Many programs are required to run in a single kernel processor
in many real life applications. For example, while a
text editor is used by a PC user to edit a file, several PC’s
system routines are also busy in doing its works, such as an
anti-virus routine is checking if there is a virus or not, and
so on. Traditional processors use the time-sharing technique
and the interrupt technique to run more than one program in
one processor ”concurrently”. However, it is only ”one program”
in the view of the processors. In fact, these programs
are not executed in a real parallel way.