The Free On-line Dictionary of Computing (30 December 2018):

Digital Lempel Ziv 1
DLZ1

    (DLZ1) A Lempel-Ziv compression algorithm
   which maps variable length input strings to variable length
   output symbols.  During compression, the algorithm builds a
   dictionary of strings which is accessed by means of a hash
   table.  Compression occurs when input data matches a string
   in the table and is replaced with the output symbol.

   DLZ1 is used on Digital Linear Tape.

   (1997-04-05)