Paper 2

Question 1

Check digit

Answer 1

A digit calculated using an algorithm and generated using other digits in a sequence

Question 2

ADC process

Answer 2

The analouge signal is sampled at fixed time intervals

The amplitude of a signal wave at each sample point is measured which is then coded in binary

Question 3

Nyquists theorem

Answer 3

Sample rate is double the highest frequency in the original sound

Question 4

Register

Answer 4

Memory location inside a processor

Question 5

Stored program concept

Answer 5

Instructions are stored in main memory
Intructions are fetched, decoded and executed by the processor which allows Programs to be moved in and out of the main memory

Question 6

Difference between harvard and von neumann

Answer 6

Harvard- execution of instructions are faster as fetching of coded and data are simultaneous
Von neumann- instructions and data have combined memory spaces

Question 7

Immediate addressing

Answer 7

When the operand is the datum

Question 8

Why vernam cypher is secure

Answer 8

Nothing can be learnt about the plaintext from the cipher text

Question 9

Advantage of ssd

Answer 9

Produce less heat- makes them comfortable to wear

Are silent- the won’t disturb the users

Question 10

Reasons for Compressing

Answer 10

Files take up less storage

Question 11

Lossless>lossy

Answer 11

Files can be reproduced exactly as it was in the beginning with no loss in quality
No redundant data is lost during the compression process

Question 12

Logical bus network topology

Answer 12

A node sends data to the entire network
All nodes on the network receives the data
A node checks the received data to check if it is the intended recipient
Only one node can successfully transmit data at a time

Question 13

Performing error detection on a recieved byte

Answer 13

If number of 1s recieved is even - data is recieved correctly
If number kf 1s received is odd - data is corrupted

Question 14

Adavantage of serial over parallel

Answer 14

Serial is cheaper - less wire is required

Serial does not suffer from cross talk - there is only one transmission line

Question 15

Natural numbers and integer numbers

Answer 15

Natural - doesnt include negative numbers

Integer - includes negative numbers

Question 16

Rational and irratianol numbers

Answer 16

Rational - can be represented as a fraction

Irrational - cannot be represented as a fraction

Question 17

Why use hexadecimal

Answer 17

More compact when displayed

Easier for the user to intepret

Question 18

Unicode > ascii

Answer 18

It can represent characters from languages all around the world

Question 19

Sample rate equation

Answer 19

Size / (sample resolution x time)

Question 20

Hardware

Answer 20

Physical component of a computer system

Question 21

Software

Answer 21

The instructions that tell a computer what to do

Question 22

Difference between system and application software

Answer 22

System - allows the user to operate a computer

Application - used to carry out tasks that are user oriented

Question 23

Example of system software

Answer 23

Compiler

operation system

Question 24

Why use both magnet disk and ssd

Answer 24

Magnet disk - useful for large capacity

SSD - useful for fast access to data

Question 25

Why is it faster to access data from ssd

Answer 25

No movable parts | Purely electronic

Question 26

Why use peer to peer instead of client server network

Answer 26

Doesnt need a central server | Easier to set up

Question 27

Protocols

Answer 27

Set of rules

Question 28

Baud rate

Answer 28

Number of signal changes in the medium in a second

Question 29

Bandwith

Answer 29

Range of frequencies that can be transmitted accross a network connection

Question 30

Majority bits > parity bits

Answer 30

Can detect multiple bit errors | More efficient of detecting errors

Question 31

Difference between machine code and assembly language

Answer 31

Machine code is binary/ assembly code is written using mnemonics Machine code can be executed without needing to be translated whereas assembly language does

Question 32

Similarity and differences of an assembler and compiler

Answer 32

Similarity - both convert source code into object code Differences - compiler is used to convert high level programming code into machine core whereas assembler converts assembly code into machine code

Question 33

Difference between analogue data and digital data

Answer 33

Analogue data is continuous data | Digital is stored as binary

Question 34

MIDI > sample sound

Answer 34

More compact | Easy to modify

Question 35

Encryption

Answer 35

Using an algorithm to convert a message into cipher text

Question 36

Vernam cipher > Caeser cipher

Answer 36

Verbam is harder to crack | Doesn’t always translate cipher text to the same plaintext

Question 37

Role of an Operating system

Answer 37

To hide complexities of the hardware from the user

Question 38

What does the Operating system manage

Answer 38

processors resource

Question 39

Why one processor might be faster than another

Answer 39

It can execute insructions quickly dependinng on the clock speed on both processors

Question 40

Physical topology

Answer 40

How nodes are physically laid out

Question 41

Logical topology

Answer 41

How data flows through a network

Question 42

Difference in interpreter and compiler

Answer 42

Compilers: produce machine code Translates the whole source code Interpreter: Does not produce any object code Always needs source code at run time

Question 43

Difference in direct and immediate addressing

Answer 43

Immediate means when the operand is the datum whereas direct means the operand is the register number of the datum

Question 44

Bit rate

Answer 44

Number of bits transferred between devices in one second

Question 45

Latency

Answer 45

Time delay before a component in a computer system responds to an instruction

Question 46

How does disabling SSID increase security of a network

Answer 46

SSID of the network cannot be seen when they trying to connect to a network Meaning only trusted users who knows the SSID of the network can connect

Question 47

How does MAC address white list increase security of a wireless network

Answer 47

MAC is a unique code that can identify a particular device on a network and whitelisting means that only certain trusted people on an network can access it

Question 48

Why must the data bus in a computer system must be biredirectional

Answer 48

When data is needed they have to be transferred from memory to the processor using the data After the execution, the data needs to be transferred back to memory using the data bus

Question 49

How can bit rate of a communications channel be higher than its baud rate

Answer 49

If more than one bit is encoded in each signal

Question 50

How can data be compressed using dictionary based compression

Answer 50

Variable length strings of su strings of data are represented by single tokens A dictionary is formed using the tokens as the key The strings of symbols are used as the entries

Question 51

Kilobyte/kibibyte

Answer 51

1000 bytes / 1024bytes

Question 52

Physical and logical topology

Answer 52

Physical - how nodes are physically laid out | Logical - how data flows through a network

Question 53

Physical star topology

Answer 53

Every device is connected to a central hub Every device sends data to the central hub The hub sends data back to the right recipient

Question 54

Why does some compilers produce byte code as the final output instead of executable code

Answer 54

The code may need to run on multiple platforms

Question 55

Imperative high level language code

Answer 55

When instructions are executed in a programmer defined order