On Fri, 10 May 96 14:34 PDT, [log in to unmask] (Dan Hollis) wrote:
|Does anyone know why when you BUILD a message file with a 'DISC=xxxx' that
|the file limit always ends up being set 7 greater than you requested?
|
|This doesn't happen with normal files.
 
Correct.  Message files (also Circular files) are relatively complex objects.
As Stan Sieler pointed out in another reply already, there is a good bit of
overhead in a small message file.  Also remember that all message files are
variable record length files.  That alone implies a certain amount of
additional complexity in setting the FLIMIT of the file.  Also, you should
be aware that the FLIMIT of any variable record length file is the number of
BLOCKS, not the number of records, and the record size reported is actually
the block size.  If you are writing records which can fit more than one
record (with the overhead for each one) in a single block, it's very
possible for the EOF to exceed the FLIMIT.  With variable data record sizes
and large block sizes, I have seen EOF numbers several times the FLIMIT on
message files.
 
In general, I consider message files to be the most arcane feature of MPE's
file system visible to the casual user.  Although the POSIX functionality
and its interaction with traditional the MPE paradigm may now deserve that
distinction.
--
Jeff Woods
[log in to unmask] at Unison Software
[log in to unmask]   at home
[PGP key available]
Native American proverb:
We did not inherit the Earth from our parents, nor they from theirs;
We are borrowing the Earth from our children, just as our parents did from us.