[AccessD] shutting down

jwcolby jwcolby at colbyconsulting.com
Mon Dec 17 12:55:41 CST 2007


In electronics they have a concept called a "deadman timer".  Essentially a
deadman timer is a memory location that is updated every time activity is
sensed.  A timer comes along and checks the memory location every N time
units.  If the location has not been updated in X time units then something
occurs, typically (in electronics) a system reset.  The program that
controls the device is tasked with updating the deadman timer location
periodically just to inform the OS that the task hasn't hung.  If the
program hangs, the OS restarts the program.

To apply that concept to your application, you would create a table variable
(local in this case) or even a global variable.  The timer on your form now
modifies that table / global variable every time a new control is sensed.
This solves the "yea but they might have just come back to the same control"
issue.  Similarly any process that needs to keep the application alive can
update the table / local variable once every N time units.  How the process
does that is up to the process, but there would be a rule "if the location
is not updated for more than X time units you're history".  Thus the
application could do it once every time through a loop etc.

Just one more way to do this.


John W. Colby
Colby Consulting
www.ColbyConsulting.com 
-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Susan Harkins
Sent: Monday, December 17, 2007 11:35 AM
To: Access Developers discussion and problem solving
Subject: Re: [AccessD] shutting down

>
>  Really to do shutdown right, it needs to be built into the app itself 
> and is not something you can simply add on easily.

======Jim, after doing a little research and testing, I think I agree with
you. I had agreed to write about this, but given the limitations, I think I
will pass.

Susan H. 

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