External hard drives can be used for a number of reasons: expanding your computer's storage, easily transferring large content from one place to another, and backing up your computer's files, just to name a few. There are now many sorts of hard drives to choose from on the market. Among these are portable hard drive options. A true portable hard drive is not only easy to transport, as the name implies, but it also has one key feature: it does not need an external power source.

Power and Data

[caption id="attachment_525" align="alignleft" width="227"] A closeup of a USB 2.0 cable. Pin 1 supplies 5 VDC power. Pins 2 and 3 transfer data. Pin 4 serves as a ground terminal.[/caption] Most portable hard drives on the market utilize a USB (Universal Transfer Bus) interface to connect to a computer. USB cables have power lines embedded in them, as you may know from their ability to charge your phone or other device. If a portable hard drive is designed to use a minimal amount of electricity, the disk can be powered by solely the USB connection. Power wires are included in all versions of USB, FireWire, and Thunderbolt connectors. Therefore, portable hard drives are not necessarily limited by interface, and speeds can range up to 20 gigabits per second using Apple's Thunderbolt 2 cable. Of course, the speed is also limited by the hard disk itself, as it can only spin so fast. Portable solid state drives also exist, like the LaCie Rugged USB 3.0, if you don't mind paying a premium for its increased caliber in speed and reliability.

Why a Portable Hard Drive?

Primarily using a portable hard drive in a single stationary location defeats the purpose. Rather, they're designed mainly for avid laptop users. If you're constantly using your laptop on the go, rather than solely at your workstation(s), finding an AC outlet or a stable position for a desktop drive may be problematic at times. On the other hand, a portable hard drive can easily remain plugged into your computer virtually anywhere. It can be stably used inside a moving vehicle. Even walking with a portable hard drive in use is a feasible task, granted that you can somehow hold it. Carrying an unwieldy desktop disk back and forth between multiple locations, like home and work, can also become tedious. This is also a situation where having a portable hard drive can prove useful, as only one connection must be made from the disk. What's more, most portable disks tend to be on the smaller, lighter side, so they're not at all difficult to transport between locations.

Disk Content

Another question might be, what type of content would be stored on a portable hard drive? One major use of hard disks in general is to expand the storage capacity of a computer. For example, one may find that they're heavily working with space-hogging high-definition videos, and before they know it, their computer's internal disk drive is almost full. The most economical solution to this problem would be to buy an external hard drive of some sort, which will likely be a portable one if the aforementioned reasons apply. Similarly, one may have purchased their computer with a solid state drive, most of which are very limited in capacity. Once again, an external disk would be necessary to solve this issue. Portable hard drives can also be useful for use in devices other than your computer. In one scenario, a high-definition home movie could be loaded on the disk. The drive could then be connected to a TV or Blu-Ray player with a USB port to show the home movie. This eliminates the need for optical media which can quickly add up in price. Further, the same drive could be taken to a friend's abode, allowing the video to be shown on their TV if it has USB support. Optionally, the video could easily be transferred to their computer, barring the need for slow online transfers.

Limitations

Of course, portable hard drives aren't always the solution. Stationary desktop hard drives tend to be cheaper and come in larger capacities than similar portable drives. A desktop drive is more economical if it will only be used in one location. Particularly, a desktop drive is sufficient if it's solely used for backing up a computer. Additionally, using network attached storage is another option to consider. They allow for the data to be accessed from anywhere without transporting a physical drive, but they are higher in cost and depend on Internet connectivity. Also note that mobile devices likely won't connect to a portable hard drive, but they can connect wirelessly to NAS and wireless drives. All in all, portable hard drives are great ways to transport large amounts of data with relative ease. Only a connection to a computer is necessary, as no AC outlet is required. They're excellent for avid laptop users who need a storage expansion from their internal capacity. They also work well for transporting information between multiple locations, including multimedia devices. You can buy a portable hard drive today from several manufacturers, like Western Digital and Seagate. What do you think of portable hard drives?