Every computer user should have a competent for of backup, and an external hard drive is a great choice to this end. It can also serve as a place to store large files such as videos and free up some space on your computer’s internal hard drive, increasing the internal drive’s speed at the same time. Before buying an external hard drive, though, there are a few things you should know to make sure you know what you’re getting.
1. All external hard drives consist of a standard internal drive in an enclosure. An external drive is no more or less likely to fail than a standard hard drive (unless a RAID is set up, which is explained below). Don’t think of your external drive as an indestructible data fortress–it’s simply another place to keep your data. If you’re using it for backup, copy files onto it and keep the original copy on your internal hard drive. That way, if either drive fails, you’ve still got your data on the other.
2. Some external hard drives contain multiple internal drives. This is done to offer the user more space or to provide automatic backup depending on how the setup is configured.
Two drives working together is known as a RAID. Some RAIDs can be very complex and contain dozens of drives, but consumer-ready externals usually don’t have more than two.
Check the box of the external drive you’re buying to see if a RAID setup is offered. If it is, you can usually choose to either have half the storage capacity with automatic backup (this is known as a RAID 1 and it’s accomplished by writing two both drives at the same time in case one fails) or the maximum possible capacity (this is called a RAID 0, which is accomplished by “striping” information across both disks. If one disk fails, the RAID fails, so it’s not the best setup for data backup).
3. Brand is important. Cheap external hard drives usually have higher failure rates, so buy from a known company such as Western Digital, Seagate, Maxtor, Lacie, or another company that has a history of making hard drives. Generic hard drives usually just have internal hard drives from a major company with less-than-fantastic electronics to help make the price decrease more profitable.
4. “Used” means “more likely to fail.” Don’t ever buy a used hard drive, especially externals–you don’t know how long they were used, how they were treated, or what they were exposed to. Often external hard drives are plugged in without proper surge protection, dropped, or overloaded before being wiped and returned. Buy new; it’ll cost about $20 extra, but it’s certainly worth it.
5. USB or Firewire? Both Mac and Windows computers support USB, but only some Windows computers support Firewire, so be sure to buy the best hard drive for your needs–some Mac users prefer Firewire 800 to USB 2.0 due to its considerable speed advantage, so if you’re sure you’ve got a Mac with Firewire 800 (or a Windows computer with a Firewire 800 card) and you’re going to be using your external for high-performance tasks like video editing, you might as well spring for the Firewire version.