>Thus writing a winmodem driver should be possible even on normal Linux,
>while softmodem might be much harder to implement, and might need a
>fair amount of either RT or kludges in the kernel.
There is at least two softmodems on MacOS (Apple's Geoport and SAT ISDN
adapter) and they work. The trick is to have some hardware support for
DMA transfer of the synchronous data flow. This way, you can have the HW
transfert quite large frames of samples and separately (asynchronously)
process them (from a kernel thread or an interrupt handler). This will
slow down the kernel but it looks possible.
I think the SAT ISDN adapter also works without DMA support (polling or
interrupt every 3 byte) but the machines slows down horribly.
--
E-Mail: <mailto:bh40@calva.net>
BenH. Web : <http://calvaweb.calvacom.fr/bh40/>
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