Princess Nora Bint Abdulrahman University NET201- Principles of Information & Technology Systems Faculty of Computer and Information Sciences Second Semester 1437/1438 HInformation TechnologyHomework 1 – Operating Systems

Due date Sunday 26 March

Solve the followings:

1- Suppose that a computer has a monoprogramming operating system. If the size of memory is 13 GB and the memory reserved part for the operating system is 3 GB, what is the maximum size of program that can be run by this computer?

2- Monoprogramming operating system runs programs that on average need 5 microseconds access to the CPU and 30 microseconds access to the I/O devices. What percentage of time is the CPU idle?

3- A multiprogramming operating system divides a 128 KB of memory into 5 partitions as follows: the first partition is 30 KB, the second is 40 KB, the third is 28 KB, the fourth is 11 KB and the fifth is also 11 KB.The first program needs 22 KB to be run, the second needs 20 KB, the third needs 8 KB, the fourth needs 10 KB and the fifth needs 36 KB.

a) What is the partition and memory used by each program (Fill in the table)?.

b) What is the total memory used?

Partition 1 2 3 4 5Program

Princess Nora Bint Abdulrahman University NET201- Principles of Information & Technology Systems Faculty of Computer and Information Sciences Second Semester 1437/1438 HInformation TechnologyHomework 1 – Operating Systems

c) What is the total memory wasted?

d) What percentage of memory is wasted?

4- A multiprogramming operating system uses paging,. The available memory is 30 MB divided into 10 frames, each of 3 MB. The first program needs 11 MB, the second program needs 12 MB, the third program needs 6 MB.

a) How many frames are used by the first / second / third program?

b) How many frames are un-used

c) What is the total memory un-used ?