[Asterisk-Users] Digium should develop and sell just Dummy card. For timing...

Steven Critchfield critch at basesys.com
Wed Oct 15 10:28:24 MST 2003


On Wed, 2003-10-15 at 11:56, Andrew Kohlsmith wrote:
> > Some one else here has mentioned the quality of software design due to
> > the need for hardware timing. This should be addressed by the fact that
> > many tools are using hardware timing. Mp3 players use the sound device
> > as a timing source. They can only be feed so much data at a time as it
> > is being serviced. When you can feed it more, you do. In the case of the
> > mp3s on voip only systems, the mp3 player no longer is directly coupled
> > to a device that can control speed. The mp3 player is dumping data as
> > quickly as it can, and as asterisk tosses it into the correct format and
> > gets it out on the ethernet wire, it can then service more data. In the
> > case of Digium hardware, or the appropriate dummy drivers, we get a
> > timing source to directly couple to the channels.
> 
> I agree -- I think what that particular poster's point was was that there 
> are already sufficiently jitter-free timing sources in the PC and that it 
> seemed assinine to add another for a paltry 1KHz (IIRC).  He has a point, 
> but (again, speculation) Asterisk boxes may or may not have RTCs or even 
> USB ports, and using a processor-specific timer is even worse for 
> portability.  By locking on to an add-on card that can be added to any 
> system with a PCI bus, Asterisk gains portability.

My need to flame is over for the moment, semi rational thoughts appear
below.

Why make additional hardware whose driver needs be ported to other
systems when you can make similar dummy interfaces? What happens to the
systems that don't have PCI buses. I can think of some older MAC
hardware that can run linux, but not PCI cards. Not that I would bother
my self with one of them, but the point stands only to say that building
hardware for a timing source that doesn't have another function is
stupid. 

BTW, according to /usr/src/linux/Documentation/rtc.txt, I doubt there is
many systems we will encounter that don't have a rtc.   

> And again, where is the official Digium response?  This is all speculation.  
> I was just putting out a request to end this stupidity and have an official 
> response so everyone can point to it and say "that's why."

The official response is in the code if you ever take time to read it.
Since Mark is the chief maintainer of CVS, he probably agreed to
anything that made it's way into the code base.

> I didn't think it'd end up in this mini flame war.

Well at least I stayed out of the email formatting war of late. I've
been ignoring almost any HTML email, and for the most part quit dealing
with this list.
-- 
Steven Critchfield  <critch at basesys.com>




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