The 10 Entry Limit in Windows NT/2000/XP
Since the introduction of Windows 2000 we have been regularly contacted by a few costumers, who were experiencing the following errors:
The errors mentioned above concern all Windows
versions of NT, 2000 and XP up to the latest XP SP1. And in all cases it is
the same error. Since NT, Windows has an internal list of the 32bit MIDI and
wave drivers. These lists can carry up to 10 entries maximum each, after that
they will never be reset, deleted or carried further.
Before doing this, you should have understood the list management in order to efficiently take over Windows' job.
Location and Creation of the Entries
Via 'Start/Run', the registry editor can be
started by typing in 'regedit'. The relevant entries are in the path 'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows
NT\CurrentVersion\Drivers32' (left part of the window). As can be seen in
the picture above, in case of an error all 10 entries for MIDI (midi to midi9)
and/or audio (lower end of the list, wave to wave9) have already been created.
But not only real hardware, also virtual ports
emulating hardware use up entries. In the picture the entry midi9 is taken
by gmidi.dll, which provides the virtual MIDI ports for Gigastudio. Even internal
hardware can be problematic. The driver 'wdmaud.drv', Microsoft's WDM audio
mapper, is actually only needed once per WDM (blaster) hardware, but it showed
up 7 times in one of our customers' notebook - and this with an internal sound
card, of which the resources never change!
Deleting the Entries
For doing this, you move the mouse to the desired entry midix or wavex in the right window, right mouse button, delete. But which entries may be deleted? The best thing would of course be a new creation of the list, i. e. deleting all entries midi up to midi9 and wave up to wave9. In this case you have to be sure that you have the drivers for every hardware concerned at hand. We warn against this method and recommend a more specific procedure.
In our example the procedure was easy: all
MIDI entries with hdspmme.dll were deleted and the drivers of the Hammerfall
DSP were installed again. This way the list of 10 entries shrank to 5. The
entries wdmaud.drv and gmidi.dll were not renewed. As can be seen in the picture
it is no problem, if this creates gaps in the numbering.
Copyright © Matthias Carstens, 2002. All entries in this document have been thoroughly checked, however no guarantee for correctness can be given. RME cannot be held responsible for any misleading or incorrect information provided throughout this document. Lending or copying any part or the complete document or its contents requires the written permission from RME.
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