As files grow ever larger, and processor speeds and memory sizes also
increase, might it be time for the file prefetch size used by MPE/iX be
revisited and increased?

On our 995 systems we frequently notice that programs reading large
files serially often show a state of BLKMM on the SHOWPROC command or
MEMORY PREFETCH in Glance.

In previous analyses by knowledgeable MPE'ers (that means you Stan), it
appears that the prefetch done by the file system is usually 16 pages.
With the speed of optimized native mode programs and the availability of
large memory sizes on most HP3000 models, I would suggest that a much
larger figure may be needed.

A review of the SUPRTOOL help text for SET BUFFER and SET PREFETCH imply
that SUPRTOOL is prefetching 24 pages ahead of its 12 page buffer (how
is this done, by the way - FREADSEEK, AIF routine, other?)

What does this assemblage think?  Might this be an issue to be reviewed
in conjunction with the large file enhancement that is currently under
development?

Robert Joseph
The NPD Group
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