This option sets the maximum size of a merged file group when adding files
to an archive.  This sets an upper limit on the amount of file data that can
be merged together.

The only reason a maximum merge group size exists is to prevent the
situation where one may wish to delete or update one file in a very large
merged group (e.g. 10 MB of merged files).  Since all undeleted data must
be compacted (recompressed) after a deletion, it is advantageous to make
the merged group size not too large.  On the other hand, if the merged group
size is too small, then compression suffers.

The default merged group size is 260K.  The minimum allowable is 8K, and the
maximum allowable is just over 8000K (8 Megabytes).

The parameter to this option is specified in 1000's of bytes (not 1024); for
example, -M500 would specify a maximum merged group size of 500,000 bytes.


This option is valid with the following commands:

   a (add)
   d (delete)
   f (freshen)
   r (replace)
   u (update)