Data is any company’s most valuable asset. Archiving systems are essential to ensuring that valuable data is preserved. A wide variety of technologies exists, but tape medium remains a popular choice for data backup due to its comparatively low cost and large capacity for data storage. Although tape drives are far from new, Linear Tape- Open (LTO) technology is a recent innovation that was developed jointly by Hewlett-Packard Company (HP), IBM, and Seagate. LTO replaces proprietary formats for corporate backup solutions with an open tape format, making it easier for customers to choose products.

Inside an Ultrium Backup Tape Drive, two rollers stabilize the tape as it is wound from a cartridge reel, across the tape heads, and into a take-up reel. The MES results, superimposed over the photo, show the stress in the tape as it is wrapped around the rollers and fed into the take-up reel.
Historically, the backup tape drive industry has been fragmented, and a proliferation of formats and technologies complicated customer buying decisions. LTO was defined as a best-ofbreed, open tape format that can better serve multiple market needs and be supported by multiple suppliers through an open licensing process.

LTO maximizes capacity and performance by combining a linear, multichannel, bi-directional tape format already in common usage. It also adds enhancements in the areas of timingbased mechanisms, hardware data compression, optimized track layouts, and high-efficiency error correction code. Customers benefit from this format specification through the availability of multiple sources of product and tape cartridges, and common tape format specifications for interchange.

The Ultrium format from HP is a high-capacity, single-reel implementation of LTO, best suited for backup, restore, and archive applications for standalone and automated environments. Cartridges have a capacity of up to 200 GB.

In the process of designing tape drives to meet the LTO specifications, HP engineers conducted extensive analysis and testing to ensure that their product would stand out among available LTO drives for its reliability. In addition to extensive laboratory testing, HP used finite-element analysis (FEA)- based Mechanical Event Simulation (MES) software from ALGOR, Inc. to analyze the behavior of the magnetic recording tape as it is wound through the tape drive in order to find a way to reduce wear on the tape and increase durability.

The challenge was to optimize the LTO drive in order to increase tape durability while maintaining tape path stability. To study the tape’s behavior, the software had to simulate motion, contact between parts in an assembly, large displacement, elastic material behavior, and stresses.

HP modeled the magnetic tape with isotropic shell elements and the drive assembly using kinematic elements. In the MES, the tape wraps around two rollers and across a tape head, and is then pulled into a take-up reel. The MES results showed the motion of the tape and resulting stresses. These results helped HP find a proprietary solution that keeps the tape on track while reducing stresses on its edge, thus extending the life of the backup tape.

This work was done by Paul Poorman of Hewlett-Packard Company. Visit to view the complete report. For more information on using ALGOR’s finite element analysis products, contact ALGOR, Inc., 150 Beta Drive, Pittsburgh, PA 15238; Tel: 800-48-ALGOR;

NASA Tech Briefs Magazine

This article first appeared in the September, 2002 issue of NASA Tech Briefs Magazine.

Read more articles from the archives here.