[TUHS] Comments in early Unix systems

Steve Johnson scj at yaccman.com
Thu Mar 22 10:31:18 AEST 2018



"I was told in school (in 1985) that if I was ever lucky enough to
have access to the unix source, I'd find there were no comments. The
reason, I was told at the time, was that comments would make the
source code useful, and selling software was something AT&T couldn't
do due to some consent decree. I've never been able to verify this
story, but it came from someone who started with v5. Sadly, he passed
away 15 years ago, or I'd just ask him again..."

Ah, the consent decree.   The basic idea of the consent decree was
to prevent AT&T's regulated monopoly from giving it an unfair
advantage in other areas.   And, since the regulation guaranteed a
rate of return, certain restrictions were put on the ability of AT&T
to do business outside of the telephone arena.  In particular, one
requirement was that AT&T MUST patent anything they did that was
patentable.  And furthermore, they must license that patent to all
comers at a "reasonable" rate.

The decree was signed in 1956.   And then, along came software! 
AT&T foundi itself required to patent software inventions at a time
that nobody was sure what that meant, or whether software was even
patentable.  There were some very strange patents, or at least patent
applications, that came out of this.  I remember an algorithm for
generating permutations that was recast as a relay computer because
that was probably patenable and, if so, AT&T had to do it.  

Also, the mindset of AT&T was to plan in 20 year timescales, and they
had trouble understanding the increasing speed of software
innovation.  The patent department's attitude about a lot of the
issues of Unix licensing, etc., was basically to wait 5 years until
there was some precedent before acting.  Meanwhile, when they took an
interest they would issue some directive, often to reverse themselves
several months later.  I remember before one of the releases we had
to make sure we had a copyright notice on every file, only to be told
six months later to make sure that we removed all copyright notices
from all files.

One run-in that I had with the legal team happened just as Unix and C
were beginning to become popular, and some new C compilers were
appearing.  I made a strong appeal, with the support of my
management, to release the front end of PCC (or at least the Yacc
grammar for C) into the public domain, to try to encourage some
consistency in what we intended to be a portable language.  Meetings
dragged on for months, and we were finally told no.   I don't know
whether, had I been successfu, we could have avoided all the ANSI /
Posix confusion that came later, or at least limit the number of
incompatibilities that rapidly appeared in "C" compilers.  But it
might have helped...

Steve


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