You are required to submit a document that satisfies the requirements below.
Number your answers carefully, using precisely the numbering scheme used
in the specification of requirements below. Failure to number your answers
correctly may lead to loss of marks.
1. Process management
A typical behaviour of a user of the Unix operating system is to enter
a command such as ps -eF | grep named into a terminal emulator.
This command is interpreted by the shell to create two processes that
communicate via a pipe to execute the required programs.
(a) Explain briefly what is meant by the following: terminal emulator,
shell, program, process, pipe.
(5 marks)
(b) Describe the mechanisms of process creation and program execution
that might be used in the execution of the command
ps -eF | grep named. Draw a diagram to illustrate the relationship
between the processes that are created.
(5 marks)
(c) Explain how a pipe can be created and used to allow communication
between the processes. Explain clearly which processes can
read and write to/from the pipe. Draw a diagram to illustrate
your answer.
(5 marks)
(d) Describe briefly what happens to each process after it has completed
its execution. How does a parent process discover the termination
status of its children? Consider both successful and unsuccessful
termination.
(5 marks)
2. Memory management
It is important to illustrate your answers to this question with diagrams,
when appropriate.
(a) Describe the typical memory model of a user process (task), running
under the control of an operating system.
(5 marks)
4
(b) Discuss the importance of memory protection in ensuring the reliability
of a multi-tasking system. Describe a simple hardware
mechanism that supports the implementation of memory protection.
(5 marks)
(c) What is address binding and when can it be done? Make sure
that your answer clearly distinguishes between symbolic, relocatable
and absolute addresses.
(5 marks)
(d) Explain the distinction between logical and physical addresses in
the context of OS memory management. Describe a simple hardware
mechanism that supports the mapping of logical to physical
addresses.
(5 marks