Describe the two main kinds of Real Time Tasks: Periodic and Aperiodic Tasks.

With the help of block diagram, explain the working of a typical embedded$/$concurrent system for controlling a plant using microcontroller. The components of the system are:

a$)$ Microcontroller,

b$)$ Sensors

c$)$ Actuators

d$)$ Data$/$Control bus

Suppose that we want to generate the following periodic square signal on pin P$2\mathrm{.}5$ of the microcontroller $8051.$ Time scale is given in millisecond.

a$)$ Find the values of TLx and THx for both ON and OFF signals.

b$)$ Write the corresponding assembly language program. Use Timer $1$ in mode $1$ to generate the considered signal.

Repeat Question $3$ using timer $1$ in mode $2.$

Define the following:

Earliest Deadline First $($EDF$)$ Scheduling algorithm.

Rate Monotonic Scheduling $($RMS$)$ algorithm

Following data are related to a scenario of a real time system task scheduling.

$\backslash$table$[[$task ${}_i,C_i($Execution time$),P_i($Period of task$)],[{}_1,30,100],[{}_2,15,50],[{}_3,60,150],[{}_4,20,80],[{}_5,55,160]]$

a$)$ Apply the Utilization Bound $($UB$)$ test to this set of tasks. Conclude about their schedulability $($Use the values $U(1)=1,U(2)=0\mathrm{.}828,U(3)=0\mathrm{.}779,U(4)=0\mathrm{.}756$ and $U(5)=0\mathrm{.}743).$

b$)$ Explain Response Time $($TR$)$ test, definition and equations for task ${}_i($Assume we have $n$ tasks$).$

c$)$ Using RT test check whether tasks ${}_4$ and ${}_5$ are schedulable. Write down all the steps and the equations used.

d$)$ Draw the timeline in the time interval $(0,600).$ Write your answers on the separate answer sheet.

$7.$ Define the reliability of a system. What property of a system the reliability characterizes? In which situations is high reliability required?

$8.$ What is the difference between the reliability and the availability of a system?

$9.$ Explain main differences between software and hardware faults.

$10.$ Define the failure rate.

$11.$ What is the difference between the mean time to repair and the mean time between failures?

$12.$ A heart pace$-$maker has a constant failure rate of $=\frac{8\mathrm{.}167}{{10}^9}hr.$

a$)$ What is the probability that it will fail during the first year of operation?

b$)$ What is the probability that it will fail within $5$ years of operation?

c$)$ What is the MTTF$?$

$13.$ An automatic teller machine manufacturer determines that his product has a constant failure rate of $=77\mathrm{.}16$ per ${10}^6$ hours in normal use. For how long should the warranty be set if no more than $5\%$ of the machines are to be returned to the manufacturer for repair?

$14.$ A car manufacturer estimates that the reliability of his product is $99\%$ during the first $7$ years.

a$)$ How many cars will need a repair during the first year?

b$)$ What is the MTTF$?$

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