[linux-audio-user] Interuptions While Recording

Tobias Ulbricht up5a at stud.uni-karlsruhe.de
Mon Feb 10 06:10:00 EST 2003


> I appoligize for my lack of savy. Does this answer the VIA/SiS
> question? If so, do you have any other ideas of where I may need
> to investigate next?

Your "hdparm -Tt" experiments will not be the same every time you do it,I had around 1-2 MB/sec in both reads.
But even 30 MB/sec should be far enough to get dropout-free recording. 
44100 * 16 * 2 (bit/sec) = 1411200 bit/s
44100*16*2/8             =  176400 byte/s = around 200 kB/sec.

See? Even if you play at the same time (duplex), your 30 MB/sec is far more than that.

One more thing, but be aware, I heard switching the dma-transfer-rate might be dangerous if you don't have the new 80pin cables. (right?)

you might want to check. "hdparm -i" which gives you some "*" on the options that are set.
see the "dma1 dma2 dma3 dma4 dma5" line, which (in my case has the "*" at the dma4=100MB/secautomatically set.)

I once tried with changing that value around, but I believe you need a 80pin cable to set anything higher than dma2 = 33 MB/sec

see e.g.: 
http://www.intel.com/support/graphics/linux/udma.htm.

for the settings you might want to try out.

But in anycase. I don't think it's the bandwidth onto/off your harddrive.

cheers, tobias.


> 
> According to the article, I have the _exact_ Ultra ATA/133 PCI Adapter Card _and_  Hard Drive to acheive the highest speeds. The _Hard Drive's_ specs say:
> 
> Buffer size:
> 8 MB
> Average seek time
> 9.1 MS
> DATA Transfer rate:
> 133 MBytes / sec
> (Ultra ATA/133)
> Rotational Speed:
> 7200 RPM
> 
> So with the ATA/133 Card, the Hard Drive and (following)
> Hardware/Software specs, shouldn't this be enough to allow flawless multitrack recording:
> 
> My Software/Hardware:
> 
> SuSE 8.1
> k7SEM Mother Board
> AMD Duron 1Ghz Processor
> 256 Megs Ram
> Soundblaster Live! 5.1
> alsa Version 0.9.0.cvs20020903-13
> (That's the Alsa that installed with SuSE 8.1 - It
> hasn't been altered in any way)
> 
>  If you remember, when I installed the card and then did:
> "hdparm -Tt /dev/dsp"
> the Timing buffered disk reads MB/sec were lower than before I installed it. So, if you think the card is a worth fooling with, do you have any idea why the Timing buffered disk reads were lower (and how to bring them up)?
> 
> Thanks,
> Rocco
> 
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