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LTO tape drives, from their very first generation, offer hardware compression that, theoretically, allows a maximum of 2 - 2.5x the rated data capacity of each cartridge to be stored, with only a slight penalty to read/write rates.

I'm having difficulty finding out what algorithm this hardware compression uses, and what its characteristics are. Specifically, what I'd like to know is:

  • Is this compression based on a standard algorithm (DEFLATE/bzip/gzip/etc)?
  • How is it operating on the incoming data (blocks/files/streams)?
  • Are these characteristics identical across tape standard generations, hardware vendors, or individual drives?
Mikey T.K.
  • 1,447

1 Answers1

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  • The compression is part of the LTO standard, called SDLC, and is a variant of the LZS algorithm

  • It operates on the data in a block fashion. LTO6 and onward apply this compression to larger data blocks to support higher compression rates.

  • And, since it's part of the standard, it's the same across the entire LTO ecosystem (minus the change in LTO6+).

Mikey T.K.
  • 1,447