Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!pt.cs.cmu.edu!MATHOM.GANDALF.CS.CMU.EDU!lindsay
From: lindsay@MATHOM.GANDALF.CS.CMU.EDU (Donald Lindsay)
Newsgroups: comp.arch
Subject: Re: Personal OS
Message-ID: <9437@pt.cs.cmu.edu>
Date: 27 May 90 03:34:46 GMT
References: <402@newave.UUCP> <3300131@m.cs.uiuc.edu>
Organization: Carnegie-Mellon University, CS/RI
Lines: 38

In article <3300131@m.cs.uiuc.edu> gillies@m.cs.uiuc.edu writes:
>There is a very
>beautiful paper by Butler Lampson, I believe, called "An open
>Operating System for a Single-User Machine" (circa 82-84).  Basically,
>Lampson observes that the advent of the personal computer allows us to
>return to the golden days of the 1950's, with a single programmer, a
>library, and a dedicated machine.  Apple's OS is a very close
>approximation of lampson's ideal environment.

>Some of the things that are important in a single-user operating
>system are:
>   2.  no protected kernel, to allow easy modification of software
>   3.  single address space, to maximize modifiability of software

I realize that Butler convinced some PARC people of the correctness
of this view.  I have a great deal of respect for these people: but
on this point, I consider them to be naive and deluded.  Not everyone
out there is a PARC-quality researcher, and not every user out there
will run only sanctified applications.  The hardware cost argument
has gone away, and any speed argument has gone away.  Plus, that
famous "bloat" leaves me with 65 processes on my workstation as I
type.  Don't ask me what they all do.  Do I trust that they are all
debugged?  Hah! I KNOW that some of them aren't, and I don't trust
the rest.  Nor do I want the nightmare of making "easy modifications"
to these intricate, hard-to-test things.  Is this "golden age" going
to simplify them, going to reduce this bloat?  Would you like to buy
this bridge I own in Brooklyn?

In summary: if my workstation had a single address space, I'd sell it
and buy something adequate.  (Sorry, Ed.)

>   7.  overlay loader (because early macs (& Alto) had no VM)

I'm old enough to remember when overlays were the way you built
applications on minicomputers.  They were a god-awful source of bugs
and grief, and a horrendous waste of effort.  In summary: bletch.
-- 
Don		D.C.Lindsay 	Carnegie Mellon Computer Science