sslug-teknik team mailing list archive

[Jørgen Heesche <heesche@xxxxxxxxxxx>]

Kristian Nørgaard wrote:
>
SKIP
> > > 2) Hvad afgør om et device er registreret som
> > > /dev/ttyS0
> > > /dev/ttyS1
> > > ...
> > > /dev/ttyS4
> > COM1 -> /dev/ttyS0
> > Com2 -> /dev/ttyS1
>
> hmmmm, spørgsmålet kom af at jeg havde en maskine med to serielle porte 
> som var registreret som /dev/ttyS0 (port på bundkort) og /dev/ttyS4 ( 
> PCI kort )
Det kan du også noget om i http://tldp.org/HOWTO/Serial-HOWTO.html
11.2 The PCI Bus
Since DOS provided for 4 serial ports on the old ISA bus:
COM1-COM4, ttyS0-ttyS3 (tts/0-tts/3) most serial ports on the newer PCI bus
use higher numbers such as ttyS4 (tts/4) or ttyS14 (tts/14) for kernel 2.6.
This permits one to have both ISA serial ports and PCI serial ports on 
the same PC
with no name conflicts. 0-3 are reserved for the old ISA bus and 
4-upward (or 14-upward)
are used for PCI. It's not required to be this way but it often is.
On-board serial ports on motherboards which have both PCI and ISA slots 
are likely to still be
ISA ports. Even for all-PCI-slot motherboards, the serial ports are 
often not PCI.
They are either ISA, on an internal ISA bus or on a LPC bus which is 
intended for
slow legacy I/O devices: serial/parallel ports and floppy drives.

--
Med venlig hilsen

Jørgen Heesche
mailto:heesche@xxxxxxxxxxx
Registered Linux User #401007