cameroon gce A level June 2015 computer science 2
IBM wants to build a computer chip that compares English Language words to see if they are the same.
To begin with, they would like to build a smaller one that bit-wise compares two characters. Each
character is coded in 8 bits. The principle they follow here is that in bit-wise comparisons, a 1 (one) is
generated if the two corresponding bits are the same otherwise a 0 (zero) is generated.
Give a truth table for the comparison of two bits.
A CPU-scheduling algorithm determines an order for the execution of its scheduled processes. Given n
processes to be scheduled on one processor, how many different schedules are possible? Give your
answer as a formula in terms of n.
(ii) Explain the main difference between preemptive and non-preemptive scheduling strategies. (4 marks)
(iii) Given that the following processes arrive for execution at the times indicated, each process
will run for the amount of time listed. In answering the questions, use non-preemptive
scheduling and base all decisions on the information you have at the time the decision is made.
