Well, when a computer registers a key press it usually turns that in to an action. The action is usually visible to some extent.
According to a dictionary ( oxforddictionaries.com/us/definition/american_english/register ), the verb "register" could mean "detect and show". So, this:
"The radar registered an aircraft."
is good English, because a radar can certainly "detect and show" an aircraft. But in some computer science literature, phrases like this are found:
"The computer didn't register the key press."
Certainly, a computer can "detect" a key press. But a computer doesn't really show a key press. It might process a key press though. So, could it be that "register", in computer science context, is hijacked to mean "detect and process"?
Clone of banned user.