tar: Large or Negative Values

1 
1 8.3.9 Large or Negative Values
1 ------------------------------
1 
1      _(This message will disappear, once this node revised.)_
1 
1    The above sections suggest to use 'oldest possible' archive format if
1 in doubt.  However, sometimes it is not possible.  If you attempt to
1 archive a file whose metadata cannot be represented using required
1 format, GNU 'tar' will print error message and ignore such a file.  You
1 will than have to switch to a format that is able to handle such values.
1 The format summary table (⇒Formats) will help you to do so.
1 
1    In particular, when trying to archive files larger than 8GB or with
1 timestamps not in the range 1970-01-01 00:00:00 through 2242-03-16
1 12:56:31 UTC, you will have to chose between GNU and POSIX archive
1 formats.  When considering which format to choose, bear in mind that the
1 GNU format uses two's-complement base-256 notation to store values that
1 do not fit into standard ustar range.  Such archives can generally be
1 read only by a GNU 'tar' implementation.  Moreover, they sometimes
1 cannot be correctly restored on another hosts even by GNU 'tar'.  For
1 example, using two's complement representation for negative time stamps
1 that assumes a signed 32-bit 'time_t' generates archives that are not
1 portable to hosts with differing 'time_t' representations.
1 
1    On the other hand, POSIX archives, generally speaking, can be
1 extracted by any tar implementation that understands older ustar format.
1 The only exception are files larger than 8GB.
1