Tandberg previews faster-access tape


Tandberg Data recently gave the storage community the first glimpse of its O-Mass tape technology, which it claims will significantly boost both tape-drive capacity and performance.

O-Mass could safeguard tape's current role as the leading secondary storage technology against lower-priced, faster-access disk-based alternatives and could potentially enable tape to enter new markets (e.g., digital video and video streaming), according to Jack Robinson, corporate director of worldwide marketing at Tandberg.

First-generation devices, due to ship in late 2003, will reportedly feature 600GB of native capacity, a 64MBps native transfer rate, and an average access time of less than 3.5ms. Media cost is projected to be less than $0.10 per gigabyte. The current road map calls for a 2.4TB/256MBps product in the 2005/2006 time frame, with a theoretical limit of 10TB and 1GBps.

"This would be the first time a tape drive could offer high capacity, high performance, and low access time," claims Robinson. "StorageTek, with its 9840, was able to drop access time significantly by shortening the length of the tape, but in doing so, it sacrificed [potential] capacity." The 9840 has an average first search time of 8 seconds; the average time for subsequent searches is 11ms.

The O-Mass product, in contrast, uses a very short (300 feet)-but wide-standard metal-particle tape and a dual-hub reel cartridge to reduce the average seek time to data from the center park position to less than 3.5ms. The cartridge is the same form factor as both Super DLT and LTO and can be easily automated, says Robinson.

To boost capacity and throughput rates, O-Mass engineers-along with an undisclosed partner-have developed new write-array and optical-read heads. Unlike conventional magnetic heads, which "interleave" data tracks one at a time, the O-Mass heads write data in "track packages." Each package consists of 32 parallel tracks, which are written simultaneously. The heads, which are made out of a silicon substrate, do not contact the media; the write driver is directly connected to the back of the chip during wafer processing (see chart).

There are several advantages to writing data this way, explains Jorn Raastad, senior development engineer at Tandberg. For example, tolerances such as lateral tape motion and media stability become less critical and signal-to-noise ratio (SNR) margins become wider, he says. Also, higher data transfer rates are possible at lower tape speeds.

Data is read by a high-speed optical servo system, which essentially takes a snapshot of the data on the tape and sends it through a beam splitter and then through a servo and cross-talk decoder, explains Robinson. (For key features and the associated benefits, see chart.)

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Tandberg claims the head technology can be implemented in other tape platforms (e.g., LTO, Super DLT, and Magstar) to achieve a quantum leap in both capacity and performance. "However, since they wouldn't be using the new cartridge, they would not see the lower access rates," says Robinson.

The greatest obstacle facing O-Mass will be Tandberg's ability to get a product to market in a time frame deemed realistic by both vendors and industry analysts alike. By most accounts, including Tandberg's, a 2003 release is about a year off the mark. "We're looking to join forces to get our product to market faster," says Robinson. "The write and read element is ready. The cartridge is the challenge."

The company was expected to demonstrate a working prototype of the drive at this month's Comdex and will continue to court partners in an effort to expedite the development cycle. Tandberg officially spun off O-Mass as a separate business in December 2000.

This article was originally published on November 01, 2001