Anyone who works with computers learns to fear their capacity to forget. Like so many things with computers, memory is strictly binary. There is either perfect recall or total oblivion, with nothing in between. It doesn't matter how important or trivial the information is. The computer can forget anything in an instant. If it remembers, it remembers for keeps.
This doesn't map well onto human experience of memory, which is fuzzy. We don't remember anything with perfect fidelity, but we're also not at risk of waking up having forgotten our own name. Memories tend to fade with time, and we remember only the more salient events.