Grade 12 2022
Disclaimer: Content taken from Exploring IT: THEORY by
D. Kench, L.A. Coker, and R. Bradbury
,Table of Contents
Word Size ............................................................................................................. 14
IPv4 vs IPv6 Addressing ....................................................................................... 15
MAC Address ....................................................................................................... 15
Screen Resolution ................................................................................................ 15
CPU Design ............................................................................................................. 16
Control Unit ........................................................................................................... 16
Arithmetic Logic Unit ............................................................................................. 16
Registers .............................................................................................................. 17
Serial Processing .................................................................................................. 17
Parallel Processing ............................................................................................... 17
Hyperthreading.................................................................................................. 17
Multicore ........................................................................................................... 18
Multiprocessing ................................................................................................. 18
Processor Cache .................................................................................................. 19
RAM ......................................................................................................................... 20
Latency ................................................................................................................. 21
Motherboard ............................................................................................................. 21
Chipset ................................................................................................................. 22
System Clock ........................................................................................................ 22
Overclocking ..................................................................................................... 23
32-bit vs 64-bit ...................................................................................................... 23
Speed vs Throughput ........................................................................................... 24
Internal Bus/ Front Side Bus (FSB)....................................................................... 24
Data Bus ........................................................................................................... 24
Address Bus ...................................................................................................... 24
Control Bus ....................................................................................................... 25
External Buses ..................................................................................................... 25
PCI Express ...................................................................................................... 25
SATA................................................................................................................. 25
USB................................................................................................................... 25
Non-Volatile Memory Express ........................................................................... 25
M.2 Format ........................................................................................................ 25
Secondary Storage................................................................................................... 26
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, Size/Speed/Cost comparison ............................................................................... 26
Cloud Storage ....................................................................................................... 26
Size ................................................................................................................... 26
Speed................................................................................................................ 26
Cost................................................................................................................... 26
Other Types of Caching ........................................................................................... 26
Disk Cache ........................................................................................................... 26
Browser Cache ..................................................................................................... 27
Web Cache ........................................................................................................... 27
Start Up and Boot Software ...................................................................................... 27
BIOS ..................................................................................................................... 27
CMOS ................................................................................................................... 28
UEFI ..................................................................................................................... 28
Interrupts .................................................................................................................. 29
Software Interrupts ............................................................................................... 30
Hardware Interrupts .............................................................................................. 30
IRQs ..................................................................................................................... 30
IO Range .............................................................................................................. 30
Processing techniques ............................................................................................. 30
Multitasking ........................................................................................................... 31
Multithreading ....................................................................................................... 32
Virtual Memory ......................................................................................................... 32
Translators ............................................................................................................... 33
High-level languages ............................................................................................ 33
Low-level Languages ............................................................................................ 33
Assembler ............................................................................................................. 33
Interpreters ........................................................................................................... 33
Compilers ............................................................................................................. 34
Machine Code Generation ................................................................................ 34
Intermediate Representation ............................................................................. 34
Machine Code .......................................................................................................... 35
Physical Aspects of a LAN ....................................................................................... 36
Bounded Connection Media ..................................................................................... 36
Twisted-pair cable................................................................................................. 36
Unshielded Twisted-Pair (UTP) cable ................................................................... 36
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, Fibre-Optic Cable.................................................................................................. 37
Unbounded Connection Media ................................................................................. 38
Wireless ................................................................................................................ 38
Bluetooth .............................................................................................................. 38
Near Field Communication ................................................................................... 38
Radio Waves ........................................................................................................ 38
Broadcast vs Point-to-Point Communication ............................................................ 39
Topology .................................................................................................................. 39
Star Topology ....................................................................................................... 39
Bus Topology ........................................................................................................ 40
Ring Topology ...................................................................................................... 40
Hybrid Topology.................................................................................................... 41
Ethernet.................................................................................................................... 41
Network Addressing ................................................................................................. 41
IP Address ............................................................................................................ 41
IPv4 ...................................................................................................................... 41
IPv6 ...................................................................................................................... 41
MAC Address ....................................................................................................... 42
Internet Protocols ..................................................................................................... 42
Address Resolution Protocol ................................................................................ 42
DHCP ................................................................................................................... 42
DNS ...................................................................................................................... 43
TCP/IP Protocol .................................................................................................... 43
UDP and TCP ................................................................................................... 43
LAN Network Devices .............................................................................................. 43
NIC ....................................................................................................................... 44
Repeater ............................................................................................................... 44
Bridge ................................................................................................................... 44
Switch ................................................................................................................... 44
Router ................................................................................................................... 45
OSI Model ................................................................................................................ 45
Application, Presentation, and Session Layers ..................................................... 46
Transport Layer .................................................................................................... 47
Network Layer ...................................................................................................... 47
Data Link Layer..................................................................................................... 47
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, Physical Layer ...................................................................................................... 47
Packet................................................................................................................... 48
Header .............................................................................................................. 48
Payload ............................................................................................................. 48
Trailer ................................................................................................................ 48
Frame ................................................................................................................... 49
Frame Check Sequence ................................................................................... 49
VLAN .................................................................................................................... 50
VLAN Tag ......................................................................................................... 50
Wireless LAN ........................................................................................................... 50
Wireless Access Point .......................................................................................... 50
Hotspots ............................................................................................................... 51
Wireless Bridge..................................................................................................... 51
Wi-Fi Router ......................................................................................................... 51
Wireless Mesh Network (WMN) ............................................................................ 51
Bounded Connections vs Unbounded Connections.............................................. 52
Fibre Optic Backbone ............................................................................................... 52
WAN ......................................................................................................................... 53
Devices .................................................................................................................... 53
Gateways.............................................................................................................. 53
Transmission ............................................................................................................ 53
Satellite Radio Waves........................................................................................... 53
Microwave ............................................................................................................ 54
Internet Connection Technologies ............................................................................ 54
Cellular Technologies ........................................................................................... 54
3G ..................................................................................................................... 54
LTE ................................................................................................................... 55
4G ..................................................................................................................... 55
5G ..................................................................................................................... 55
Wi-Fi Calling ......................................................................................................... 55
Fibre ..................................................................................................................... 55
ADSL .................................................................................................................... 55
Ethernet Switch..................................................................................................... 55
Ethernet ................................................................................................................ 56
Servers ................................................................................................................. 56
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, Bandwidth Comparisons ....................................................................................... 56
Protocols .................................................................................................................. 57
Email protocols ..................................................................................................... 57
SMTP ................................................................................................................ 57
POP3 ................................................................................................................ 57
IMAP ................................................................................................................. 57
Web Protocols ...................................................................................................... 57
НТТР ................................................................................................................. 57
HTTPS .............................................................................................................. 57
Download Protocols .............................................................................................. 58
FTP ................................................................................................................... 58
WebDAV ........................................................................................................... 58
Evolution of the Internet ........................................................................................... 58
Web 1.0 ................................................................................................................ 58
Web 2.0 ................................................................................................................ 58
Web 3.0 ................................................................................................................ 59
Web 4.0 ................................................................................................................ 59
Scripting................................................................................................................ 59
Client-side ......................................................................................................... 60
Server-side ........................................................................................................ 60
The Combination of Client-Side and Server-Side.............................................. 60
Cookies................................................................................................................. 61
Web-Based Applications .......................................................................................... 61
Mobile Websites ....................................................................................................... 62
Mobile Applications .................................................................................................. 63
Native Mobile App................................................................................................. 63
Hybrid Mobile App ................................................................................................ 63
Design Factors for Mobile Technology ..................................................................... 64
Screens ................................................................................................................ 64
Processing Demands............................................................................................ 64
Storage Demands ................................................................................................. 64
Bandwidth Requirements ...................................................................................... 64
Plug-Ins and Extensions........................................................................................... 64
Search Engines ........................................................................................................ 65
Searching for Sound ............................................................................................. 65
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, Reverse Image Lookup ......................................................................................... 65
Advanced Search Criteria ..................................................................................... 65
Using Multimedia Online .......................................................................................... 65
Download.............................................................................................................. 66
Streaming ............................................................................................................. 66
Effect on Bandwidth .............................................................................................. 66
Video On-Demand ................................................................................................ 66
VOIP ..................................................................................................................... 66
Podcast/Vodcast ................................................................................................... 67
Compression Technology......................................................................................... 67
Lossy .................................................................................................................... 67
Lossless................................................................................................................ 68
Lossy Compression of Audio Files........................................................................ 68
Sample Rate ..................................................................................................... 68
Bit Depth ........................................................................................................... 68
Bit Rate ............................................................................................................. 69
MP3 Compression............................................................................................. 69
Quality vs. Bandwidth and Speed ......................................................................... 69
Source of Errors ....................................................................................................... 69
Human Errors - GIGO and Input Errors ................................................................ 69
Arithmetic Errors ................................................................................................... 70
Data Transmission Errors ..................................................................................... 70
Solutions for Errors................................................................................................... 71
Verification ............................................................................................................ 71
Validation .............................................................................................................. 71
Techniques for Input ............................................................................................. 72
Keyboard Input .................................................................................................. 72
Barcode Scanner .............................................................................................. 72
QR Codes ......................................................................................................... 72
GUI Components .............................................................................................. 73
RFID (Radio Frequency Identification) .............................................................. 73
Biometric Input .................................................................................................. 73
Optical Character Recognition (OCR) ............................................................... 73
OMR.................................................................................................................. 74
Database Management System Integrity ................................................................. 74
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, Accuracy ............................................................................................................... 74
Correctness .......................................................................................................... 74
Currency ............................................................................................................... 74
Completeness ....................................................................................................... 74
Relevance............................................................................................................. 74
Threats to Computer Systems .................................................................................. 74
SQL Injection ........................................................................................................ 74
Hardware Failure .................................................................................................. 75
Storage ............................................................................................................. 76
Power Failure .................................................................................................... 76
Malware ................................................................................................................ 76
Phishing and Spoofing ...................................................................................... 76
Virus .................................................................................................................. 77
Trojan Horse ..................................................................................................... 77
Spyware ............................................................................................................ 77
Pharming ........................................................................................................... 77
Ransomware ..................................................................................................... 78
Denial of Service Attacks ...................................................................................... 78
DoS Attacks ...................................................................................................... 78
DDoS Attacks .................................................................................................... 78
Open Ports ........................................................................................................... 78
Botnets ................................................................................................................. 79
Wi-Fi Vulnerabilities .............................................................................................. 79
Security Solutions..................................................................................................... 80
RAID ..................................................................................................................... 80
RAID Level 1 ..................................................................................................... 80
RAID Level 5 ..................................................................................................... 80
Backup .............................................................................................................. 80
Onsite backup ................................................................................................... 80
Remote Backup................................................................................................. 81
Uninterruptible Power Supply (UPS)..................................................................... 81
Redundant Power Supplies .................................................................................. 82
Passwords and Biometrics ................................................................................... 82
Multiuser Access Control ...................................................................................... 82
Authentication ................................................................................................... 82
Page 7 of 152
, User-Level Security ........................................................................................... 82
Share-Level Security ......................................................................................... 83
Encryption 128 vs 256 .......................................................................................... 83
Encryption ............................................................................................................. 83
Digital Signatures .............................................................................................. 84
Key Length ........................................................................................................ 85
Temporal Key Integrity Protocol ........................................................................ 85
WEP, WPA, WPA2, and WPA3......................................................................... 85
Firewall ................................................................................................................. 85
Port Filtering ...................................................................................................... 86
Audit Trails ............................................................................................................ 86
Anti-Malware ......................................................................................................... 86
Antivirus ............................................................................................................ 86
Anti-Spam ......................................................................................................... 87
Updates and Upgrades ......................................................................................... 87
Effect on Workplace and Employment Practices ...................................................... 87
Acceptable User Policy ......................................................................................... 87
Decentralisation of the Workplace ........................................................................ 88
Mobile Offices ................................................................................................... 88
Virtual Offices .................................................................................................... 88
Decentralisation of Labour .................................................................................... 88
Replacement of Work Force ................................................................................. 89
Robotics ............................................................................................................ 89
Artificial intelligence........................................................................................... 89
Unmanned Aerial Vehicles ................................................................................ 89
Effects of Computer Crime ....................................................................................... 90
Social Engineering ................................................................................................ 90
Shoulder Surfing ............................................................................................... 90
Dumpster Diving................................................................................................ 90
Phishing ............................................................................................................ 90
Reverse Social Engineering or Role Playing ..................................................... 90
Use of Social Media for Social Engineering ...................................................... 90
Hackers, Crackers and Virus Authors ................................................................... 91
Hackers and Crackers....................................................................................... 91
Virus Writers...................................................................................................... 91
Page 8 of 152
, Theft ..................................................................................................................... 91
Hardware Theft ................................................................................................. 91
Software Theft ................................................................................................... 92
Information Theft ............................................................................................... 92
Identity Theft ..................................................................................................... 92
Bandwidth Theft ................................................................................................ 92
Theft of Time ..................................................................................................... 93
Theft of Services ............................................................................................... 93
Effect of Cyber Crimes.......................................................................................... 93
Safeguards against Computer Crimes ..................................................................... 93
Evaluating Information.............................................................................................. 94
Fake News ............................................................................................................ 94
Evaluating Websites ............................................................................................. 95
Affiliation ........................................................................................................... 95
Audience ........................................................................................................... 95
Authority ............................................................................................................ 95
Content ............................................................................................................. 95
Currency ........................................................................................................... 95
Design ............................................................................................................... 96
Objectivity ......................................................................................................... 96
Computer Performance and Reliability ..................................................................... 96
Modular Design..................................................................................................... 96
Improving Processor Speed ................................................................................. 97
Expansion Cards vs Onboard Controllers ............................................................. 97
Co-Processors ...................................................................................................... 97
Graphics Processor........................................................................................... 97
Graphics Card ................................................................................................... 98
Integrated Graphics........................................................................................... 98
Maths Co-Processor ......................................................................................... 99
Increasing the Speed and Size of RAM ................................................................ 99
Virtual Memory .................................................................................................. 99
Buses.................................................................................................................. 100
Internal Busses ............................................................................................... 100
External Busses .............................................................................................. 100
Ports ................................................................................................................... 100
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