Systems Administrators Must Decide Which Tape Formats to Stick To
The market for tape backup systems is no longer dominated solely by the DLT format. Today, you can choose from LTO, MammothTape, AIT, VXA, depending on your needs for capacity and reliability.
For the past five years, Quantum Corp.'s Digital Linear Tape (DLT) format for tape backup systems has dominated the midrange of the magnetic tape marketplace. Now systems administrators have other new tape formats to consider.
Digital Linear Tape
Linear Tape Open
IBM, Seagate Technology, and Hewlett-Packard have all created their own versions of Linear Tape Open (LTO) Ultrium, which is a 100GB-per-tape technology designed to compete directly with Quantum's SuperDLT. Although LTO and SuperDLT offer a similar capacity, LTO is an open tape format being manufactured by several companies. Competition among companies could hike up the performance of LTO and give it more innovative features, such as cartridge memory with an identification and tracking mechanism, and data-rate matching of the recording speed to that of the material.
Exabyte has been slowly recovering from the reliability issues of its 8-mm tape, a format used in camcorder design. MammothTape, the product that Exabyte hopes will make up for the 8-mm, is the first helical scan product built for data applications. Likewise, Mammoth-2 offers a larger scanner than that found in helical scan drives and packs greater recording speed and density. To be released within five years, Mammoth-5 will offer 400GB storage capacity and 30MBps transfer speed.
Advanced Intelligent Tape
Sony's AIT-3 (Advanced Intelligent Tape) offers 100GB of capacity; it reads and writes to tape at 11MBps. As a result of a 2.6-to-1 compression ratio, systems administrators will get a whopping 160GB of capacity and 28MBps transfer speed. These capabilities are possible because AIT uses a non-contact, smart-card technology that enhances access to data formats.
With Excrix Corp.'s VXAtape, the newest of the tape formats, systems administrators won't lose a byte of data. This format saves data in individually addressed packets rather than long data tracks; so, a system can put all the data back together even if the tape track is distorted or warped. VXAtape does not have head-to-track alignment issues and, in turn, uses fewer mechanical parts. Released in 1999, VXAtape is less expense than the other tape formats.
Making a Choice
Before you select a tape format, determine what's most important to you: capacity, speed, reliability, or cost. Then ask these questions:
- How much data do I need to back up?
- How much time do I have to back up that data?
Your answers will narrow the list. Then, ask yourself:
- What does the medium cost? Will it fit into my budget?
- What are the maintenance requirements?
- How reliable are the drives?
- Can the product meet my future requirements?
Elizabeth M. Ferrarini is a free-lance author based in Arlington, Massachusetts.