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Date:      Fri, 02 Sep 2005 19:34:04 +0200
From:      "Poul-Henning Kamp" <phk@phk.freebsd.dk>
To:        Marcel Moolenaar <marcel@xcllnt.net>
Cc:        arch@freebsd.org
Subject:   Re: Consoles, past and future. 
Message-ID:  <36330.1125682444@phk.freebsd.dk>
In-Reply-To: Your message of "Fri, 02 Sep 2005 09:55:57 PDT." <75AF001F-473A-4D0E-9DF5-5A25F02B3749@xcllnt.net> 

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In message <75AF001F-473A-4D0E-9DF5-5A25F02B3749@xcllnt.net>, Marcel Moolenaar 
writes:
>On Sep 2, 2005, at 12:39 AM, Poul-Henning Kamp wrote:

>>     2. Single user terminal connection
>>     For manually fixing things before /etc/rc is run.
>>     API: Any tty(4) (and various other) devices will do.
>>
>>     3. System initialization progress indicator.
>>     The output from /etc/rc and its spawn.
>>     API: any file, pipe, stream socket and most devices will do.
>>          Using a tty(4) gives the ability to SIGINT processes which
>>          hang/sleep/get confused during startup.
>
>2 & 3 are in essence the same thing currently. That is, both depend  
>on the
>tty device /sbin/init uses. Whether they should be the same thing or not
>is not expressed with this statement.

That's why I listed them separately :-)

>> gdb(9) has its own hooks into the device driver.  I'm not sure I
>> know why, but it probably makes sense.
>
>Because a debug port is not a tty. The communication over a debug port
>is not bound to the rules and regulations of a tty. It therefore demands
>a separate interface. That you can implement one in terms of the other
>is merely an upshot.

Right, as I said: it probably makes sense :-)

>If we want to think radically, we probably should shift our thinking.
>We still treat the console as a central and fundamental piece of the
>kernel. I think we should instead make a 180 degrees turn and start
>off with a kernel that's deaf and dumb. I think it goes without saying
>that such an OS is still functional.

I must admit that I avoided this bit of the discussion to not get
diverted into the "we need a graphic installer" bikeshed.

I agree that we should look at this also, but I do consider it
somewhat secondary in the sense that my email is about what
mechnisms we have whereas this question is more about what we
use them for.

Knowing how the bikesheds grow bigger as we get closer to the 
user interface, I'd prefer if we could constrain ourselves to
the first part for now, but certainly keeping the second part
in sight.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.



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