Unit 1
1) What is the purpose of a CPU?
A) To display output on a screen
B) To store data for future use
C) To perform calculations and control the flow of data in a computer system
D) To connect peripherals such as printers and scanners
C) To perform calculations and control the flow of data in a computer system
Frida compresses the document for storage. The compression algorithm she uses recognizes repeating patterns in the data and indexes these patterns. No data is permanently removed. Identify the type of compression Frida has used.
Lossless Compression
HTTP stands for _____.
Hypertext Transfer Protocol
Adele also encrypts the data on her mobile device to keep it more secure. State how encryption will keep the data more secure.
It makes the data meaningless if stolen.
What is the main feature/purpose of a primary key?
It is a unique identifier.
2) Which of the following is a type of non-volatile memory?
A) RAM
B) ROM
C) Cache
D) Virtual memory
B) ROM
What is binary?
A) A system of counting using the digits 0-9
B) A system of counting using the digits 0-1
C) A system of counting using the digits 0-2
D) A system of counting using the digits 0-3
B) A system of counting using the digits 0-1
What is the purpose of a router?
A) To connect a computer to the internet
B) To transmit data between networks
C) To store and retrieve data
D) To convert digital signals into analog signals
B) To transmit data between networks
Online security attacks can maliciously damage data. One security method to keep data safe from online attacks is a firewall. Identify TWO other security methods that keep data safe from online attacks.
Encryption Password Two-step / Two-factor authentication/verification Biometric device Anti-malware // Anti-virus Proxy-server
What is hexadecimal?
A) A system of counting using the digits 0-9
B) A system of counting using the digits 0-1
C) A system of counting using the digits 0-16
D) A system of counting using the digits 0-32
C) A system of counting using the digits 0-16
What is the purpose of ASCII?
A) To represent numbers in binary
B) To represent letters and symbols in binary
C) To represent colours in binary
D) To represent sounds in binary
B) To represent letters and symbols in binary
Define the term "bandwidth" in the context of computer networks.
Bandwidth refers to the maximum amount of data that can be transmitted over a network in a given amount of time.
Millions of emails are sent between users on a daily basis. (a) Identify two online security attacks that can be carried out using email. Describe how email is used to enable the attack.
1) Online security Attack 1 and Description -
2) Online security Attack 2 and Description -
1) Phishing
Email is sent to user to encourage them to click link and … that takes user to fake website
2) Pharming
Email is sent to user to encourage them to click link/download attachment … that triggers download of malicious code that will redirect user to fake website
3) Virus/malware Email is sent to user to encourage them to click link/download attachment … that triggers download of virus/malware
4) Denial of service // DoS A very large number of emails are sent to a server/network at the same time … crashing the server/network
An aeroplane has a small display screen above each seat, to display the seat number.
(a) The seat number is a hexadecimal value. A 12-bit binary register is used to store the data to display each seat number. Three seat numbers, 05A, 18C and 29F, are allocated to passengers. Give the 12-bit binary value that would be stored for each hexadecimal seat number.
05A
18C
29F
05A is 0000 0101 1010
18C is 0001 1000 1100
29F is 0010 1001 1111
• Byte 4
• Bit 5
How was this done? • Counted all the 1s • An even parity has been used • Odd number of ones in that row (byte 4) and column (bit 5)
1) _______ = Software/application that allows users to view web pages / render HTML
2) ________ = this is the company that provides a user with a connection to the Internet
HTTP // HTTPS
3) ________ = this is a protocol that is used to send data for web pages across the Internet Uniform Resource Locator (URL) a text-based version of a web address
4) ______ = a text file (stored by web browser) that contains data about a user’s browsing habits/details/preferences
1) Browser
2)Internet Service provider // ISP
3) HTTP/HTTPS
4) Cookie
Jian’s system for his website has a proxy server. Explain why Jian uses a proxy server as part of the system for his website. Give FOUR points.
Any four from: • To act as intermediary between browser and web server • to filter/examine/monitor traffic to the web server • to help stop malicious traffic to the web server • To cache frequently viewed web pages • to allow faster response time for requests • to reduce the number of requests the server needs to process • To help prevent DoS • stopping the webserver being overloaded with requests • by redirecting away from server // by stopping DoS attack reaching server • To act as a firewall
Two of the registers store the values 010000001101 and 000001111110 Give the hexadecimal seat number that would be displayed on the screen for each of these binary values.
010000001101
000001111110
40D and 07E
An image is stored on a computer. The image is 16‑bit colour and is 100 pixels high and 150 pixels wide. Calculate the file size of the image in bytes. Show all your working.
100 x 150
15 000 16 // 15 000 x 2
240 000 / 8
30 000 bytes
Jason wants to distribute a computer program he has written. He is considering distributing it to users as freeware or free software.
(i) Explain one drawback to a user if the program is distributed as freeware.
(ii) Explain one benefit to a user if the program is distributed as free software.
4(b)(i) The user is not allowed to access the source code … … so, they cannot tailor the software to their needs … so, they cannot fix any bugs in it The software is still covered by copyright The user must get the owner’s permission to do anything beyond using it
(b)(ii) The user can access the source code … … so, they can tailor the software to their needs … so, they can fix any bugs in it … so, the source code could be studied for educational purposes The user can redistribute the software/program … … but this must be done under the same terms as the original software
Consider the following logic statement: X = (((A AND NOT B) OR (NOT (B NOR C))) AND C)
(a) Draw a logic circuit to represent the given logic statement. Do not attempt to simplify the logic statement. All logic gates must have a maximum of two inputs.