In terms of compatibility with other versions of LTO tape technology, LTO-4 media can only be read and written in an LTO-4 tape drive. LTO-4 can read LTO-2 and LTO-3 cartridges, but only LTO-3 media can be written to an LTO-4 tape drive. Archive shelf life of the LTO-4 cartridge is reported to be greater than 30 years.
Other versions of proprietary tape formats besides LTO also may have backward compatibility with each other, but typically not across product families. For example, the Oracle/Sun StorageTek T10000 series is not compatible with its previous generations, T9840 and T9940 tape media. But IBM TS1120 devices do support older format media, such as the 3590 series. Also, support can be an issue with proprietary tape drives and media, especially when used in libraries.
Whatever technology you choose to purchase, my advice would be to carefully study the compatibility charts to ensure the devices and media will operate properly, and that they are supported in your data backup storage environment.
For more information on LTO tape technology:
This was first published in March 2010