Subject: Re: TTY virtualization driver
From: David Laight <email@example.com>
Date: 01/22/2002 18:18:50
> | > What if we add a driver that uses the minor number to traverse the
> | > ttylist to locate an instance and redirects to that driver? That
> | > way you can create a set of `/dev/tty??' and `/dev/dty??' and not
> | > have to mess with a different set of names for each serial controller.
> | why it is a mess? it is an adventage.
> Because now you need to be concerned whether your serial port is
> /dev/ttya or /dev/ttyZa or /dev/ttyCa or /dev/ttyHa or /dev/ttyEa....
Yes - it's great, I can add extra hardware and nothing moves...
If I add an extra scsi controller and/or another disk it can take ages
to find where the other disks have gone to, and to fix vfstab.
If you are going to merge devices from a set of drivers into a single
list, then you have to be very careful to ensure that they don't get
renumbered if the hardware is reconfigured. Typically this involves
keepeing the map is a file. I did something similar giving interface
names to ethernet drivers (so they were always eth<n> regardless of the
card type). The scripts (etc) to get this to work 'as expected' were
non-trivial, and even then it didn't necessarily do what you wanted!