[TUHS] Some notes on running UNIX v6 in 2015, using SimH and a healthy dose of documentation

Noel Chiappa jnc at mercury.lcs.mit.edu
Fri Dec 4 01:42:00 AEST 2015

    > From: Will Senn <will.senn at gmail.com>

    > a deeper read will require the reader to have knowledge beyond what is
    > required of most modern software developers (PDP-11 architecture,
    > assembly language, and UNIX are prerequisite).

Well, for pretty much any _operating system_ (as opposed to applications),
one will need to know something about the details of the machine it is
intended to run on; depending on which part of the OS one is looking at, it
will be more or less. E.g. switching processes probably requires a fair
amount, since one needs to know about internal CPU registers, etc; whereas
working on the file system, one probably doesn't need to know very much about
the machine.

    > It will also require access to a lab where the ideas covered can be
    > experimented with. 

Actually, Lions/V6 was used in operating systems courses using simulated
machines; one at MIT, 6.828 "Operating Systems Engineering":


used it for a while before the students started complaining about being
forced to learn an obsolete machine. They thereupon wrote a V6 clone for the
x86 architecture, 'XV6' (see the top of that page), which is apparently now
used for similar courses at quite a few other universities.

    > The v6 kernel ... packs in features that were either unavailable in
    > larger more established systems or may have been present in some form,
    > but were orders of magnitude more lines of code and attendant
    > complexity. It was and remains an amazing operating system and worthy
    > of contemporary study.

I don't think you will find too many people here who disagree! ;-)

    > So, I was thinking that next up, I would write up notes to help the
    > modern reader engage with v6 more easily in order to follow works like
    > Lyons.

Check around online to see what exists, first; there has been stuff written
since Lions! ;-)


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