[Asterisk-Users] four wildcards in a single pc

[Rich Adamson]

> I have installed successfully more then four cards in a machine before.
> I had a firewall with eight network interfaces (one quad card, one duo
> and two singles)
> I have machines with two dialogic boards, a pci display card, and a
> network interface.
> And I know I've had machines at home that had a display adaptor, modem,
> network, scsi, and soundblaster all together.
> 
> Yet, people claim it won't work because of lack of IRQs, and that it's
> not related to Digium.
> 
> What am I missing?

There has been a lot of comments over the last 12 months or so relative
on this. The issue is _not_ the number of interrupts, but rather the
ability of those interrupts to handle the flow of data across the bus
_without_ injecting delay. That ability seems to be directly related 
to exactly how the interrupts are handled on _each_ motherboard, and 
seems to have some relationship to the pci support chips on the 
motherboard.

There are plenty of implementations that _do_ share interrupts with
absolutely no problems, and at least some of those are represented to
be rather heavily loaded.

There's also been a fair number of people that have had problems with
the latest/fanciest/fastest system, and swapping out the motherboard
with a 800 mhz P3 fixed their issues. What else actually changed
during that swap? No one knows for sure, but supposedly nothing.

The current list of symptoms/issues reads something like this:
- processor speed has little/nothing to do with it
- dual vs single processors has nothing to do with it
- amount of ram, etc, has nothing to do with it
- the linux distro in use has nothing to do with
- digium cards expect a solid 1000 interrupts/second/card with no
  interrupt service latency
- those heavily involved with audio (not voip audio) have known about
  pci & interrupt latency issues with certain motherboards. They seem
  to be more sensitive to the issues then * is. No one has found
  a list of what _they_ consider to be bad boards.
- there is no consolidated list of what motherboards work vs don't
  partially due to the difficulty of describing boards from vendors
  (eg, Dell, HP), and in some cases, different boards used in the
  same model number of system.
- if a particular motherboard has an issue, the problem typically
  appears as echo on pstn calls (one direction only)
- there are no tools that anyone has written/found to help identify
  which systems/motherboards have issues
- although some people represent that digium support is working on
  something, those words have been heard before and the problems
  still exist (at least for some).

So, it seems the only _reliable_ answer to your question is to try it
on whatever hardware you have available.