Re: New /dev/console and /dev/tty0

Kohtala Marko (Marko.Kohtala@ntc.nokia.com)
Tue, 29 Apr 1997 18:06:45 +0300

Geert Uytterhoeven <Geert.Uytterhoeven@cs.kuleuven.ac.be> writes:
> On 29 Apr 1997, Kohtala Marko wrote:
>> Geert Uytterhoeven <Geert.Uytterhoeven@cs.kuleuven.ac.be> writes:
>>
>>> In summary, while we created an `automatic' /dev/console, we lost the ability
>>> to access the current virtual console (formerly /dev/tty0), or am I missing
>>> something??
>>
>> When I wrote the change, my thought was that /dev/console would
>> continue to work as before (it already was automatic) when there are
>> the virtual terminal devices. However, I failed to bring this thought
>> into the code.

> I think you've got a bit confused by devices.t{ex,xt}. This document
> (incorrectly) states that c 4 0 should be /dev/console, while it was supposed
> to be /dev/tty0. If you read the statement about the console at the end, this
> becomes clear (and I did ask H. Peter Anvin).

I do not know what statement you are talking about, but you are right
that I got confused.

This thing is a bit confusing. MAKEDEV 2.2 from 1995 makes /dev/tty0
and links /dev/console to it. It seems that /dev/tty0 was intended to
open the foreground /dev/tty[1-9]*, and here works the same as the
/dev/vcs0. As /dev/tty0 was the only console, the link was sensible.

Now that /dev/console can be another device, this is a problem. You
are right that there is a reason to designate some other device as the
console.

Theodore suggested using a magic pty. That sounds good. While at it,
one could enhance the writing to copy the output to all console
devices.

However, I'd need to study the kernel a bit to decide how to go about
implementing it.

-- 

---
Marko Kohtala - Marko.Kohtala@ntc.nokia.com, Marko.Kohtala@hut.fi