Y13 Mocks

Question 1

What is a CPU?

Answer 1

Central Processing Unit

key component of a computer system
contains the necessary circuitry to interpret and execute program instructions

Question 2

ALU

Answer 2

All arithmetic and logic operations

Question 3

CU

Answer 3

controls operations in the ALU and directs data flow

Question 4

MDR

Question 5

MAR

Answer 5

Memory Address Register
holds the memory address of data about to be used by the ALU
so that the ALU can fetch the content from memory and process it
may also hold the address of where processed data needs to go

Question 6

What is unicode?

Answer 6

• an international coding standard
• for use with different languages and scripts
• each letter, digit or symbol is assigned a unique numeric value
• that applies across different platforms and programs
• each character is represented in 2 bits and the whole set is represented in 16 bits

Question 7

What is RAM?

Answer 7

see notes

Question 8

What is cache?

Answer 8

see notes

Question 9

What is the purpose of an array/collection?

Answer 9

to store multiple pieces of data of the same data type together

Question 10

What is an OSI?

Answer 10

Open systems interconnection
the communications between a computing system are split into 7 abstraction layers

Question 11

What are the 7 OSI layers?

Answer 11

Physical
Data Link
Network
Transport
Session
Presentation
Application

Question 12

hardware components of 7 osi layers

Answer 12

look at OSI downloaded image

Question 13

What are legacy systems?

Answer 13

old method, computer, technology, application or program

Question 14

Reasons for using legacy systems

Answer 14

old data still not recovered to new system
discontinued software
( no new releases and that business needs that sofware)
interacting with old hardware

Question 15

disadvantages of maintaining a legacy system

Answer 15

high cost
tech support
data compatibilty
security threats
There is a high cost to maintaing any legacy system. It might even be costlier than maintaining a more updated version. Staff training might be needed since staff might not be familiar with the older version of the software.
* Tech support may no longer be available.
* The data In the system might not be compatible with newer systems and conversion may not be possible.
* Legacy systems are more vulnerable to security threats due to lack of patches * Integration of new systems will be complicated as the system might be so old that the new system is using completely different technology.

Question 16

requirement gathering

Answer 16

see notes

Question 17

Examples of new systems

Answer 17

Data migration
Parallel running
Direct changeover
Training

Question 18

Data migration

Answer 18

process of transferring data between two different formats
Problems:
* Incompatible file formats.
* Data structure differences.
* Conflicting Validation rules.
* Incomplete data transfers.
* International conventions on dates, currencies & character sets.

Question 19

Parallel Running

Answer 19

old and new systems run together
advantages: if the new system has problems, the old one will still wokr
disadvantages: expensive + shortage of memory

Question 20

Direct changeover

Answer 20

old system is removed and immediately replaced by the new system
advantages - fast and cheap
disadvantages - risky because old systems can’t be recovered

Question 21

Trainings

Answer 21

self instruction, formal classes, remote classes

Question 22

self instruction classes

Answer 22

• users read manual or watch tutorial
• only suitable for experienced computer systems
• as they are more confident in using a familiar system on their own
• gives user more freedom with study schedule

Question 23

formal classes

Answer 23

• users sit in a formal class and are taught by a teacher
• useful in training large amounts of staff
• cheap and fast
• if class size is too big, might be ineffective

Question 24

remote/online training

Answer 24

• instructor trains a single user
• most effective
• but v expensive

Question 25

What is a VPN?

Answer 25

Virtual Private Network
* Makes a ‘tunnelled’ network connection through the Internet or any other public network
* Ideal for establishing a secure connection between private networks with remotes users
* Enables a device to exchange data across the internet as if it was directly connected to a private connected

Question 26

What is the technology required for a VPN?

Answer 26

a LAN is connected to the internet
one computer outside of the LAN is also connected to the internet
VPN client and server running on the lone machine and the original LAN
Internet connection

Question 27

What factors affect the speed of transmission on VPN?

Answer 27

see notes

Question 28

Data compression + VPN

Answer 28

see notes

Question 29

What is encryption?

Answer 29

• Uses complex mathematical algorithms and encryption keys to alter a message into a form that is not understand to an unauthorised person
• Only the person with the correct key can decode the message and read it

Question 30

What are two computer encryption categories?

Answer 30

• Symmetric key encryption
• Public key encryption

Question 31

What is symmetric key encryption?

Answer 31

• Single key or secret key encryption
• Same key used for encryption and decryption
• Each device has a secret code that is sued to encrypt a packet before it is sent over an untrusted network
• Receiving device should know and use the same key to decode the packet received
• A well-known symmetric algorithm developed for computer was the Data Encryption Standard (DES)
• Uses a 56-bit key
• 72,057594,037,927,936 possible combinations for a brute force attack btw

Question 32

What is a public key encryption?

Answer 32

• Also known as asymmetric key encryption
• Uses a public key for encryption and a private key for decryption
• Two keys are mathematically linked
  This type of encryption is used on the interne t
• Transport Layer Security (TLS) AND Secure Socket Layer (SSL) encryption protocols, used for secure web communication, are based on public key encryption

Question 33

file encryption + protection

Answer 33

compressed data where data is scrambled and is unintelligible

Question 34

advantages of public key

Answer 34

Two sides don’t need to have already shared secret key to communicate using encryption.

Question 35

disadvatanges of public key

Answer 35

Messages take more time to encrypt and decrypt.
Public key authenticity needs to be verified.

Question 36

advantages of symmetric key

Answer 36

Encryption speed is faster and uses less resources that public-key encryption

Question 37

disadvatanges of symetic key

Answer 37

Keys must be shared before they can be used.
If the key becomes
unknown by unauthorized individuals then a new key must be made

Question 38

What is a firewall?

Answer 38

computer or software package used for a NETWORK
- needs specific hardware
- monitors and protects the network traffic of a computer or computer network
- decides which computer gets access to the network based on a set of rules
-

Question 39

What is a software firewall?

Answer 39

a network security system that determines what data comes in and goes out of a network or pc
- may slow down computer

Question 40

What is a router hardware firewall?

Answer 40

will prevent hackers and unauthorised people on the internet from getting onto the network
- but can’t stop people in range from getting wifi

Question 41

What is an array?

Answer 41

fixed size structure of data of the same type

Question 42

Sequential search definition

Answer 42

sequential search
used to find specific component in array
does this by checking each component sequentially

Question 43

Sequential search pseudocode

Answer 43

PSEUDOCODE:
Array = [2,9,5,6,7,8]
Search = 7
Found = false
Counter = 0
loop Counter from 0 to Array.length – 1
if Array[Counter] = Search
Found = true
output Array[Counter]
end if
end loop
if Found = false
output Search, “ is not found in this array”
end if

Question 44

Binary search definition

Answer 44

used on SORTED ARRAYS
splits the array into two and checks it the middle term is higher or lower than the search term
discards the list accordingly

Question 45

Binary search pseudocode

Answer 45

Array = [11,12,15,16,112,118,123,145]
Search = 15
Min = 0
Max = Array.length -1
Found = false
Answer = 0
Mid = 0
loop while Found != true and Min <= Max
Mid = (Min + Max) div 2
if Array[Mid] = Search
Found = true
Answer = Mid
else if Search > Array[Mid]
Min = Mid + 1
else
High = Mid – 1
end if
end while
if Found = true then
output Search, “was found at”, answer
else
output Search, “was not found in this array”
end if

Question 46

web browser and function

Answer 46

• an application software
• used to find, receive and display content on the WWW
• Includes texts, images and audio