Q. 56 Consider a uniprocessor system executing three tasks T1, T2 and T3, each of which is composed of an infinite sequence of jobs (or instance) which arrive periodically
at intervals of 3, 7 and 20 milliseconds, respectively. The priority of each task
is the inverse of its period and the available tasks are scheduled in order of
priority, with the highest priority task scheduled first. Each instance of T1, T2
and T3 requires an execution time of 1, 2 and 4 milliseconds, respectively. Given
that all tasks initially arrive at the beginning of the 1st milliseconds and task
preemptions are allowed, the first instance of T3 completes its execution at the
ends of _______milliseconds.
(A) 5
(B) 10
(C) 12
(D) 15
Answer: (C)
Explanation:
