In a hard real-time system, is it necessary that every task in the system be of
hard real-time type? Explain your answer using a suitable example.
In a real-time system what is the difference between a performance constraint
and a behavioral constraint?
What is an open system? What are its advantages compared to a closed
Explain a real-time communication protocol that can be used in a CAN.
What is a watchdog timer?
What do you mean by scheduling point of a task scheduling algorithm? How
are the scheduling points determined in clock-driven, event driven and hybrid
schedulers? How will your definition of scheduling points for the three classes
of schedulers change when (i) self-suspension of tasks and (ii) context
switching overheads of tasks are taken into account.
Briefly explain while scheduling a set of hard real-time periodic tasks, why
RMA cannot achieve 100% processor utilization without missing task
Consider a real-time system which consists of three tasks T1, T2 and T3 which
have been characterized in the following table.
If the tasks are to be scheduled using a table-driven scheduler, what is the
length of time for which the schedulers have to be stored in the precomputed
schedule table of the scheduler.
Explain the operation of priority ceiling protocol (PCP) in sharing critical
resources among real-time tasks. Explain how PCP is able to avoid deadlock
and chain blockings.
A set of hard real-time periodic tasks need to be scheduled on a uniprocessor
using RMA. The following table contains the details of these periodic tasks
and their use of three non-preemptable shared resources. Can the tasks T2
and T3 meet their respective deadlines when priority ceiling protocol is used
for resource scheduling?
pi indicates the period of task T i and ei indicates its computation time. The
period of each task is the same as its deadline. The entries in the R1, R2 and
R3 columns indicate the time duration for which a task needs the named
resource in non-preemptive mode. Assume that after a task releases a
resource, it does not acquire the same or any other resource.
Explain some of the features that you would require a real-time operating
system to support.