Re: real-time threaded IO with low latency (audio)

yodaiken@chelm.cs.nmt.edu
Fri, 23 Jul 1999 13:27:34 -0600


On Fri, Jul 23, 1999 at 03:06:27PM -0400, Paul Barton-Davis wrote:
>
> the soundcard ADAC might look like a file, and it might be represented
> by a node in a filesystem, but it isn't a file. a device like an ADAC,
> or a serial port, or a parallel port, or a network interface, isn't
> capable of being bypassed by the page cache - its essentially a bit
> bucket. the i/o subsystem's efforts on behalf of such devices can be
> precisely nil - bytes sent to them are never available for retrieval
> unless the hardware itself does something funky.

So you need high speed copy memory<->device_memory
and what else? What do I need to have in RTL to make it easy for
you to use?

> no, we/i don't need it for disk i/o. we need it for output to an ADAC.
> i don't know where the locks are that i referred to above, but i know
> that mingo and andrea and maybe even dave miller have confirmed their
> existence when Benno first started discussing his latency test.

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