grandfather, father, son

Grandfather, Father, Son
GFS

   <operating system> (GFS) A {backup rotation} scheme in which a
   "grandfather" backup is performed on the first Monday of each
   month, a "father" backup is performed on every other Monday
   and a "son" backup is performed on every other day of the
   week.  Grandfather tapes are kept for a year, father tapes for
   a month and son tapes for a week.  The exact schedule (and
   thus the number of tapes required) may vary, as may the choice
   of {full backup} or {incremental backup}, but the idea is that
   it should be possible to restore versions of any file of
   different ages: e.g. yesterday's, last week's or last year's
   version.

   (2004-10-11)