Consider a system that uses Round-Robin scheduling and with a scheduling overhea

Question

Consider a system that uses Round-Robin scheduling and with a scheduling overhead of duration o=0.1ms. We represent the execution timeline of a job mix on this system by indicating 1ms of computation for a process via an uppercase letter. For example, the following string: AAAoBoCoAAoDDD means that process A executes for 3ms, then process B for 1ms, then process C for 1ms, then process A again for 2ms, then process D for 3ms, with appropriate context-switches. This example execution lasts 10ms + 4*0.1ms = 10.4ms (10ms of actual process execution, .4ms of context-switch overhead).

Question #1: Consider the following execution: AAAAAoBBoCoDDDDDoAAAAAoCoDDDDDoAAAoCoDDDDDoAAAAAoBBB Knowing the there is at least one CPU-intensive job in this mix, what is the tightest lower bound on the time quantum used by the scheduler? Why? Which process seems to have the longest I/O burst? Why? Which process would you say is interactive (e.g., a text editor in which a user is typing text)? Why? What fraction of the time is spent doing context-switch overhead in this execution?

Explanation / Answer

In Case of given String There are Total 12 Jobs of string mix

Process A excutes in 5ms, B in 2ms, C in 1ms, D in 5ms, Again A in 5ms, C in 1ms, D in 5ms, A in 3ms,C in 1 ms, D in 5ms, A in 5ms, B in 3 ms with appropriate context switching, So Job lasts 41ms+11 *0.1ms = 42.1ms (41ms actual ececution and 1,1 context switching overhead.)

1. There is a tightest lower bound on the time quantum is 3 becuase there is minumum number of time needed for the least job is Job C appears indiviually 3 times.

2. Process A seems to be logest I/O Burst due to there are 3 swicthing and and total 18 times A occure in the execution of the process.

3. We can say that C is a process that is interactive due to it seems to be appears one time each in whole string where as other appears more than onece .

4. Total time of the jobs is 41ms and context switching is 1.1 ms so total fraction time is 0.03.

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