Over the years, I have heard the "real time OS" phrase many times. In the last week, there was an article describing how some companies are trying to build real-time capabilities into a Linux distribution. Googling it says that a "real time OS" is an environment that allows execution of specified tasks within a given time constraint.

Here's what I am thinking:
1. A real time OS attempts to get all tasks with time constraints done in the specified time.
2. If there are too many tasks, then some with time constraints cannot be finished in time due to the load of other tasks that have similar needs.
3. If such a case exists, then there would need to be a priority system designed to tell the OS which task to run first.

In my opinion, this describes any OS out there:
1. The OS (lets say Windows 2000 for example) tries to execute all tasks (processes) as quickly as possible.
2. If there are many tasks, the OS switches between them, sometimes delaying the execution of other tasks.
3. To determine how much processing power to use, it uses a priority system to determine which gets the bigger slice of the pie.

So how is a real-time OS different from any other OS?