Data Recovery in a Photo-Digital Storage System
Robert L. Griffith · IBM Journal of Research and Development · 1969
A data-recovery feature has been developed for recovering electron-beam recorded information which is microscopic in dimension and has been partially obliterated by flaws in a photographic-film recording medium. This feature provides (1) backup procedures that exploit redundancies in the recording format for the synchronization and identification of data, (2) coding for error detection and correction of 5 independent characters in 50 data character lines, (3) variation of machine parameters that affect reading performance, and (4) statistically optimized schedules for applying a variety of recovery techniques. Error rate is reduced from one error line in about 100 lines to less than one error line in 2.7×106lines.