VXA
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VXA is a tape backup format originally created by
Ecrix Exabyte Corporation was a manufacturer of magnetic tape data storage products headquartered in Boulder, Colorado, United States. Exabyte Corp. is now defunct, but the company's technology is sold by Tandberg Data under both brand names. Prior t ...
and now owned by
Tandberg Data Tandberg Data GmbH is a company focused on data storage products, especially streamers, headquartered in Dortmund, Germany. They are the only company still selling drives that use the QIC (also known as SLR) and VXA formats, but also produce ...
. After the merger between Ecrix and Exabyte on 17 November 2001, VXA was produced by
Exabyte Corporation Exabyte Corporation was a manufacturer of magnetic tape data storage products headquartered in Boulder, Colorado, United States. Exabyte Corp. is now defunct, but the company's technology is sold by Tandberg Data under both brand names. Prior ...
. On November 20, 2006, Exabyte was purchased by Tandberg Data that has since stopped further development of the format.


How it works

Exabyte and Ecrix describe the data format as "packet technology."Exabyte whitepaper describing VXA Packet Technology
Since VXA is based on
helical scan Helical scan is a method of recording high-frequency signals on magnetic tape. It is used in open-reel video tape recorders, video cassette recorders, digital audio tape recorders, and some computer tape drives. History Earl E Masterson from ...
technology, data is written across the tape from side to side in helical strips. The novel part of VXA packet technology is that each stripe starts with a unique packet ID and ends with an ECC packet checksum. As each stripe is written to tape, it is immediately read back to verify that the write was successful. If the write was not 100% successful the packet can be rewritten at another point on the tape without stopping. When the data is read back, the packets are reassembled into a "buffer" by their packet ID. The buffer has 3 additional ECCs to ensure data integrity. Another aspect of VXA is that there are 2 read heads for each stripe, slightly offset in relation to each other to allow for more flexibility in reading tapes written by other drives. Due to the relatively slow tape speed inherent to helical scan technology, the drive is able to stop and start the tape much more quickly to avoid the need to backhitch.


Market context

The VXA format competes mainly against the DDS, and DLT-IVExabyte's DLT to VXA migration sales pitch
/ref> formats.


Overview


VXA-3

Exabyte released two different product lines based on VXA-3 technology, VXA-320 in 2005 and VXA-172 in 2006. VXA-172 drives are limited to 86 GB per tape cartridge, but can be unlocked (for a fee) to remove the limit. They are otherwise the same. VXA-3 was the first helical scan system in production to feature thin film MR heads.


Notes

* Data Capacity figures above are for uncompressed data. Exabyte assumes a 2x compression factor in their marketing material.


Media

Media was released on two families (V and X), with different capacities based on the length of the tape, and the drive it is being used in.


Gallery


Cartridge / tape

Vxa-tape-v17-top-front.jpg, VXA tape V17 (170m), top view Vxa-tape-v17-bottom-rear.jpg, VXA tape V17 (170m), bottom view Vxa-tape-v17-cartridge-disassembled-1.jpg, VXA tape V17 (170m), partially disassembled Vxa-tape-cartridge-nocover-top-rear.jpg, VXA tape V17 (170m x 8mm) magnetic tape, no cover


Mechanism / drive

Vxa1-drive-front-qtr.jpg, VXA-1 tape drive, front bezel view Vxa1-drive-nocover-top-front.jpg, VXA-1 tape, drive, cover removed, top front view Vxa1-drive-nocover-top.jpg, VXA-1 tape drive, cover removed, top view Vxa1-drive-rear.jpg, VXA-1 tape drive, rear view, showing ATAPI interface Vxa1-drive-ecrix-label-under-compaq-label.jpg, bottom rear, showing original and rebrand labels Vxa1-drive-nocover-nobezel-front.jpg, front view, cover and bezel removed, rotary head visible


Tape and drive together

Vxa1-drive-loading-tape-1.jpg, VXA-1 tape drive with tape inserted Vxa1-drive-loading-tape-2.jpg, VXA-1 tape drive with tape loaded and threaded Vxa1-drive-loaded-tape-path-rightside-rear.jpg, VXA-1 tape drive with tape loaded, view from right side Vxa1-drive-loaded-tape-path-leftside-rear.jpg, VXA-1 tape drive with tape loaded, view from rear left


References


External links


ECMA 316
Specification of VXA-1.

Specification of ALDC, the data compression standard for VXA-1.
VXA Alliance
{{Ecma International Standards Computer storage tape media Ecma standards