Message-ID: <4384C3E1.3060208@tmr.com>
Date: Wed, 23 Nov 2005 14:32:49 -0500
From: Bill Davidsen <davidsen@tmr.com>
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.11) Gecko/20050729
MIME-Version: 1.0
To: Vojtech Pavlik <vojtech@suse.cz>
CC: Marc Koschewski <marc@osknowledge.org>, Greg KH <greg@kroah.com>,
       lkml <linux-kernel@vger.kernel.org>, rmk+lkml@arm.linux.org.uk
Subject: Re: Christmas list for the kernel
References: <9e4733910511221031o44dd90caq2b24fbac1a1bae7b@mail.gmail.com> <20051122204918.GA5299@kroah.com> <9e4733910511221313t4a1e3c67wc7b08160937eb5c5@mail.gmail.com> <20051123121726.GA7328@ucw.cz> <9e4733910511230643j64922738p709fecd6c86b4a95@mail.gmail.com> <20051123150349.GA15449@flint.arm.linux.org.uk> <9e4733910511230712y2b394851rc17fa71c6f9c6ecf@mail.gmail.com> <20051123155650.GB6970@stiffy.osknowledge.org> <20051123160520.GH15449@flint.arm.linux.org.uk> <9e4733910511230837v1519d3b3t28176b1fd6017ffc@mail.gmail.com> <20051123164907.GA2981@ucw.cz>
In-Reply-To: <20051123164907.GA2981@ucw.cz>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 2194
Lines: 54

Vojtech Pavlik wrote:
> On Wed, Nov 23, 2005 at 11:37:23AM -0500, Jon Smirl wrote:
> 
> 
>>Before everyone gets excited, I realize that all of this has
>>historical implications. But that doesn't mean we can't discuss
>>possible future alternative solutions.
>>
>>Thinking about this for a while it seems to me that the problem is
>>that the various apps (init, syslog) etc should not have a tty name as
>>part of their command line parameters. Instead these apps could use
>>ptys instead. Ptys would solve all of the race problems too.
>>
>>Is there any good reason (other than history) for using a device node
>>name (tty0, etc) instead of some other naming scheme if names are
>>needed at all?
>>
>>If init, syslog, etc can be converted to ptys, do we need ttys? Xterms
>>use ptys I don't notice that they aren't connect to a fix tty name.
>>The virtual consoles would still be 0,1,2 but do they have to be
>>hooked to tty0, 1, 2 instead of a pty?
> 
>  
> The basic difference between a pty and tty is that a pty connects to a
> program (that created it by opening the ptmx node, for example xterm or
> ssh) on the other end, while a tty connects to the kernel doing all the
> character drawing in the framebuffer.
> 
> You can't easily use one instead of the other, they're very different
> beasts.
> 
> Of course, a way to use a pty would be to have the console
> implementation in userspace.
> 
> The fact that no program is on the other end of a tty is also the reason
> why they cannot be created dynamically like ptys, there is noone to open
> a "ttmx" to create the ttys.
> 
> Hence, the device nodes are pre-created by the kernel, while the real
> devices are only created on open.
> 
Thank you, you can omit answering my previous post if you like, I can 
understand ugly but necessary.

-- 
    -bill davidsen (davidsen@tmr.com)
"The secret to procrastination is to put things off until the
  last possible moment - but no longer"  -me

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/