Skilled Bug Investigation Illustrated - Examine symptoms of the problem

In a presentation titled Skilled Testers and Their Enemies, James Bach identifies the steps involved in skilled bug investigation:

The following post is part of a 13-part series illustrating those points using A Study in Scarlet by Arthur Conan Doyle.

Examine symptoms of the problem w/o disturbing system state

Holmes examined the room at No. 3, Lauriston Gardens:

“As he spoke, he whipped a tape measure and a large round magnifying glass from his pocket. With these two implements he trotted noiselessly about the room, sometimes stopping, occasionally kneeling, and once lying flat upon his face. So engrossed was he with his occupation that he appeared to have forgotten our presence, for he chattered away to himself under his breath the whole time, keeping up a running fire of exclamations, groans, whistles, and little cries suggestive of encouragement and of hope. As I watched him I was irresistibly reminded of a pure-blooded, well-trained foxhound, as it dashes backward and forward through the covert, whining in its eagerness, until it comes across the lost scent. For twenty minutes or more he continued his researches, measuring with the most exact care the distance between marks which were entirely invisible to me, and occasionally applying his tape to the walls in an equally incomprehensible manner. In one place he gathered up very carefully a little pile of gray dust from the floor, and packed it away in an envelope. Finally he examined with his glass the word upon the wall, going over every letter of it with the most minute exactness. This done, he appeared to be satisfied, for he replaced his tape and his glass in his pocket.”

and the body:

“As he spoke, his nimble fingers were flying here, there, and everywhere, feeling, pressing, unbuttoning, examining, while his eyes wore the same far-away expression which I have already remarked upon. So swiftly was the examination made, that one would hardly have guessed the minuteness with which it was conducted. Finally, he sniffed the dead man’s lips, and then glanced at the soles of his patent leather boots."