We'll see | Matt Zimmerman

a potpourri of mirth and madness

Bohrbugs: OpenOffice.org won’t print on Tuesdays

This is one of my favorite bugs of all time: Ubuntu bug #248619, where OpenOffice.org won’t print to Brother printers on Tuesdays (but works on other days of the week).

Read some of the duplicate reports to follow the analysis and developer/user cooperation which isolated the bug.

It’s a great example of a Bohrbug, where the circumstances which trigger the problem can be very difficult to isolate. It’s likely that many such bugs exist in Ubuntu and other software today, but have not yet been isolated, as bug 248619 has been.

We’ve all observed a complex software stack misbehaving in ways we would never expect. It’s just as confusing when things suddenly start working again, for no apparent reason. We start to doubt our senses, or the person who is reporting their observations.

In The Psychology of Computer Programming (chapter 5), Jerry Weinberg presents a case where two identical systems, physically isolated from each other but running the same software, exhibited precisely the same error at the same time. This obviously pointed to a software bug, but after two weeks of searching, the problem could not be replicated and the root cause was not found. The team gave up on finding it, and the system went into production, only to have the bug recur and cause a serious operational outage.

Bugs which occur very rarely may not always be worth investigating, but they are real, and can be explained. When it really matters, we should remember not to disregard them.

Written by Matt Zimmerman

August 15, 2009 at 23:01

21 Responses

Subscribe to comments with RSS.

  1. […] Posted in Datorer by br0ther on 16/8 2009 Via Matt Zimmerman hittar vi idag ett felet i OpenOffice som innebär att Brother-skrivare inte kan skriva ut på […]

  2. Wrong bug #?


    August 16, 2009 at 01:28

    • I checked the link, and it looks correct. It might be non-obvious because the bug summary and description describe the root cause, rather than its colorful symptoms.

      Matt Zimmerman

      August 16, 2009 at 01:39

  3. LP #255161 is better for context. Wow.

    Faidon Liambotis

    August 16, 2009 at 02:11

  4. That duplicate bug was in the Mercury Program tracking system. Since human life was at risk, our rules said the we could not launch with any unexplained bugs remaining, but project management caved to political pressure and ordered that we declare the bug a “coincidence” and proceed with the launch

    What actually happened was several of us went against management orders to drop the search. We kept searching and found the bug just before John Glenn’s first flight. If it had not been corrected, John Glenn might very well have died because of it.

    Definitely worth investigating in this instance…

    Gerald M. Weinberg

    August 16, 2009 at 04:40

    • I assumed that you anonymized the details in your stories, but didn’t expect that this could have related to such a prominent global event. Thanks for sharing this memory.

      Matt Zimmerman

      August 16, 2009 at 11:21

      • I figured that after 50 years, we could finally shed the anonymity, so the story would have its full significance. Then, Mercury was a rare system, but half a century later, life-critical systems are far more frequent.

        And even if it’s only a billion dollars or so that’s at stake, tracking down these “obscure” bugs is still important, I think.

        Maybe if we keep publishing these stories, some people won’t have to learn the hard way. That’s why I’m now writing novels that show these consequences in dramatic form. Maybe people will learn these lessons for a “tuition” less than a billion dollars or a human life.

        Gerald M. Weinberg

        August 16, 2009 at 15:13

        • On behalf of the generation of programmers that followed in your footsteps, and indeed as an admirer of the space program, thank you for sharing this with us.

          Earle Martin

          September 5, 2009 at 11:41

  5. Nice bug :-) One of those reasons why no matter how obvious it is, you should _always_ test your assumptions when troubleshooting. If only I didn’t have to learn that the hard way!

    Adrian Bridgett

    August 16, 2009 at 08:24

  6. One of my clients is a small company with 5 PCs and a server, all of them running Debian Lenny.

    The printer is a Brother one and –here comes the bohrbug– sometimes and always the same user –not others–, can’t print from Openoffice to that printer.

    At that very moment, he can print whatever –PDFs, txts, etc– but not Openoffice documents.

    The next day, all works perfectly again.

    Debianero Rumbero

    August 16, 2009 at 18:48

    • The tuesday thing sounds like some remnant of an easter egg, or a leftover debugging trick from long ago.


      September 5, 2009 at 16:27

      • No, it was a bug introduced unintentionally in file(1), a program used to guess the type of a file based on its contents. The file in question contained a date, and when the date included the string “Tue”, this was close enough to confuse the program into thinking it was a different type of file. The type database contained a pattern which was too general.

        Matt Zimmerman

        September 5, 2009 at 17:54

  7. As someone who writes software I readily admit to a low tolerance for buggy software – they piss me off.

    In the last six years or so, the most upset I get is while using Open Office. It’s absolutely amazing how many basic usability issues that POS program has. It’s pitiful! It’s just barely competent, IMO.

    Makes you want to post nasty rants really giving it to the monkeys responsible, but then you remember it’s open source.


    September 4, 2009 at 19:54

  8. “We start to doubt our senses, or the person who is reporting their observations.”

    it’s my experience that a developers _first_ instinct is to doubt the person reporting the issue. then again, i work QA at a for-profit software company, so most developers are there for the paycheck rather than a love of the product.


    September 5, 2009 at 01:17

  9. […] OpenOffice.org won’t print on Tuesdays […]

  10. […] on Planet Debian: a discussion of a recent Ubuntu bug. This is one of my favorite bugs of all time: Ubuntu bug #248619, where OpenOffice.org won’t […]

  11. […] Bohrbugs: OpenOffice.org won’t print on Tuesdays […]

Comments are closed.

%d bloggers like this: