> > So you never really know what device node corresponds to the port you just
> > plugged your serial cable into.
>
> Just as with disks the only real solution is to hard-wire your kernel
> configuration so that you know what major/minor numbers correspond to
> what hardware device(s).  Unfortunately unlike disks there's no way to

exactly. it's thing i like very much in netbsd which is missing in for eg.
linux.

> do this for serial ports without renaming files in /dev.

what a problem?

com0    at isa0 port 0x3f8 irq 4
com1    at isa0 port 0x2f8 irq 3

puc0    at pci0 dev 8 function 0
com2    at puc0 port 0
com3    at puc0 port 1