Information Technology Theory Study Guide

Hardware and System Architecture

The performance of a computer is determined by the synergy of its components. The CPU (Central Processing Unit) relies on clock speed—the frequency at which it executes instructions—and cache memory to function efficiently. Cache is a small, high-speed memory located on or near the CPU that stores frequently accessed data to prevent the slower RAM from creating a bottleneck.

Storage technology has also evolved. While HDDs are traditional, SSDs (Solid State Drives) are faster, more robust, and use less electricity because they have no moving parts. Because they lack mechanical components, there is no need to perform defragmentation on an SSD.

At the most basic level, the BIOS (Basic Input/Output System) is firmware that controls hardware at the lowest level, performs the Power-On Self-Test (POST), and loads the operating system.

Networking and Communication

Networks allow devices to share resources and communicate. A star topology is a common layout where every device connects to a central hub or switch; this makes it easy to add or remove devices and troubleshoot issues.

When discussing data transmission, we distinguish between different media:

• UTP (Unshielded Twisted Pair): Uses electrical signals; it is stable and reliable but susceptible to interference.
• Fibre Optic: Uses light to transmit data; it offers much higher bandwidth and is immune to electromagnetic interference (EMI).

The amount of data that can be sent over a network in a specific time is known as bandwidth. It is important to note that your actual network speed is limited by the device with the lowest bandwidth in the chain.

Data Management and Emerging Technologies

Modern businesses rely on massive amounts of data. Data warehousing involves collecting and managing large volumes of data from various sources to support business intelligence. From this data, companies use data mining to extract patterns and knowledge using techniques like clustering or classification.

We are also seeing the rise of decentralized and intelligent technologies:

• Artificial Intelligence (AI): The simulation of human intelligence/decision-making by computer systems.
• Blockchain: A distributed database that uses cryptography to link a growing list of records.
• Cloud Computing: Using internet-based resources to store, manage, and process data.
• Virtual Reality (VR): A computer-generated 3D environment that users interact with via specialized equipment.

Cybersecurity, Ethics, and Privacy

As technology advances, so do the threats. Malware is an umbrella term for any software written with malicious intent. Common types include:

• Ransomware: Malware that encrypts a user's files and demands payment for the decryption key.
• Botnets: Networks of "zombie PCs" (compromised computers) used to launch DDoS (Distributed Denial of Service) attacks to crash websites.
• Phishing vs. Pharming: Phishing uses "bait" (like fake emails) to trick users into giving info, whereas pharming uses malware to redirect users to fake websites automatically.

To protect data during transmission, we use asymmetric encryption (also known as public key encryption). This method uses two related keys: a public key for encryption and a private key for decryption.

Exam Tip: When discussing privacy, remember that we are never truly anonymous online. Identifiers like your IP address, MAC address, and browsing history can always be used to trace activity.

Finally, ethical considerations are paramount. Ethical hackers use their skills to test and evaluate security rather than for criminal gain. Users must also be mindful of their digital footprint—the trail of data collected about their online activities.