Experimental Physics and
Industrial Control System

[email protected] (Deb Kerstiens) · Thu, 22 Feb 96 10:01:09 MST

Andy writes:

> Another requirement of the Gemini Project is to be
> able to dynamically change access to various records and
> fields. If my understanding is correct, you can do this by
> calling a special routine from a SUB record which re-initialises
> access security by re-reading the ACF.
> 
> What would happen, under these circumstances, to a "dm" display?
> This change in access security could well mean that
> controllers which previously only had read permission now 
> have write permission as well.
> 
> Could "dm" be made to update dynamically? My feeling is that
> it could, if it were only displaying simple text like "Access denied"
> and didn't require redrawing of boxes with different colours.
> 
> Andy

Dm is currently set up to get changes in access using a
CA callback that gets executed when access changes, so it
will be able to dynamically reflect the change.  Currently
it just ignores the information.  I hadn't anticipated 
changes to access being really frequent, so I hadn't viewed 
it as real performance issue.  I was planning to move from
"access" appearance to "no-access" appearance, etc. dynamically.
This could be fairly ugly if access will be changed really
rapidly.  Anyone planning to change back and forth faster 
than once a second or so??  (Even that rate could drive the 
viewer nuts!)

The change is easiest for controllers that move between 
read/no write and read/write, since they're already basically
visible in a normal state.  Changing between no read and read
would be the biggest hit.

BTW, thanks to all for the input.  I'll mull it over and try
to write up a strawman.  

Deb

**********************************************************************
Deb Kerstiens		[email protected]
Phone			(505)667-3396
LANL AOT-8,MSH820	PO Box 1663, Los Alamos, NM. 87545 
**********************************************************************

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System