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Written by J. Laroche at the Center for Music Experiment at UCSD, San Diego California. December 1990. Advanced Topics and Future Directions. Multiple channel DMA. The DMA controller has a bandwidth of 2 Mbytes/sec. This means that in theory, it can handle 10 stereo 44.1 KHz sample streams. It is now possible to use several DMA channels in any direction. This means for example that you can have two DMA channels to the DSP and one back to the host, and perform real time mixing of two sources. Or two DMA from the DSP, one for the sound and one for additional data (midi data, acoustical caracteristics etc...) Unfortunately, there is no documentation about how to do that. It seems that there are some primitives somewhere in /usr/include/?. If we found a way to do it, would DMA make it possible to process two or more sounds in real time? It seems that processing two stereo 22015 sounds or two mono 44100 sounds will be possible, since DMA in and out works for stereo 44100...
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.