Creating
Other Registry Entries
To obtain the
performance data for some applications (those that return counters using the DeviceIOControl function), it is necessary
to use the CreateFile
function to open the device associated with the application. In this case, the
name specified in CreateFile
must also be installed in the DOS Devices node of the registry, as shown here:
HKEY_LOCAL_MACHINE
\SYSTEM
\CurrentControlSet
\Control
\Session Manager
\DOS Devices
Applications
that manage multiple device instances with performance data for each device,
must put a Linkage key in the its Services key. The Linkage
key contains an Export value whose data is a list of the device names.
For example, a system with two Etherlink cards could have the following
registry entries:
HKEY_LOCAL_MACHINE
\SYSTEM
\CurrentControlSet
\Services
\Elnkii
\Linkage
Export =
"\Device\Elnk01" "\Device\Elnk02"
\Performance
Library =
"ElnkStat.dll"
Open =
"OpenElnkStats"
Collect =
"GetElnkStats"
Close =
"CloseElnkStats"
\Elnk01
\Linkage
\Parameters
\Elnk02
\Linkage
\Parameters
When the
system calls the Open function in an application s performance DLL, its
argument is a string containing the list of device names from the application s
Export value, if it is present. The Open function can then use these names to
determine the devices for which to collect performance data.