Donna,

MPEX merely (ignoring for a moment all the verifications that it does)
opens up the file and closes it with the option that returns to the system
any 'unused' space on the 'last' extent of the file (NO second file).  So a
file with 10 equal extents, for example, will end up with 9 equal extents
and 1 smaller (if there was any 'empty' space).  This became 'achievable'
as a result of how disc space is allocated in MPE/iX.

One thing that you should keep in mind is that the 'mod date' of all
'xltrimmed' files will be changed (unless ';keepamdates' is used) and that
may impact your next backup.  I got bitten by it the first time that I used
it and then my backup needed another tape, thus I got paged in the middle
of the night, etc....

Regards
Paul Christidis




(yet another mpex question :-)

hi again!

at least for a change i'm not asking how to do something in
mpex :-)

if i say 'altfile <somefileset>;xltrim' -- what really
happens?  is mpex working directly on each file or does it
make a 'work' copy?  if it's making a copy, i'm guessing
there's only one copy file in existence at a given
moment?           - d

--
Donna Garverick     Sr. System Programmer
925-210-6631        [log in to unmask]

Come, my friends, 'Tis not too late to seek a newer world.
Tho' much is taken, much abides; and tho'
We are not now that strength which in old days
Moved earth and heaven, that which we are, we are.
"Ulysses", A. Tennyson

>>>MY opinions, not Longs Drug Stores'<<<

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