  This paper presents new fast exact feasibility tests for uniprocessor
real-time systems using preemptive EDF scheduling. Task sets which are accepted
by previously described sufficient tests will be evaluated in nearly the same
time as with the old tests by the new algorithms. Many task sets are not
accepted by the earlier tests despite them beeing feasible. These task sets
will be evaluated by the new algorithms a lot faster than with known exact
feasibility tests. Therefore it is possible to use them for many applications
for which only sufficient test are suitable. Additionally this paper shows that
the best previous known sufficient test, the best known feasibility bound and
the best known approximation algorithm can be derived from these new tests. In
result this leads to an integrated schedulability theory for EDF.
