Cooperative multitasking OS-??

Dear experts,

Sorry if this sounds novice.I would like to really understand whats
meant by Cooperative multitasking OS?I read another thread in this
group which was explaining about the advantages and disadvantages it
has over a preemptive system.
From what I understood going through the discussion,Cooperative to me
looks like FIFO scheduling mechanism.
Can any of you throw some light on this or provide some links to
understand about this concept?I hit google and wikipedia but did not
get a satisfactory explaination.
Wikipedia IIRC says,Cooperative multitasking systems existed during
pre win9xOS days and non existant almost in current scenerio.Is this
true?

How different is this Cooperative system from roundrobin or FIFO?How
does the OS kernel decide which task/process to promote at any point
of time?

What sort of applications need cooperative functionality?

Looking farward for all your replies,

Advanced thanks to all,

Regards,
s.subbarayan
.