Lesson Notes By Weeks and Term v5 - Grade 12

Lesson Video

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Performance objectives

• Explain factors influencing system and network performance.
• Identify common security threats.
• Describe appropriate security measures to counter threats.
• Implement practical strategies to improve computer security.

Lesson summary

This week, we delve into the critical aspects of system and network performance, security, and backups. In today's interconnected world, from online banking to accessing educational resources, reliable and secure systems are essential. This knowledge is not just theoretical; it's practically vital for protecting your personal data, understanding how businesses operate, and even contributing to a safer and more efficient digital South Africa. Imagine a spaza shop running a point-of-sale system, a school managing student records, or a clinic scheduling appointments – all rely on these concepts to function effectively and protect sensitive information.

Lesson notes

2.1 System and Network Performance System performance refers to how efficiently a computer system executes tasks. Network performance relates to how quickly data is transmitted across a network.

Several factors influence both: CPU (Central Processing Unit)

Usage: The CPU is the "brain" of the computer. High CPU usage indicates that the computer is working hard, and if it's consistently high, it can slow down the system. Programs that are poorly written or resource-intensive (like video editing software) can cause high CPU usage.

RAM (Random Access Memory): RAM is temporary storage for data that the CPU needs to access quickly. If the system runs out of RAM, it starts using the hard drive as virtual memory, which is much slower. Having enough RAM is crucial for smooth multitasking. Hard Drive/SSD (Solid State Drive)

Performance: The speed of the hard drive or SSD affects how quickly the system can read and write data. SSDs are generally much faster than traditional hard drives, leading to improved boot times and application loading speeds. Disk fragmentation (where files are scattered across the drive) can also slow down hard drive performance.

Network Bandwidth: This refers to the amount of data that can be transmitted over a network connection in a given amount of time. Low bandwidth can lead to slow internet speeds and network congestion. Factors like the type of network connection (e.g., fibre vs. ADSL), the number of users on the network, and the distance from the internet exchange point can affect bandwidth.

Network Latency: This is the time it takes for data to travel from one point on the network to another. High latency can cause delays in online games and video conferencing. Distance, network congestion, and the number of network devices (routers, switches) involved can contribute to latency.

Software Optimization: Poorly optimized software can consume excessive resources and slow down the system. Regularly updating software and removing unnecessary programs can improve performance.

Example: Imagine you are working on a graphic design project with multiple large image files. If your computer has limited RAM, it will frequently access the hard drive to swap data, significantly slowing down your work. Upgrading the RAM to a higher capacity would drastically improve performance. Similarly, if many people in a household are streaming videos simultaneously on a low-bandwidth internet connection, everyone will experience buffering and slow loading times.

Optimization Techniques: Defragment your Hard Drive: Regularly defragmenting a hard drive rearranges files to improve access times. Windows has a built-in defragmentation tool.

Close Unnecessary Programs: Closing programs that are not in use frees up RAM and CPU resources.

Upgrade Hardware: Upgrading to a faster CPU, more RAM, or an SSD can significantly improve performance.

Optimize Network Configuration: Ensure your router is properly configured and use a wired connection (Ethernet) instead of Wi-Fi for devices that require high bandwidth.

Use a Content Delivery Network (CDN): For websites with many users, using a CDN can improve loading times by caching content on servers located closer to users. 2.2 Security Threats and Measures Security threats are actions or events that can compromise the confidentiality, integrity, or availability of a computer system or network.

Malware: This is a broad term for malicious software, including viruses, worms, Trojans, ransomware, and spyware. Malware can steal data, damage files, disrupt system operations, or encrypt data and demand a ransom.

Phishing: This involves tricking users into revealing sensitive information (e.g., passwords, credit card numbers) by disguising as a legitimate entity (e.g., a bank, a social media site). Phishing emails often contain links to fake websites that look identical to the real ones.

Social Engineering: This involves manipulating people into divulging confidential information or performing actions that compromise security. For example, an attacker might call a help desk pretending to be a user who has forgotten their password.

Denial-of-Service (DoS)

Attacks: These attacks flood a system or network with traffic, making it unavailable to legitimate users.

Brute-Force Attacks: These involve repeatedly trying different passwords until the correct one is found.

Security Measures: Firewalls: These are hardware or software systems that control network traffic, blocking unauthorized access to a network or computer.

Antivirus Software: This software detects and removes malware from a computer system.

Strong Passwords: Passwords should be long (at least 12 characters), complex (containing a mix of uppercase and lowercase letters, numbers, and symbols), and unique (not used for multiple accounts).

Multi-Factor Authentication (MFA): This requires users to provide multiple forms of identification (e.g., password and a code sent to their phone) to log in.