Chapter 8, Problem 8.9HW

Program Plan Intro

Given:

Process	Start time	End Time
A	5	7
B	2	4
C	3	6
D	1	8

Explanation of Solution

Determine whether the pair of processes run concurrently or not:

Diagram for processes AB:

Explanation:

• In the above timing diagram, process “A” starts with “5” and end with “7”.
• Process “B” starts with “2” and end with “4”.
• Process “A” and “B” are not concurrent with respect to each other because their corresponding executions do not overlap, that is, process “A” completes before process “B” starts.

Therefore, the processes “AB” are do not run concurrently.

Diagram for processes AC:

Explanation:

• In the above timing diagram, process “A” starts with “5” and end with “7”.
• Process “C” starts with “3” and end with “6”.
• Process “A” and “C” are concurrent with respect to each other because their corresponding executions overlap, that is, process “C” starts before the process “A” completes.

Therefore, the processes “AC” are run concurrently.

Diagram for processes AD:

Explanation:

• In the above timing diagram, process “A” starts with “5” and end with “7”.
• Process “D” starts with “1” and end with “8”.
• Process “A” and “D” are concurrent with respect to each other because their corresponding executions overlap, that is, process “D” starts before the process “A” completes.

Therefore, the processes “AD” are run concurrently.

Diagram for processes BC:

Explanation:

• In the above timing diagram, process “B” starts with “2” and end with “4”.
• Process “C” starts with “3” and end with “6”.
• Process “B” and “C” are concurrent with respect to each other because their corresponding executions overlap, that is, process “C” starts before the process “B” completes.

Therefore, the processes “BC” are run concurrently.

Diagram for processes BD:

Explanation:

• In the above timing diagram, process “B” starts with “2” and end with “4”.
• Process “D” starts with “1” and end with “8”.
• Process “B” and “D” are concurrent with respect to each other because their corresponding executions overlap, that is, process “D” starts before the process “B” completes.

Therefore, the processes “BD” are run concurrently.

Diagram for processes CD:

Explanation:

• In the above timing diagram, process “C” starts with “3” and end with “6”.
• Process “D” starts with “1” and end with “8”.
• Process “C” and “D” are concurrent with respect to each other because their corresponding executions overlap, that is, process “D” starts before the process “C” completes.

Therefore, the processes “CD” are run concurrently.

Completed table:

Process pair	Concurrent?
AB	No
AC	Yes
AD	Yes
BC	Yes
BD	Yes
CD	Yes