I was being facetious Before another "task" ("thread", "process", whatever it's called) can be run, the OS has to save the state of the current task (mostly CPU registers) to RAM so it can restore the state of the other task; therefore, multitasking is a form of state-saving (it's just done automatically by the OS many many times a second). You are right, though, in pointing out that some OSes essentially freeze the "backgrounded" tasks and won't give them slices of CPU time until the user "foregrounds" them, thereby effectively making those OSes single-tasking systems.

Be careful with the term "real-time" though; it has very specific meanings in OS land, and the truth is that hardly anything runs in real-time and doesn't really need to. Hardware is so high powered these days, and typical user requirements (even developers and power users) don't necessarily require it.