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.