Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!auspex!guy
From: guy@auspex.auspex.com (Guy Harris)
Newsgroups: comp.os.misc
Subject: Re: What constitutes a good OS?
Message-ID: <5298@auspex.auspex.com>
Date: 16 Jan 91 19:22:21 GMT
References: <41679@nigel.ee.udel.edu> <1991Jan15.084127.4044@kithrup.COM> <41754@nigel.ee.udel.edu>
Organization: Auspex Systems, Santa Clara
Lines: 53

>Not so.  None of the editors on UNIX use keys (line numbers). Why? Because
>none of the other programs (say, compilers) know about them. How many
>files would benefit from having keys that were quick to access?
>/etc/passwd /etc/group termcap /etc/hosts and many more, including every
>directory on the system.

Well:

	1) the keys you *want* on the aforementioned files aren't line
	   numbers, they're things like the user name, the user ID, the
	   terminal type, etc;

	2) some file system types for UNIX might well *give* directories
	   indices - directories generally aren't plain-text files in any
	   case;

	3) some UNIX systems have keyed-access versions of some of those
	   files, although the keyed-access version has to be generated
	   by a separate program after you edit them - but, if the
	   program that edits them doesn't know the format of the file,
	   that'd have to be the case *anyway*, unless you had, as an
	   attribute of the file, something that told the keyed access
	   package or the editor how to scan the text of a line to
	   figure out the key.

>I agree that the windowing system should not be in the kernel.  My only
>point was that if it *was* in the kernel, it would have to work when
>you got it.

I.e., kernels don't have bugs?  I don't believe that.  I'm not convinced
that merely by putting the window system, or the print spooler, or
whatever into the kernel, you necessarily increase the chances that
it'll work when delivered - except perhaps by putting it there reducing
its complexity, probably by trading away functionality....

>I realise that.  However, if I can't write and install my own device
>drivers from a non-privledged account (hopefully without rebooting),
>then I can't replace the windowing system and it might as well be in
>the kernel.  Here, I can run sunview or X as needed.  I don't know if
>plan-9 can do that or not.

Then perhaps it can, and your argument against it is incorrect.  As they
note, the window system is a user-mode server; I suspect that, in fact,
you *can* run your own window system server without needing privileges
(and run it within a window of another instance of the window system).

>Basically, that pretty much sums it up.  I think relatively minor
>additions in the kernel of UNIX (primarily file handling)

"kernel" in the sense of "privileged supervisor" or "core set of OS
services"?  The object-oriented scheme suggested by some postings might
be better implemented, to a large degree, outside the privileged
supervisor.