Algorithm Evaluation in Operating System:
There are a number of scheduling algorithms and strategies. The choice of
algorithms depends heavily on the most important criteria. Once an algorithm is
selected, it should evaluated. Here are some ways to evaluate an algorithm:
1. Deterministic Modeling:
Take a particular predetermined workload (set of processes) and define the
performance of the algorithm dependant on that workload. This form of evaluation
is simple 'and can be done quickly. However, it is not very general. We might
get ft completely different idea about the performance of an algorithm if we
chose a different set of processes.
2. Queuing Models:
We can examine the distribution of CPU burst and I/O wait times. We can apply a
formula and compute one of three things.
- Average length of the queue
- Average waiting time of the queue
- Average arrival rate
This approach does have some limitations. For example, the results may not be
very exact as they rely on an approximation of the actual system.
A lot of processes are required to simulate an operating system. The processes
should mimic those of typical users and the operating system itself that can be
difficult. The simulation may take a long time to complete. For more accurate
results, it may be necessary to use process information from a real system.
The only real way to test an operating system is to write the code and run it.
However, this approach is very expensive.