[TUHS] the guy who brought up SVr4 on Sun machines

Joerg Schilling schily at schily.net
Mon Jan 9 23:40:08 AEST 2017

Larry McVoy <lm at mcvoy.com> wrote:

> The VM system was ported from SunOS 4.x to System 5.  Your statements that
> SVr4 is based on SunOS are flat out wrong.  SVr4 got a lot of SunOS goodness
> but the starting point was ATT System V.

This looks like a response made from gut.

Let us check things that are verifiable, by looking at the basic elements
of the OS kernel that together cover the majority of the kernel.

		SVr3		SunOS-4		SVr4

Networking	if: BSD		BSD		STREAMS
				Networktap	New code written
				allows STREAMS	by Lachman

Driver		Svr0		BSD based	SunOS-4 based

Kernel virtual	V7/Svr0		SunOS-4		SunOS-4

VFS		-		SunOS-4		SunOS-4 based

There are few things in SVr4 that are not the same as in SunOS-4,
e.g. the way parameters to ioctl() are copied to/from the kernel
but this are minor parts.

So why should someone start with the AT&T sources when the expected result
is > 70% identical with SunOS-4?

Even the TTY streams implementation is the one seen in SunOS4, and not
a possible AT&T internal implementation, as this contains a design flaw
that caused switching from/to coocked mode to loose data. This is not
permitted by the UNIX definitions for the TTY driver and has been fixed
by an enhencement that occured in SunOS-4 and is in Svr4 as well.

BTW: My statements are from a talk from Bill Joy from the Sun User Group 
meetings. Bill claimed that he was responsible for the Svr4 kernel and did this 
on a new location in Denver Colorado that was as a joint venture from Sun and 

The SunOS-5 kernel and the Svr4 kernel still differ, but they are more close 
together than Svr4 and Svr3. Note that I did not only write Joliet and 
ISO9660:1999 support code for SunOS and SCO UnixWare but also for SCO 
OpenServer that is based on Svr3. So I had legal access to SunOS, Svr4 and Svr3 
based code. Did you have access to this code? Did you compare?

> > Interesting: Do you mean "Bill Shannon"? Was he involved in SCCS or smoosh
> > as well? I know Bill as the author of "cstyle" and I pushed him to make it OSS
> > in 2001 already, before it appeared in OpenSolaris.
> Yup, that Shannon.

OK, so he was also working on SCCS?

> > In January 2015, I talked with Glenn Skinner about SCCS and smoosh and he 
> > pointed me to his smoosh patent:
> > 
> > 	http://patentimages.storage.googleapis.com/pdfs/US5481722.pdf
> > 
> > that has been expired in late 2014. 
> The fact that Glenn didn't put me on that patent is a sore point.  Yes,
> he wrote the lisp code that showed it could be done.  I wrote the C code
> that did that in one pass (his stuff was N+M where N was how many deltas
> were on the local side and M was how deltas were on the remote side).

I have been told that a patent can be void if it does not list the right 

I would guess that this was a decision made by the lawyer that helped to file 
the patent.

Are you responsible for the original idea?


 EMail:joerg at schily.net                  (home) Jörg Schilling D-13353 Berlin
       joerg.schilling at fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/
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