Select your localized edition:

Close ×

More Ways to Connect

Discover one of our 28 local entrepreneurial communities »

Be the first to know as we launch in new countries and markets around the globe.

Interested in bringing MIT Technology Review to your local market?

MIT Technology ReviewMIT Technology Review - logo


Unsupported browser: Your browser does not meet modern web standards. See how it scores »

{ action.text }

But digital video is a different animal entirely. MiniDV video cameras record digital video on tape at 250 megabytes per minute, or 15 gigabytes per hour. Many new digital video cameras have flash RAM or miniature hard drives that can capture several gigabytes of compressed video per shooting. And these days, most digital cameras will create video clips – files that can quickly grow to hundreds of megabytes in length. Just a few vacation videos will stuff the hard drive that came with your PC. (The largest hard drives for off-the-shelf desktop or laptop computers these days hold only about 500 gigabytes.) So as digital recording technologies become more commonplace, consumers will face a very real dilemma: either purchase terabytes of extra storage or discard their digital memory chests. I suspect many will opt for the storage.

Although there are other ways to capture and archive digital information, none offers the permanence, reliability, and convenience of hard drives. It’s certainly cheaper to keep your video on miniDV tape, which costs about $4 for each recorded hour, but it’s much more convenient to have all your videos on a single drive than to have them scattered across two or three shelves. Hard drives don’t degrade as fast as tapes do, and unlike tape drives, they don’t need to be cleaned to maintain picture fidelity.

What’s more, as download services like iTunes, YouTube, the Google Video store, and Movielink become more popular, consumers will be storing not just the songs they’ve purchased online but also TV shows and movies. Some computers even act as digital video recorders, copying data directly from a cable or satellite feed – which will further fuel the need for storage. Devices like the Maxtor OneTouch III will fill that need.

Combining two 500-gigabyte drives is more than just a gimmick to let Maxtor
say it sells a terabyte hard drive. Having two drives is actually a blessing. It makes the system either faster or more reliable than a similarly equipped single drive could possibly be.

Unfortunately, you need to choose between speed and reliability: you can’t have them both. Under the default RAID configuration, called “drive striping,” the OneTouch III alternates between drives as it records data files, writing the first segment to drive one, the second to drive two, the third to drive one, and so on. Because the device has two disk controllers and two sets of cache memory, it writes data roughly twice as fast as a single drive. But drive striping is risky: if either drive fails, all the data on both drives may be lost. A second RAID configuration is called “drive mirroring.” In this mode, every block of data is stored on both drives. Mirroring reduces the capacity of the OneTouch III from a terabyte to 500 gigabytes, but it dramatically improves reliability: both drives have to fail at precisely the same time for you to lose data.

13 comments. Share your thoughts »

Tagged: Computing

Reprints and Permissions | Send feedback to the editor

From the Archives


Introducing MIT Technology Review Insider.

Already a Magazine subscriber?

You're automatically an Insider. It's easy to activate or upgrade your account.

Activate Your Account

Become an Insider

It's the new way to subscribe. Get even more of the tech news, research, and discoveries you crave.

Sign Up

Learn More

Find out why MIT Technology Review Insider is for you and explore your options.

Show Me