Path: utzoo!attcan!uunet!mcsun!ukc!dcl-cs!aber-cs!rupert!pcg
From: pcg@rupert.cs.aber.ac.uk (Piercarlo Grandi)
Newsgroups: comp.arch
Subject: Re: the Multics from the black lagoon :-)
Message-ID: <PCG.90Feb13150345@rupert.cs.aber.ac.uk>
Date: 13 Feb 90 15:03:45 GMT
References: <8859@portia.Stanford.EDU> <20571@watdragon.waterloo.edu>
	<PCG.90Feb11213549@rupert.cs.aber.ac.uk> <756@dgis.dtic.dla.mil>
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In-reply-to: jkrueger@dgis.dtic.dla.mil's message of 12 Feb 90 05:04:31 GMT

In article <756@dgis.dtic.dla.mil> jkrueger@dgis.dtic.dla.mil (Jon) writes:

   pcg@rupert.cs.aber.ac.uk (Piercarlo Grandi) writes:

   >(use Multics RDMS, and then read what Stonebraker
   >has to say about how suitable is Unix for Ingres).

   A reading from the book of Stonebraker, The INGRES Papers: Anatomy of a
   Relational Database System, Chapter 8, Operating System Support for
   Database Management, (originally CACM 24:7, July 1981):

I was actually thinking of the retrospection paper (very good
reading!  very amusing, and candid, and full of humour, and
really useful).  The OS support paper you cite looks, in my
opinion, a bit skewed by the mention of Pr1mos, which is after
all a Multics inspired system.

Stonebraker constantly gripes against the lack of locking, the
lack of suitable IPC instead of pipes, the buffered nature of
file system IO, the inability to guarantee writes, the coarse
protection system (and the limited address space of the PDP-11, a
problem later obviated by the VAX), the lack of shared memory, of
shared libraries, etc...

The Ingres people spent an appalling amount of effort fighting
the limitations of the os, and building grotty work arounds,
instead of concentrating fully on their job. The RDMS people didn't
have such problems. Ingres and RDMS are both successes, but RDMS is
obviously far smoother.

So, you ask, why did they use Unix at all, and on a PDP-11 as to
that?  Herein lies the answer to our discussion: Unix was free,
the PDP-11 inexpensive, and the time of grad students essentially
free as well. By contrast Multics would cost a lot, run on very
expensive hardware, and require expensive system programmers. In
other words, a computing center thing. Unix was written by people
that wanted their own little inexpensive thing, and did not like
using the computer center, and this was like the Ingres project,
and the people they wanted their database work for.

Beyond all the discussion of technical issues, they built a
system that was fit economically and politically very well
(except for one major detail) the same environment as most CS
departments and VARs targeting small businesses, and rode on the
wave of the (super)(mini/micro)computer boom, the single largest
development in the computer business, that has made the fortunes
of DEC, Apple, SUN, COMPAQ, IBM ESD, SCO, at one time or another.

	   "A DBMS would prefer a small efficient operating system
	    with only desired services provided ... most general
	    purpose operating systems provide all things to all
	    people at much higher overhead.  Hopefully, future
	    operating systems will be able to provide both sets
	    of services in one environment."

I think that Multics fits the bill here. It has a very small set
of primitive concepts, and very few low level services. It builds
on those an all-singing all-dancing set of higher level ones, but
you can cut through all those.
--
Piercarlo "Peter" Grandi           | ARPA: pcg%cs.aber.ac.uk@nsfnet-relay.ac.uk
Dept of CS, UCW Aberystwyth        | UUCP: ...!mcvax!ukc!aber-cs!pcg
Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg@cs.aber.ac.uk