Method and apparatus for reading down-level tapes having distorted media

摘要

A tape reader is designed to read down-level linear track tapes having a multiple number of new tacks in the positions of each older wider track and having tape subject to pack level tape distortions which may result from environmental stresses and inter-use delay time. If tracks are displaced with respect to ideal servo reference positions, then optimal down-level reading may require selecting segments from different new track choices along the length of the tape. Decision choices of tracks and longitudinal break points are based on a; combination of gathered metrics per tape and engineering knowledge of each product. These data are stored first in internal memory. Longer-term memory storage particular to each tape may include cartridge memory either in the form of possible cartridge chip memory or writing to a section of tape in each cartridge. Decisions may be optimized with increasing number of read cycles and supplemented by knowledge in longer-term cartridge memory. For strong tape distortion, an intermediate step requirement may be the separate reading of whole tracks into buffer memory per channel and then reading the alternate track choice separately while selecting the proper segment of each track on a per channel basis.