Experimental Physics and
Industrial Control System

Eric Norum <[email protected]> · Fri, 2 Nov 2007 08:53:54 -0500

On Nov 2, 2007, at 8:30 AM, Ned Arnold wrote:

You may be able to eliminate the fanout records by careful design
of forward links and/or input link flags (PP, CP, etc).
For example, if the input record's forward link field referenced
the calc record and the calc record's forward link field referenced
the calcout record, all would process each time the input record
processed ... without a fanout.

Don't take this technique to extremes, though. I recall helping
Steve Shoaf diagnose problems with his database for a video switching
system. The database contained 128 records FLNK'd together. This
caused very weird IOC faults that we finally realized were caused by
stack overflow of the task processing the records -- 128 recursive
calls to the record processing routine forced the task stack pointer
past the end of the stack space.

--

Eric Norum <[email protected]>

Advanced Photon Source

Argonne National Laboratory

(630) 252-4793

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System