THE BRITISH COMPUTER SOCIETY
THE BCS PROFESSIONAL EXAMINATIONS
BCS Level 4 Certificate in IT
COMPUTER & NETWORK TECHNOLOGY
Wednesday 8th October 2008 - Afternoon
Time: TWO hours
Section A and Section B both carry 50% of the marks. You are advised to spend about 1 hour on Section
A (30 minutes per question) and 1 hour on Section B (12 minutes per question).
The marks given in brackets are indicative of the weight given to each part of the question.
Calculators are NOT allowed in this examination.
SECTION A
Answer TWO questions out of FOUR. Each question carries 30 marks.
1.
a)
Draw a (simplified) block diagram of the structure of a typical CPU at the level of
registers, ALU, and functional units. This may be the diagram of a real CPU or a
hypothetical CPU that is used in teaching.
By means of this diagram, explain how an instruction is read from memory and
executed.
(15 marks)
b)
An operand in a machine-level instruction can be a literal (or immediate)
operand, a direct reference to memory (absolute address), or an indirect
reference to memory (pointer-based or indexed addressing). The specific
terminology used to describe these three addressing modes varies from
computer to computer, but most computers provide at least these three
fundamental addressing modes.
Define these three fundamental addressing modes that can be used by the
assembly language programmer. Give examples of each addressing modes and
clearly state how and why it is used.
(15 marks)
2.
Today’s academics, business people, scientists, law-enforcement agents, and
engineers rely very heavily on mobile computing; that is, the ability to use
computers and access the internet and email remotely as they travel from place
to place (often around the world).
The computing facilities (typically, a so-called laptop or notebook computer) used
by such people are crucial to them and their work.
Describe the security problems (both in hardware and software) with which such
people must concern themselves and suggest possible solutions to these
problems.
(30 marks)
Turn over]
3.
4.
A computer system such as a PC may contain five or more different forms of memory
technology. Collectively, these technologies are called a hierarchy with cache memory at
the top and CD/DVD ROM at the bottom.
a)
Draw a diagram to illustrate a computer’s memory hierarchy and explain why
such a hierarchy exists (i.e., why aren’t computers built from one type of memory
component).
(10 marks)
b)
Describe the characteristics of (at least) five types of memory in terms of their
operational properties and briefly describe the underlying technology of each
memory type.
(20 marks)
It is now possible for computers to communicate with each other even if they are
thousands of kilometers apart.
I can go to a conference in Mauritius; take my laptop and read my e-mail from a server in
England just as if I were at home. Explain how computers are able to communicate with
each other across such large distances. Your answer should include a description of the
technologies involved and an explanation of how messages are correctly and reliably
routed from point to point.
(30 marks)
SECTION B
Answer FIVE questions out of EIGHT. Each question carries 12 marks
5.
A range of devices are needed when setting up a computer network. Provide a brief
description of the technical characteristics of each of these devices:
a)
b)
c)
d)
router
switch
repeater
bridge
(3 marks each)
6.
The IT Manager of your college has offered you a temporary contract to investigate into
the various security threats that the college’s IT infrastructure is subject to by its users.
You have been asked to investigate three security measures. For each of the following
security measures, describe its typical features and state the reasons why the college
should use that security measure.
a)
b)
c)
Firewall
Access Control List (ACL)
Anti virus software
(4 marks each)
7.
Operating Systems provide the vital facilities for the smooth operation of a Personal
Computer. Using an Operating System you are familiar with, describe the following
Operating System functions :
a)
b)
c)
Multi tasking
Scheduling
I/O Interrupts
(4 marks each)
8.
Multimedia computer systems are readily available today. These systems are suitable
for a range of tasks.
a)
What do you understand by the term multimedia as applied to computer
systems?
(3 marks)
b)
Produce a technical specification of hardware and software required for a typical
multimedia computer.
(9 marks)
Turn over]
9.
During the creation of a network, it is necessary to fully understand various key concepts
and how they operate. For each of the terms below, provide a brief description and
explain why they are important to the network staff.
a)
Twisted Pair and Fibre Optics Cabling
(6 marks)
b)
Media Access Control (MAC) and Logical Link Control (LLC) Sublayers
(6 marks)
10.
Copy and complete the table below. Clearly show all your workings.
Binary
Decimal
Hexadecimal
63
435
10100111
2E
330
1FB
(2 marks each)
11.
Communication technologies have significantly developed over the past few years. New
and fast technologies are now available which have made others obsolete. Compare
and contrast the following pairs of terms as used for data transmission:
a)
b)
c)
Baseband and Broadband
Synchronous and Asynchronous
Simplex and Duplex
(4 marks each)
12.
With development in technology, there has been a need for various rules and protocols.
Briefly describe each of the following and explain in which area of networking it is used:
a)
b)
c)
d)
IP address
FTP
TCP/IP
CSMA/CD
(3 marks each)