10 Questions
Draw Gantt chart and calculate the average waiting time if the ______ scheduling algorithm is followed.
FCFS
Soha A. asked to calculate the average waiting time if the ______ scheduling algorithm is followed.
FCFS
The average waiting time can be calculated when the ______ scheduling algorithm is followed.
FCFS
In CPU scheduling, one can calculate the average waiting time of the ______ algorithm.
FCFS
If you draw a Gantt chart, you can calculate the average waiting time for the ______ scheduling algorithm.
FCFS
______ Lecture 04: CPU Scheduling CS 206: Operating Systems
Mohamed
Average Waiting Time = (2 + 0 + 1) / 3 = 3 / 3 = ___ unit
1
Processes ID Arrival Time (AT) Burst Time (BT) P1 1 50 P2 P3 0 0 1 2 CT P2 Waiting Time WT = TAT - BT 52 2 1 3 0 1 53 1 2 1 0 Turn Around Time TAT = CT - AT ___ P3 53 P1
3
Small processes such as P1 – P2 didn’t wait for large BT of ___
P1
Consider the set of 3 processes whose arrival time and burst time are given below: Process ID Arrival Time (AT) Burst Time (BT) P1 1 50 P2 P3 0 0 1 2 CT P2 Waiting Time WT = TAT - BT 52 2 1 3 0 1 53 1 2 1 0 Turn Around Time TAT = CT - AT 3 ___ 53 P1
P3
Study Notes
CPU Scheduling
- CPU scheduling algorithms:
- First Come First Served (FCFS)
- Shortest Job First (SJF)
- Shortest Remaining Time First (SRTF)
- Highest Response Ratio Next (HRRN)
- Round Robin (RR)
- Virtual Round Robin (VRR)
- Priority Scheduling (PR)
- Multilevel Queue
- Multilevel Feedback Queue (MLFQ)
Processes and Scheduling
- Processes in main memory, ready and waiting to execute, are listed in a queue
- Scheduling: allocating the CPU to a process in the ready queue
Example of CPU Scheduling
- Given 3 processes with arrival times and burst times:
- Process ID: P1, Arrival Time: 1, Burst Time: 50
- Process ID: P2, Arrival Time: 0, Burst Time: 2
- Process ID: P3, Arrival Time: 2, Burst Time: 1
- Calculating waiting time and turn-around time:
- Waiting Time (WT) = Turn-around Time (TAT) - Burst Time (BT)
- Turn-around Time (TAT) = Completion Time (CT) - Arrival Time (AT)
- Average Waiting Time = (Σ(WT)) / Number of Processes
Test your knowledge of CPU scheduling in Operating Systems with a focus on the First-In-First-Out (FIFO) algorithm. Learn about the basics of FIFO and its implications on system performance.
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