  We consider the black hole information problem in an explicitly defined
spacetime modelling black hole evaporation. Using this context we review basic
aspects of the problem, with a particular effort to be unambiguous about subtle
topics, for instance precisely what is meant by entropy in various
circumstances. We then focus on questions of unitarity, and argue that commonly
invoked semiclassical statements of long term, evaporation time, and Page time
"unitarity" may all be violated even if physics is fundamentally unitary. This
suggests that there is no horizon firewall. We discuss how the picture is
modified for regular (nonsingular) evaporation models. We also compare our
conclusions to recent holographic studies, and argue that they are mutually
compatible.
