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High-performance, high-capacity storage drives--such as the three direct-attached storage devices on our chart--typically connect to a workstation or file server. Such devices offer high-capacity backup for multiple computers or redundant backup for one PC via multiple, easily removed drives and RAID, which provides high throughput and disk mirroring. Often, these devices even have a bay for an extra drive so that if one drive fails, the unit can automatically start rebuilding the failed drive onto the spare.

None of the products we evaluated in this category--LaCie's $2200 Biggest F800 (1.6TB), Silicon Image's $2200 SV2000 (800GB), and WiebeTech's $1400 RaidTech 800 (800GB)--includes backup software. All three have at least two RAID configurations; only the WiebeTech unit lacked a spare hot drive.

The most intriguing product in this group was the Silicon Image, which smoked the other direct-attached competitors--not to mention our entire field--when it came to speed. Connected to our test system via external SATA (using the included PCI SATA card), the Silicon Image finished our 3.06GB copy files and folders test in 1 minute, 18 seconds, a little over half the time of the next closest device, the WiebeTech. It completed our system backup in just over 11 minutes. The model's speed may not be due just to SATA: Since it has an on-board processor, it doesn't depend on the host PC's processor for its RAID processing.

The Silicon Image unit we tested had five 160GB hard drives: two configured as RAID 0 (striped, for performance); two more set as RAID 1 (mirroring, for data security); and a fifth set as a hot-pluggable spare. Swapping drives is easy: The pull-out carriers that hold them, and the levers that release them, work smoothly.

All that redundancy left us with only 320GB of usable storage, however. You can change those settings easily through the device's plain-looking yet functional software management utility. The tool eschews the usual RAID levels, instead using clear terms like 'Big', 'Fast', and 'Safe' to describe its settings (the default configuration was 'Safe and Fast').

The WiebeTech we received for testing was set up as RAID 0, so it gave us access to all 800GB of its drive space (two 400GB ATA-100 drives). To change the RAID configuration, you simply flick a switch on the back of the unit and reformat. The device did well in our tests: Connected via USB 2.0, it finished our copy test in about 2.5 minutes and the system backup test in under 16 minutes. The drives are held by levers, which you can lock to prevent removal. To access the product's management utility, you must connect a serial cable or use the front panel's LCD.

LaCie's Biggest F800 has 1.6TB of capacity, with four 400GB ATA-100 drives set up as RAID 5. This setting is defined as data striping with parity, which means you get the number of drives minus one--in this case, 1200GB--of usable storage, and if a drive fails you can rebuild it on the fly. The unit also supports RAID 0, 1, 5, and 10; and it has drive carriers with curved handles so that you can easily remove and swap out the drives.

The LaCie finished our copy test in about the same amount of time as the network-attached devices did--a disappointing result considering it was connected via USB. It completed the system backup test about twice as quickly as the fastest network device did, but still took about 50 percent more time than the WiebeTech model.

Alan Stafford