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Time Table Consider an operating system utilizing a single CPU for executing two distinct processes: Process P1: Comprising a 30-ms CPU burst followed by a 200-ms I/O device request and followed by a 20-ms CPU burst. Process P2: Comprising a 60-ms CPU burst followed by a 70-ms 1/O device request and followed by a 10-ms CPU burst. Draw a comprehensive timing diagram illustrates how a time-sharing operating system will manage these processes, following the specified conditions: Each process requires different I/O device. When both P1 and P2 are ready, the scheduler prioritizes P1. The time quantum for each process is set at 50 ms

User Vingtoft
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Processes P1 and P2 are scheduled based on the 50-ms time quantum with priority given to P1. P1 starts first, followed by P2, with I/O and CPU operations interleaved for efficiency. Both processes are managed within the constraints, ensuring effective time-sharing.

Time-Sharing Operating System Scheduling

Considering the given conditions and scheduler priority, we can draw a timing diagram for processes P1 and P2 execution on a single CPU. Here's how a time-sharing system will manage the two processes:

Time Quantum: The time quantum is set at 50 ms for both processes.

Initial Execution: Since P1 has priority over P2, P1 starts first and uses a 30-ms CPU burst, completing its CPU burst within the first quantum.

P1 then issues a 200-ms I/O device request and while P1 is in I/O, P2 starts its 60-ms CPU burst. P2 runs for 50 ms and is then paused because it exceeds the time quantum.

P2 resumes and completes its remaining 10 ms of the CPU burst and immediately after, it issues a 70-ms I/O request.

While P2 is in I/O, P1 has completed its I/O and resumes with a 20-ms CPU burst, finishing its execution.

Finally, P2 completes its I/O and resumes the last 10-ms CPU burst, concluding its processing.

The above steps illustrate how the CPU and I/O operations are interleaved for efficient process management by a time-sharing system.

The probable question may be:

Describe the initial execution sequence for processes P1 and P2 in the given scenario. Why does P1 start first?

User Tawfik Bouabid
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