An external hard drive is the perfect way to back up all of the information on your computer. They are simple to use and highly portable. External hard drives can be a computer user's best friend. They can even increase the available space of a conventional, built-in hard drive.

Buy the largest capacity hard drive you can afford. Multimedia files and data files are larger than ever due to new technology. 500GB equates to 500,000 photos, 125,000 songs, or 500 movies. Remember, larger external equal more storage and less portability while smaller storage devices are ultra-portable with a smaller capacity.

There are two types of external drives. Desktop-style drives, with 3.5-inch mechanisms inside, require a power adapter. Desktop drives are designed to stay in one place, usually on your work surface at home or at the office. These are also designed to be portable; some will offer shock resistant features in case they fall off a desk or out of your backpack.

External solid-state drives (SSDs) are found mostly in the notebook-style form factor, but these are still relatively rare because they're pricey in terms of cost per gigabyte. They're currently limited to smaller capacities, specifically in the 64GB and upwards. We recommend that you buy SSDs for use as internal rather than external drives.

When an external drive accesses data, it's temporarily stored in the memory buffer or cache. So choose a drive with a larger buffer to enhance performance.

The measurement of a byte. 1GB is equivalent to 1,000 megabytes.

The rate at how many megabytes can be processed within one second.

Some newer external hard drives offer a network attached storage drive (NAS). These drives come with an Ethernet port or built-in Wi-Fi. NAS is an easy way to add storage for multiple computers to share. Some NAS offer print-server capabilities, which allow you to plug a printer into its USB port to print documents from multiple computers on your network.

External hard drives with AC adapters usually contain more storage and require more power. The second option is connecting directly to your computer's USB inputs, which rely on your computer's power. This allows for greater mobility by eliminating the need for an AC adapter. However, if you are using a notebook, it will consume battery power faster.

The speed at which the hard drive can read content. The faster the RPM, the quicker files can be accessed.

Get the most use out of your purchase by choosing an external drive that comes bundled with software. External drives that come with backup or recovery software allow you to utilize your drive better.

Terabyte is the measurement of a byte. One terabyte is equivalent to 1,000 gigabytes

Universal Serial Bus. One of the most common types of computer connectors. It allows for easy connectivity and quick transfers of information between two devices.