4.1.1. Multi-user and multi-tasking
Now that we are more used to our environment and we are able to
communicate a little bit with our system, it is time to study the
processes we can start in more detail. Not every command starts a
single process. Some commands initiate a series of processes, such
as mozilla; others, like ls, are executed as a single command.
Furthermore, Linux is based on UNIX, where it has been common
policy to have multiple users running multiple commands, at the
same time and on the same system. It is obvious that measures have
to be taken to have the CPU manage all these processes, and that
functionality has to be provided so users can switch between
processes. In some cases, processes will have to continue to run
even when the user who started them logs out. And users need a
means to reactivate interrupted processes.
We will explain the structure of Linux processes in the next
sections.
