ITSA2003
Network Operating System and Configuration
Assignment
March 2020
Question 1: Banker Algorithm
A Banker algorithm is deadlock avoidance algorithm used for resource allocation. In the following example, there are five processes, P1, P2, P3, P4, P5 and three resource types A (with 10 instances), B (with 5 instances) and C (with 7 instances). The Available, Allocation and MAX matrices are given as:
Available
A B C
3 3 2
Allocation
A B C
P0 0 1 0
P1 2 0 0
P2 3 0 2
P3 2 1 1
P4 0 0 2
MAX
A B C
7 5 3
3 2 2
9 0 2
2 2 2
4 3 3
a. Compute the Need matric
b. After calculating the Need matric, show that the current state is safe by showing a safe sequence of processes.
Question 2: Page Replacement Algorithms
a. Page replacement algorithm decide which memory pages to page out when a page of memory needs to be allocated. And it happens when a page fault occurs, and a free page cannot be used to satisfy the allocation. Based on this statement, explain the different page replacement algorithms and how are they different from each other. What are the advantages and disadvantages of using those algorithms?
b. Given a page reference string: 1 2 3 4 2 1 5 6 2 1 2 3 7 6 3 2 1 2 3 6. If we consider the frame size is 4. What is number of page faults in optimal page replacement algorithm?
Question 3: Process Scheduling Algorithms
a. Explain different types of process scheduling algorithms. If you have a very long process and short processes keep coming up then names any of these algorithms which leads to starvation.
b. Using the Highest Response Ratio Next (HRRN) algorithm, you are required to perform the following tasks:
i. Develop Gantt Chart showing execution of the processes given in the following table.
ii. Calculate Average Waiting Time for the following processes.
Thread Arrival Time CPU Burst Time
A 0 3
B 2 6
C 2 5
D 5 1
E 3 5
Note: In this algorithm, we need to find the response ratio of all available threads/processes and select the one with the highest Response Ratio.
Response Ratio = (W + S)/S
Question 4: Operating System Configuration and Standards
a. What is the REACT methodology. Explain the different steps of REACT methodology.
b. 802.11 refers to a family of specifications developed by the IEEE for wireless LAN (WLAN) technology. Explain in details different specifications in the 802.11 family in terms of transmission speed and frequency.