Question 1: What is the decimal value for (10001000)2 ?

a)    136

b)   138

c)    140

d)   142

Question 2: What is the binary value for (98)10 ?

a)    1110001

b)    1110010

c)    1100010

d)    1110010

Question 3: What is the binary value for (98)16 ?

a)    10001001

b)    10011001

c)    10001000

d)    10011000

Question 4: Which of the following is an email protocol?

a)   BNN

b)  IMAP

c)   POP

d)  b and c

Question 5: Which of the following is the first step in booting a computer?

a)    Identifying drive holds the OS

b)   Loading the OS

c)    Initialising the 3D card

d)   None of the above

Question 6: A “byte” is a sequence of _____ adjacent bits and a “single bit” can be expressed by ______ or ______.

a)    6 and 1, 0

b)   8 and 7, 6

c)    8 and 1, 0

d)    16 and 1, 0

Question 7: Which sequence of instructions in MARIE assembly code results in the value stored at address 20 to be triple?

a)    Load 20, Add 20, Add 20, Store 20

b)    Load 20, Add 20, AddI 20, StoreI 20

c)    Load 20, Mult 3, Store 20

d)    Load 120, JnS Mult, Store 120

Question 8: Which of the following architectures involves the most work being done by the client’s machine?

a)   Server- Based

b)   Thin-Client

c)    Client- Based

d)   Client-Server

Question 9: _____ keys are required for secure communication between 10 users in asymmetric cryptography.

a)    10

b)   100

c)    20

d)   45

Question 10: The dotted-decimal subnet mask of /25 is:

a)    255.255.255.255

b)   255.255.255.128

c)    255.0.0.0

d)   0.0.0.25

Question 11: The slash subnet mask of 255.255.128.0 is:

a)   /15

b)   /16

c)    /17

d)   /18

Question 12: A local area network is:

a)    a large central network that connects other networks in a distance spanning exactly 5 miles.

b)   a group of personal computers or terminals located in the same general area and connected by a common cable.

c)    a network spanning a large geographical area (up to 1000s of miles).

d)   a network spanning exactly 10 miles with common carrier circuits.

Question 13: The _____ layer is responsible for routing of messages from the sender to the final destination.

a)    data communication layer

b)   resident layer

c)    application layer

d)   network layer

Question 14: IMAP (Internet Message Access Protocol):

a)    is a set of standards that define how email is to be processed between mail servers

b)   is exactly the same as SMTP

c)    permits an e-mail message to remain stored on the mail server even after they have been read by a client computer

d)   is exactly the same as POP

Question 15: With a client-based network, one fundamental problem is that:

a)    all data on the server must travel to the client for processing

b)   the clients must perform the data storage logic

c)    the server does not have any data storage capability

d)   the clients each must store all the data

Question 16: IPv4 uses _____ bytes per Internet address.

a)    2

b)   4

c)    6

d)   8

Question 17: IPv6 uses _____ bits per Internet address.

a)    32

b)   48

c)    64

d)   None of the above

Question 18:  Which does IDS stand for in network security?

a)    Information Decryption System

b)    Intrusion Detection System

c)    International Defence Society

d)    Internet Decoding Specification

Question 19:  Which property is required for storing passwords?

a)   Confidentiality

b)  Authenticity

c)   Non-repudiation

d)  Privacy

Question 20:  Which of the following mechanism can be instantiated as software on individual PCs or in hardware as a special device in the network?

a)   Firewalls

b)  Virus scanners

c)   Intrusion detection

d)  Backup

Part B: Short Answer Questions (120 marks total)

Question 1 (3 Marks):

Explain the subtraction of two positive integers using 2's complement arithmetic.

Question 2 (3 Marks):

Convert the following numbers as specified. Show all workings.

1.   From base 10 to base 16: 1286

2.   From base 10 to base 2: 2050

3.   From base 16 to base 2: AF81C

Question 3 (3 Marks):

Draw a combinational circuit for the following Boolean function using only NOT, OR, and AND gates: (X1, X2, X3) = X1¬X2¬X3 + X1X2¬X3 + ¬X1X2¬X3

Q4 to Q8 are related

Question 4 (3 Marks):

Prepare a truth table for the following Boolean expression (use the table below)

Note: there may be more columns than you need

Z = ̅ + ̅D + B  + D

Question 5 (3 Marks):

Use Boolean algebra to simplify the Boolean expression (Z) given in the previous question.

Question 6 (3 Marks):

Consider the following truth table:

Draw a circuit diagram which matches the above truth table

Question 7 (3 Marks):

Write the Boolean equation for the truth table given in the previous question in sum of products form.

Question 8 (3 Marks):

Use a Karnuagh map to produce a simplified Boolean expression given in the previous question

Question 9 (3 Marks):

Briefly explain the concept of a process, including the states it can be in.

Question 10 (3 Marks):

Explain the following:

a-   Compiled Language

b-   Interpreted Language

c-    Combination Language

Question 11 (3 Marks):

Identify and briefly explain the roles of the three main components of a Central Processing Unit

Question 12 (3 Marks):

Briefly explain the concept of a flipflop circuit. Name a computer component where a flipflop is used.

Question 13 (3 Marks):

Use the following symbol for a full adder and draw a diagram for a 4-bit ripple carry adder.

Question 14 (3 Marks):

Explain two restrictions for a PC during firmware (BIOS/UEFI) configurations, when compared to a PC running a full operating system.

Question 15 (3 Marks):

Name and briefly explain the mechanism that operating systems use to provide each process with its own address space.

Question 16 (3 Marks):

Briefly explain how a router works.

Question 17 (3 Marks):

Explain the advantage of roaming in wireless networks.

Question 18 (3 Marks):

Explain the high-level structure of the Internet.

Question 19 (3 Marks):

Write the difference between ‘three-way handshake’ and ‘four-way handshake’ .

Question 20 (3 Marks):

Certificates are used to identify servers when using TLS.  Give one reason, why certificates can be problematic.

Question 21 (3 Marks):

What is a currently recommended hash function for use in digital signatures and which hash function is still used, but no longer recommended.

Question 22 (3 Marks):

Name two different methods for transmitting digital data through cables.

Question 23 (3 Marks):

Explain how digital data can be transmitted using digital signal (in unipolar and bipolar) with examples.

Question 24(3 Marks):

Explain how digital data can be transmitted using analog signal (in Frequency, Amplitude and Phase Modulation) with examples.

Question 25 (3 Marks):

Explain:

a)    POST

b)   CSMA/CD

c)    System Call

Question 26 (3 Marks):

Explain:

a.    SSL/TLS protocol.

b.   What is a VPN?

c.    TOR

Question 27 (3 Marks):

A 16-bit word in memory contains two 7-bit ASCII characters and one additional even parity bit for each character. The parity bit is the right-most bit.

ASCII Hexadecimal

030

031

032

033

034

035

036

037

038

039

041

042

043

044

045

046

047

048

ASCII Binary (7-bit)

0110000

0110001

0110010

0110011

0110100

0110101

0110110

0110111

0111000

0111001

1000001

1000010

1000011

1000100

1000101

1000110

1000111

1001000

Character Value

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

G

H

b) If you find 01101000 10001110. Would this be a valid representation of two characters?

c) Which two characters are encoded in 10001101 01101010?

Question 28 (3 Marks):

Give one reason why signed integer arithmetic is not suitable for computation of 3D graphics.

Question 29 (3 Marks):

Using a truth table show that y( + x) = y for all values of x  and y

Question 30 (3 Marks):

Identify the function of the circuit below. Give an example of inputs A and B (by writing into the squares) and fill in all intermediate and final outputs (dotted squares and circles).

 

Question 31 (3 Marks):

Add two 3-bit binary numbers 101 and 100 using circuit below. Fill in input, intermediate and

output bits in space provided.