What is an operating system

What is an operating system? Explain how throughput, turnaround time and response time are used to measure the overall performance of a computer system?

Answer:

Operating system is an integrated set of programs that
a. Controls the resources of a computer system.
b. Provides its user an interface that is easier to use as compared to a bare machine.
There are several possible purposes of an operating system: To provide an environment for
a computer user to execute programs on computer hardware in a convenient and efficient
manner. To allocate the separate resources of the computer as needed to solve the problem
given. The allocation process should be as fair and efficient as possible.
Throughput means number of processes completed / time unit.
Turnaround Time is the average time elapsed from when process is submitted to when it
has completed.
Response Time - Average time elapsed from when process is submitted until useful output
is obtained.

Typically, Utilization and Throughput are traded off for better Response Time. Response
time is important for OS's that aim to be user-friendly. In general, we would like to
optimize the average measure. In some cases, minimum and maximum values are
optimized, e.g. it might be a good idea to minimize the maximum response time.