Does anyone know if the file system still uses classic mode code to
handle circular files?

Several of our applications use large (more than 100K records) circular
files.  We found
that reading and writing Circular files in MPiX 5.5 is running 70%
classic mode, even
when the applications are native mode programs.

According to GLANCE, reading and writing to a 600,000 record circular
file would use
90% of the CPU; 70% of this time was classic mode.  During this same
test, GLANCE indicated
that the program was only using an index of 0.1 on DISC I/O.  It was
purely CPU bound on
a file copy operation.

In contrast, non-circular files contained NO classic mode switches.
GLANCE shows a DISC
index of approximately 40.0 and indicates the program is DISC I/O bound
(which is what you
would expect in a file copy operation).  DISC index of 0.1 versus 40.0:
that's about a
400:1 performance difference.

Variable versus Fixed record lengths made no appreciable difference, and
non-circular files
used no perceptible classic mode operations.  Our programs are pure
Native Mode.  Why would
it be invoking CM operating system code?

Does anyone know if there is a way to access circular files in native
mode?


Best regards,
Steve Donnelly
Expeditors International