CompTIA A+ 1201 & 1202

Cheatsheet Content

### Core 1 (220-1101): Mobile Devices - **Laptops:** - **Components:** LCD, LED, OLED displays; Digitizers for touchscreens. - **Hardware:** SODIMM RAM, M.2/mSATA/2.5" SSDs/HDDs, Mini-PCIe/M.2 Wi-Fi cards. - **Features:** Fn keys, docking stations, port replicators, physical locks, webcams, microphones. - **Power:** AC adapters, DC jacks, Lithium-Ion batteries. - **Mobile Devices (Smartphones, Tablets):** - **Operating Systems:** Android (open source), iOS (proprietary). - **Features:** Accelerometer, gyroscope, GPS, NFC, cellular (GSM/CDMA/LTE/5G), Wi-Fi, Bluetooth. - **Security:** Passcodes, biometrics, remote wipe, screen lock, encryption. - **Synchronization:** Cloud (iCloud, Google Drive, OneDrive), desktop (iTunes, Android File Transfer). - **Connectivity:** USB-C, Lightning, Micro-USB, Wi-Fi, Bluetooth. ### Core 1 (220-1101): Networking - **Network Cables:** - **Twisted Pair:** UTP (Unshielded), STP (Shielded). Cat5e (1 Gbps), Cat6 (10 Gbps up to 55m), Cat6a (10 Gbps up to 100m). - **Coaxial:** RG-6 (cable TV/internet), RG-59 (short-distance video). - **Fiber Optic:** Multimode (short distance), Singlemode (long distance). SC, ST, LC connectors. - **Network Devices:** - **Router:** Connects different networks, routes packets. - **Switch:** Connects devices within a LAN, forwards frames based on MAC addresses. - **Hub:** Basic central connection point, retransmits all data to all ports (collision domain). - **Access Point (AP):** Connects wireless devices to a wired network. - **Modem:** Converts digital signals to analog for transmission over phone/cable lines. - **Firewall:** Filters network traffic, blocks unauthorized access. - **Network Topologies:** Star, Mesh, Bus, Ring. - **Network Types:** LAN, WLAN, WAN, MAN, PAN. - **IP Addressing:** - **IPv4:** 32-bit (e.g., 192.168.1.1). Classes A, B, C. Subnet masks. - **IPv6:** 128-bit (e.g., 2001:0db8::1). - **DHCP:** Automatically assigns IP addresses. - **DNS:** Resolves domain names to IP addresses. - **APIPA:** 169.254.x.x (self-assigned if no DHCP). - **Common Ports:** - **20/21:** FTP (File Transfer Protocol) - **22:** SSH (Secure Shell) - **23:** Telnet (Unsecure remote access) - **25:** SMTP (Simple Mail Transfer Protocol) - **53:** DNS (Domain Name System) - **67/68:** DHCP (Dynamic Host Configuration Protocol) - **80:** HTTP (Hypertext Transfer Protocol) - **110:** POP3 (Post Office Protocol v3) - **137/138/139:** NetBIOS/SMB (Server Message Block) - **143:** IMAP (Internet Message Access Protocol) - **3389:** RDP (Remote Desktop Protocol) - **443:** HTTPS (HTTP Secure) - **445:** SMB (Server Message Block) - **3389:** RDP (Remote Desktop Protocol) ### Core 1 (220-1101): Hardware - **Motherboards:** - **Form Factors:** ATX, Micro-ATX, Mini-ITX. - **Components:** CPU socket (LGA, PGA), Chipset (Northbridge/Southbridge - integrated into CPU/PCH), BIOS/UEFI, CMOS battery, expansion slots (PCIe). - **CPU (Central Processing Unit):** - **Architecture:** x86 (32-bit), x64 (64-bit). - **Features:** Cores, threads, cache (L1, L2, L3), clock speed (GHz), hyper-threading, virtualization (VT-x, AMD-V). - **Cooling:** Heat sinks, fans, liquid cooling. - **RAM (Random Access Memory):** - **Types:** DDR4, DDR5 (SDRAM). SODIMM (laptops), DIMM (desktops). - **Features:** ECC (Error-Correcting Code), Parity, Single/Dual/Triple/Quad Channel. - **Storage Devices:** - **HDD (Hard Disk Drive):** Magnetic platters, slower, higher capacity, cheaper. SATA interface. - **SSD (Solid State Drive):** Flash memory, faster, more expensive, durable. SATA, NVMe (PCIe) interfaces. - **M.2:** Small form factor for SSDs, can be SATA or NVMe. - **RAID (Redundant Array of Independent Disks):** - **RAID 0 (Striping):** Speed, no redundancy. - **RAID 1 (Mirroring):** Redundancy, no speed gain. - **RAID 5 (Striping with Parity):** Speed and redundancy (requires 3+ disks). - **RAID 10 (1+0 - Striping of Mirrors):** Speed and redundancy (requires 4+ disks). - **Power Supplies (PSU):** - **Form Factors:** ATX. - **Connectors:** 20/24-pin ATX, 4/8-pin CPU (EPS), PCIe 6/8-pin, SATA, Molex. - **Wattage:** Match to system requirements. - **Expansion Cards:** GPU (Graphics Processing Unit), Network Card (NIC), Sound Card, Capture Card. - **Peripherals:** - **USB:** USB 2.0 (480 Mbps), USB 3.0/3.1 Gen 1 (5 Gbps), USB 3.1 Gen 2 (10 Gbps), USB 3.2 (20 Gbps), USB4 (40 Gbps). Type-A, Type-B, Type-C, Micro, Mini connectors. - **Video:** HDMI, DisplayPort, DVI, VGA. - **Printers:** Laser, Inkjet, Thermal, Impact (Dot Matrix). - **Maintenance:** Toner/ink replacement, fuser cleaning, calibration, printhead cleaning. - **Networking:** Wired (Ethernet), Wireless (Wi-Fi, Bluetooth). - **Cloud Computing:** IaaS, PaaS, SaaS. Public, Private, Hybrid, Community. Virtualization. ### Core 1 (220-1101): Virtualization & Cloud Computing - **Virtualization:** - **Hypervisor:** Software that creates and runs VMs (Type 1 - bare metal, Type 2 - hosted). - **VM (Virtual Machine):** Emulated computer system. - **Resource Allocation:** CPU, RAM, storage. - **Benefits:** Resource isolation, portability, disaster recovery. - **Cloud Computing:** - **Deployment Models:** Public, Private, Hybrid, Community. - **Service Models:** - **IaaS (Infrastructure as a Service):** VMs, storage, networks (e.g., AWS EC2, Azure VMs). - **PaaS (Platform as a Service):** Development environment, runtime (e.g., Heroku, Google App Engine). - **SaaS (Software as a Service):** Fully managed applications (e.g., Office 365, Salesforce). - **Benefits:** Scalability, elasticity, cost-effectiveness, global access. ### Core 2 (220-1102): Operating Systems - **Windows:** - **Versions:** Windows 10, Windows 11. - **Tools:** - **Task Manager:** Processes, performance, services. - **Services.msc:** Manage background services. - **Event Viewer:** System, security, application logs. - **Device Manager:** Manage hardware devices and drivers. - **Disk Management:** Partitioning, formatting, drive letters. - **System Configuration (msconfig):** Startup options, services, boot. - **Registry Editor (regedit):** Edit system registry. - **Command Prompt (CMD) / PowerShell:** - `ipconfig`: IP configuration. - `ping`: Test network connectivity. - `tracert`: Trace route to a host. - `netstat`: Network connection statistics. - `chkdsk`: Check disk for errors. - `sfc`: System File Checker. - `dism`: Deployment Image Servicing and Management. - `gpupdate`: Update Group Policy. - `gpresult`: Display Group Policy results. - `shutdown`: Shut down/restart system. - `taskkill`: Terminate processes. - **File Systems:** NTFS (Windows), FAT32 (legacy, removable drives), exFAT (large removable drives). - **macOS:** - **Features:** Finder, Dock, Spotlight, Time Machine, Mission Control. - **Tools:** Disk Utility, Activity Monitor, Terminal (`sudo`, `ls`, `cd`, `cp`, `mv`, `rm`, `chmod`). - **Linux:** - **Distributions:** Ubuntu, Fedora, Debian. - **File System:** ext4, XFS. - **Command Line:** - `ls`: List directory contents. - `cd`: Change directory. - `pwd`: Print working directory. - `cp`: Copy files. - `mv`: Move/rename files. - `rm`: Remove files. - `mkdir`: Create directory. - `grep`: Search text. - `ps`: Process status. - `top`: Monitor processes. - `kill`: Terminate processes. - `chmod`: Change permissions. - `chown`: Change ownership. - `apt-get`, `yum`, `dnf`: Package managers. - `vi`/`nano`: Text editors. - **Virtualization:** Hyper-V (Windows), VirtualBox, VMware Workstation. ### Core 2 (220-1102): Security - **Threats:** - **Malware:** Virus, Worm, Trojan, Ransomware, Spyware, Adware, Rootkit, Keylogger. - **Social Engineering:** Phishing, Spear Phishing, Whaling, Vishing, Tailgating, Shoulder Surfing, Dumpster Diving, Impersonation. - **Attacks:** DoS/DDoS, Brute Force, Dictionary, Zero-day, Man-in-the-Middle, SQL Injection, Cross-Site Scripting (XSS). - **Security Best Practices:** - **Physical Security:** Locks, alarms, cameras, mantraps, biometrics. - **User Account Control (UAC):** Windows security feature. - **Antivirus/Antimalware:** Keep updated. - **Firewall:** Network and host-based. - **Updates/Patches:** OS, applications, firmware. - **Backup/Recovery:** Regular backups, disaster recovery plan. - **Encryption:** BitLocker, EFS (Windows), FileVault (macOS). - **Strong Passwords:** Complexity, length, unique. - **Multi-factor Authentication (MFA):** Something you know, something you have, something you are. - **VPN (Virtual Private Network):** Secure remote access. - **Principle of Least Privilege:** Users only have necessary permissions. - **Wireless Security:** WEP (weak), WPA, WPA2 (AES), WPA3. MAC filtering. - **Data Disposal:** Shredding, degaussing, wiping (multiple passes). ### Core 2 (220-1102): Software Troubleshooting - **Troubleshooting Methodology:** 1. Identify the problem. 2. Establish a theory of probable cause. 3. Test the theory to determine cause. 4. Establish a plan of action to resolve the problem and implement the solution. 5. Verify full system functionality and, if applicable, implement preventive measures. 6. Document findings, actions, and outcomes. - **Common OS Issues:** - Slow performance, boot errors, application crashes, blue screen of death (BSOD), black screen. - Missing DLLs, incorrect drivers, incompatible software. - **Network Troubleshooting:** - `ipconfig`/`ifconfig`: Check IP settings. - `ping`: Test connectivity. - `tracert`/`traceroute`: Identify where connection fails. - `netstat`: View active connections. - `nslookup`: Test DNS resolution. - Check cables, Wi-Fi settings, router/switch status. - **Malware Removal:** 1. Identify and research malware symptoms. 2. Quarantine infected systems. 3. Disable System Restore (Windows). 4. Remediate: - Update antimalware. - Scan and remove. - Schedule scans. 5. Enable System Restore and create a restore point. 6. Educate end user. ### Core 2 (220-1102): Operational Procedures - **Documentation:** Network diagrams, baseline configurations, inventory management, change management. - **Change Management:** Planning, approval, testing, implementation, rollback plan, documentation. - **Backup and Recovery:** Types (full, incremental, differential), locations (local, cloud, offsite). - **Safety Procedures:** MSDS (Material Safety Data Sheet), proper disposal of batteries/toner/electronics. - **Environmental Controls:** HVAC, humidity, proper air flow, surge protectors, UPS (Uninterruptible Power Supply). - **Professionalism:** - **Communication:** Listen actively, clarify, be clear and concise, avoid technical jargon, manage expectations. - **Customer Service:** Professional attitude, empathy, patience, integrity, respect. - **Privacy:** Confidentiality, PII (Personally Identifiable Information). - **Licensing/Compliance:** Software licenses, open source vs. commercial.