ACSMay03

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Graduates of ACS examinations can complete an Australian undergraduate degree in two years at any
of the following universities: Australian Catholic University, Charles Sturt University, Deakin
University, Royal Melboune Institute of Technology, and the University of South Australia. For
further information, see the ACS web site http://www.acs.org.au/.

ACS Examinations in Information Technology May 2003 Examiners’ Report
Page 2
Contents
Contents .......................................................................................2
Introduction..................................................................................3
Candidate Awards........................................................................5
Examiners’ reports.......................................................................6
Systems Analysis..................................................................7
Programming.......................................................................10
Computer Organisation.......................................................13
Data Management...............................................................17
Object Oriented Systems Development.............................24
Computer Communications................................................26
Professional Practice .........................................................30
System Principles ...............................................................31
Appendix - Examination Papers ................................................33

Page 3
Introduction The ACS May 2003 exams, the second offering using the
2001 syllabuses, attracted many fewer candidates than those
using the old syllabus. While this is perhaps understandable,
it is disappointing. It seems that potential candidates are
unaware of, or do not appreciate, the opportunities offered by
the new syllabuses.
It is imperative that the Australian Computer Society, and
organisations such as the Computer Society of Sri Lanka,
communicate more effectively the benefits of the new ACS
exams. In particular the societies must communicate with
young people seeking a career in the information technology
profession, and also with older people seeking to enter or
advance their careers in the profession.
As in all professions, and indeed all activities generally
considered worthwhile, practitioners in the information
technology profession require a mindset of life long learning.
No matter how intelligent or elite their initial education, no-
one can hope to be a competent and effective information
technology practitioner without constantly updating and
improving their knowledge and skills.
Unfortunately, in many countries of the World, an
internationally recognised education is expensive and
unattainable. The new ACS exams offer an affordable, yet
comprehensive, diploma-level education in information
technology.
Graduates of the ACS exams can continue their education
from the second year of an Australian university degree in
information technology, with the potential of completing the
degree in just two years.
The ACS exams offer young people the opportunity to test
their competency and interest in information technology,
before spending large amounts of money continuing their
education to a full bachelor’s degree level.
They also provide an opportunity for existing information
technology practitioners, who maybe without any formal
qualifications, to advance and grow their careers.
And importantly, the ACS exams offer practitioners from
other professions, for example accountancy, law and the
military, to broaden their knowledge and skills into the
information technology field.

Page 4
In conclusion, the number of candidates in this latest offering
of the ACS exams, totalling 671, is a substantial reduction on
the number sitting the exams in previous years.
Notwithstanding this fact, it is noteworthy that candidates
came from countries as diverse as Australia, India, Papua
New Guinea and Sri Lanka. Also noteworthy, and worthy of
high praise to the candidates concerned and their teacher, is
that the two highest marks in the Programming paper were,
for the first time, achieved by candidates from Papua New
Guinea.
David Lindley PhD MACS
ACS Chief Examiner

Systems
Analysis
Programming Computer
Organisation
Data
Management
Object
Oriented
Systems
Development
Computer
Commi-
cations
Professional
Practice
System
Principles
Pass Fail Pass
%
Pass Fail Pass
%
Pass Fail Pass
%
Pass Fail Pass
%
Pass Fail Pass
%
Pass Fail Pass
%
Pass Fail Pass
%
Pass Fail Pass
%
152 129 54% 187 61 75% 154 65 70% 89 130 41% 4 3 57% 5 2 71% 2 0 100% 1 0 100%
Summary of results by exam

Page 5
Candidate
Awards
The examiners extend their special and sincere
congratulations to the following candidates. These
candidates achieved the highest performances in each of the
papers indicated and will receive a certificate of
commendation from the Society.
1st
15270 - Kulapputhanthirige Geethani Samarasinghe
2nd
17242 - Jayakodi A G D A Navodani Nanayakkara
Systems Analysis
3rd
17057 - Thushantha Lakruwan Widanapathirana
1st
17340 - Alma La'a
2nd
17324 - Nixon Roma
Programming
3rd
16837 - Ashanthi Geethani Perera
1st
17059 - Kasun Anuradha Weligamage
2nd
17118 - Wanigasooriya M M Eranga Wanigasooriya
Computer
Organisation
3rd
16922 - Padukkage Chamila Dilani Perera
1st
17118 - Wanigasooriya M M Eranga Wanigasooriya
2nd
17348 - Kenny Cheuk Kin Shum
Data Management
3rd
16390 - Koruwakankanamge Desitha Ganaka
Puranadu
No achievement awards were made for the Object Oriented
Systems Development, Computer Communications,
Professional Practice and System Principles papers because
of the low numbers of candidates.

Page 6
Examiners’
reports
The full text of every examination is provided in the appendix
following the examiners’ reports.

Page 7
Systems Analysis Candidates for Systems Analysis and Design were expected
to demonstrate a practical ability in modelling systems and
were tested for this in Part A of the paper. To pass the
examination, a minimum number of marks were required in
Part A.
A theoretical understanding of system development issues
was also expected and was tested in Part B.
At this level, candidates were expected to exhibit a depth of
understanding for each topic.
The following observations are made for each question:
Part A Compared to past years, fewer students answered Part A
poorly relative to Part B and thus limiting the number of
marks obtained.
Question 1
This question was based on a structured approach to
modelling and was attempted by a majority of candidates.
Marks were normally distributed.
The topics are covered in considerable detail in chapter 8, pp.
176 – 209 and chapter 9, pp. 220 – 242 of the prescribed
textbook for this unit, namely:
Hawryszkiewycz, I. T., Introduction to systems analysis and
design, Sydney, NSW, Prentice Hall of Australia, 2001.
Common reasons for loss of marks for a data flow diagram
include an insubstantial model, many dataflows not named
and a lack of detail. For a data model, marks were often lost
because of an insubstantial model, poor relationship
connections and insufficient description of entities.
Modelling of a system is an important part of the analysis
function because everybody in a development team must
understand all parts of an existing and new system. A data
flow diagram is of little use when only dataflows from
external entities are named, no detail such as temporary stores
are provided, different dataflows enter and leave a context
diagram and its related diagram zero and, for a data diagram,
little thought in developing data relationships connections.
Question 2
Most students attempting this question exhibited a reasonable
understanding of an object-oriented analysis modelling
process and obtained good marks.

Page 8
The process is covered in chapter 11, pp. 270 – 293 and
chapter 12, pp. 304 – 316 of Hawryszkiewycz (2001).
Part B Question 3
(a) Most candidates attempting this question exhibited a
reasonable knowledge of these modules, although
often in insufficient detail.
(b) Candidates attempting this question generally
understood the operation and place of the financial
service module
(c) Candidates appeared to be less sure of integration
issues between modules.
The topic is covered in chapter 3, pp. 50 – 63 of
Hawryszkiewycz (2001).
Question 4
Many candidates attempted this question and generally
provided a methodological approach, although often with
insufficient detail.
Question 5
(a) Many students knew set answers for objects,
encapsulation, inheritance and polymorphism that
were acceptable. Some students appeared to have a
lesser understanding of the concepts of abstraction into
a class and of polymorphism.
(b) Candidates attempting this section were generally able
to provide a reasonable explanation of the object-
oriented analysis techniques of use case, state and
event trace diagrams.
Question 6
Most candidates attempted this question and most answers for
both parts (a) and (b) were very good. Quality Assurance is
covered in chapter 20, pp. 468 – 475 of Hawryszkiewycz
(2001).

Page 9
Question 7
(a) Many students could discuss steps in managing a
project, although often with insufficient detail.
(b) A reasonable number of students attempting this
question understood that modifications during
development must be managed with a change control
process.
The topic is covered in chapter 6, pp. 128 – 136 and pp. 148 –
150 of Hawryszkiewycz (2001).

Page 10
Programming Like several other examinations, the Programming paper is a
new offering, and this is the second set of students to sit
under it.
It is related to the previous Programming and Software
Technology exam. The most important distinction is the use
of a genuine and freely available programming language –
namely, Java – as opposed to a plausible (but unavailable)
pseudocode.
The chief examiner and fellow examiners will well know my
repeated disappointments that students consistently
demonstrated a significant lack of ability to produce working
programs by their own efforts.
Consequently, the Java exam has also received a solid change
in focus. Students of this paper have not been asked to
produce fully working programs – or to perform file-handling
which has also historically proven troublesome.
However, this new paper has introduced aspects of
programming that were not examined in the previous subject,
but which are important to Java. This includes event-
handling, graphical user interface design and a practical
emphasis on object-oriented programming.
Overall, the results are pleasing with the bulk of students
readily taking to Java. I would very much hope that students
are taking advantage of the fact Java is a genuine and freely-
available programming language to perform their own
experimentation and practice in preparation for the exam.
Responses to individual questions are elaborated on below.
Most of these questions – and their answers – have now been
included in a separately published study guide the details of
which can be acquired from the Australian Computer Society.
Question One This question contained a series of multiple choice and yes/no
questions and was worth 20% of the marks for the paper.
a. This question was answered correctly almost without
exception. Typically the students who did not answer this
question left most of their paper blank anyway.
b. This question was mostly well answered.
c. This question was mostly well answered.
d. This question is where responses began varying wildly,
but over half the responses were correct.

Page 11
e. This question was answered poorly and I was extremely
disappointed by the high proportion of students who
believed the code would not compile because a variable
had been declared twice – with one declaration being
global and the other local. An understanding of scope is
fundamental to programming.
f. This question was largely answered correctly.
g. This question was also well answered.
Question Two On the whole, this question was well answered. The great
bulk of the question consisted of correct program code, with
three methods left blank, for the students to complete. To my
mind, this question was straightforward and the responses
concur with this. However, the first question – requiring the
students to actually determine for themselves what the
program did and how one interacted with it – was poorly
answered.
Question Three The answers to this question were attempted by most
students, who mostly were able to identify which statements
about garbage collection were true and which were false.
However, only a small number of students actually attempted
to explain why the statements were true or false which made
it hard to determine whether students had a genuine
understanding of the issues involved.
Further, some students cheated themselves by electing to
determine simply which statements were true and just discuss
those – however, the question required each statement to be
analysed and have its truth or falseness explained.
Question Four Pleasantly, this question was answered well, with the majority
of students attracting full marks and demonstrating an
understanding of data types and type conversions.
I had presumed this to be a complex question but it definitely
demonstrated the bulk of students grasp the concept of data
types and the implicit and explicit castings required to
perform calculations across data types.
Question Five This question was easily the most complex in the entire
paper, but was accordingly weighted 25%. Unsurprisingly,
this was the worst-answered question on the paper.
A reasonable number of students attempted the question, but
most did not demonstrate an understanding of the standard
Java library classes StringTokenizer and TreeSet – or make
any attempt to do so.
I considered these classes may be obscure, but neither the
code nor the questions actually required students to have any

Page 12
knowledge of the inner-working of these classes or even to be
aware of their existence. Students who carefully read the
scenario and the supplied program code should be able to
determine the purpose of the classes.
Part A asked for an explanation of how the program worked,
and attracted a small response – although the answers given
were largely on the right lines.
Part B required students to write a method to compare two
strings. In reality, this should have been trivial but was very
poorly answered.
Part C asked students to explain a particular line of code. This
was better answered, which did demonstrate students either
knew the purpose of the StringTokenizer class or were able to
deduce its purpose given a specific example. Yet, this should
have then meant students were able to answer part A as
satisfactorily but this was not the case in practice.
Part D asked students to consider a command-line argument
and should have been extremely trivial. Yet, only a minority
of students attempted a response and only a minority of these
were correct.
I am not sure what to make of the poor and varied responses.
I do believe students need not actually know how the Java
classes used work. However, perhaps the sheer bulk (and
moderate complexity) of the supplied program code was
intimidating to students – which is unsatisfactory for students
taking a programming exam but was my observation over
several years of administering the Programming and Software
Technology exam.
Further, I am left to wonder why careful students, who were
able to correctly deduce how the program worked by the time
they reached part C, did not return to part A and revise their
answers.
Question Six The bulk of students gave a pleasing response to this
question, which required understanding and expanding code
to provide a simple graphical user interface.
Students demonstrated an understanding of event-handling
and the use of Java’s standard library classes that implement
graphical objects.
I believe a mastery of Java GUI design was well
demonstrated.

Page 13
Computer
Organisation
About 250 candidates sat for this paper. Overall, candidates
did reasonably well, although there was evidence of some
rote learning. This report provides some brief comments on
candidates' performance and sample solutions.
Question One This question tested candidates' general knowledge and
understanding of some common terms in computer
organization. Most candidates knew something about these
terms, but their description was not accurate and clear.
Expected answers should be brief but to the point.
Sample Solution
(i) Stands for Reduced Instruction Set Computers.
The main features of RISC architecture are: a
limited and simple instruction set, a large number
of general purpose registers, and optimized use of
the instruction pipeline.
(ii) Refers to a mechanism that other
modules/processes request attention of the CPU
which is running another process/program. It is
mainly used to improve processing efficiency.
CPU is much faster than external devices. CPU
can server these devices when needed using
interrupts.
(iii) Virtual memory refers to the external
memory/disks used to store data of processes
being executed. It is used to extend the internal
memory/RAM so more
(iv) Refers to the process an instruction is executed.
The cycle consists of steps of fetching, decoding,
execution and storing results.
(v) Refers to the main interconnection among CPU,
memory and external devices. It consists of data
buses, address buses and control buses.
Question Two Most candidates did Questions (a) and (c) well. There was
some confusion for Questions (b) and (d).
Sample solution
(a) Convert 10110111.011 into decimal:
(10110111.011)2= (128+32+16+4+2+1+0.25+0.125)10
= (183.375)10
Convert 10110111.011 into hexadecimal:
(10110111.011)2 = (1011 0111.0110)2=(B7.6)16
(b) E= AB+C(A’+B’)’+AB(BC)’

Page 14
=AB+CAB+ABB’+ABC’
=AB+ABC+ABC’=AB(1+C+C’)=AB
(c) The four main components and their functions are:
Central Processing Unit (CPU): Controls the operation of
the computer and performs its data processing function.
Storage devices: Store data and instructions.
I/O devices: Move data between the computer and its
external environment.
System Interconnection: Some mechanism that provides
for communication among CPU, storage devices and I/O
devices
(d) Clock speed: the faster the clock speed, the higher the
computer performance (for the same type of computer
architecture).
Data bus width: the wider the bus width, the higher the
computer performance (for the same type of computer
architecture).
Address bus width: the wider the bus width, the higher
the computer performance (for the same type of computer
architecture).
Amount of on chip registers/memory: the more the
memory, the higher the performance.
Question Three (a) This question was not done as well as expected. Many
candidates cannot work out that the hit ratio for virtual
memory is 10%.
(b) Few candidates did this correctly. See the sample solution
below for explanation.
(c) This question was done well. But some candidates did not
give any explaination.
Sample solution
(a) Average access time = 10 x 0.8 + 200 x 0.1 + 500 x 0.1
=8+20+50=78 ns.
(b) Assume the bit mapped image has height of H pixel,
width of W pixel and pixel depth of D bits per pixel, then the
amount of storage is
H x W x D bits = HxWxD/8 bytes.
For example, if H=200 pixels, W=200 pixels, D = 8 bits per
pixel, then the required storage = 200 x200 x8/8= 40000
bytes.

Page 15
(c) There are many types of memories such as RAM,
harddisk, magnetic tapes. There is a trade-off among the three
key characteristics of memory, namely cost, capacity and
access time. In a given computer, a variety of technologies
are used to implement memory systems. There are normally
the following relationships among these three characteristics:
Shorter access time but greater cost per bit
Greater capacity but smaller cost per bit
Greater capacity but greater access time
On the one hand, it is desirable that we use memory
technologies that provide for large-capacity memory, both
because the capacity is needed and because the cost per bit is
low. On the other hand, we need to use expensive, relatively
low-capacity memories with fast access time in order to meet
performance requirements.
The solution to the above dilemma is that we don’t rely on a
single memory component or technology, but to employ a
memory hierarchy.
A common memory hierarchy is shown in the figure. As we
go down the hierarchy, the following occur:
• Decreasing cost per bit
• Increasing capacity
• Increasing access time
• Decreasing frequency of access of the memory by the
CPU
Registers
Cache
Main
Disk Cache
Magnetic Disks
Magnetic Tape Optical Disk

Page 16
Question Four (a) About half of candidates answered this
question correctly..
(b) This was answered reasonably well,
although some answers were not accurate
and clear.
(c) Disappointingly, this question was done
poorly, although it is easy one if the basic
concept is understood.
Sample solution
(a) RAID stands for Redundant Array of Inexpensive
Disks. Many cheap disks form an array of storage to
increase storage capacity and to improve reliability
through the use of redundancy.
(b) In direct memory access (DMA), a DMA module is
used to transfer blocks of data from one memory
location to another without direct involvement of
CPU. After CPU issues a command to the DMA
module, it can work on other processes/program.
(c) Bus cycle = 16 /4 = 4 MHz
Data transfer rate = 32 x 4 = 128 Mbps.
Question Five (a) This first part was done well. But the second part was
done poorly.
(b) Not many candidates knew user-visible registers.
Sample solution
(a) (i) Multiprogramming refers to the concept/technique
in which the processor works on more than one
program at a time.
(ii) Different devices have different operation speed.
A program needs to access different devices at
different time. When multiple programs are executed
at the same time, they can use available
resources/devices fully, improving the efficiency.
(b) (i) User visible registers are those can be accessed
using the machine language.
(ii) Two user visible registers are:
Stack pointer: pointing to the top of the stack.
Index register: used for indexed addressing.

Page 17
Data Management This paper was the second paper on the recently revised
syllabus, but was identical in format to most recent
examinations.
As in the previous examination, the average mark awarded
was quite low compared to previous examinations, but the
number of good candidates was much the same as in previous
years. Marks awarded followed a bimodal distribution, with
candidate marks falling into two groups, those who were
prepared, and those who were not.
With the change in structure for the examinations, there were
more candidates sitting this examination than had been the
case in recent examinations, although less than for the last
examination. Once again, it was clear that many of these extra
candidates, lacking the filter previously provided by the
previous Fundamentals of Information Technology 2 paper,
did not possess even the most basic understanding of
computing principles in general, and data management in
particular. These candidates were in many cases unable to
address any of the issues examined, let alone sufficient to
pass the paper. This extended to sometimes even producing
rehearsed answers to previous examination questions. A
number of candidates failed to answer the required five
questions out of the seven set, and a even larger number did
the opposite, answering more than the maximum number of
questions allowed to be answered. It needs to be pointed out
that these extra answers are never marked, so the candidate
gains nothing by this approach, they simply waste time that
could perhaps be better spent answering the other five
answers.
The following comments are made about each question.
Question 1 This question asked for the production of an entity-
relationship (E-R) model (or something equivalent) to be
drawn from a scenario, in this case a property sales system.
Most candidates who attempted this question understood the
basic symbols for entities, attributes and relationships, and
with minor flaws, produced acceptable models of at least
some aspects of the scenario. While in many cases there was
a failure to model every aspect of the scenario given, quite
often however, models produced were over-elaborate, with
extraneous entities being included, often being based on
dynamic process concepts. Some candidates produced
rehearsed models, based around completely different
scenarios, for example, club membership records!
A wide variety of modelling techniques were accepted,
including object-oriented models, as were a variety of
interpretations of what was significant in the scenario. The

Page 18
examiners looked for a reasonable attempt to model
significant aspects of the scenario using a recognisable
modeling method, documenting any assumptions on which
the model was based. The following model is one possibility:
Vehicle
Employee
Customer
Service
requests
performs
Is-
allocated
-to
1
1
1
M
1 M
Licence#
Employee#
Date
Extra-
chargesFee
Name
Address
A number of assumptions were made in developing this
model. First, that vehicles were identified by the licence plate
number. Second, that employees were identified by an
employee number. Third, that no customer had more than one
service call per day, so that a service could be identified by a
customer name and a service date.
One common error in models produced was to draw the
company as an entity. The corporate entity (the notional
“owner” of the database) is not an entity. It is in fact the
entire diagram. Another common error was to include the
vehicle pool as an entity. The fact that every employee had a
vehicle, but that there were some vehicles unallocated in a
pool makes this a 1-to-1 relationship, which is mandatory at
the vehicle end, but optional at the employee end.
Question 2 This question asked candidates to identify the important
characteristics of data and the proceeses used to produce
useful information. Far too many candidates missed the point
of the question, and chose to describe the features of a typical
database instead. Other misdirected approaches included
discussions about meta-data. Closer to the mark were
discussions of entity and referential integrity concerns.
To be valuable, data and information should be:
(a) accurate – free from mistakes, errors and bias
(b) timely – delivered when required

Page 19
(c) relevant – to answer What, Why, When, Where and How
questions
Information can be regarded as a resource, as an asset, and as
a commodity.
(a) A resource because it can be used to advantage in
improving the effectiveness of an organisation (for
example, which products are selling well, and which are
not).
(b) An asset because data collected today can be used as a
store of future value (for example who buys what from us,
who owes us money).
(c) A commodity because information can be sold (for
example survey results, names and addresses and so on).
Data might be summarised, sequenced, selected and so on to
produce information.
Question 3 This question asked candidates to identify functional
dependencies in two user views, and then to use these
dependencies to consolidate the user views into a set of
relations in third normal form.
This question was very poorly answered, with most
candidates being unable or unwilling even to identify key
attributes, let alone link then to dependent non-key attributes.
Simply gathering attributes up into two or three tables does
not demonstrate an ability to undertake database design
unless appropriate keys are identified.
Many candidates failed to appreciate that the word “view” in
the context of database analysis refers to user view, what a
particular class of user sees, or wants to see, in the database.
This is not the same as the use of the term view in SQL,
which refers to the definition of “virtual” tables either to
simplify query writing, or to provide for varied levels of
access to table data.
In the two user views, it is clear that the Price in the
ORDER_DETAILS user view is the same as the Price in the
INVENTORY view, being the price of items held, and the
price charged for an order.
It is equally clear that the Quantity in ORDER_DETAILS is
not the same as the similarly named field in the
INVENTORY user view. The former is obviously a quantity
ordered, while the latter is just as obviously a quantity held in
stock. In other words, there are two homonyms “price” where
the same word has two different meanings. Homonyms
appear quite often during analysis, for example it would be
not unusual for the word “name” to mean Customer name in
one user view, Employee name in another, and Item name in

Page 20
a third. Homonyms can be contrasted with synonyms – two
different words with the same or similar meaning, for
example wages and salary.
In the ORDER_DETAILS user view, the following functional
dependencies can be identified:
CustomerID, PartID, Description, CustomerName, Price, QuantityOrdered
while in the INVENTORY view we have
PartID, Warehouse, Price, QuantityHeld
By putting each unique key combination into its own relation,
along with the non-key fields dependent upon that key, we
can produce the relations:
CUSTOMER ( CustomerID, CustomerName)
PART ( PartID, Description, Price)
INVENTORY ( PartID, Warehouse, QuantityHeld)
ORDER ( CustomerID, PartID, QuantityOrdered)
Question 4 This question asked candidates to explain a selection of
technical terms in a description of the transaction processing
facilities provided by some DBMS software. As expected, of
all the questions in the paper, this was the best answered.
Very good answers addressed the specific terms given, while
poorer answers gave more general answers and were
penalised accordingly.
In concurrent transaction processing, a lock can be applied on
behalf of a transaction to some data to prevent access to that
data by some other transaction for a period of time. An
exclusive lock prevents all other access, while a shared lock
would allow limited read access by other transactions. Locks
can be applied to whole tables, to rows, or to individual
fields. Lock granularity is the term used to describe these
levels of locking. Deadlock is when two transactions hold
each other up because each has locked data the other wants to
access, and each hangs on to the locks it has acquired, in the
hope that the other transaction will release its locked data. By
keeping track of which transaction has locked which data, and
comparing this to failed attempts to acquire further locks, a
DBMS with deadlock resolution facilities can detect that
deadlock has occurred, and by aborting one transaction, allow
another to proceed to conclusion.

Page 21
Question 5 This question asked candidates to describe how a DBA
should go about investigating a report that certain transactions
in a distributed system have slowed down, and also to
identify possibilities for improving the situation.
This question was done by large numbers of candidates, most
of whom failed to answer the question as set. The question
did not ask for a general description of the duties of a DBA,
or how their role compared with that of a DA.
First of all, the DBA could check system logs and system
snapshots and compare them with previous logs and against
benchmarks established during system development. If this
shows that there is a slowing down, then they need to
establish if transaction volumes have increased, or if the mix
of transactions has changed.
If communication bottlenecks are identified, then for read
transactions replication might help, and for update
transaction, a review of partitioning could be carried out.
Increased transaction volume might require an upgrade to
hardware. Re-organising files by indexing and clustering
could speed things up where transaction volumes or
transaction mix have changed.
Finally, there is also the possibility that locking is increasing
as more and more transactions raise the possibility of access
clashes.
Question 6 This question asked candidates to explain why backup of a
24x7 enterprise-wide database was more complex than for a
personal database on a PC.
In these cases, a cold backup, requiring a system shutdown,
may be impractical. Hot backups, where only part of the
database is shutdown at a time. Incremental backups, where
record changes are copied to journal files can be carried out.
Another possibility is to mirror the database, with processes
updating two copies simultaneously, so that if one goes down,
the mirror copy can still be used.
Question 7 This question asked candidates to give SQL statements for a
number of activities centred on a ticket booking agency. With
SQL providing more features than was once the case, more
complex problems can be addressed through the language.
Candidates are finding it harder to come to grips with this
greater complexity, and answers to this popular question were
fairly poor.
The following solutions were tested on a Microsoft Access’97
database.

Page 22
a) This question asked candidates what output would be
produced from the application of the count, sum and
average single-row functions when applied to a table
containing an empty (null value) cell. Not many
candidates seemed aware that the null value would be
ignored by these functions.
b) SELECT EventCode, sum(tickets) AS Sold
FROM Booking
GROUP BY EventCode;
c) SELECT *
FROM Event
WHERE EventCode NOT IN (Select Distinct
EventCode from Booking)
ORDER BY EventDate;
d) A standard SQL join such as
SELECT Booking.EventCode, Name, Tickets
FROM Event, Booking
WHERE Booking.EventCode=Event.EventCode
ORDER BY Booking.EventCode, Name;
operates as an inner join, so that only matching rows
are paired up. Unmatched rows are ignored. If it is
required to select every row from one of the joined
tables, then an appropriate outer join is required.
SELECT Event.EventCode, Name, Tickets
FROM Booking RIGHT JOIN Event ON
Booking.EventCode=Event.EventCode
ORDER BY Event.EventCode, Name;
An incorrent solution was to suggest changing the
SELECT clause target list to refer to the Event table,
as the query
SELECT Event.EventCode, Name, Tickets
FROM Event, Booking
produces exactly the same result as the form given in
the question.
There is an alternative, though more complex solution,
based on the UNION set operator:

Page 23
FROM Event, Booking
ORDER BY Booking.EventCode, Name
UNION
SELECT EventCode, NULL, NULL
FROM Event
WHERE EventCode
NOT IN (SELECT DISTINCT EventCode FROM
Booking);
e) This question could be answered with an uncorrelated
sub-query such as
SELECT Name, EventCode
FROM Booking
WHERE EventCode IN
(SELECT EventCode
FROM Booking
group by EventCode
Having COUNT(EventCode)=1);
or by the following correlated sub-query.
SELECT Name, EventCode
FROM Booking AS B
WHERE EventCode NOT IN
(SELECT Distinct EventCode
FROM Booking
Where Name <> B.Name);

Page 24
Object Oriented
Systems
Development
The paper consisted of 10 questions. The first 8 questions
referred to a case study. The last two questions were short
answer questions
Most candidates showed that they had a general
understanding of this topic. However they either did not fully
understand some of the questions posed or failed to answer
these questions fully, resulting in low marks for questions 1,
3, 5, 6, 7, 8 and 10a.
Question 1 This question was poorly answered. Only one candidate
received 50% or more of this question. The most common
errors were:
- not completing the Use Case Diagram (eg not showing a
minimum of 4 use cases, no boundary, etc);
- using the wrong naming conventions for use cases (eg nouns
instead of verbs); and
- inappropriate actors or actor names, incorrect interaction
between actors and use cases.
Question 2 This question was generally well answered, however no
candidate received full marks. The most common errors were:
- placing system responses in the actor actions column;
- incorrect alternatives; and
- missing actor actions.
Question 3 This question was not well answered.
Only half of the candidates received 50% or more for this
question. No candidate received full marks. The most
common errors were:
- not enough or inappropriately named concepts; and
- missing or incorrect association.
Question 4 This question was generally well answered, however only one
candidate received full marks. The most common errors were:
- naming of system events was often incorrect;
- system responses were often incorrect or inappropriate;
- actors were not always shown.
Question 5 This question was poorly answered. Only 30% of the
candidates received 50% or more for this question.
Most candidates did not seem to understand contracts in
general. The most common errors were:
- incorrect or inappropriate pre-conditions and post-
conditions; and
- sections either missing, incomplete or incorrect.

Page 25
candidates received 50% or more for this question.
Most candidates did not seem to fully understand
collaboration diagrams.
The most common errors were:
- sequence numbers missing or inappropriate; and
- message naming and message format incorrect or
incomplete.
candidates received 50% or more for this question. The most
common errors were:
- associations incorrect, inappropriate or missing;
- navigation and attributes missing or incorrect; and
- methods incomplete.
Question 8 This question was very poorly answered. Only 20% of the
candidates received 50% or more for this question. The most
common errors were:
- code had inappropriate or incorrect names, and
- code was missing or incorrectly placed.
Question 9 a) This question was reasonably well answered, however no
candidate received full marks.
b) This question was also reasonably well answered, however
the answers were not fully developed and no candidate
received full marks.
Question 10 a) Half of the candidates did not answer this question. The
other half generally answered this question quite well.
b) This question was reasonably well answered, however no
candidate received full marks.

Page 26
Computer
Communications
Very few candidates sat for this paper as this subject belongs
to the 2nd
group of the new eight subjects. Overall, candidates
did reasonably well. This report provides some brief
comments on candidates’ performance and sample solutions.
Question One Comments
This questions tested candidates’ general knowledge and
understanding of some common terms in computer
communications. Most candidates knew something about
these terms, but their description was not accurate and clear.
Sample solution
(i) Refers to the communication architecture which
consists of a number of layers and each layer has
its own protocols. For example, OSI reference
model consists of seven layers and the Internet
architecture consists of five layers.
(ii) In this transmission mode, synchronization
between the transmitter and receiver fully depends
on the clock synchronization. No start bit and stop
bit are used.
(iii) This is a sub-layer of data link layer. It is needed
to control which station/node can access the
transmission medium at any given time.
(iv) Refers to techniques to control the data
transmission rate so that the receiver is not
overwhelmed.
(v) This is a switching technique in which a physical
path is set up between the transmitter and receiver
for the duration of data transmission.
Question Two Comments
(a) This was done very well.
(b) Most candidates knew something about data link
layer. But few can describe it clearly.
(c) Most candidates answered it well.
Sample solution
(a) Communication protocol is a set of rules that governs
the required communications. It is needed to ensure
that the communication entities can understand each
other and can carry out meaningful communication
(b) Data link layer is the second layer of the OSI
reference model. It’s main function is to break the
continuous bit stream of physical layer into
meaningful frames/blocks. In addition, it provides
medium access control function.

Page 27
(c) Similarity: both are layered architecture and most
layers are similar in the two architectures.
Differences: the OSI reference model has seven layers
while the TCP/IP architecture has only five layers.
The main functions of session later, presentation layer
and application layer of the OSI model are combined
to form the application layer in the TCP/IP
architecture
Question Three Comments
(a) This was answered very poorly. The main reason may
be that this question has not been tested before.
(b) Not many answered this correctly either.
(c) This was done poorly, again, possibly due to the fact
that this was not tested before. This indicates that
candidates have focused on the answers of the previous
exams instead of trying to understand basic concepts.
Sample solution
(a) (i) The spectrum of a signal is the range of frequencies
that it contains.
(ii) The sampling rate is determined by the Nyquist
theorem, ie, the sampling rate should be at least be
twice of the signal frequency in order to represent the
signal completely.
(b) In the Manchester code, there is a transition at the
middle of each bit period. The mid-bit transition
serves as a clocking mechanism and as data: a low to
high transition represents a 1, and a high to low
transition represents a 0.
(c) In both types of multiplexing, the transmission time is
divided into fixed length time slots. In synchronous
time division, a transmitter can use certain time slots
(for example, every 4th
slot). But in statistical time
division, a transmitter can use any un-used slot.
Statistical time division is more efficient that
synchronous time division multiplexing.
Question Four Comments
(a) Many answers were vague, indicating that flow
control techniques were not well understood.
(b) This was done very well.
(c) This was done reasonably well.

Page 28
Sample solution
(a) Stop-and-wait: the transmitter sends a packet and
waist for the acknowledgement from the receiver
before sending another packet.
Sliding-window flow control: it can be treated as an
extension of stop-and-wait. Instead of sending one
packet and then waiting, a transmitter can
continuously sends a fixed number of packets
(window size) without needing acknowledgement
from the receiver. When a packet is acknowledged,
the number of packets equal to the window size can be
transmitted.
(b) Parity check is a simple error detection method where
a parity bit is added to detect if a bit error occurred.
For example, if we want to send data 10101110 and
even parity is used, then the data including parity bit
is 101011101. If any bit is changed, the number of 1
bits will be odd and we will be sure that one error has
occurred.
(c) Ethernet normally uses the bus topology. It uses
carrier sense multiple access with collision detection
(CSMA/CD): It is a contention media access control
mechanism. The access rules are:
(1) Check if the transmission medium is busy. If the
medium is idle, transmit; otherwise, go to step (2).
(2) If the medium is busy, continue checking until it is
idle, then transmit data immediately.
(3) If a collision is detected during transmission, send a
signal to ensure all stations know the collision and
then stop transmission.
(4) After sending the collision signal, wait a random
amount of time and then transmit again. (repeat from
step (1)).
Question Five Comments
(a) Most candidates knew something about TCP, but few
can describe its function.
(b) This was done reasonably well.
(c) This was done poorly, possibly due to the fact that this
type of question has not tested before.
Sample solution
(a) TCP is a connection oriented transport protocol. It
breaks data streams into packets and sends them to the
receivers. It is a reliable protocol. Lost packets are re-
transmitted.

Page 29
(b) (i) MIME stands for multipurpose Internet mail
extension. It can specifies a combination of different
content types and transferring encoding methods so
that message in MIME format can be transported
using SMTP (simple mail transport protocol).
(ii) It is needed because the original email format in
RFC822 allows only characters of 7-bit ASCII and
SMPT can only transport messages consisting of 7-bit
ASCII characters. Without MIME, binary files and
formatted documents cannot be transported reliably
using SMTP. Note that messages in MIME format are
still transported by SMTP. MIME does not replace
SMTP, it extended RFC822’s content types and
added encoding methods.
(c) (i) Two possible security risks are compromise of
confidentiality and authentication.
(ii) Confidentiality can be achieved by using data
encryption so that only the intended receiver can
decrypt and read the message. Basic
authentication can also be achieved by using
encryption so that the receiver knows the
message is from the original transmitter. For full
authentication, other techniques such as time
stamping can be used.

Page 30
Professional
Practice
Two candidates sat the exam in this session. The average
mark was 75% which is a very pleasing result.
The paper was divided into two sections. Section A consisted
of a scenario evaluation and was worth 55% of the marks.
Section B consisted of five short answer questions of which
candidates had to select three. This section was worth 45% of
the marks. Coincidentally, both candidates selected the same
questions to respond to.
Section A Question 1 – scenario evaluation
Both candidates handled this question reasonably well. They
were able to identify the facts that caused ethical concerns
and the appropriate stakeholders but were unable to isolate the
major ethical dilemma (email monitoring without the
knowledge of the employees). The main concern I had with
their responses however was the somewhat naïve approach to
what was a reasonable resolution. The notions of reasonable
personal use (as is usual with the use of telephones) and
informing employees that email is being monitored did not
enter into their arguments. However, both candidates raised
the issues of privacy and security, and argued their position
well in this context.
Section B Question 2 – The response to this question was variable. Both
candidates identified IT and application literacy as well as
computer usage policies as issues to discuss. Only one
candidate identified privacy and security issues. Neither
candidate identified ergonomic issues.
Question 5 – Both candidates identified appropriate privacy
concerns and were able to identify appropriate
implementation methods to assure security of data. However,
neither candidate identified the fact that appropriate business
policies and procedures need to be in place as well as relying
on the ethical behaviour of the people who have access to the
data to ensure that privacy is not breached.
Question 6 – Both candidates raised one or more of freedom
of information vs. privacy, flaws in security vs. illegality of
hacking and the hackers need to search for knowledge vs.
unethical behaviour as arguments and counter arguments for
and to hacking. However, more emphasis should have been
placed on the illegality and privacy concerns as well as the
cost to organisations of hacking.
Overall I’m pleased to see that candidates seemed better
prepared for this paper than in November. Their results
certainly reflect this.

Page 31
System Principles This paper was the second paper set for this newly introduced
syllabus.
With only a handful of candidates, no significant trends or
observations are possible.
The following comments are made about each question.
Question 1 This question asked candidates to describe how functional
information systems rely on raw data collected by the
Accounting Information System..
All businesses tend to have an accounting system, not least
because the law requires financial statements to be prepared.
From raw data collected during say order entry, delivery and
billing applications, we can derive sales reports that show
what products are selling, and what are not. This information
helps Manufacturing to plan production schedules and
inventory levels, and marketing to anticipate the need for new
products, and to retire old ones. By categorising customers,
Marketing can determine the effectiveness of advertising
strategies. Order and delivery data can be used to improve
logistic systems.
Question 2 This question asked for a discussion of electronic payment
systems. These systems are changing all the time, and vary in
complexity and security between B2C and B2B applications.
EFT and EFTPOS, EDI trading and purchasing, smart cards
and digital payments systems like STT, SEPP and SET were
among the topics that could have been discussed, as were
digital cash techniques such as iClickCharge.
Question 3 This question asked for a discussion of. the need for firewalls
to prevent unauthorised access from outside the organisation,
and also to restrict Internet access by employees.
A firewall can simply log traffic into or out of a server. This
alone could be used to detect abnormal access patterns, and
might results in user education and/or restrictions being
implemented.
A firewall can also filter traffic using IP addresses, domain
names, and user Ids and passwords. This can be used to limit
access to sensitive inside information, and to restrict outside
web browsing to desirable sites.
More sophisticated firewalls can hide information, and carry
out audits of data trails including say, eMail traffic.
Question 4 This question asked for a discussion of design criteria for an
agricultural machine site serving S.E. Asia and the Pacific.
The company has to decide what sort of site they want. What
parts of the sales cycle should the site support? Is it just to
provide pre-sale information or are actual sales to be carried

Page 32
out on-line? If it perhaps just used to build a brand image, or
is detailed technical information required. Is it to be used to
provide after-sales service, for example fault diagnosis?
Language issues need to be understood – for example is this
an industry that uses English as the business language, or do a
variety of languages need to be supported? Are band-with
issues likely to limit the site to text only, o are graphic and
video displays possible?
Question 5 This question asked candidates to discuss recent proposals to
supplant HTML with SGML/XML.
What was wanted here was a discussion of the need to
transport complex data types and document types, and the
need to separate descriptions of document structure from
document layout. Discussion of extensions to HTML like
CSS and scripting languages was relevant. The difficulty in
displacing entrenched technologies like current web browsers
is also an issue.
Question 6 This question asked candidates to discuss how realistic are
predictions about the future dominance of on-line shopping.
Like the paperless office and the cashless society, in their
early days such predictions are accompanied by a great deal
of hype, partly fuelled by fervent hope, and partly by a lack of
understanding of the difference in attitudes and desires
between Internet pioneers and the ordinary consumer.
Some of the limiting factors that merited discussion include
product suitability, willingness to change, level of consumer
risk aversion, cultural issues, availability of technology and
infrastructure, governmental regulation and so on.
Question 7 This question asked candidates to discuss the difficulties
encountered in authenticating WWW sites. There are lots of
issues here, including the unregulated nature of the Internet as
a whole. Domain name piracy is an issue. Illegal duplication
of brand-named fashion clothing and pirate recordings and
CDs are old issues that are likely to carry over into the
Internet world. Traditional regulation such as exists for
trademarks, company names, head office locations, and
control over false representation are all issues that legislators
are grappling with at present.

Page 33
Appendix -
Examination
Papers
The following pages contain the full text, with original
formatting, of every paper in the November 2002 exam
offering.

AUSTRALIAN COMPUTER SOCIETY
(Incorporated in the A.C.T.)
EXAMINATION IN INFORMATION TECHNOLOGY
May 2003
Please complete this cover sheet and attach
securely to the front of your answers.
FAMILY NAME ……………………………………
GIVEN NAME(S) …………………………….…….
ACS EXAMINATION NUMBER __ __ __ __ __ __ __ __
PAPER: Systems Analysis
Please:
• Write your Exam Number at the
TOP of every answer page.
• Write your answers in INK.
• Write CLEARLY and NEATLY.
• Use only ONE side of the paper.
Questions
Attempted
(please tick)
Examiners
Mark Only
1
2
3
4
5
6
7
Total Mark

Australian Computer Society Systems Analysis exam May 2003 Page 1 of 4
May 2003
Systems Analysis
Attempt one (1) question from Part A, and any four (4) questions from Part B.
Part A = 36 marks
Part B = 64 marks
Total = 100 marks
Candidates must obtain a minimum of 50 marks to pass this paper, at least
15 of which must come from Part A. Candidates who obtain less than 15
marks in Part A will be given a maximum of 40 marks for the paper.
Time allowed : Reading 15 minutes
Writing 3 hours
PART A – Case Study [36 of 100 marks]
Rileys Recreation is a recreation centre consisting of a hall, a gymnasium and a shop.
The hall is hired for social and community activities such as a basketball team based
at the hall (they charge a small admission price) and private groups that book the hall
for family celebrations. In addition to a hiring fee, groups must also pay a refundable
deposit against damage to the hall, which must be paid in advance along with the
hiring fee. All hirers must clean up after their function. If they fail to clean up
satisfactorily a standard "clean up" fee is charged.
The gymnasium is only available to people who purchase a yearly pass, which is valid
from 1st October to 30th September each year. If a pass is purchased after 1st March,
it costs half the annual rate. The gymnasium pass is shown on entry.

The shop sells food such as ice cream, cool drinks, confectionary and a small range of
sporting goods. Entry to all facilities is through the shop, which is open from 6:00 am
to 11:30 pm every day.
Bookings are mostly taken by telephone by whoever picks up a call. Two telephones
are located within the shop facility and others are located in the manager's office, staff
room and at convenient places around the recreation facility. Any call can be picked
up from anywhere. A large book is located within the shop. Bookings for the hall are
marked in this book, along with hiring details such as how long the hall is hired, hirers
name, address, telephone number, amount of hire, amount paid, amount refunded after
hire and any comments that may be relevant.
An order book is used for purchases, from which an order is sent to suppliers who
then invoice the recreation center. Signatories for both cheque account and order
book are the recreation center manager and a nominated deputy - either to sign.
Attempt either question 1 or question 2 – questions are of equal value.
Question 1 [36 marks]
For the case study example given and using structured systems analysis and design
techniques:
a) Draw a levelled data flow diagram and briefly describe the major processes.
[18 marks]
b) Draw a data model (ie. entity relationship diagram or similar). Ensure
relationships and relationship cardinalities are clearly identified.
[18 marks]
Annotate your diagram with explanatory notes where necessary.
OR
For the case study example given and using object oriented systems analysis and
design techniques, draw appropriate diagrams (eg. object or class diagrams,
interaction or sequence diagram, etc.)
Ensure the diagrams clearly identify:
a) links and relationships between object classes. [18 marks]
b) attributes of object classes. [9 marks]
c) methods (ie. services) available to object classes. [9 marks]
Annotate your diagram with explanatory notes where necessary.

PART B – Analysis and Design Theory [64 of 100 marks]
Attempt only FOUR (4) of the following questions –questions are of equal value.
(a) Within organisations, information systems are made up of modules or
subsystems. Describe the:
human resources module; [2 marks]
materials module; and [2 marks]
client relations module; [2 marks]
(b) The financial services module incorporates general accounts, accounts
payable, accounts receivable and payroll. Describe this module.
[4 marks]
(c) Explain issues in integrating information systems modules.
[6 marks]
Describe a development life cycle. Then, for each phase within a development life
cycle, provide headings for a documentation methodology and a detailed explanation
of contents for each heading.
a) Using object-oriented representation as examples, provide a detailed explanation
for objects, classes, encapsulation, inheritance, and polymorphism.
[10 marks]
b) Describe the following object-oriented techniques:
Use case diagram [2 marks]
State diagram [2 marks]
Event trace diagram [2 marks]

(a) Discuss issues for each of the following quality assurance steps:
Quality assurance program; [2 marks]
Quality assurance review; and [2 marks]
Inspections. [2 marks]
(b) Explain how a walkthrough is conducted and describe preparation, team roles and
methodology. [10 marks]
(a) Discuss issues for each of the following steps in managing a project:
determine tasks; [2 marks]
estimate resources required; [2 marks]
identify risks; [2 marks]
schedule tasks; and [2 marks]
monitor progress. [2 marks]
b) What should occur when changes to a system specification are desired midway
through system development? [6 marks]

May 2003
FAMILY NAME ……………………………………
GIVEN NAME(S) …………………………….…….
PAPER: Java Programming
Please:
Questions
Attempted
(please tick)
Examiners
Mark Only
1
2
3
4
5
6
Total Mark

Australian Computer Society Programming Exam May 2003 Page 2 of 10
May 2003
Java Programming
Answer all six (6) questions. The questions on this paper total 100 marks.
Writing 3 hours
Question One [20 marks]
A. Which of the following is the correct way to start a file to define a class that will
be in the default package and use classes from the java.awt package?
a) package default;
import java.awt;
b) import java.awt.*;
c) package default;
import java.awt.*;
B. Which of the following statements declaring and initialising a primitive variable
would not be rejected by the Java compiler?
a) boolean flag = true;
b) Boolean flag = true;
c) boolean flag = TRUE;
d) Boolean flag = TRUE;

C. Given the following code
String alpha = “alpha “;
String beta = “beta “;
alpha += beta + “gamma”;
What is contained in alpha after the code executes?
a) “alpha beta”
b) “alpha beta gamma”
c) “beta gamma”
d) “beta gamma alpha”
D. Given the following method to compare two boolean primitive values:
public void testB (boolean a, boolean b)
{
Boolean A = new Boolean (a);
if (A.equals (b))
System.out.println (“Equal”);
else
System.out.println (“Not equal”);
}
Which of the following statements about testB is true?
a) testB will always output “Not equal”, no matter what input parameters are
used
b) testB will not compile as written
c) The method call testB (true, true) will output “Equal”
E. What is the output of the following program?
public class Counter
{
int count;
public static void main (String[] args)
{
for (int i = 0; i < 5; i++)
new Counter (i);
}
public Counter (int count)
{
System.out.print (count + “ “);
}
}
a) 0 0 0 0 0
b) 1 2 3 4 5

c) 0 1 2 3 4
d) The program won’t compile because count is declared twice.
F. The following code causes a compiler error. Which answer best describes the
reason?
double x;
static double multiply (float y)
{
return (float) x * y;
}
a) The function attempts to return a float instead of a double
b) multiply is a static method attempting to access the instance variable x
c) x is not initialised
G. The following code generates a compiler error. Which one of the following
answers best describes the reason for the error?
public class A
{
public static double var1 = 3245;
private double var2;
public A ()
{
var1 = var2;
}
public void function (int var3)
{
double var4;
var2 = var3 * var4;
}
}
a) var2 is not initialised correctly before use
b) var4 is not initialised correctly before use
c) var3 and var4 are not of the same type and thus can’t be used together in an
expression without explicit casting
Question Two [10 marks]
Following is a segment of a file called Stereo.java which implements a stereo as a
Java object. Some of the code is missing. Inspect this code carefully, and then answer
the following questions.
import java.io.*;
public class Stereo
{
public static final int ON = 1;

public static final int OFF = -1;
protected int power;
protected Amplifier amp;
public class Amplifier
{
protected final int MINVOLUME = 0;
protected final int MAXVOLUME = 10;
protected int volume;
public Amplifier ()
{
volume = 5;
}
public void turnVolumeUp ()
{
if (volume < MAXVOLUME)
volume++;
displayVolume ();
}
public void turnVolumeDown ()
{
if (volume > MINVOLUME)
volume--;
displayVolume ();
}
public void displayVolume () { }
}
public Stereo ()
{
amp = new Amplifier;
power = OFF;
}
public void togglePower ()
{
if (power == ON)
{
power = OFF;
System.out.println (“Power is off”);
}
else
{
power = ON;
System.out.println (“Power is on”);
}
}
public void turnVolumeUp () {}
public void turnVolumeDown () {}
public static void main (String [] args) throws IOException
{
Stereo s = new Stereo ();
BufferedReader in = new BufferedReader
(new InputStreamReader (System.in));

String userinput;
while (true)
{
System.out.println (“Stereo> “);
Userinput = in.readLine ().toLowerCase ();
if (userinput.equals (“up”))
s.turnVolumeUp ();
else if (userinput.equals (“down”))
s.turnVolumeDown ();
else if (userinput.equals (“power”))
s.togglePower ();
}
}
}
A. What user input does this program take, and what are the effects?
B. Implement the displayVolume () method, and be sure it is consistent with the
stereo object.
C. Implement the turnVolumeUp () and turnVolumeDown () methods.
Question Three [10 marks]
Following are four statements. Consider each statement and explain why it is either
true or false.
A. The garbage collection mechanism is platform dependent.
B. You can suggest when garbage collection will run but you cannot be certain when
it will take place.
C. A reference to a primitive variable is eligible for garbage collection when it is set
to null.
D. The automatic garbage collection of the Java Virtual Machine prevents programs
from ever running out of memory.
Question Four [10 marks]
The following code is compiled and executed. Inspect this code carefully and then
answer the following question.
1 public class CstTest
2 {
3 public static void main (String [] args)
4 {
5 long x = Long.MAX_VALUE – 1;
6 double d = (double) x;
7 long y = (long) d;
8 System.out.println (“original x = “ + x);
9 System.out.println (“cast back to long = “ + y);
10 }
11 }

Explain why each of the following statements is true or false.
A. The explicit cast in line 7 is not required.
B. We should not be surprised if the value of y does not equal the original x value.
C. The explicit cast in line 6 is not required.
Question Five [25 marks]
You have been asked to write a program which creates a sorted list of words. Inspect
the following code carefully then answer the questions.
import java.util.*;
import java.io.*;
public class TokenSort
{
public static void main (String[] args)
{
TokenTwo t = new TokenTwo (args[0]);
try
{
t.parseFile ();
t.dumpSet (System.out);
}
catch (IOException e)
{
System.out.println (“Error “ + e);
}
System.out.println (“Finished”);
}
}
class TokenTwo
{
String filename;
TreeSet tSet;
TokenTwo (String filen)
{
filename = filen;
tSet = new TreeSet ();
}
void parseFile () throws IOException
{
InputStream is = new FileInputStream (filename);
BufferedReader br = new BufferedReader
(new InputStreamReader (is));
String wrk = br.readLine ();
while (wrk! = null)
{
if (wrk.length () > 0)
{
StringTokenizer st = new StringTokenizer (wrk,
“;:.,()/{}[]ntr ””);
while (st.hasMoreTokens ())
tSet.add (st.nextToken ());

}
wrk = br.readLine ();
}
}
void dumpSet (PrintStream ps)
{
Iterator it = tSet.iterator ();
while (it.hasNext ())
ps.println (it.next ());
}
}
A. Explain how this program produces a sorted list of words using the
StringTokenizer and TreeSet classes.
B. The natural sorting order of String objects is to sort lowercase letters after
uppercase letters. By default, the TreeSet uses this natural sorting order when
adding Strings. Suppose you want to impose a different comparison by using the
TreeSet constructor that takes a Comparator and by defining the methods required
by the Comparator interface in an anonymous inner class. Fill out the code below,
so that the value returned by the compare method is the alphabetically earlier
string, regardless of whether it is upper- or lowercase.
tSet = new TreeSet (new Comparator ()
{
public int compare (Object oA, Object oB)
{
// compare oA to oB and return the alphabetically earlier string
}
public Boolean equals (Object obj) {return false;}
});
C. What is the purpose of this line of code?
StringTokenizer st = new StringTokenizer (wrk,
“;:.,()/{}[]ntr ””);
D. The program requires a filename to be passed in as a command-line parameter.
Yet, it does not check that this is the case. Add code to the main() method of the
TokenSort class to verify that a String has been passed in on the command-line,
and to exit with an error message if this is not the case.
Question Six [25 marks]
You want to generate a simple graphical user interface (GUI) using components from
the original AWT library and event handling in the original AWT style. The following
code has been started for you.

import java.awt.*;
public class AWT1 extends Frame
{
public static void main (String args[])
{
new AWT1 ();
}
Label label1;
TextField edit1;
Button button1;
public AWT1 ()
{
super (“AWT1 window”);
setLayout (null);
setSize (290, 190);
label1 = new Label (“Text Label”);
label1.setBackground (Color.cyan);
label1.setForeground (Color.black);
add (label1);
edit1 = new TextField (19);
add (edit1);
button1 = new Button1 (“Start”);
add (button1);
setLocation (50, 50);
setVisible (true);
}
public boolean handleEvent (Event event)
{
if (event.id == Event.WINDOW_DESTROY)
{
setVisible (false);
dispose ();
System.exit (0);
return true;
}
return super.handleEvent (event);
}
public boolean action (Event event, Object arg)
{
if (event.target == buton1)
{
edit1.setText (“Start!”);
return true;
}
return false;
}
}

A. Write code to be added to the constructor, for the purpose of adding a menu bar to
your GUI, containing a File menu, with options New, Open, Save and Exit, and a
Help menu containing an option About. Don’t worry about connecting events,
simply make the user interface.
B. What does the user interface for this program look like (draw a simple picture)?
C. What events does this program handle? How are the events generated?
D. What is the purpose of this line in the handleEvent method?
return super.handleEvent (event);
E. What is the result of this line of code?
setLayout (null);
F. Modify the code so that it uses the BorderLayout layout. What happens if the
window is resized when the program is running?

May 2003
FAMILY NAME ……………………………………
GIVEN NAME(S) …………………………….…….
PAPER: Computer Oganization
Please:
• Write your Exam Number at the TOP of every
answer page.
• Write your answer in the space provided below
each question.
Questions
Attempted
(please tick)
Examiners
Mark Only
1
2
3
4
5
Total Mark

Australian Computer Society CompOrg exam – May 2003 Page 2 of 10
May 2003
Computer Organization
Answer all five (5) questions
Question 1 = 20 marks
Writing 3 hours
All answers must be written on this paper and should not exceed the space provided.
No additional paper will be supplied.
This paper must not be removed from the examination room.

Question One
Briefly describe the following terms. (20 marks)
(i) RISC
(ii) Interrupt
(iii) Virtual storage/memory
(iv) Instruction cycle
(v) System Bus

Question Two
(a) Convert the binary number 10110111.011 into decimal and hexadecimal numbers. You must
show the working process. (6 marks)
(b) Simplify the following logic expression:
E= AB+ C(A’+B’)’ +AB(BC)’ (6 marks)

(c) What are the main functional components of a computer and what are their main functions?
(4 marks)
(d) Briefly describe the four main parameters or factors that determine the performance of a
computer. (4 marks)

Question Three
(a) Suppose that a computer has a cache, main memory and a disk used for virtual memory. Access
time for cache, main memory and virtual memory is 10 ns, 200 ns and 500 ns respectively. If the
cache hit ratio is 80%, the main memory hit ratio is 10%, what is the average access time of the
memory system? (6 marks)
(b) Use an example to show how to calculate the storage requirement of a bit-mapped
graphics/image. (6 marks)

(c) Briefly describe a common memory hierarchy. In your description, you should explain why a
particular memory device is used. (8 marks)

Question Four
(a) What is RAID and why is it used? (6 marks)
(b) Briefly describe the operation principle of the direct memory access technique. (6 marks)

(c) Consider a 32-bit microprocessor, with a 32-bit external data bus, driven by a 16-MHz input clock.
Assume that this microprocessor has a bus cycle whose minimum duration equals four input clock
cycles. What is the maximum data transfer rate that this microprocessor can sustain?
(8 marks)

Question Five
(a) (i) What is multiprogramming? (4 marks)
(ii) How does multiprogramming improve efficiency/utilization of a computer system?
(6 marks)
(b) (i) In the internal structure of a CPU, what are user-visible registers? (4 marks)
(ii) Name two user-visible registers and describe their functions. (6 marks)

May 2003
FAMILY NAME ……………………………………
GIVEN NAME(S) …………………………….…….
PAPER: Data Management
Please:
Questions
Attempted
(please tick)
Examiners
Mark Only
1
2
3
4
5
6
7
Total Mark

Australian Computer Society DM exam - May 2003 Page 1 of 4
May 2003
Data Management
Answer any five (5) questions. All questions are worth equal marks.
Writing 3 hours
Consider the following scenario:
“A company provides home maintenance services to registered clients, and
employs a number of tradespeople. Each of these employees is assigned a
company vehicle, which is reserved for their exclusive use. There are a
number of spare vehicles, so that, if an employee’s vehicle breaks down, they
are reallocated a spare vehicle, and the broken down vehicle is held in the pool
for repair.
Customers request services, and a single employee is sent for each request. It
is possible that different tradespeople are sent to the same client on different
occasions.
There is a set fee for each service call, but there will be an extra charge
depending upon whether any materials were used.”
Model this scenario using an entity-relationship (sometimes called entity-association)
diagram or some equivalent modelling technique (for example object-oriented
modelling), documenting any additional assumptions you have made. Show in your
model entity classes, associations between entities, and major attributes, paying
particular attention to identifying primary keys.
A database is used to store raw facts (data) from which database users will produce
hopefully useful information. Describe the important characteristics of this data and
the process of producing information if the information is to be considered valuable
by its users.

Consider that, during analysis, the Sales Department has requested the database store
ORDER_DETAILS (CustomerID, PartID, Description, CustomerName, Price,
Quantity)
to record the descriptions and quantity of parts ordered by the named customer.
Consider further that the Stores Department wants to see
INVENTORY (PartID, Warehouse, Price, Quantity)
to record the quantity of each part held at a specific warehouse. They tell you that the
price of a product is the same for all warehouses.
Identify the functional dependencies in these two user views, and from these
dependencies consolidate the two user views into a set of relations in third normal
form.
Imagine that you are working for an organisation that has just received a specification
for some DBMS software that is being considered for purchase. The software
specification contains the following comments about its transaction management
provisions:
The level of lock granularity is the record level. Provision is made for both
shared and exclusive locks. The DBMS incorporates deadlock resolution
facilities.
Further imagine that your manager asks you to explain these terms. What explanation
can you give of the technical terms given in the scenario?
Consider the scenario that in a distributed database system some users have reported
to the DBA that the response time for certain queries has slowed noticeably in recent
months.
What should a DBA do to investigate this problem, and what options need to be
considered in seeking to improve the situation?
With personal databases, a common backup technique is to stop database processing
and take a copy of the entire database in this inactive state.
However, where databases are required to be operational 24-hours a day and 7-days a
week, different strategies must be adopted for backups. What options are available,
and what disadvantages have to be accepted for each technique compared to the
backup of a personal database?

Question Seven [20 marks]
Consider the following test data contents for two tables used within a ticket agency.
Ticket sales for each scheduled event are recorded in the Booking table. Customers
are identified by name, and may make only one booking per event.
[In the following question, remember to produce general answers, not just ones that
will work with the test data given.]
(a) What output will be produced by the SQL statement
SELECT sum(deposit) AS Total,
count(name) AS Bookings,
avg(deposit) AS Average
FROM Booking;
[4 marks]
(b) Write an SQL query to list the event code and number of tickets sold for each
event for which at least one sale has been recorded.
[4 marks]

(c) Write an SQL statement to list the details of all events where no tickets have
been sold, with events sequenced by date from earliest to latest.
[4 marks]
(d) Explain why the following query
FROM Event, Booking
designed to list tickets sold for every event scheduled, would not, if applied to the
test files given, list event B11 or C12? What, if anything, can be done to
overcome this potential problem.
[4 marks]
(e) Write an SQL query to display the booking name and event code of any event for
which only one booking has been made.
[4 marks]

Australian Computer Society OOSD Examination -May 2003 Page 1 of 4
May 2003
FAMILY NAME ……………………………………
GIVEN NAME(S) …………………………….…….
PAPER: Object-Oriented Systems Development
Please:
Questions
Attempted
(please tick)
Examiners
Mark Only
TOP of every answer page 1
• Write your answers in INK 2
• Write CLEARLY and NEATLY 3
• Use only ONE side of the paper 4
5
6
7
8
9
10
Total mark

May 2003
OBJECT-ORIENTED SYSTEMS DEVELOPMENT
The questions on this paper total 100 marks.
Candidates must obtain a minimum of 50 marks to pass.
Writing 3 hours
This paper has 10 questions, consisting of a case study with 8 questions,
and 2 short answer questions.
Candidates should attempt all questions.

Case Study
You have been asked to create an information system for a library using the following
attributes and constraints:
• The lends out books, CDs and DVDs
• The borrowing period for books is four weeks, for CDs two weeks and for DVDs one
week
• Each library item (i.e. each book, CD, DVD) is identified by a unique number
• Overdue items attract a fine, for which only cash payments are accepted
• Only members can borrow from the library; members are identified by a unique
membership number
• On completion of a borrowing transaction, the member receives a printed docket
showing the item(s) borrowed and the due date(s) for each item.
Question 1 (5 marks)
Identify at least 4 primary use cases and related actors. Draw the results in a UML use
case diagram. Call one of the use cases Borrow Items.
Write the Borrow Items use case in expanded, essential, conversational style. Include
both a typical course of events, and an alternatives section. In the alternatives section, list
two frequent alternatives.
Create a conceptual model based on the Borrow Items use case and illustrate it in UML
notation. Show concepts, associations, and attributes.
Create a system sequence diagram in the UML notation based on the Borrow Items use
case. Show actors and at least three (3) system events.
Create a contract for the recordBorrowItems operation. Show responsibilities, pre- and
post-conditions.

Using the recordBorrowItems operation contract as a starting point, complete the UML
collaboration diagram. Annotate every message with the GRASP (Expert, Creator, and so
on) and/or other pattern that justifies it.
Draw a partial design class diagram for the Library and Membership classes. Show all
simple attributes, associations (with navigability) between these two classes.
Based on the design class diagrams and collaboration diagrams in this case study, show
the class definition for the class Library. Show all instance variable (data member)
definitions, but only show the complete method (member function) body definition for
one method: getMembership(). Ignore fine details of syntax. Use the object-oriented
programming language indicated by the syllabus.
a. (5 marks) Explain the difference between a Domain Model and a Design Class
Diagram.
b. (5 marks) What are some reasons for creating 1) domain models, and 2) system
sequence diagrams?
a. (5 marks). What does the acronym GRASP stand for? Briefly explain each of the
GRASP patterns.
b. (5 marks). The terms Collaboration diagram and Sequence diagram are often
interchanged. Briefly contrast and explain these two terms.

May 2003
FAMILY NAME ……………………………………
GIVEN NAME(S) …………………………….…….
PAPER: Computer Communications
Please:
• Write your Exam Number at the TOP of every
answer page.
• Write your answer in the space provided below
each question.
Questions
Attempted
(please tick)
Examiners
Mark Only
1
2
3
4
5
Total Mark

Australian Computer Society CompComm exam – May 2003 Page 2 of 11
May 2003
Computer Communications
Answer all five (5) questions
Writing 3 hours
All answers must be written on this paper and should not exceed the space provided.
No additional paper will be supplied.

Question One
Briefly describe the following terms. (20 marks)
(i) Layered protocol architecture
(ii) Synchronous data transmission
(iii) Media Access Control
(iv) Flow control
(v) Circuit switching

Question Two
(a) What is a communication protocol and why is it needed? (5 marks)
(b) What are the main functions of the data link layer? (5 marks)

(c) Briefly describe the similarities and differences between OSI Reference Model and the TCP/IP
architecture. (10 marks)

Question Three
(a) (i) What is the spectrum of a signal? (4 marks)
(ii) In pulse code modulation, how is the sampling rate decided? (4 marks)
(b) Briefly describe the Manchester encoding format. (6 marks)

(c) Compare synchronous time-division multiplexing and statistical time-division multiplexing.
(6 marks)

Question Four
(a) Briefly describe two flow control techniques. (6 marks)
(b) Using an example, explain how parity check is used to detect data error. (6 marks)

(c) Briefly describe the operation of the Ethernet local are network. (8 marks)

Question Five
(a) One of the main protocols of the Internet is the Transport Control Protocol (TCP). Briefly describe
the main functions of the TCP. (6 marks)
(b) What is MIME and what are its main functions? (6 marks)

(c) (i) Briefly describe two main security risks of data transmission over the Internet? (4 marks)
(ii) Describe techniques to reduce/overcome these risks. (4 marks)

`
May 2003
FAMILY NAME ……………………………………
GIVEN NAME(S) …………………………….…….
PAPER: Professional Practice
Please:
Questions
Attempted
(please tick)
Examiners
Mark Only
1
2
3
4
5
6
7
Total Mark

Australian Computer Society Prof Practice exam – May 2003 Page 1 of 7
May 2003
Professional Practice
Answer question one in Section A and any three questions from section B.
Section A is worth 55 marks.
Section B is worth 45 marks. Questions in section B are of equal value.
The ACS Code of Ethics is included at the end of the paper. Please refer to it when
answering the questions.
Writing 3 hours

SECTION A (compulsory)
“The information security manager in a large company was also the access control
administrator of a large electronic mail system operated for company business among its
employees. The security manager routinely monitored the contents of electronic
correspondence among employees. He discovered that a number of employees were using the
system for personal purposes; the correspondence included love letters, disagreements
between married partners, plans for homosexual relations and a football betting pool. The
security manager routinely informed the human resources department director and the
corporate security officer about these communications and gave them printed listings of the
content of the electronic mail messages. Employees objected to the monitoring of their
electronic email, claiming that they had the same right of privacy as they had using the
company’s telephone system or internal paper interoffice mail system.”
a) Who are the stakeholders?
b) Which facts raise ethical concerns? Why?
c) Identify the major ethical dilemma which must be resolved.
d) What are the rights and duties of each of the stakeholders?
e) What guidance does the Australian Computer Society’s Codes of Ethics provide in
this situation (the ACS Code of Ethics is provided with this exam paper for your
reference)?
f) How would you resolve the dilemma identified in point (c) above? Justify your
decision.
g) How are the stakeholders affected by your decision?
h) What should have been done or not done in the first place to avoid the major
dilemma?

SECTION B (answer any three questions)
As an IT professional you have been asked to advise new staff on issues relating to computer
use. Briefly describe five issues you would discuss with them. Why have you selected these
ones?
Briefly describe the components of a model of communication you are familiar with. Explain
why gaining an understanding of the audience is particularly important when planning a
communication.
Describe the effect that implementation of information systems in organisations has had on
organisational structure. Why have these changes occurred?
What are the key privacy concerns related to eCommerce? How can businesses overcome
customers’ concerns?
Provide three arguments that can be given in defence of hacking. What are the counter
arguments to each of these defences?

Australian Computer Society Code of Ethics
A Requirement
An essential characteristic of a profession is the need for its members to abide by a Code of Ethics.
The Society requires its members to subscribe to a set of values and ideals which uphold and advance
the honour, dignity and effectiveness of the profession of information technology.
The code is part of the Society's Regulations and the numbering sequence has been maintained.
Code Of Ethics
4. Code of Ethics
4.1 To uphold and advance the honour, dignity and effectiveness of the profession of
information technology and in keeping with high standards of competence and ethical
conduct, a member must:
a.be honest, forthright and impartial, and
b.loyally serve the community, and
c.strive to increase the competence and prestige of the profession, and
d.use special knowledge and skill for the advancement of human welfare.
4.2 The personal commitments set out in NR4.3 and NR4.4 bind each member with
regard to that member's professional conduct.
4.3 Values and Ideals: I must act with professional responsibility and integrity in my dealings
with the community and clients, employers, employees and students. I acknowledge:
4.3.1 Priorities: I must place the interests of the community above those of personal or
sectional interests.
4.3.2 Competence: I must work competently and diligently for my clients and
employers.
4.3.3 Honesty: I must be honest in my representations of skills, knowledge, services
and products.
4.3.4 Social Implications: I must strive to enhance the quality of life of those affected
by my work.
4.3.5 Professional Development: I must enhance my own professional development,
and that of my colleagues, employees and students.
4.3.6 Information Technology Profession: I must enhance the integrity of the
information technology profession and the respect of its members for each other.
4.4 Standards of Conduct
The standards of conduct set out in these National Regulations explain how the Code of
Ethics applies to a member's professional work. The list of standards is not necessarily
exhaustive and should not be read as definitively demarking the acceptable from the
unacceptable in professional conduct in all practical situations faced by a member. The
intention of the standards of conduct is to illustrate, and to explain in more detail, the meaning
of the Code of Ethics in terms of specific behaviour. The fact that a member engages in, or
does not engage in, these standards does not of itself guarantee that a member is acting
ethically, or unethically, as applicable. A member is expected to take into account the spirit of
the Code of Ethics in order to resolve ambiguous or contentious issues concerning ethical
conduct.
4.5 Priorities
In accordance with NR4.3.1:

4.5.1 I must endeavour to preserve continuity of information technology services and
information flow in my care.
4.5.2 I must endeavour to preserve the integrity and security of the information of
others.
4.5.3 I must respect the proprietary nature of the information of others.
4.5.4 I must endeavour to preserve the confidentiality of the information of others.
4.5.5 I must advise my client or employer of any potential conflicts of interest between
my assignment and legal or other accepted community requirements.
4.5.6 I must advise my clients and employers as soon as possible of any conflicts of
interest or conscientious objections which face me in connection with my work.
4.6 Competence
4.6.1 I must endeavour to provide products and services which match the operational
and financial needs of my clients and employers.
4.6.2 I must give value for money in the services and products I supply.
4.6.3 I must make myself aware of relevant standards, and act accordingly.
4.6.4 I must respect and protect my clients' and employers' proprietary interests.
4.6.5 I must accept responsibility for my work.
4.6.6 I must advise my clients and employers when I believe a proposed project is not
in their best interest.
4.6.7 I must go beyond my brief, if necessary, in order to act professionally.
4.7 Honesty In accordance with NR4.3.3:
4.7.1 I must not knowingly mislead a client or potential client as to the suitability of a
product or service.
4.7.2 I must not misrepresent my skills or knowledge.
4.7.3 I must give opinions which are as far as possible unbiased and objective.
4.7.4 I must give realistic estimates for projects under my control.
4.7.5 I must qualify professional opinions which I know are based on limited
knowledge or experience.
4.7.6 I must give credit for work done by others where credit is due.
4.8 Social Implications
4.8.1 I must protect and promote the health and safety of those affected by my work.
4.8.2 I must consider and respect people's privacy which might be affected by my
work.
4.8.3 I must respect my employees and refrain from treating them unfairly.
4.8.4 I must endeavour to understand, and give due regard to, the perceptions of
those affected by my work.
4.8.5 I must attempt to increase the feelings of personal satisfaction, competence, and
control of those affected by my work.
4.8.6 I must not require, or attempt to influence, any person to take any action which
would involve a breach of the Code of Ethics.
4.9 Professional Development
4.9.1 I must continue to upgrade my knowledge and skills.
4.9.2 I must increase my awareness of issues affecting the information technology
profession and its relationship with the community.
4.9.3 I must encourage my colleagues, employees and students to continue their own
professional development.
4.10 Information Technology Profession
4.10.1 I must respect, and seek when necessary, the professional opinions of
colleagues in their areas of competence.
4.10.2 I must not knowingly engage in, or be associated with, dishonest or fraudulent

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