I remember a raidcontroller in my office beaping for 2 or 3 weeks because one harddisc was defective and replacement unavailable. If I would have had a bazooka, it would have exploded.

Real, video memory was (and still is without OS) writeable just like any memory. When an application went berserk writing into memory, you got garbadge on your screen. today the application simply segfaults in the same condition.