Darius Bacon and I have spent some time trying to figure out a buffer data structure that can scale to large files while guaranteeing predictable latency for basic operations like typing a character. (What's "making find call"?)
I think you mean "soft real time", though. A hard real-time system is one which is unusable if it fails to meet a deadline even once; a jet engine control system, say, where failing to meet a deadline could result in engine parts penetrating the fuselage. A "soft real time" system is one where failing to meet a deadline is a failure, but tolerable if infrequent; say, once every million keystrokes, or every 7 days of video play time.
I think you mean "soft real time", though. A hard real-time system is one which is unusable if it fails to meet a deadline even once; a jet engine control system, say, where failing to meet a deadline could result in engine parts penetrating the fuselage. A "soft real time" system is one where failing to meet a deadline is a failure, but tolerable if infrequent; say, once every million keystrokes, or every 7 days of video play time.