Doesn't this also depend on how directly a sound card can be
"approached".  I know in Windows there is all this crap (called layers)
you have to deal with, which DirectX tries to deal with.  And we now
have DMA, which is nothing new of course, and which is another more
direct road to your devices.  Unix is probably much better at that
(i.e., accessing devices directly) and Linux should be, I presume.  Has
anyone any experience with BeOs in this regard?  

Job van Zuijlen   

Paul Barton-Davis wrote:
> 
> >Hehe, I get 90 on my lowly, 7-year old 133 MHz Indy!  Adjusted for
> >MHz, that is 304.5 oscillators on the MIPS chip.  Puts the Pentium II
> >in perspective, doesn't it?
> 
> It certainly does. But more than, it makes me wonder what is going on.
> I don't believe that the a PII that has a clock 3.4 times faster than
> the Indy can be that much slower. So something here is really wrong. I
> doubt that its Linux, since its scheduling performance exceeds that of
> most other Unices. It could be the soundcard driver.
> 
> Any other ideas ?
> 

In message <37435DDB.71911279@ibm.net>you write:
>Doesn't this also depend on how directly a sound card can be
>"approached".  I know in Windows there is all this crap (called layers)
>you have to deal with, which DirectX tries to deal with.  And we now
>have DMA, which is nothing new of course, and which is another more
>direct road to your devices.  Unix is probably much better at that
>(i.e., accessing devices directly) and Linux should be, I presume. 

yes, it would interesting to try out the OSS mmap() interface, and see
if it helps. it eliminates a layer of copying from the transfer to the
soundcard. I know from past stuff that it does make things a little
better, but not as much as Tobias' comparison with the 133MHz Indy
would suggest it should.

i'm too busy right now to try this, but i'll keep it in the back of my
head. 

> Doesn't this also depend on how directly a sound card can be
> "approached".  I know in Windows there is all this crap (called layers)
> you have to deal with, which DirectX tries to deal with.  And we now
> have DMA, which is nothing new of course, and which is another more
> direct road to your devices.  Unix is probably much better at that
> (i.e., accessing devices directly) and Linux should be, I presume.  Has
> anyone any experience with BeOs in this regard?  

The entire "Media Kit" of BeOS is being overhauled for the next version.
As I'm fortunate enough to be in the beta program, I can say two things about
it[1]:

- it is much more complex than the older version
- it offers very precise control of things like latency etc.

Unfortunately, it may take me a while to understand the new stuff, and still
longer to make Csound use it (my older port was crap in the real-time area
anyway; I'll have to try harder).

Greetings,

        Jens.

[1] In fact, I could say a lot more, but then I would probably never get
    another beta version :-)
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