Note: Consultation times are available on the the course web page.
Units of Credit: 6
Note that COMP3231/9201/3891/9283 are taught in parallel. The
lectures are common for all courses. We cater for the differing needs
of postgraduate and undergraduate students by weighting assessment
components more flexibly in the case of postgraduate students. See the
section on assessment below for details.
For students doing Extended Operating Systems (COMP3891/9283),
your tutorial is an advanced tutorial where lecture topics are covered
in extended depth, and new topics are introduced and discussed.
Operating systems are an essential part of computer systems, a
course on operating systems is an essential part of any computer
science or computer engineering program. This course is oriented
towards exposing students to the essential concepts and issues that
underly operating systems and their design.
In general terms, the course aims to educate students in the basic
concepts and components of operating systems, the relevant
characteristics of hardware, and the tradeoffs between conflicting
objectives faced by the operating systems in efficiently supporting a
wide range of applications.
This course provides an understanding of the underlying operating
systems which students have implicitly relied upon in developing
applications in foundational courses within Computer Science and
Engineering, and will rely on in their future careers when developing
systems and applications. The course also builds upon COMP2121/9032
Microprocessors and Interfacing by illustrating how more
complex software systems are supported on microprocessor-based
Specific Aims and Outcomes
Make students understand the key concepts and mechanisms of
modern operating systems:
- processes and process management,
- memory management techniques aimed at optimising system
utilisation and responsiveness,
- on-line storage methods (file systems),
- security and protection (optional),
- concurrency issues,
Make students understand the reasons why operating systems are
built the way they are, and what the implications and lessons are for
other software systems. Specific learning objectives are:
- appreciation of design trade-offs and design decisions and
their dependence on the target environment;
- appreciation of the distinction between mechanisms and policies,
and why this is important;
- exposure to low-level code;
- exposure to current trends in operating systems research and
The tutorial formats will give students practice in the
presentation of solutions to an audience of peers, and will challenge
them to critique peer technical presentations. Furthermore, the whole
course encourages critical examination and analysis of "standard"
The assignments give students an opportunity to develop skills
required to work as a team on a technical project, and the opportunity
to work with a substantial body of code created by a third-party.
Our approach to teaching operating systems is
- introducing operating system theory in the lecture component of
the course, including case studies of real systems
- and active engaging students in the practical application of
that theory through challenging assignments, including assessment
and feedback on their efforts.
- We also seek engagement of students by encouraging dialogue
between staff and students both in lectures and tutorials to
re-enforce concepts being taught.
- Students also are encouraged to learn collaboratively through
group assignments, which also hones their skills as "team players"
for future entry into the works force.
We strive to continually improve this course, and actively seek
feedback both during session, and via various evaluation surveys
(CATEI and my own) at the end of the course. The results of surveys
and any feedback are taken seriously and are actively used as input to
further improvements in the course. See the survery archive
for what students thought about the course, and how the course is
evolving based on their feedback.
It is assumed that the student is familiar with the general
organisation of a general-purpose computer (in particular, CPU,
memory, bus, registers, machine instructions,
Students are also assumed to be competent in
the C programming language. More specifically, students should
understand pointers, function pointers, memory
allocation (malloc()), and be comfortable navigating around an
existing code base.
COMP1921 or COMP1927
These are the foundational data struture and algorithms
courses. You should be able to use standard data structures
and algorithms such as trees, hashing, heaps, sorting,
COMP2121 or ELEC2142.
These are Microprocessors and Interfacing courses. We
expect you to be comfortable with low-level
microprocessor-based hardware, registers, interrupts, memory,
devices, and programming in assembler.
- COMP9024 Data Structures and Algorithms
- COMP9032 Microprocessors and Interfacing
- As for COMP3231. Additionally, we would expect students
enrolled in Extended OS would have achieved a mark of at least
70 in each prerequisite.
- As for COMP9201. Additionally, we would expect students
enrolled in Extended OS would have achieved a mark of at least
70 in each prerequisite.
- COMP9201/9283 Operating Systems (for COMP3231/3891)
- COMP3231/3891 Operating Systems (for COMP9201/9283)
Broadly, the course consists of lectures, tutorials, assignments,
and a final exam.
The lecture delivery (3 hours per week) and material covered is
common for all operating system students, independent of the course
code your enrolled under.
Lectures will cover roughly the following topics (although not in
A detailed list of lecture topics and the slides used for the lectures
will be posted on the course website as session progresses.
- Introduction and Overview
- Introduction to operating systems, computer systems
structures, operating system structures
- execution abstraction, state, context, preemption, scheduling,
- Process Management
- resources, address spaces, multi-threading
- Storage Management
- memory management, virtual memory, file systems
- Protection and Security
- goals of protection, access matrix and its implementations,
capabilities, authentication, encryption, design for security,
- Note: I'm trying to get this topic back into the course this
semester, but it depends on how succesful I am in compressing other
- Case Studies
- drawn from
UNIX, Linux, Windows and OS/161 will be used throughout the
Tutorials start in Week Two. Part of the allocated tutorial time
will be devoted towards solving problems and discussing solutions
related to lecture topics, while the remaining time will be used to
discuss topics relevant to assignments.
Students will be required to present tutorial problems under the
guidance of the tutor. Individual student participation (presentation,
critiquing solutions and suggesting alternatives) in tutorials will be
assessed and forms part of the final mark for the course (COMP3231 only). To obtain
the tutorial marks, you have to attend your registered tutorial. Other
tutors cannot award participation marks.
Note that tutorial marks will be based on
participation only, there are no marks allocated just for
For students doing
Extended Operating Systems (COMP3891/9283), your tutorial is an
advanced tutorial where lecture topics are covered in extended depth,
and new topics are introduced and discussed.
There will be four assignments, due approximately in weeks 4,6,9,
and 13. Note that the first assignment is a really trivial
familiarisation exercise, and should not be used to judge the
difficulty of the other assignments. Except for the first
familiarisation assignment, the three main assignments are done in
groups of two. Assignments will use the OS/161 educational operating
system running on a simulated MIPS R3000 computer called
System/161. Both the operating system and the simulator were
developed at by
Research at Harvard group. The simulator is relatively platform
independent, it runs on Unix as well as Windows systems. Assignment
solutions will be submitted in C code. Details will be released in
The last 2 assignments have advanced components which
provide a significantly higher level of challenge than the standard
assignments (which most students find fairly challenging
already). We want students to do the advanced assignments for the
challenge rather than the marks, therefore the opportunity to earn
marks towards you assessment is intentionally kept small compared to
the amount of extra work required. The marks are limited to a max of
10% of the class mark component of the course, see the Assessment
section below for details.
Extended Operating Systems (COMP3891/9283) are required to attempt
the advanced assignment components, and marks awarded form part of
Students have, unfortunately, a tendency to underestimate the time
required to do the assignments. Experience from the last few years
shows that the assignments in this course are considered
challenging, and they consume a fair amount of time. It is important
to start early. If you start on them on the weekend before the
deadline you'll almost certainly miss the deadline. As a tip, the
majority of the assignment is learning how to solve the problem
(approx. 75% of the effort). The programming component is actually
the minority of the work required (approx 25%).
In order to encourage students to start early, we are also
offering 10% bonus marks (10% of the raw mark awarded) for
submitting their final solution one week before the
deadline (i.e., you lose the bonus marks if you re-submit less
than a week before the deadline). Such bonus marks will allow you to
make up for missed marks in the same assignment (i.e., you cannot
get above the full marks for the assignment that way).
Penalty for late submission of assignments will
be 4% (of the worth of the assignment)
subtracted from the raw mark per day of being late. In other words,
earned marks will be lost. For example, assume an assignment
worth 25 marks is marked as 20, but had been submitted two days
late. The late penalty will be 2 marks, resulting in a mark
of 18 being awarded. No
assignments will be accepted later than one week after the
deadline. The late penalty is purposely lenient due to the
tendency of students to underestimate the work required.
- Assignments will be marked as a group, i.e. groups of one will
be marked the same as groups of two or three.
- All group members are expect to contribute equally to EACH
assignment.. In submitting your assignment, you are agreeing you
have contributed equally unless we recieve an agreed-to statement
from all group members identifying differing levels of
What is Plagiarism?
Plagiarism is the presentation of the thoughts or work of another
as one's own.
- direct duplication of the thoughts or work of another,
including by copying material, ideas or concepts from a book,
article, report or other written document (whether published or
unpublished), composition, artwork, design, drawing, circuitry,
computer program or software, web site, Internet, otherelectronic
resource, or another person's assignment without appropriate
- paraphrasing another person's work with very minor changes
keeping the meaning, form and/or progression of ideas of the
- piecing together sections of the work of others into a new
- presenting an assessment item as independent work when it has
been produced in whole or part in collusion with other people, for
example, another student or a tutor; and
- claiming credit for a proportion a work contributed to a group
assessment item that is greater than that actually contributed.
For the purposes of this policy, submitting an assessment item
that has already been submitted for academic credit elsewhere may be
Knowingly permitting your work to be copied by another student may
also be considered to be plagiarism.
Note that an assessment item produced in oral, not written, form,
or involving live presentation, may similarly contain plagiarised
The inclusion of the thoughts or work of another with attribution
appropriate to the academic discipline does not amount to
The Learning Centre website is main repository for resources for
staff and students on plagiarism and academic honesty. These
resources can be located via: www.lc.unsw.edu.au/plagiarism
The Learning Centre also provides substantial educational written
materials, workshops, and tutorials to aid students, for example,
- correct referencing practices;
- paraphrasing, summarising, essay writing, and time management;
- appropriate use of, and attribution for, a range of materials
including text, images, formulae and concepts.
Individual assistance is available on request from The Learning
Students are also reminded that careful time management is an
important part of study and one of the identified causes of plagiarism
is poor time management. Students should allow sufficient time for
research, drafting, and the proper referencing of sources in preparing
all assessment items.
We always check for cheating (i.e. plagiarism), and while
we will never catch all cheaters, we always catch a
significant number. We deal with them severely. Don't take chances!
This is no idle threat. We catch and penalise cheaters to
protect the reputation and integrity of the University, and the
interests of those who get their marks through honest work. A sample
from past years is included below.
* Note: full penalty was not 0FL prior to
There will be no mid-session quiz.
A two hour written final examination will be conducted. Note:
Extended and normal OS have different exams with approximately 75%
Supplementary exams will only be awarded in well justified cases,
in accordance with School policy for Special
Consideration, not as a second chance for poorly
performing students. In particular, it is unlikely that a
supplementary will be awarded to students who have actually sat the
proper exam. Make up your mind whether or not you are sick before
attempting the exam!
Supplementary exams will be oral. The supplementary final
exam will be held after the written supplementary exams held for
Tutorial participation (COMP3231 only) and
assignments will determine the ``class
mark'' component towards the final
assessment. (Note that the class mark
is capped at 100, irrespective of how
many bonus marks you have
accumulated.) The exam will be the
second component of the final
assessment. The weighted harmonic mean
of the ``class mark'',
C, and the final exam mark, E, is used
to determine the final mark, M, according to
- For COMP3231/3891:
The harmonic mean is weighted 50/50.
- For COMP9201/9283:
The final mark will be M
= max(M1,M2), where
M1 is a 50/50 weighted harmonic mean as above, and
M2 is a 20/80 weighted harmonic mean (20 class, 80
exam) as shown below.
This method of weighting is to cater for postgraduates working
full time who are unable to invest significantly in assignment work
(hence 20/80 weighting), while not penalising postgraduates who do
commit to the assignment component of the course (50/50
For COMP3231 students the class mark is determined as the sum of
tutorial participation plus any advanced assignment bonuses (max 10%)
and the base assignments (max 90%). COMP3231 students who attempt the
advanced assignments can use marks earned to make up for lost
For 3891/9283 students the class mark is determined as the sum of
the assignment advanced assignments (max 10%) and the base assignments
COMP9201 students who wish to participate in tutorials can arrange
with their tutor at the start of semester to recieve a
participation mark, in which case, the class component of their mark
will be calculated as for COMP3231. Otherwise, the class mark will be
determined solely from the base assignments scaled to 100%.
A final mark of 50% is required in order to pass, however, it is
furthermore required for a pass that a minimum of 40% is achieved in
the exam E component.
We reserve the right to scale mark components of the individual
courses (COMP3231/9201/3891/9283) separately where appropriate.
More information on harmonic means in general is available here.
- A. Tannenbaum, Modern
ed., Prentice Hall, 2008
For Operating Systems:
For the C language:
- A. Silberschatz, P.B. Galvin and Greg Gagne, Operating
Concepts, 7th ed. (2004)
- William Stallings, Operating Systems:
Internals and Design
Principles, 5th edition, 2005,
- A. Tannenbaum, A. Woodhull, Operating
ed., Prentice Hall, 2006
- John O'Gorman, Operating Systems,
- Uresh Vahalla, UNIX Internals: The New
- B Kernighan and D. Ritchie, The C
Language, 2nd ed, Prentice
- S. Harbison and G. Steele, C: A
Reference Manual, Prentice
Copies of lecture slides and other
information can be found under the
course's WWW home page at URL http://www.cse.unsw.edu.au/~cs3231/.