An Affordable Tape for Ordinary Needs

By Lowell Rapaport

There’s a big battle brewing in the tape storage market, and all the top players have a stake in the outcome. SDLT, Ultrium, AIT and Mammoth are reaching for the high-end and automation markets.

But even as storage and backup requirements for enterprises get larger, there are still those who don’t need terabytes of RAID storage and for whom thousand-slot libraries would be overkill. These users don’t need complexity and expensive software, and there’s no reason they should pay for high-end tape drives that are out of line with their needs.

It is for these users that Tandberg (www.tandberg.com) is positioning the SLR100, a quarter-inch cartridge (QIC) that stores 50 gigabytes (GB) uncompressed, making it the highest capacity mid-range tape available. To reach this capacity, Tandberg licensed special technology from Overland Data that allowed them to double data density over their previous generation SLR tape drives. This puts the format on par with AIT-2 (at 50 GB) and makes it 25 percent higher-capacity than DLT8000 (at 40 GB).

SLR100
Tandberg
Simi Valley, CA, 805-579-1000
www.tandberg.com
Rated Speed: 5 MB/sec (uncompressed), 10 MB/sec (compressed)
Capacity: 50 GB (uncompressed)
Interface: Ultra Wide SCSI, single-ended and low-voltage differential
Mean time between failure: 30,000 hours
Drive price: $2,050 external, $1,950 internal
Cartridge price: $80
Advantages: Fewer moving parts for improved reliability. Low drive and cartridge costs relative to their speed and capacity.
Disadvantages: Few loaders and libraries support the SLR format. Currently, Tandberg is the only source.

Tandberg’s SLR100 tape drive comes with an Ultra2 Low-Voltage Differential or Single-Ended SCSI interface. The drive is offered as a stand-alone device or as an internal drive for eight-slot autoloaders and libraries ranging from 10 to 40 slots.

In our tests, the SLR100’s performance was 5 Megabytes per second without compression and 10 Mbytes/sec. with compression turned on. Remember, though, that compressed image files don’t respond well to additional compression. Therefore document image archives should be backed up at the slower, uncompressed rate. The SLR100 nearly matches the 6 Mbyte/sec. speed of AIT-2.

The usual advantages and disadvantages of linear tapes apply to SLR100. Linear tape drives have fewer moving parts than helical-scan tape drives, which makes them inherently more reliable than AIT, Mammoth or other helical-scan devices. SLR tape cartridges include the take up reel, so the drives are simpler than DLT and Ultrium drives, which have the take-up reel built into the drive. These features also make SLR drives less expensive than the competition, priced at about $2,000, versus $3,800-$4,300 for an AIT-2 drive or $4,500 for a DLT8000 drive.

SLR tape drives tend to run hot after prolonged use. After just a few minutes in our tests, the tape cartridges were noticeably warm to the touch. SLR tape cartridges address this problem with a large aluminum plate that acts as a heat sink. Tape loader and library makers have to make sure that SLR tape drives will have adequate cooling. If you use a stand-alone SLR drive or if you mount one in a computer case, make sure air can circulate around it. This may pose a problem if you plan to mount the tape drive in a low-end RAID case or in a server alongside an Athlon or Pentium III processor.

One disadvantage of SLR is that it is not as widely supported as 8mm or DLT tape drives. The only loaders and libraries currently available for this format are supplied by Tandberg (from an OEMmanufacturer). The drives are certainly fast and rugged enough for heavy-duty use. Mean time between failure is 30,000 hours. That’s more than enough service to take you to the next great new generation of tape technology that comes out.