$($c$)1$able $1\mathrm{.}1,1\mathrm{.}2$ and $1\mathrm{.}3$ show exercpts of the Process Control Block for Process

B$,$ Process C$,$ and Process D$,$ respectively. Process ID $9000$ is a terminal.

Table $1\mathrm{.}1$

Table $1\mathrm{.}2$

Table $1\mathrm{.}3$

Illustrate the parent$-$child relationship among the shell terminal, Process B$,$

Process C$,$ and Process D using a simple diagram. Include details such as arrows,

process names and process IDs in your diagram.

$(8$ marks$)$

$\text{'}$d$)$ For each of the following, determine the type of real$-$time task $($hard or soft real$-$

time$)$ in the application or system and briefly justify your answer:

A biped robot $($i$.$e$.$ two$-$legged$)$ calculates data read from multiple

sensors and then determines its motors movement so that it will maintain

its balance during walking.

$(2$ marks$)$

$($ii$)$ The main task of thermal camera systems in airport is to detect travellers

with fever during the Covid$-19$ pandemic.

$(2$ marks$)$

$($b$)$ Assume that your main memory has a total of $6$ frames. Process A and Process

B are each initially allocated frames as shown in Figure $2,$ where frame #$4$ and

frame #$5$ represent empty blocks.

Figure $2$: Current state of memory frames

Assume the sequence of page requests arrival is A$2,$ B$4,$ A$1,$ B$0.$ Then, the

following page trace occurs $($process name and its respective page number$)$:

$A3,B2,B4,B6,B7,A3,B5,A1,A0,B4$

Variable Allocation and Global Replacement Scope are used. Show the steps

of each page replacement performed if:

$($i$)$ First$-$In$-$First$-$Out policy is used.

$(5$ marks$)$

$($ii$)$ Clock replacement policy is used. Indicate the use$-$bit in your answer.

Assume the use$-$bit in frames #$0$ and #$3$ in Figure $2$ are set to $1$ and

frames #$1,$#$2,$ #$4,$ and #$5$ are set to $0.$ The clock arrow is now pointing

at frame #$4.$

$(6$ marks$)$