Larry Osterman: my favorite bug is the one we found on ICL PWS-400. It was a new platform from ICL (a British company, bought by Fujitsu in 2002 ), and our task was to port MS-DOS 4.1 to this platform. The project involved five - two from Microsoft and three from ICL. The PWS-400 hardware was quite unusual: for example, real-mode programs could switch memory banks page by page — due to this, applications could run in the background without interfering with one another.
We were five developers, we did not have testers; so we tested the new system with everything that comes handy. My favorite “testing tool” was a game that Valori ( wife ) brought with her to study. I don't remember exactly what the game was like; but every time I played it and reached a certain place, the car suddenly rebooted.
We hooked up to the ICE machine (in-circuit emulator — a device that lets us know what's going on inside and outside the processor), and found that the processor receives a reset signal from the outside. So at least the bug was not in the code. ')
The guys who collected the car, took the game from me, and began to understand.
A couple of days later they returned the game and told that they had found a malfunction. It turned out that the track to the dynamics passed on the motherboard too close to the restart track. When a signal of a certain type was applied to the speaker, electromagnetic radiation from the first track induced a sufficiently high voltage on the second track to be recognized by the processor as a signal to restart.
Matt Williams: I remember a couple of bugs that drove me crazy.
The first story happened in New York City. A mouse was connected to one of the computers, which randomly jumped when it only spent on a certain part of the desktop. But it did not always work. After some time, we discovered a pattern: the mouse went crazy only at a certain time of the day. And the place on the table in which she was going crazy also moved with time. We spent a lot of time before we found the cause of what is happening. But first I’ll tell you about the second bug: they are related to one another, although they have been separated for about 5 years.
By the time I moved to California and purchased a used car. Before you give it to me, the previous owners told about the strange features of the radio: spontaneously insert the disc for no reason at all. They contacted the workshop several times about this, but they could not find a fault, and the mechanics simply replaced the radio tape recorder with a new, same model. This did not help: the fault remained. Having traveled on this car for several months, I discovered a pattern: the tape recorder spat out a disc only when I was driving in a certain direction ... and, moreover, only at a certain time of the day.
So what was the matter? Both times the sun was to blame. The mouse had a small gap between the buttons, and when the sun shone at it at a certain angle, the light penetrated inside the photo pairs and caused a reaction, as if from a ball rotating in all directions. In the same way, when the sun fell through a skylight into the charging slot of the radio, the sensor of the inserted disc worked, and the radio was spat out.