Multiple Application Access on PCI-6503

[Neal Stublen]

I have two applications which would like to use a PCI-6503 card through the
NI-DAQ API. One of these applications runs as an NT service, the other as a
desktop application.

If the service application begins using the card first, the desktop
application fails miserably. If the desktop application accesses the card
first, everything works fine. I have experienced similar problems sharing
memory between service and desktop applications and had to change the
service application so it would use an empty DACL in the security descriptor
when it allocated the shared memory. Does the NI-DAQ software have a
similar problem?

Thanks,
Neal Stublen

[kbcafe@my-deja.com]

Another guess, but information that might help.
I'm assuming the service starts as the local system account. Some driver
inherits credentials from the service running as the local system
account. These credentials are inadequate for the interactive user. But
when the interactive user launches the driver, the credentials are
adequate for the local system account.
My guess is that if you change the configuration of the service to start
w/ specific user credentials, then the problem disappears. Goto Control
Panel | Services | {service name} | Startup and change the user from
local system account to the interactive user. Don't check interact w/
desktop, rather change to a specific user and specify the user that will
log on to the system.
--
Randy Charles Morin [M
VP] - http://www.kbcafe.com/
Author of "Programming Windows Services"
http://www.kbcafe.com/047138576X

In article <39871811@newsgroups.ni.com>,
"Neal Stublen" wrote:
> I have two applications which would like to use a PCI-6503 card
through the
> NI-DAQ API. One of these applications runs as an NT service, the
other as a
> desktop application.
>
> If the service application begins using the card first, the desktop
> application fails miserably. If the desktop application accesses the
card
> first, everything works fine. I have experienced similar problems
sharing
> memory between service and desktop applications and had to change the
> service application so it would use an empty DACL in the security
descriptor
> when it allocated the shared memory. Does the NI-DAQ software have a
> similar problem?
>
> Thanks,
> Neal Stublen
>
>



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