sched

sched - From RTS 93 Final Exam Problem 1: A real time...

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Unformatted text preview: From RTS 93 Final Exam Problem 1: A real time system generates ve events. Details of the respective interrupts and their handlers are described in the incomplete table below. Complete the table. 25 pts Interrupt Strong Weak Loading Loaded Maximum Name Priority Priority Frequency Duration Load Factor Duration Duration Latency A 3 3 100 kHz 1 s B C D E 3 3 2 1 2 1 1 1 50 kHz 30 kHz 100 Hz 0:5 Hz 3 s 5 s 11 s 10 ms From RTS 92 Midterm Exam Problem 2: A processor has an interrupt system that uses a combination of strong and weak priority. There are ve event types, A through E . Event type A uses strong priority level 3; within any 20 s interval event A will occur no less than 5 times and no more than 10 times. The handler duration is 1 s. Event B requests an interrupt of strong priority 2 and will occur at 100 kHz; the duration of its handler is 2 s. Events C; D; and E each request interrupts of strong priority 1. Event C has weak priority 3, occurs at 100 Hz, and its handler has a duration of 1 ms. Event D has weak priority 2, occurs at 20 Hz, and its handler has a duration of 3 ms. Event E has weak priority 1, occurs at 5 Hz, and its ISR has a duration of 2 ms. For each interrupt compute maximum latency, actual duration, and loading factor. 34pts Based on RTS 92 Final Exam Problem 3: A processor has an interrupt system that uses strong priority. There are three event types, A through C . Event A requests an interrupt of strong priority 3, occurs at 100 kHz, and its handler has duration 2 s. Event B requests an interrupt of strong priority 2, occurs at 700 Hz, and its handler has duration 90 s. Event C requests an interrupt of strong priority 1, occurs at 300 Hz, and its handler has duration 2 ms. For each event compute maximum latency, response time, and loading factor. 25pts 1 Based on a RTS 92 Homework Problem 4: A real time system uses ve events, names A to E . The computer uses both strong and weak priority. Event A occurs at a frequency of 15 Hz and its handler has a duration of 1 ms; interrupt B occurs at a frequency of 50 kHz and its handler has a duration of 3 s; interrupt C occurs at a frequency of 1 Hz and its handler has a duration of 100 ms; interrupt D will occur no less than 500 ms after itself, its handler has a duration of 20 ms; and interrupt E occurs at a frequency of 100 kHz and its handler has a duration of 3:5 s. The handlers for interrupts E and B cannot be interrupted; the maximum acceptable latency for interrupt C is 1:5 ms, the maximum acceptable latency for interrupt A is 50 ms. The acceptable latency for interrupt D is very large. Assign each interrupt a priority level so that the system functions properly and compute the latency, actual run time, and response times. From RTS 92 Midterm Exam Problem 5: full credit. Part 1: In class conventional operating system scheduling was discussed. Why was that scheduling not adequate for RTS? How could the scheduling be modi ed for RTS use? 11 pts Part 2: In a RTS what can be done in the event a task will not complete on schedule? 11pts Part 3: Is it good to thoroughly test a large system? A small system? Explain. 11 pts Answer all of the following. Please be brief; long but correct answers will not receive 2 ...
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This note was uploaded on 11/28/2011 for the course EE 4770 taught by Professor Staff during the Fall '99 term at LSU.

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