Test Specs

We evaluated the performance of these 12 tape libraries by timing their network backup and restore speeds. Our testers also examined the tape auto-loaders to see which ones were the easiest to set up and then picked the units' most important features. We tested and scored each element separately and computed an overall score in each media-technology area (i.e., DLT, 4 mm, and 8 mm) by assigning a weight to each element: technology (10 percent), implementation (40 percent, which is further divided into 45 percent for features, 45 percent for usability, and 10 percent for value), and performance (50 percent).

We ran our PC-based performance benchmarks on a 120-MHz Pentium system from S.A.G. Electronics running Windows NT. We created a directory tree with 920 MB of data on the computer's hard drive; the files in the directory tree varied in size and had different levels of compression. We tested the performance of the tape libraries by backing up and restoring the directory using Cheyenne Software's ARCserve 2.01 for Windows NT. We also ran another restore test by backing up a single 115-MB directory from within the tree.

Usability scores are based on such aspects as the clarity and organization of the user's manuals. Our testers check to see whether the documentation clearly defines status-indicator functions, and we also examine the illustrations to see if they are easy to understand. In addition, we make sure the LED indicators let you know if compression is on or if the tape is dirty. Our hands-on approach to testing includes evaluating how easy it is to install the tapes and the magazine clips and how accessible the jumper switches are to get to.

For features, we weight and score the important characteristics that we believe a tape library should have. As with most products that we test, the len gth and coverage of a warranty are always a primary concern. It's also important to pick a tape auto-loader that supports as many network OSes (NOSes) and third-party backup software applications as possible. Finally, we consider the cost and size of the units for the budget-minded and for those who are concerned with conserving office space.

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