Erik,

The cornerstone of a real time system is the determinism - not the actual time involved. So what do you mean when you talk about a URTOS? And who has misused the term RTOS to describe a product that is not deterministic? This subject has been brought up a few times and you seem to repeat the same banter without actual qualification.

Linux and Windows are not real time systems - I think we all know this. The basic reason is that they can get hung up on doing something to the detriment of something else.

There is a real time addition to linux that linux itself is subservient to, that does in fact, deliver on the real time promise.

Later Windows CE are real time systems.

If I am to assume your term URTOS means 'un real time operating system' then using that term simply confuses the issue - can we not simply say there operating systems (OS) and some that can claim to be realtime (RTOS). You are the only person that I know of that uses the term 'URTOS' and I have not come across it in any of the texts I have read. Please correct me if this is not so.

In previous subjects we have been through the different sorts of task switchers and that being pre-emptive does not make the os realtime. You also maintain that a co-operative tasker doesn't have more than one task - actually it can and does have more than one task - it only has one thread of execution. A task is merely a concept, a thread of execution is concrete. Whilst this can be considered to be symantic, these are accepted terminologies.

So what is the point you're trying to make? You've got Ian and myself somewhat perplexed.