"Remember that one bug that had you tearing your hair out and banging your head against the wall for the longest time? And how it felt when you finally solved it? Here's a chance to share your greatest frustration and triumph with the community.
One that I vividly recall occurred back in the early 90's at a startup that was developing custom PBX hardware and software. There was the current development prototype rack and another rack for us in Quality Assurance (QA). Our shipping deadline for a major client was fast approaching, and the pressure level was high as development released the latest hardware and software for us to test. We soon discovered that our system would not boot up successfully. We were getting all kinds of errors; different errors each time. Development's machine booted just fine, *every* time. We swapped out our hard disks, the power supply, the main processing board, the communications boards, and finally the entire backplane in which all of these were housed. The days passed and the system still failed to boot up successfully and gave us different errors on each reboot.
What could it be? We were all stymied and frustrated as the deadline loomed before us. It was then that I noticed the power strips on each rack into which all the frames and power supplies were plugged. The power strip on the dev server was 12-gauge (i.e. could handle 20 amps) but the one on the QA rack was only 14-gauge (15 amps). The power draw caused by spinning up the drives was just enough to leave the system board under-powered for bootup.
We swapped in a new $10 power strip and it worked perfectly. And we made the deadline, too! So, fellow Soylents, what have you got? Share your favorite tale of woe and success and finally bask in the glory you deserve."
My various favorites (if you want to call them that considering how much hair was extracted from my scalp during the debugging process) are as follows:
-- A bug in some Unix implementation with what happened to output I/O buffers when some SIGPIPE is processed. The fix was to force the signal handler to flush it.-- A compiler bug in the IBM C compiler for AIX that generated incorrect code for a certain math expression. The fix was to break it up into several pieces creating intermediate results.-- A bug in the Java 1.2 String implementation that caused major headaches. The substring() methods apparently shifted indexes around internally and returned the same instance but toString() didn't take that into account.
The bug I enjoyed exploiting the most when I was a lowly student was on the university mainframe. If you wanted more memory than your account was allowed to consume, you simply forced your program to trigger an out-of-memory exception. The OS would then allocate more in order to handle the exception. Repeat as necessary. Eventually, you had enough and the error handler ran your business logic.