Experimental Physics and
Industrial Control System

[email protected] · Wed, 2 Feb 2000 11:32:09 +0100 (MET)

  > ...I feel that there _should_ be explicit control over whether
  > output records read the VxWorks variable at initialization
  > time. Also, I think that this is necessary in order to achieve
  > backwards compatibility.

I don't think anyone ever set an output record to PINI=YES without
setting DOL, right? So ... if one uses a tool from the olden days (that
always puts something into DOL), everything will still work the same.

The only way to mess up things is using an editor or a new db generation
tool, not setting the DOL field and continue believing that this means a
CONSTANT 0. (Which isn't true anymore, anyway.) This would make the
record read the variable unintentionally.

Do you actually think someone might run into this?

  > The result is that you can now use VxWorks global variable device
  > support for direct access to device registers if you so desire.

Which (if the addresses are mapped to VME address space) - *sigh* - pops
up the topic of semaphore guarding again ... can you promise that all
kinds of VME accesses on all architectures using all the possible VME IO
cards are non-interruptable?

You should at least include a warning message in the doc (24pt bold red).

Ralph

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System