Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!uwvax!tank!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.unix.questions
Subject: Re: Remote Logins that Start X-Windows
Message-ID: <18373@mimsy.UUCP>
Date: 3 Jul 89 22:39:16 GMT
References: <20125@adm.BRL.MIL>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 18

In article <20125@adm.BRL.MIL> 91erm@bigbird.cc.williams.edu writes:
>As far as Suns go, the ability to seize the console derives mostly
>from the fact that the screen buffer device is usually left at mode 666 ...

You can easily make the case that the frame buffer device(s) on a
Sun are much like tape drives, which (since V7 at least) have been
`single use devices'.  A driver for such a device should permit
only one process to open the device.  (One open, the file descriptor
can still be passed around through dup() and fork(), and, on some
systems, as a message.)

Of course, this does not keep people from logging in remotely when
the console happens to be free, and opening it then.  But this is
sometimes legitimate, whereas sharing the bitmap hardware is not.
(Unless you make the opposite case :-) )
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris