There are also plenty of hard drives that connect through Firewire, and some that even connect through Thunderbolt. The vast majority of external hard drives connect to a computer through USB, and nowadays it's through USB 3.0, but there are still some USB 2.0-capable hard drives. If on the other hand, you're simply transferring Microsoft Word documents to and from work, then you won't need as much storage and could save a few bucks by getting a lower storage drive. If you're a videographer or photographer, chances are you could easily fill up a hard drive quickly, so you'll want a higher-capacity drive. The tradeoff is that SSDs are a lot more expensive.

SSDs, on the other hand, have no moving parts and are thus more reliable as portable hard drives. HHDs store information on a spinning disk and that disk can be a source of hard drive failure.

SSD: There are two main types: HHDs, or hard disk drives, and SSDs, or solid-state drives.