Patent ID: 8667235

Claim:
A data storage method comprising: dividing input subject data into a succession of subject data chunks, each chunk comprising chunk subject data; for each chunk, writing a corresponding data item in a serial-access storage medium in association with a logical location mark, the corresponding data item comprising the chunk subject data where the chunk subject data is a first occurrence of the chunk subject data as a chunk of the input subject data, and otherwise the corresponding data item comprising a chunk-data identifier identifying the chunk subject data; generating a chunk database and a duplicated-chunk database; wherein the chunk database comprises a multi-field entry for each unique chunk in the input subject data; and the duplicated-chunk database comprises an entry for each chunk that is duplicated one or more times in the input subject data, each entry comprising a corresponding chunk-data identifier which is a signature specific to the chunk subject data and a logical location indicator indicative of a first occurrence location of the chunk subject data; and writing the duplicated-chunk database to the serial-access storage medium.