ASSIGNMENT : ITS 235- Windows Operating Environment

1) Under what circumstances do page faults occur? Describe the actions taken by the operating system when a page fault occurs.

2) Discuss the hardware support required to support demand paging.

3) Suppose that you want to use a paging algorithm that requires a reference bit (such as second-chance replacement or working-set model), but the hardware does not provide one. Sketch how you could simulate a reference bit even if one were not provided by the hardware, or explain why it is not possible to do so. If it is possible, calculate what the cost would be.

4) Consider a demand-paged computer system where the degree of multiprogramming is currently fixed at four. The system was recently measured to determine utilization of CPU and the paging disk. The resultsare one of the following alternatives. For each case, what is happening? Can the degree of multiprogramming be increased to increase the CPU utilization? Is the paging helping?
a. CPU utilization 13 percent; disk utilization 97 percent
b. CPU utilization 87 percent; disk utilization 3 percent
c. CPU utilization 13 percent; disk utilization 3 percent

5) Discuss the advantage and disadvantage of solid state drive.

SAMPLE SOLUTION

Question One
A page fault is an interrupt that takes place when a program in a personal computer makes a request on data that is not located in the actual memory. Consequently, this request triggers the operating system to obtain the required data from the virtual memory and load it into the random access memory. In support of this, a page fault is a process that takes place when the access to a given page has not been brought into the main memory at the time when the access takes place. As such, the program tries to access code or data that is located in the address space. When the page fault takes place, the operating system undertakes to verify the access of the memory by the program and subsequently terminates the program activities if it is established to be invalid. However, in case the program is found to be valid, the operating system reads a free frame that is located in the input-output request which is associated with the…