From: Peter S. <stu...@cd...> - 2006-08-10 11:25:56
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On Thu, Aug 10, 2006 at 10:13:10AM +0200, Guenther Sohler wrote: > > Keep in mind that isochronous transfers don't have the same > > error-detection capabilities of bulk transfers. Unless you need > > to do guaranteed bandwidth stuff like streaming, I'd stick with > > bulk transfers and figure out whey they're so slow for you. > > My Final Application gets a lot of samples from an AD Converter and > software shall display somehow an oscilloscope > Dont know which usb transfer best fits it. > Its not important, that every byte gets correctly transferred, but > my maximum error Rate should be bewlow 0.01 % Bulk transfers guarantee no loss of packets and high bandwidth. Isoc transfers guarantee a certain packet transfer time at the cost of possibly dropping a transfer here or there. Isoc is only really useful for volatile data, streaming audio or video, IMHO. Go with bulk transfers. The difference between sync and async transfers is that Linux will immediately fire off any queued async transfers while with sync transfers there has to be a couple of task switches between kernel and your application before the next transfer is initiated. //Peter |