Network Types & Hardware 20%

• SOHO: Small Office/Home Office. Typically uses a combined modem/router/switch/AP.
• Switch: Layer 2 device, forwards frames based on MAC address table (CAM table).
• Router: Layer 3 device, forwards packets between different networks based on IP addresses.
• Access Point (AP): Provides wireless connectivity to a wired network.

Network Troubleshooting Tools

• ping: Tests Layer 3 connectivity using ICMP echo requests/replies.
• tracert / traceroute: Maps the path to a destination, showing latency at each hop.
• ipconfig / ifconfig: Displays IP configuration. ipconfig /release and /renew interact with DHCP.
• nslookup / dig: Queries DNS servers to resolve hostnames to IP addresses.
• Speed test: Measures actual bandwidth (throughput) vs. theoretical speed.

PC Hardware Components 25%

• CPU: The brain. Key specs: cores, threads, clock speed (GHz), cache, socket type.
• RAM: Volatile memory. DDR4 (288-pin) and DDR5 (different notch, higher speed, on-die ECC). Laptops use SODIMM.
• Storage: HDD (spinning platters, cheap, high capacity), SSD (flash memory, fast, durable), NVMe (PCIe-based, fastest).
• PSU: Power Supply Unit. Converts AC to DC. Rated in Watts. Look for 80 PLUS certification for efficiency.
• Motherboard Form Factors: ATX (standard, most expansion), microATX (smaller, fewer slots), Mini-ITX (smallest, 1 expansion slot).

BIOS / UEFI

• POST: Power-On Self-Test. Checks hardware integrity before booting.
• UEFI: Modern replacement for legacy BIOS. Supports larger drives (>2.2TB), faster boot times, Secure Boot, and a graphical interface.
• CMOS Battery: CR2032 coin cell that maintains BIOS settings and system time when the PC is unplugged.

Cloud Computing 11%

• IaaS (Infrastructure as a Service): Provider gives raw compute/storage/networking (e.g., AWS EC2). Customer manages OS and up.
• PaaS (Platform as a Service): Provider gives OS + runtime environment (e.g., Google App Engine). Customer manages only the app and data.
• SaaS (Software as a Service): Provider manages everything (e.g., Microsoft 365, Gmail). Customer just uses the software.
• Shared Responsibility Model: Cloud provider secures the physical infrastructure; customer secures their data, identities, and configurations.

Virtualization

• Hypervisor Type 1: Bare-metal. Installs directly on hardware (e.g., VMware ESXi, Microsoft Hyper-V). Better performance, used in enterprise.
• Hypervisor Type 2: Hosted. Runs as an application on top of an existing OS (e.g., VirtualBox, VMware Workstation). Used for testing/development.
• VDI (Virtual Desktop Infrastructure): Desktop environments are hosted on a central server and streamed to thin clients.

CompTIA Troubleshooting Methodology 29%

1. Identify the problem: Gather info, question the user, identify symptoms, duplicate the problem, establish a theory.
2. Establish a theory of probable cause: Question the obvious, consider multiple approaches.
3. Test the theory to determine the cause: If confirmed, move to next step. If not, re-establish a new theory or escalate.
4. Establish a plan of action to resolve the problem and identify potential effects.
5. Implement the solution or escalate as necessary.
6. Verify full system functionality and, if applicable, implement preventive measures.
7. Document findings, actions, and outcomes.

Common Hardware Troubleshooting

• No POST / No power: Check PSU, power cable, 24-pin/8-pin motherboard connectors, RAM seating.
• Overheating: Clean dust, reapply thermal paste, ensure CPU fan is plugged in and spinning.
• Artifacting on display: Failing GPU, overheating GPU, or bad video cable.
• Slow boot / sluggish performance: Failing HDD (check SMART status), insufficient RAM, malware, too many startup apps.