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

packet writing

    A technique for writing CD-Rs and CD-RWs that is
   more efficient in both disk space used and the time it takes
   to write the CD.

   Adaptec's DirectCD is a packet writing recorder for Windows
   95 and Windows NT that uses the UDF version 1.5 file
   system.

   [Is this true?  How does it work?]

   (1999-09-01)