Robust embedding of longitudinal position into tape servo signals

Abstract

In linear tape open technology, the longitudinal position (LPOS) on magnetic tape is embedded into the timing-based servo format by modulating the positions of magnetic transitions during the servo-writing process. An efficient method for embedding LPOS information into tape servo signals that is robust to LPOS detection errors is presented. The proposed concept is based on the serial concatenation of three data-processing stages: a lossless compression stage with a fixed compression ratio, an errorcorrection coding (ECC) stage and a runlength-limited coding stage. Various algorithms have been designed to compress and decompress the LPOS information. Errorcorrection codes, such as Hamming codes, Reed-Solomon codes and Golay codes, are used to protect LPOS and manufacturing information from detection errors. Finally, the random-error and the burst-error performance of various compression/ECC schemes are evaluated by computing the LPOS word error rate for servo signals corrupted by additive white Gaussian noise and by determining the burst-error correction capability of the proposed LPOS formats, respectively.