In Windows 2000, and early versions of Windows XP, there was a hard limit of 10 USB MIDI devices that could ever be connected to a single system. This limit was because the drivers for such devices were enumerated in registry keys with names of the form
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Drivers32\midiN
where N is empty or a single digit. Each of these keys would have an associated value that would be the name of the driver associated with a MIDI device; when that table filled up, no new MIDI devices could be added.
Recently, I mistakenly installed an extra MIDI device on my machine, and to my surprise it worked. When I looked at the registry keys, they were all still there, but they now all refered to WDMAUD.DRV instead of referring directly to the various device drivers. This happened on Windows XP SP2 and is presumably the same way on SP3.
So I am wondering whether there has been a quiet change to how USB MIDI drivers are handled, and whether WDMAUD.DRV is some kind of general-purpose forwarding program that figures out which driver is relevant. If so, are there new limits on the number of USB MIDI devices, and what are they?
Or am I completely mistaken about what's going on and my devices are working only by sheer coincidence?
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Drivers32\midiN
where N is empty or a single digit. Each of these keys would have an associated value that would be the name of the driver associated with a MIDI device; when that table filled up, no new MIDI devices could be added.
Recently, I mistakenly installed an extra MIDI device on my machine, and to my surprise it worked. When I looked at the registry keys, they were all still there, but they now all refered to WDMAUD.DRV instead of referring directly to the various device drivers. This happened on Windows XP SP2 and is presumably the same way on SP3.
So I am wondering whether there has been a quiet change to how USB MIDI drivers are handled, and whether WDMAUD.DRV is some kind of general-purpose forwarding program that figures out which driver is relevant. If so, are there new limits on the number of USB MIDI devices, and what are they?
Or am I completely mistaken about what's going on and my devices are working only by sheer coincidence?
