Suppose in a multiprogramming environment, the following C program segment is executed. A process go

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Question

Suppose in a multiprogramming environment, the following C program segment is executed. A process goes into I/O queue whenever an I/O related operation is performed. Assume that there will always be a context switch whenever a process requests for an I/O, and also whenever the process returns from an I/O. The number of times the process will enter the ready queue during its lifetime (not counting the time the process enters the ready queue when it is run initially) is ______.int main() {
    int x=0, i=0;
    scanf("%d", &x);
    for(i=0; i

Accepted Answer

Answer: 21Concept — Process State Transitions in Multiprogramming: In a multiprogramming OS, when a process performs an I/O operation, it transitions: Running → Blocked (enters I/O queue). When I/O completes, it transitions: Blocked → Ready (enters ready queue). This happens for every I/O call.Identifying I/O operations in the program:scanf("%d", &x) — 1 I/O operation (standard input). This causes the process to block and then return to the ready queue once.printf("%d
", x) inside a loop that runs i = 0, 1, ..., 19 → 20 iterations → 20 I/O operations (standard output). Each printf causes one block→ready transition.Counting ready queue entries (excluding the initial):1 entry after scanf completes (I/O returns).20 entries after each of the 20 printf calls completes.Total = 1 + 20 = 21 times.Note: The problem says "not counting the time the process enters the ready queue when it is run initially" — so we only count the re-entries after I/O completions. Each I/O call results in exactly one such re-entry.

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