Dear sir
Thank u so much for very good explanation of BSD & SysV . I am really very
much happy with write up. It is really a great write up.
Thank u very very much.
Selim
----- Original Message -----
From: "Michael R. Jinks" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, October 03, 2000 1:06 AM
Subject: Re: BSD & SysV
> On Sat, Sep 30, 2000 at 01:39:15PM +0600, Selim Jahangir wrote:
>
> > what is the fundamental diff between BSD and SysV unix ?
>
> I'm not really qualified to answer this but it looked as though nobody
else
> has mailed the list about it so I'll have a go.
>
> The _fundamental_ difference is historical. For a long time during the
70's
> and 80's AT&T allowed third parties to write their own versions of Unix,
and
> one version that caught on was written at the University of California at
> Berkeley, hence "BSD" for Berkeley Software Distribution. System V was
the
> last in-house AT&T version (which actually incorporated a lot of features
of
> BSD Unix and previous AT&T-derived versions).
>
> Both BSD and AT&T/System V Unix spawned a lot of offshoots, and inspired
> a lot of imitation in Unix-like OS's which weren't direct offshoots.
Sun's
> "SunOS" was a BSD offshoot up through the 4.0 series, but at 5.0 they
rewrote
> it extensively, incorporated a lot of "SysV'isms", and started calling it
> "Solaris". They still make a lot of the BSD-style commands available
under
> their /usr/ucb directory (ucb == "University of California, Berkeley").
>
> AIX is a completely independent, from-scratch rewrite of a Unix-like OS,
but
> it usually gets classed in the System V family because it has more in
common
> with SysV than with BSD.
>
> IRIX has some AT&T code in it, but also exhibits some BSD-style behaviors
> (though I'd be hard pressed to come up with examples off the top of my
head).
>
> Linux tries to be a sensible hybrid of both systems, to the delight of
some
> and the frustration of others, but the real lesson I get from it is that
the
> BSD/SysV distinction is really only useful in a historical context; as
Linux
> demonstrates, you can mix and match where appropriate.
>
> The most obvious differences in style have to do with the way each system
> handles initialization and service control during runtime. Under BSD,
there
> are a few files under /etc which list the services to run at boot time,
and
> that's about it; there is no such notion as a "runlevel", although I think
> that BSD does have a "single user" mode for system maintenance.
>
> Under System V, things get a little more complex (and, in my opinion, more
> elegant). Most of the system services have their own script
(traditionally
> stored in /etc/init.d/ or in RedHat under /etc/rc.d/init.d/) which
controls
> how that service is started and stopped. SysV also has the notion of
> runlevels, different system states which are defined by the list of
services
> that the system runs in each given state. The precise behavior of each
> runlevel varies a lot among systems, and can be extensively customized by
> the system administrator. (man init for the details on how it all works.)
>
> There are a lot of differences deeper down as well, but the distinction
starts
> to get a little blurry. Most SysV-style systems use Berkeley-style
network
> sockets, for example. Printing could be SysV or BSD or both. And many
common
> commands will have different behaviors; an obvious example is the "ps"
command.
> Historically "ps" took different arguments and displayed completely
different
> behavior under BSD vs. SysV, and each camp thought their ps was the
superior
> implementation. Modern Red Hat systems come with a ps that merges the
two:
> run "ps -[options]" and you get SysV behavior; run "ps [options]" (no
dash) and
> you get BSD behavior. Again, the manpage explains the details.
>
> Well I had to leave this for a couple of hours, and by now somebody has
> probably handled this better so I'll stop. Hope this helps somehow.
>
> -m
>
> --
> Michael Jinks, IB
> Systems Administrator, CCCP
> finger [EMAIL PROTECTED] for public key
> Vote Duke! http://www.entertaindom.com/pages/duke2000/home.jsp
>
>
>
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