[WriteLog] WriteLog, shared IRQs and COM ports

[K4SB]

Robert Peterson wrote:
> 
> Eric -  I want to echo Clive's comments....snip... handled it without any problems.  > I'm assuming that systems that allow IRQ sharing have some way of telling which device requested the interrupt and activate the appropriate interrupt handler.

Well, as it was explained to me, Robert hit it right on the head. The
card sharing the IRQ (say IRQ 11) just sits there and polls how many
ports are present on the card. If it finds data coming in, it assigns
the IRQ to that port until business if transacted, and then goes back
to polling. It very well say, get a packet announcement, then get an
answer from the Radio in response to an earlier request.

However, only 1 port has the IRQ at a time. But then, at several
hundred thousand polls per mili second, most of us can't keep it with
it.

Sounds like witchcraft to me.

73
Ed