Learning About External Hard Disks

Create local backups of the important files and sensitive data on your computers by copying them onto external hard disks. Unlike internal drives, external storage units don't sit inside computers. Rather, they have protective enclosures, and connect to computers via USB.


Types of External Hard Drives

An external hard disk can be a desktop or portable unit. Portable storage units are pocketable devices that use 2.5-inch hard disk drives (HDDs). They connect to computers via USB, and use the same connection for power and data. Desktop drives are larger, use 3.5-inch HDDs, and offer higher storage capacities. While they're also USB hard drives, they have higher power consumption and require external power supply units.

Some desktop storage units have multiple HDDs. These are usually network-attached storage devices used as file servers. Featuring built-in Wi-Fi, wireless storage units are portable hard drives. In addition to computers, these also connect to smartphones and tablets. They offer the convenience of quick wireless file transfers.


What Are External SSDs?

These are portable drives that use solid-state drives (SDD) for file storage. SSDs are faster than HDDs. Since they have no moving parts, they run silently and are more energy-efficient options. External SSDs are smaller and more durable than external HDDs.


Shopping for External Drives

Features to think about when shopping include drive speed, capacity, and interface. Consumer HDDs have two rotational speeds: 5400 or 7200 revolutions per minute (rpm). Models with 7200 rpm platters are faster, but draw more power from host computers. If you're looking for a portable drive to back up essential files, pick one with less than 1TB of storage capacity. Portable and desktop units with up to 4TB capacity are suitable for system backups. For media servers and gaming computers, consider models with 6TB or more of storage capacity.

USB is the more common connectivity interface used by external HDDs and SSDs. Look for a unit with a USB 3.0 port or later. This is 10 times faster than USB 2.0. A USB 3.1 port is twice as fast as a USB 3.0. Desktop external HDDs may also have eSATA, FireWire, and Thunderbolt ports. The fastest of these is Thunderbolt. Thunderbolt 3 ports are two to four times faster than USB 3.1 ports, and use USB-C connectors.


Converting Internal HDDs to External HDDs

To use internal hard disks as external storage drives, you'll need compatible hard drive enclosures and docks. There are different enclosures for 2.5- and 3.5-inch drives. In addition to protecting internal HDDs, enclosures and docks also provide connectivity ports and cables. Choose an enclosure with multiple HDD bays to make a RAID drive to use as a file server.


Make sure you never lose important files, by regularly backing up your PCs onto external hard disks. You'll find a wide selection of these computer storage products, as well as external hard drive accessories, at B&H Photo and Video.