[LAD] Towards a truely realtime capable FOSS audio distribution | A guide to the Jack Source Code

micu micuintus at gmx.de
Thu Jul 24 20:23:52 UTC 2008

Hello everybody,

my name is micu and I study computer science at the Dresden University of 
Technology. During an internship at the operating systems chair of the 
university, I ported ALSA to the chairs operating system DROPS aka TUD:OS 
[1,2]. To let ALSA talk to the hardware and provide to it the usual linux 
kernel environment DDEKit / DDELinux [3] were used. As a kernel-userland 
interface I wrote a very small emulation layer, which makes it possible to 
link SALSA-lib [4] against the ALSA "kernel" part.

So right now, we have a somewhat stable ALSA server running in userland on top 
of DROPS without changing ALSA or the SALSA-lib source code.

I have been continuing this project within my diploma thesis. The remit of the 
thesis can be found here [5]. It is the goal of the thesis to take some steps 
towards a truly realtime capable (meaning with time constraints to be 
guaranteed) FOSS audio distribution. Here [6] you can see a raw version of my 
requirements definition.

The architecture we are going to use is --- how could it be different :) --- 
Jack or Jackdmp (with a strong bias towards Jackdmp). To get the mess out of 
my head, I wrote a short guide [7] to the Jack source code. It is a pretty 
raw version and it isn't finished in any way yet; but I won't work on it any 
longer. Nevertheless, it might be helpful to other developers new to Jack. 
Therefore, if you will, you may get it under any license you wish 
(attribution of the author is appreciated :) to publish and improve it.

Of course, the long term goal of the project won't be met to any extent during 
my thesis and I have no idea, if this project will be continued here at the 
university. Neither do I know, whether I will have time to work on it 

To make a long story short: I would like to ask my first three questions.... 
so far :) 

	1.) Do you agree on having a truly real-time capable architecture in the FOSS 
audio world would be a really great thing --- and would you say, getting such 
a thing maybe could get a (major) goal of the pro audio FOSS community?

	2.) Concerning our Jack vs. Jackdmp decision: http://jackaudio.org/ says, 
Jackdmp is going to be Jack 2.0. How likely and how soon do you think is this 
going to happen?

	3.) I guess, there is a very minor bug in the lines 236, 237 of 
libjack/driver.c, svn revision 2734: The type castings should be switched.

Thanks a lot in advance and please excuse my bad english :(.


BTW: I love Jack and I love ardour --- and therefore I love you :).
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