>
> Heres a question about Linux serial and parallel ports..
> I know that in DOS, you can piggyback com 1 and 3 onto irq 4 and com 2 and
> 4 ont irq 3, and lpt 1 and 2 onto the same irq (either 5 or 7)
> I also know that Win95 will allow the com port piggyback, but not the lpt
> one...
The standard linux setup for com ports is Com 1,3 = 4, Com 2,4 = 3...
You change thses settings via setserial, e.g Say you want com2 on irq 4:
/bin/setserial -b /dev/cua1 uart {8250,16450,16550} port 0x2F8 irq 4
com1 on irq 3
/bin/setserial -b /dev/cua0 uart {8250,16450,16550} port 0x3F8 irq 3
Where you place these commands depends specifically upon your distro's
config, such as Slackware's BSDish should be called for /etc/rc.d/rc.M
(the newer versions have an /etc/rc.d/rc.serial script), and redhat, in
its specific /etc/rc* structure).
There is a problem with this approach, that I am too lazy to fix is: I
had a modem on /dev/cua2, and a vt on /dev/cua0, when both were set for
irq 4, and I attempted to access either at the same time, the one that was
accessed first would get the IRQ... my quick hack around this was to set
the modem to irq 7 temporarily until I got a multiport card which handles
this internally. (Although my line pronter and parallel Zip drive did not
like this)
To add more to this thread, I have a Compaq Comtura 486dx/25 laptop which
I would kill to set a plip up on: The bios only allows you to set the lpt
port as lpt1:irq7, lpt2:irq5, lpt3:irq2(9)... when I attempted to use lp1
it tried to access it at irq 5, when set as lp2 it tried 7, when I tried
lp3 it tried 5 again, is there a quick command line option to force an IRQ
for PLIP? (I have tried compiled in kernel and modules, kernel 2.0.0 ->
2.0.28)
- Neptho T
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Neptho T. A "No" uttered from deepest conviction is better or greater
neptho@neptho.unixgeek.com than a "Yes" merely uttered to please, or
http://www.greatbasin.net/~hagan what is worse, to avoid trouble.
Programmer/Systems Engineer/System Designer - Mahatma Ghandi
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