The Basics:  Portable Hard Drives

Portable storage drives include external hard drives ranging from tens to hundreds of gigabytes of storage space to diminutive Flash thumb drives with mere megabytes of memory that can be carried comfortably on a keychain or wrist lanyard. These portable drives have soared in popularity in recent years, partially at the expense of removable media like Iomega Zip drives. If you're looking to transfer a handful of files from PC to PC, or if you need to create safe and transportable backups of your entire internal hard drive in case of a disastrous event, there's a portable drive for you.

Internal hard drives are the standard storage medium for personal computers. They've significantly grown in capacity and their connections and transfer rates have gotten much faster, but today's internal drives essentially work the same as they did ten years ago. Data is still stored on the drive and accessed by your computer's operating system when needed.

On the other hand, portable drives have undergone a revolution in recent years. Capacities of external hard drives now reach 1.5 terabytes (that's 1,500 gigabytes!) or more, but these monster externals generally aren't considered "portable." That designation is usually reserved for models ranging in capacities from less than 10GB up to 200GB, and larger capacities are certainly available.

Prices have dropped considerably for both hard drives and Flash-memory thumb drives. In fact, thumb drives have supplanted floppy disks (and in many cases, writeable optical media like CD-R) as the standard media for small-scale portable storage. Some companies even send out promotional materials on essentially disposable 32MB thumb drives.

Large or small, portable drives function the same way. After plugging a drive into your computer, you simply transfer data to and from the device as if it was an internal hard drive. You may need to install a driver before first use, but generally, portable hard drives are plug-and-play with modern operating systems like Windows XP. Thumb drives utilize a USB connection, and since the USB link supplies power, you don't have to worry about replacing batteries. In addition to USB, larger portable hard drives sometimes offer a selection of connection options including FireWire (IEEE 1394) and SATA. Keep in mind that more power-hungry portables may require an additional power source.

Most computers now have USB 2.0 slots instead of USB 1.1, and the significantly higher data throughput rate of the newer format makes portable drives much more practical. Theoretically, USB 2.0 allows transfer rates up to 40 times faster than USB 1.1. In practice, you won't achieve the theoretical maximum, but portable drives using USB 2.0 have no problem transferring data at 30MB per second or faster. That means you can put a lot of data on a portable hard drive or thumb drive in a short amount of time.

Unlike traditional hard drives, thumb drives use solid-state Flash memory, so the information you store on a thumb drive is safer than other backup means. Some manufacturers estimate that Flash-saved data is safe for ten years or more. Flash drives can even survive getting wet, and you never have to worry about scratches as with optical media.

External hard drives can run applications, and this feature has recently been added to thumb drives as well. Web browsers and other applications can operate directly from the drive, so you can take your necessary software with you. A new specification called U3 has been created to allow more applications to be run directly from specially formatted thumb drives.

Unfortunately, as these drives have gotten smaller and more portable, the possibility of your data being misplaced or stolen has grown. A number of drives incorporate encryption and other security measures to keep your data safe, even if the drive itself falls into the wrong hands. Some drives go so far as to include biometric protection such as a fingerprint scanner, so only you will be allowed access to the drive's contents. The ability to run applications allows portable drives to carry passwords and web forms for use on public computers, and you don't have to worry about leaving behind cookies or other traces of your activity.

Data storage devices have been further modified to fit specific needs. For example, some external hard drives include rechargeable power supplies and let you transfer image files directly from digital cameras and camcorders. If you are an avid digital photographer and have ever run out of space on your memory card, you can image how useful this feature can be. A drive might even have a compact LCD display, so you can preview your photos and share them with friends and colleagues without the need for a computer connection.

One emerging portable drive trend is the inclusion of digital audio playback. With a headphone input, volume control and simple navigation controls, a portable drive becomes a basic (but potentially high-capacity) MP3 player. Data storage has been incorporated into traditional items as well. You can get a Swiss Army knife with a thumb drive inside, and the USB port swings out like a blade, file or other pocketknife implement. There are even portable hard drives disguised to look like sushi, dim sum and even a Barbie-esque doll, where removing the head reveals the USB port.

How to Shop

The obvious first consideration when shopping for a portable storage device is its intended use. If you need to transport a few office files while on the road or transfer a handful of digital images and audio files from one computer to another, a thumb drive should be sufficient. Thumb drives are small and easy to use, and with a great cost-per-megabyte ratio, you can get a decent memory capacity for a relatively low price. On the other hand, if you require a large storage capacity for a library of images or music, or if you need a separate, portable medium for backing up significant amounts of data, you should seek a portable external hard drive with sufficient memory for the task at hand. Some external hard drives are small enough that you can pop them in a laptop bag and easily transport massive amounts of information.

Hard-drive speeds are rated in RPM (rotations per minute), with rates of 10,000 RPM or more available. The higher the RPM, the faster data can be written to and read from the drive. Another factor is connectivity. Traditional drives are linked to your computer via ATA cables (new drives now use the SATA format for faster throughput). You can also connect hard drives in a RAID configuration, which pairs twin drives for double the space or with mirrored data for additional security. This is also faster than a traditional ATA connection. Of course, portable hard drives usually offer a USB connection as well, and this is a simple and hassle-free method for connecting to your computer.

It may be worth your while to spend a little extra for a portable storage device with security features built in or applications pre-installed. If you're in the market for an MP3 player as well, consider that some drives can double as digital audio players. At the same time, remember that many MP3 players can also serve as basic data storage devices, so this might fit your needs instead.

More expensive are the specialty drives for transferring photos from digital cameras. If you're really into digital photography, they can be quite handy for offloading stored images from your camera. These units will also serve as traditional data storage devices.

Whether you need a small Flash thumb drive to replace your old floppy disks or a high-capacity portable hard drive, portable hard drives and thumb drives are a great way to get your data from one place to another or create backups to protect your information.