Using internal modem cards with SCO Xenix

[Chip Rosenthal]

In article <56 at .UUCP> root at .UUCP (Larry Snyder) writes:
>I thought that only COM1 and 2 were support by the stock release versions
>of SCO unless you were using a smart card - or multiport board since SCO
>expects the first com board on IRQ 4 and the second on IRQ 3.

XENIX doesn't expect any magic cookie -- it uses whatever you've programmed.
If you haven't programmed anything, then it uses whatever default SCO gave
you.

It turns out that /usr/sys/io/sioconf.c is distributed with two entries
for dumb cards which correspond to the usual DOS COM1 and COM2 parameters.
The structure of this file allows you to associate any of SCO's serial
drivers with any of a number of addresses and interrupts.  About your
only limit here (other than keeping I/O addresses and interrupt vectors
unique) is the fact that /usr/sys/conf/master only allows four interrupt
vectors per device driver, hence there is a limit of four devices per
driver (unless the driver allows some sort of interrupt sharing, which
the dumb COM driver doesn't).  There is absolutely no reason why you can't
move your dumb COM cards to other addresses or interrupts, or throw in a
couple more.
-- 
Chip Rosenthal / chip at vector.Dallas.TX.US / Dallas Semiconductor / 214-450-5337
"I wish you'd put that starvation box down and go to bed" - Albert Collins' Mom