Due to the linear technology of QIC drives, the tape is not threaded out of the cartridge like with DAT or 8mm tapes. It is kept on a constant tension level by an integrated drive mechanism in the cartridge and it does not leave the tape housing.
The advantage: a professional MLR drive has to correct only ca. 100 errors per hour despite the proportion of utilizable data to correction data. Under 0,9% of missing data blocks (e.g. through scratches, breaks, tape jam) can be reconstructed up to a length of ca. 2cm (that is every 20 cm).
MLR technology is based on quarter inch data cartridge technology (QIC). The enormous increase in capacity and speed is possible due to the parallel use of several read/write channels. An additional read channel follows marked servo tracks on the tape. This way an optimal positioning of the read/write head and the highest data integrity is reached.
The read-while-write process guarantees an absolute copy of your information on the magnetic tape in that the data is read back during the recording and is compared to the original data. Some MLR drives use special thin magnetized heads i.e. the same technology which enabled the enormous capacity increase of the last generation of hard drives.
