer, which is especially difficult if using a laptop. An external drive is just a hard drive (HDD) or solid-state drive (SSD) that is connected to a computer on the outside rather than on the inside. Some external drives draw power over their data cable, which of course comes from the computer itself, while others may require an AC wall connection to derive power on their own.
One way to think of an external hard drive is as if it were a regular, internal hard drive that has been removed, covered in its own protective casing, and plugged into the outside of your computer. Internal hard drives can even be converted into external hard drives via what’s called a hard drive enclosure. External hard drives come in varying storage capacities, but they all connect to a computer either by USB, FireWire, eSATA, or wirelessly. External hard drives are sometimes called portable hard drives. A flash drive is one common and very portable, type of external hard drive.
If your computer is always giving you low disk space warnings or is sluggish because it’s working hard to keep things running on the little bits of free space it has left, it’s probably time to get an external hard drive so that you can copy some of your files to it and free up storage on your primary hard drive. The external hard drive can also be used to provide additional storage to an entire network (though internal hard drives are usually more common in these scenarios). These kinds of network storage devices can be accessed by numerous users at once and often serve as a way for users to share files within a network to avoid emailing or uploading the data online.