A Scheduling Problem: Comparing Earliest Deadline First $($EDF$)$ and

Deadline Monotonic $($DM$)$ Algorithms

In a real$-$time system, ensuring that tasks are scheduled and executed

efficiently to meet their deadlines is crucial. Two prominent scheduling

algorithms used in real$-$time systems are Earliest Deadline First $($EDF$)$ and

Deadline Monotonic $($DM$).$ Both algorithms have their unique approaches to

scheduling, leading to differences in how tasks are prioritized and managed.

Given Scenario:

Consider a system that needs to handle four tasks, T$1$ through T$4,$ with the

following characteristics:

T$1$: Execution time $=1$ unit, Period $=4$ units, Deadline $=4$ units

T$2$: Execution time $=2$ units, Period $=5$ units, Deadline $=5$ units

T$3$: Execution time $=1$ unit, Period $=8$ units, Deadline $=8$ units

T$4$: Execution time $=2$ units, Period $=10$ units, Deadline $=10$ units

Assume the system starts at time $0.$

Tasks:

Scheduling with EDF:

Determine the scheduling order of the tasks over the first $20$ units of time

using the Earliest Deadline First $($EDF$)$ algorithm. Assume tasks are

preemptive.

Calculate the total number of context switches that occur.

Identify any instances where tasks miss their deadlines, if any.

Scheduling with DM:

Determine the scheduling order of the tasks over the first $20$ units of time

using the Deadline Monotonic $($DM$)$ algorithm. Unlike EDF, DM assigns

priorities based on the deadlines; the shorter the deadline, the higher the

priority.

Calculate the total number of context switches that occur.

Identify any instances where tasks miss their deadlines, if any.

Analysis and Comparison:

Compare the performance of EDF and DM in this scenario based on deadline

adherence, number of context switches, and CPU utilization.

Discuss the advantages and disadvantages of using EDF over DM in this

specific context and vice versa.

This problem requires you to apply both the EDF and DM algorithms to the

given tasks, evaluate their effectiveness in scheduling, and understand the

operational differences and outcomes that result from each method.