

Dmr: Odd Comments and Strange Doings in Unix - robinhouston
http://cm.bell-labs.com/cm/cs/who/dmr/odd.html

======
un1xl0ser
In regards to /* You are not expected to understand this */, the most
resonating part of the example was the fact that it didn't work at all the way
the implementor expected it to. I sometimes come across comments that were
written when the code was meant to be consumed by one person where a well
needed explanation is missing. This is a mistake that I sometimes make myself;
I feel we all do.

What I sometimes don't realize early enough, in testing and debugging strange
behavior is that the code may not have ever worked the way the person
expected.

I had a need to implement some fairly trivial case folding in C (I was/am a
noob at C). The code was meant to check a policy database to see if something
was allowed or denied. Some policy decisions were deemed critical and
therefore hard coded, and they happened to be the easiest ones to test with so
I changed one character of each case and expected it to fail the static check
and move on to the database lookup. After an hour of testing without a
debugger and reviewing only my code that changed, I broke out GDB and noticed
where the problem was. The code that I assumed working was broken. The code
had an || where an && was desired in an optimization to avoid comparing the
strings if the length wasn't the same.

If I had added a character, I would have never noticed the bug.

------
cstross
Some UNIXen had distinctly ... odd ... error messages in the old days.
Including kernels dmr had nothing to do with.

One day in 1996 I was in the NOC of a certain ISP in London when I noticed
folks crowding around a terminal. I shambled over to see what had gotten their
attention. This ISP ran a lot of NetBSD boxes (for security reasons). Lo and
behold, there was a strange message on the console:

Alien abduction overflow: core dumped.

(I never did learn just what triggered that one, but I heard it made it back
to the kernel developers by way of a bug report.)

~~~
1amzave
Of course there's always the classic "lp0 on fire!", but I think most people
know about that one.

Also, I've noticed that when GNU screen crashes, it prints "Suddenly the
Dungeon collapses!! - You die..." (though I think that may be dependent on
nethack-mode). I've yet to decide whether I think that makes the crash more or
less infuriating.

------
tmsh
This guy seems like a pretty amazing C hacker.

~~~
Stratoscope
Yeah, I wonder who this dmr guy was, anyway. He sure seemed to know a lot
about C.

It sounds like he worked at Bell Labs - maybe he knew the guys who wrote the
language!

