Word 97's ghost in the machine: The crash that vanished the moment anyone looked at it
Microsoft veteran recalls how a CPU errata, a mythical ICE, and a single sneaky NOP saved Clippy's big debut
Veteran Microsoft engineer Raymond Chen recounted a haunting tale from the Word 97 release cycle: a bug that eluded detection. The issue surfaced in the test labs but vanished as soon as engineers attempted to use a debugger. The team was frantic, for a glitch that appears sporadically in the lab could wreak havoc in the real world.
Chen confessed, "The development team was very anxious, because a bug that appears only sporadically in the lab is going to occur regularly in the wild. But how do you debug a problem that resists debugging?" The bug's refusal to cooperate fueled discussions about an ICE, a device that could mimic the CPU and enable breakpoints.
To most developers, ICEs were mythical, so the prospect of acquiring one sparked excitement. After pinpointing the fault to a specific manufacturer and a CPU erratum, the developers discovered a solution: inserting a "nop" into the offending code sequence. This binary patch averted potential chaos, ensuring Word 97 remained stable.
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