Real-Time Uniprocessor Scheduling Taxonomy
     ==========================================

            /                           \
           /                             \
          /                               \

      Static scheduling            Dynamic Scheduling
   (off-line or clock driven)   (on-line or priority driven)
              

                                /                \
                               /                  \
                              /                    \
         
                   Static Task Priority      Dynamic Task Priority
                    (Rate Monotonic)

                                              /          \
                                             /            \
                                            /              \

                                   Static Job Priority  Dynamic Job Priority   
                             (Earliest Deadline First)  (Least Laxity First)
                                     
                   
CSCI 461 Lab 5
==============

Change TOSF's scheduling algorithm for EDF to Least Laxity First (LLF).

LLF Scheduling
--------------

Note, T below is to be read as Tau (task rather than period).

Laxity is the difference between the deadline and the remaining
computation time.

LLF assigns the highest priority to the to the task with the least laxity.

Example
-------
T1 = (5, 8) T2 = (2, 7). Let L1 be T1's laxity and L2 be T2's laxity.


   |    T1     |T2 |T1 |T2 |T1 |T2 |T1 |
   --------------------------------------
 t=0   1   2   3   4   5   6   7   8   9 

L1=3   3   3   3   2   2   1 
L2=5   4   3   2   2   1   1   

-------------------------------------------------------------------------

t=0
L1 = 8 - (0 + 5) = 3 dispatch T1
L2 = 7 - (0 + 2) = 5

t=1
L1 = 8 - (1 + 4) = 3 dispatch T1
L2 = 7 - (1 + 2) = 4

t=2
L1 = 8 - (2 + 3) = 3 dispatch T1
L2 = 7 - (2 + 2) = 3

t=3
L1 = 8 - (3 + 2) = 3 
L2 = 7 - (3 + 2) = 2 dispatch T2

t=4
L1 = 8 - (4 + 2) = 2 dispatch T1
L2 = 7 - (4 + 1) = 2

t=5
L1 = 8 - (5 + 1) = 2 
L2 = 7 - (5 + 1) = 1 dispatch T2 and suspend

t=6
L1 = 8 - (6 + 1) = 1 dispatch T1 and suspend

t=7
L2 = 7 - (0 + 2) = 5 dispatch T2

t=8
L1 = 8 - (0 + 5) = 3 dispatch T1
L2 = 7 - (1 + 1) = 5

Deliverables
------------

Demonstration of TOSF with LLF.
A printout of the SCHEDULER.pm and DISPATCHER.pm. 

You must be able to demonstrate the
effect of LLF using the above example (ie, add 
the example to traceApp).