Character Analysis
This computer program (or daemon) has been created to resemble and act like a person in order to facilitate research. It "looks like a pleasant, fifty-ish, silver-haired, bearded man with bright blue eyes, wearing a V-neck sweater over a work shirt, with a coarsely-woven, tweedy-looking wool tie. The tie is loosened, the sleeves pushed up" (13.36). In other words, your typical nerdy librarian/professor type.
Funny thing is, the Librarian is pretty self-aware for a computer program. Part of this is because it was written with "the innate ability to learn from experience" (13.53). But also occasionally takes something seriously that Hiro had meant as a joke, leading Hiro to suspect "that the Librarian may be pulling his leg, playing him for a fool. But he knows that the Librarian, however convincingly rendered he may be, is just a piece of software and cannot actually do such things" (27.65). We hope so, anyway. The world of Snow Crash is crazy enough without throwing in sentient computer programs.