AnsweredAssumed Answered

vrf event handling and segmentation errors

Question asked by VRFuser on Oct 13, 2004
Thanks to Willie and Shawn for comments on my problem with activeX and
segmentation errors.

I still have not got a cast iron solution to my problem but I think it is a
cautionary tale for anyone moving vee applications using low(ish) level
instrument drivers onto a much faster PC platform.  Basically, I saw no
problem when running my application on a 450MHz Pentium III.   The problem
occurs when running on a 3.2GHz Pentium 4. 

I think what is happening in my case is that the driver software is running
significantly faster on the new warp speed PC than on the old one.  Vee
isn't and also the underlying hardware instrument isn't.  The driver is
designed to return an event when it has completed processing.   On the old
PC this is fine.   When it returned an event, it had completed processing
and the hardware it was talking to had also completed its related operation.
So everything was pretty much in sync.  With the fast PC, however, the
driver is returning an event way before the underlying hardware could have
possibly done its job.   The result being that meltdown occurs at some
point.  So I guess the problem is with the activeX driver.

Anyway, thanks for the comments.  They helped!

Nick


-----Original Message-----
From: Willie Kiely [mailto:Willie.Kiely@bourns.com]
Sent: 11 October 2004 16:07
To: VRF
Subject: [vrf] RE: event handling and segmentation errors

I subscribe to the point that the ActiveX control may be the problem.

I had some issues with NI Vision ActiveX, so I wrote in VB to see if the
error went away. Again VB came up with an error.

Eventually an updated Patch for the Control 'seems' (I say in hope) to have
fixed the issue......to a factor of 10 at least... ie error in 1000 cycles
now lasts at least 10000....did not test further. So maybe check that the
activeX control may have an updated revision, that fixes memory leaks etc.

Regards,

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