This Techworld document tabulates details of the AIT and VXA tape formats and includes road map details where available. Both formats use 8mm tape and helical scan technology. With this technology data is written in tracks that slant across the tape rather than in tracks that run the length of the tape. The practical effect is that smaller tape cartridges can hold more data than traditional half inch formats such as DLT or LTO.

AIT
This is Sony's Advanced Intelligent Tape format. Sony devised it as a follow-on from DDS. A microchip in the catridge, termed a MIC, holds file positioning information resulting in a faster location of files on the tape. There is also a WORM - write once, read many - version of AIT which is beginning to be used for archival purposes. Sony claims that 2.6:1 compression is possible, which is why the compressed capacities are higher than might be expected.

AIT-1 AIT-2 AIT-3 AIT-4
Raw Capacity 35GB 50GB 100GB 200GB
Compressed Capacity 91GB 130GB 260GB 520GB
Raw Transfer Rate 3MB/sec 6MB/sec 12MB/sec 24MB/sec
Compressed Transfer Rate 7.8MB/sec 15.6MB/sec 31.2MB/sec 62.4MB/sec
Date available 1996 1999 2001 2003

AIT-3 and 4 capacities could be thought to take AIT into the mid-range market. Two further generations are forecast by Sony: AIT-5 and AIT-6. They are possibly due to appear in 2005 and 2007 respectively. The capacities, transfer rates and availability dates are speculative.

AIT-5 AIT-6
Raw Capacity 400GB 500GB
Compressed Capacity 640GB 1.28TB
Raw Transfer Rate 48MB/sec 96MB/sec
Compressed Transfer Rate 128MB/sec 256MB/sec
Date available 2005 2007

Sony has developed AIT technology into Super AIT, or SAIT, which uses half inch tape media. It will be covered in a later Techworld feature.

VXA
Exabyte's VXA format exists in two generations with a further two coming which, Exabyte says, will double capacity and transfer speed whilst holding price constant. VXA technology has been focused on accurate restoration of data. Data is written to the tape in packets and packets assembled on a read operation with information being taken from multiple read heads. VXA was invented by a spin-off from Exabyte, called Ecrix. When Mammoth sales declined Ecrix and Exabyte joined together and VXA is now the low-end offering with LTO being Exabyte's mid-range format.

VXA-1 VXA-2 VXA-3 VXA-4
Raw Capacity 33GB 80GB 160GB 320GB
Compressed Capacity 66GB 160GB 320GB 640GB
Raw Transfer Rate 3MB/sec 6M/sec 12MB/sec 24MB/sec
Compressed Transfer Rate 6MB/sec 12MB/sec 24MB/sec 48MB/sec

VXA-1 and VXA-2 are current. VXA-3 is set to be announced for a 2004 availability with VXA-4 due for 2006. The capacities and transfer rates and availability dates come from Exabyte.