Well that depends on how you define large scale data transfers FOR midi devices, what I meant to say was, properties were not implemented so one could route a whole midi stream through them. On the other hand you are totally right, properties are just a small top-level protocol for accessing data in the miniport, so it should do just fine. Date: Mon, 17 Jun 2013 10:19:16 -0700 From: timr@xxxxxxxxx To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] Re: Best way for Portclass-Driver-Application communication Max K wrote: - For once, IOCTLs are problematic, as one would have to overwrite the portclass handlers and pass IOCTLS on to the port if its meant for him, so probably not the best solution. - One could also exchange data with the driver using Filter, Node or Pin Properties by either using predefined properties or defining custom properties. This seems to be a valid solution, but it certainly wasn't intended for large scale data transfers. Well, that's not really the case. Remember that the KS property mechanism is a very thin shell over the IOCTL_KS_PROPERTY ioctl. It's just spelled a bit differently from DeviceIoControl. On the other hand, you don't ever really do "large scale data transfers" in a MIDI device. -- Tim Roberts, timr@xxxxxxxxx Providenza & Boekelheide, Inc.