[LAD] audio/midi app development

[Philipp Überbacher]

Excerpts from Gene Heskett's message of 2010-06-17 00:45:14 +0200:
> On Wednesday 16 June 2010, Patrick Shirkey wrote:
> >On 06/17/2010 04:52 AM, Ralf Mardorf wrote:
> >> Paul Davis wrote:
> >>> On Wed, Jun 16, 2010 at 2:30 PM, Ralf Mardorf
> >>>
> >>> <ralf.mardorf at alice-dsl.net> wrote:
> >>>> PS: Why not programming for savant syndrome musical gifted and 'fast'
> >>>> watching people too?
> >>>
> >>> the limits under discussion relate to monitor technology, not human
> >>> capabilities.
> >>
> >> I'm not a 'fast watching savant' ;) and even if the GUI is too slow, I
> >> won't care. I'm listening to music with my very good ears, but my bad
> >> eyes. No doubt, Linux is a good choice, but MIDI real-time could be
> >> better. For me the GUI is unimportant. BUT I prefer to do audio
> >> recordings using Linux, but MIDI recordings. It's a real pity, because
> >> MIDI would add some very cool features.
> >
> >This is only on your system right? I know a lot of people are working
> >with midi recording using linux tools.
> >
> >You see jitter at low latency but have you tried changing your hardware
> >or working with the driver developers to isolate and fix the bugs you
> >are seeing?
> 
> One of the test tools that might be enlightening for the MIDI folks here, is 
> the machine control program called emc.  Because jitter is very important 
> when feeding a stepper motor controller a steady heartbeat at high audio and 
> somewhat above frequencies, the coders have developed a 'latency-test' 
> script, which you run on one screen, then abuse the heck out of the machine 
> doing other things, (browsing the web, moving windows around, compiling a 
> kernel, whatever warms up the cpu) then come back half an hour or more later 
> and read the average and worst case latencies as displayed in nanoseconds.  
> 
> Those are generally big figures so do the math and make milliseconds out of 
> them.
> 
> Emc when running stepper motors is fussier that all get out, and that tool 
> just might point the finger at truly bad motherboard, or video hardware.  
> FWIW, an nvida video card, can only be used in a machine running emc if the 
> vesa driver is selected, all the others including nv, tie up the interrupts, 
> sometimes for many milliseconds.  For emc, that would equal a stalled motor 
> and a wrecked part you were cutting at the time it stalled.  Similar things 
> can be said about the APCI of some motherboards.  If that can't be fixed via 
> a bios setting, toss the board.  Via chipsets seem to be the most popular in 
> this latter category.
> 
> If its a complex part that you've already got several hours worth of carving 
> & cutting tool wear into, that will only happen once, because whatever the 
> culprit is, gets both found and a free airmail trip into the bin.
> 
> What?  Oh, I'll go back to lurking now. ;-)
> 
> -- 
> 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)
> The policy is not to have policy. It works as well in kernel design as 
> politics.
> 
>     - Alan Cox on linux-kernel

I fear something named simply 'emc' isn't easy to find around the net.
-- 
Regards,
Philipp

--
"Wir stehen selbst enttäuscht und sehn betroffen / Den Vorhang zu und alle Fragen offen." Bertolt Brecht, Der gute Mensch von Sezuan