of an elastic band that presses on the exterior of both reels, and also over an idler wheel on the edge of the case. A motor in the drive contacts the idler to move the tape. Because the reels wind and unwind at unequal speeds there is always some slippage occurring when the tape is in motion; frequent retensioning of the tape (achieved by winding the tape fully forwards and then backwards at high speed) is required to prevent this problem. Old tapes used many times tend to have a visibly marked stripe down the center of the tape where the band has pressed into the tape. Unlike some competing technologies such as Digital Linear Tape (DLT) and Linear Tape-Open (LTO), Travan technology does not automatically verify data after writing. Data verification must be done separately by the computer operator, to verify data was written successfully. If a separate verify operation is not performed after each backup, it is possible for backups to be found to be corrupt and unusable when the tapes need to be used. References External links Imation - Travan Data Cartridges Imation - Flyer with cartridge specs Computer storage tape media