Problem
Four processes - A, B, C and D - are ready to execute, having arrived in that order. They require different numbers of quanta to complete and request different priorities (1 is lowest, 4 is highest):
• Process A requires 2 quanta, requested priority 1
• Process B requires 5 quanta, requested priority 3
• Process C requires 3 quanta, requested priority 2
• Process D requires 4 quanta, requested priority 4.
What is the pattern of execution under the following scheduling strategies:
• first in, first out
• round-robin
• priority.
Give your answer by showing which process executes at each quantum until all processes complete, for example: A C C B B.
What is the total number of quanta required in each case?