On Monday 23 April 2007, Mario. wrote: >Yes, you are right and it is nice that you point to the isochronous >transfers, but as a Microsoft standard, USB has had poor latency. It >is not known to me how are any recent latency tests... > >On 4/23/07, Kenneth Lerman <[EMAIL PROTECTED]> wrote: >> Mario, >> >> It is my understanding that usb supports isochronous transfers with >> guaranteed access to usb bandwidth and bounded latency. That would clearly >> support realtime actions. >> >> The bandwidth is clearly high enough to support our requirements. It is >> not clear (to me) whether usb would meet our latency requirements. >> >> Ken
If I can stick an oar in here, ISTR reading someplace, Kenneth, that the worst case latency is specified as 100 milliseconds, which if true in today's realizations would absolutely rule it out. However I get the feel from what little I've noticed here at the coyotes den, that its much faster than that today. That info might have been true, or might even be true yet for a low speed device, but with today's 400 megabaud hardware it might be do-able, particularly on slower machinery such as my micromill. We need an echo dongle so we can measure the round trip, but I'm not aware of such a beast. Is anyone else? Just for grins, I'll ask Greg KH on the usb list. >> [EMAIL PROTECTED] >> Mark Kenny Products Company, LLC >> 55 Main Street Voice: (888)ISO-SEVO (888)476-7386 >> Newtown, CT 06470 Fax: (203)426-9138 >> http://www.MarkKenny.com >> [snip many copies] -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) After all is said and done, a hell of a lot more is said than done. ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
