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From: Andrew Hume <andrew@humeweb.com>
To: Douglas McIlroy <douglas.mcilroy@dartmouth.edu>
Cc: TUHS main list <tuhs@minnie.tuhs.org>
Subject: Re: [TUHS] Lorinda Cherry
Date: Tue, 15 Feb 2022 16:35:09 -0800	[thread overview]
Message-ID: <8249A4E0-92D7-4B87-83F2-45724F10F7A5@humeweb.com> (raw)
In-Reply-To: <CAKH6PiVi+JoxDG7ACMG5G+qnTkxTMsohGx6Wq3UNVkogO4N0Vg@mail.gmail.com>

for many years, my office was diagonally opposite lorinda’s.
we worked together most closely on the Unix manuals
(ninth and tenth editions); lorinda spent considerable work
on the permuted indices and the papers on Volume 2.

she also shared in my my own weird story of synchronicity.
i had been doing some work on polyhedra composed of
regular polyhedra. to prove to myself that i had gotten things
correct, i constructed a folding program to form the polyhedra
by folding a flat network of faces. i did this in bc and verified that
the vertices were sufficiently close together. and indeed, as i increased
the precision, the points coincided. except one didn’t.
for one polyhedra, one vertex stubbornly never got closer
than about 1e-6 from its (supposedly) coincident alter points.
it took about 3-4 days before i found the problem; in some exceptionally
rare cases, division in bc yielded the wrong answer.
i race around to lorinda to show her the problem (it was in the underlying
dc code). to my astonishment, lorinda listened and said
“you know, not 30 minutes ago, Vic Vyssotsky (our executive director)
came in with exactly the same problem.” he had discovered it by using
an extremely long-winded cyclical calculation used to detect errors
in arithmetic units. she then discovered the bug occurred when she converted
the original assembler code into C. the weird part was that this bug
had been latent for some years, and two different people reported it
to her with 30 minutes.


  parent reply	other threads:[~2022-02-16  0:59 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-15 22:31 Douglas McIlroy
2022-02-15 23:32 ` Steve Nickolas
2022-02-15 23:43   ` Jim Capp
2022-02-15 23:51     ` Larry McVoy
2022-02-16  0:54       ` Will Senn
2022-02-16  2:58         ` Steve Nickolas
2022-02-16  0:09 ` George Michaelson
2022-02-16  0:24   ` Dave Horsfall
2022-02-16  7:54     ` arnold
2022-02-16  8:13       ` markus schnalke
2022-02-16 14:54         ` Leah Neukirchen
2022-02-16 22:27           ` Dave Horsfall
2022-02-16 22:40             ` Andrew Diller
2022-02-17 10:14               ` Peter Jeremy via TUHS
2022-02-17 15:50                 ` Adam Thornton
2022-02-17 20:23                   ` Dave Horsfall
2022-02-17 10:24               ` Andy Kosela
2022-02-17 16:05                 ` Andrew Hume
2022-02-17 16:38                   ` Warner Losh
2022-02-16 22:42             ` Larry McVoy
2022-02-16 22:56               ` Clem Cole
2022-02-16 23:49                 ` Paul Winalski
2022-02-16 23:49               ` [TUHS] Benchmarks Bakul Shah
2022-02-17  1:02                 ` Larry McVoy
2022-02-17 12:36             ` [TUHS] Lorinda Cherry Stuart Remphrey
2022-02-17 19:59           ` Tom Ivar Helbekkmo via TUHS
2022-02-17 21:18             ` Dave Horsfall
2022-02-17 21:44               ` Bakul Shah
2022-02-18  8:33                 ` Otto Moerbeek
2022-02-22 10:39                   ` Ralph Corderoy
2022-02-22 15:53                     ` Otto Moerbeek
2022-02-20 17:29                 ` Derek Fawcus
2022-02-17 22:00               ` David Arnold
2022-02-18  9:58               ` Tom Ivar Helbekkmo via TUHS
2022-02-16 14:34     ` [TUHS] dc after bc Ralph Corderoy
2022-02-16 19:08   ` [TUHS] Lorinda Cherry Diomidis Spinellis
2022-02-16 20:55     ` John P. Linderman
2022-02-16 21:17       ` Andrew Hume
2022-02-16 21:59       ` Marshall Conover
2022-02-17  5:51     ` arnold
2022-02-17 22:09     ` Will Senn
2022-02-16  0:35 ` Andrew Hume [this message]
2022-02-16  8:02 ` Thomas Paulsen
2022-02-16 14:05 ` [TUHS] Shower of Dogs Ralph Corderoy
2022-02-16 14:09   ` Andrew Hume
2022-02-16 15:01     ` Larry McVoy
2022-02-16 16:57     ` Douglas McIlroy
2022-02-16 17:03     ` Dennis Boone
2022-02-16 17:18       ` Warner Losh
2022-02-16 14:09   ` Chet Ramey
2022-02-16 14:35     ` Ron Natalie
2022-02-16 14:41     ` Ralph Corderoy
2022-02-16 15:08   ` Rich Morin
2022-02-16 21:21     ` Dave Horsfall
2022-02-16 21:25       ` John Cowan
2022-02-17  3:31         ` Chet Ramey
  -- strict thread matches above, loose matches on Subject: below --
2022-02-22  0:02 [TUHS] Lorinda Cherry Brian Walden
2022-03-01 21:51 ` Terry Jones
2022-02-18  3:18 Norman Wilson
2022-02-18  9:10 ` Peter Jeremy via TUHS
2022-02-15 21:17 John P. Linderman
2022-02-15 21:26 ` Dave Horsfall
2022-02-15 21:33 ` Jeffrey Joshua Rollin

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