Question D $(20$ points$)$ Course name

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$$Real time systems

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$$CPRE $558$

Consider the following combined scheduling of periodic and aperiodic

tasks. Assume the system has two periodic tasks $T_1$ and $T_2*T_i=(c_i,p_i)$ :

$T_1=(3,12)$;$T_2=(1,4).$ For scheduling aperiodic tasks, a server $T_s=(2,8)$

is created.

Assume that aperiodic tasks arrive at times $2,8,12,$ and $18$ and their

respective computation times are $2,2,3,$ and $3.$ Assume the deadline of

all the aperiodic tasks is $25.$

$(1)$ Construct RMS schedules up to time $24$ using the following server

approaches: $($i$)$ Polling server, $($ii$)$ Priority exchange server, and $($iii$)$

Deferrable server.

$(2)$ What is the average response time of aperiodic tasks for each of

these three server approaches? $($Response time $=$ finish time minus

arrival time$).$