CompTIA A+ 220-1201 Core 1 Study Guide

CompTIA A+ Core 1 Exam Domains

Mobile Devices (13%), Networking (23%), Hardware (25%), Virtualization and Cloud Computing (11%), and Hardware and Network Troubleshooting (28%).

Distractors (Red Herrings)

Incorrect options included in multiple-choice questions designed to mislead, which should be eliminated to improve the chances of selecting the correct answer.

Computer

A device performing input, processing, storage, and output functions (e.g., desktops, laptops, tablets, smartphones, and IoT devices).

Basic Functions of a Computer

Input (data entry), Processing (operations by CPU), Storage (data retention), and Output (display or delivery of results).

Categories of Computers

Workstations, Servers, Laptops, Tablets, Smartphones, Smart Devices, and IoT Devices.

Essential Components of Computers

Hardware (physical components), Software (operating systems, applications, drivers), and Firmware (embedded software).

Areas of Safety (IT)

Personal Safety (prevents injuries to technicians), Component Safety (protects computer components), Electrical Safety (prevents electrocution), and Chemical Safety (safe handling and disposal of hazardous materials).

Electrostatic Discharge (ESD)

Damage caused by the transfer of electrons from a statically charged body to an uncharged component, prevented by using antistatic bags, wrist straps, and mats.

CompTIA Six-Step Troubleshooting Methodology

1. Identify the Problem, 2. Establish a Theory of Probable Cause, 3. Test the Theory to Determine the Cause, 4. Establish a Plan of Action and Implement the Solution, 5. Verify Full System Functionality and Implement Preventative Measures, 6. Document Findings, Actions, and Outcomes.

Troubleshooting Step 1

Identify the Problem: Gather information from the user, identify user and environmental changes, and perform backups before making changes.

Troubleshooting Step 2

Establish a Theory of Probable Cause: Question the obvious and research symptoms through resources like search engines or AI chatbots.

Troubleshooting Step 3

Test the Theory to Determine the Cause: Confirm or disprove the theory by testing, reestablish a theory, or escalate the issue if the theory is not confirmed.

Troubleshooting Step 4

Establish a Plan of Action to Resolve the Problem and Implement the Solution: Create a plan following manufacturer or vendor instructions.

Troubleshooting Step 5

Verify Full System Functionality and Implement Preventative Measures: Test the system to ensure the issue is resolved and apply preventative measures.

Troubleshooting Step 6

Document Findings, Actions, and Outcomes: Record the problem, solution, and results in the appropriate system.

Components of a Custom PC

Motherboard, Central Processing Unit (CPU), Memory (RAM), Storage Devices, Cooling Fans, and Power Supply Unit (PSU).

USB (Universal Serial Bus)

A widely used interface standard that connects various devices, providing both data transfer and power delivery capabilities while supporting multiple devices via daisy-chaining.

Serial Connections (Predecessor to USB)

Used DB9 and DB25 connectors, transmitted data at up to 115 Kbps by sending one bit at a time, and were limited to one device per port.

USB Versions and Data Transfer Speeds

USB 1.0 (1.5 Mbps), USB 1.1 (12 Mbps), USB 2.0 (480 Mbps), USB 3.0 (5 Gbps), USB 3.1 Gen 2 (10 Gbps), USB 3.2 Gen 2x2 (20 Gbps), and USB 4.0 (40 Gbps).

USB Distance Limitations

USB 1.0 (3 meters), USB 1.1 and USB 2.0 (5 meters), USB 3.0 and later (3 meters) to maintain high-speed performance.

USB Power Delivery

USB 1.0 and 2.0 (500 mA), USB 3.0 (900 mA), and dedicated powered USB ports (up to 1.5A).

USB Type A

Flat rectangular connector, used in USB 1.0, 1.1, 2.0, 3.0, and above, connects in one direction, common on desktops and laptops.

USB Type B

Used for larger devices like printers, with variations including Type B, Type B Mini (trapezoid), and Type B Micro (shorter, skinnier).

USB Type C

Small oval-shaped connector, compatible with USB 3 and USB 4, reversible design, common in modern laptops, tablets, and smartphones.

HDMI (High Definition Multimedia Interface)

The most widely used video interface, supporting high-definition video and audio signals, with connector types Type A (standard), Type C (mini), and Type D (micro).

DisplayPort (DP)

An open-standard video interface offering high-speed video and audio transmission, developed by VESA to compete with HDMI. Used in PC monitors and high-end gaming.

DVI (Digital Visual Interface)

An older standard that supports both analog (DVI-A) and digital (DVI-D) video signals, or both (DVI-I). Limited to 1080p resolution and no native audio support.

VGA (Video Graphics Array)

An analog video connection standard, widely used before digital connections became dominant, typically with a 15-pin D-sub connector. Limited to 640x480 pixels and susceptible to signal degradation.

Thunderbolt

A high-speed interface developed by Intel and Apple that supports video, data, and power over a single connection. Versions 1 and 2 use Mini DisplayPort, while 3 and 4 use USB Type-C, offering speeds up to 40 Gbps.

Lightning (Cable)

A proprietary cable designed by Apple for mobile devices like iPhones, iPads, and accessories, with a reversible connector. Not cross-compatible with other ecosystems.

SATA (Serial Advanced Technology Attachment)

A standard internal storage connection used in desktops and laptops, with a 7-pin L-shaped data cable and a 15-pin power cable. Speeds up to SATA III (6 Gbps).

eSATA (External SATA)

An external version of SATA for connecting external drives, offering speeds up to 6 Gbps. Less common now due to advances in USB technology.

SCSI (Small Computer Systems Interface)

A legacy storage interface for connecting multiple devices, supporting up to 7 (Narrow SCSI) or 15 (Wide SCSI) devices at speeds up to 320 Mbps.

SAS (Serial Attached SCSI)

A modern enterprise-grade storage connection used in high-performance environments, offering speeds up to 24 Gbps, supporting full duplex communication and backward compatibility with SATA drives.

Form Factors (Motherboard)

Describes the shape, layout, and type of case and power supply compatible with a motherboard, determining the number and type of components that can be installed.

ATX (Advanced Technology eXtended)

A full-size motherboard form factor (12 x 9.6 inches) for large towers, with expansion slots parallel to the shorter side. Variants include Mini-ATX and microATX.

microATX (mATX)

A smaller, square motherboard form factor (9.6 x 9.6 inches) with fewer expansion slots than ATX, suitable for compact computers.

Mini-ITX (Information Technology eXtended)

A compact motherboard form factor (6.7 x 6.7 inches) with one expansion slot and a rear port cluster, compatible with ATX cases, used in small form factor PCs.

CPU (Central Processing Unit)

Also called the processor, it fetches, decodes, and executes program code from software or firmware.

Cache (CPU)

High-speed memory located inside the processor, used for quick access to frequently used data.

x86 Architecture

Also known as IA-32 or Intel architecture 32-bit instruction set, supports up to 4GB of RAM due to 32-bit addressing, evolved from 8-bit to 32-bit processors.

x64 Architecture

Extends x86 to support 64-bit operations, supports more than 4GB of RAM, and is backwards compatible with 32-bit programs. Widely used in modern PC systems.

ARM Architecture (Advanced RISC Machines)

Designed for low-power devices like tablets, smartphones, and smart TVs, providing extended battery life and reduced heat generation. Utilizes a smaller instruction set compared to x86 and x64.

CPU Socket

A connector on a motherboard that houses the CPU and facilitates communication between the CPU and other components, with different types for Intel and AMD.

ZIF (Zero Insertion Force)

A mechanism in CPU sockets that ensures CPUs can be installed without force, reducing the risk of bending pins.

LGA (Land Grid Array)

An Intel CPU socket design where pins are on the motherboard and the CPU has corresponding contact points.

PGA (Pin Grid Array)

An AMD CPU socket design where pins are on the CPU and the motherboard has corresponding holes.

Multithreading (SMT/Hyper-Threading)

Allows multiple instructions (threads) to execute simultaneously within a single processor core, reducing task completion time and increasing CPU efficiency.

Symmetric Multiprocessing (SMP)

Utilizes multiple physical processors on a motherboard, requiring multiple processor sockets and operating system support for optimal performance.

Multi-Core Processing

Combines multiple cores within a single CPU package, appearing as one physical CPU to the motherboard, and dividing instructions among cores for execution.

Virtualization Support (CPU)

Enables hardware to emulate multiple virtual computers using technologies like Intel's VT and AMD's AMD-V, allowing software (e.g., VMware) to create virtual machines.

Second Level Address Translation (SLAT)

A CPU feature (Intel EPT, AMD RVI) that improves virtual memory management and performance, essential for running virtual servers or multiple operating systems efficiently.

AM4 Socket

An AMD-based Pin Grid Array (PGA) socket commonly used for Ryzen processors, featuring pins on the processor and holes on the motherboard with a ZIF (Zero Insertion Force) mechanism for installation.

CMOS Battery

A small coin-cell battery (CR2032) on the motherboard that retains BIOS/UEFI settings (such as date and time) when the system is powered off. Typically replaced approximately every three years.

PCI (Peripheral Component Interconnect)

An expansion card type introduced in the early 1990s for 32-bit systems, with a maximum data transfer rate of 133 MBps, common for older network, video, and audio cards.

PCIe (PCI Express)

A modern expansion card type that replaced PCI, PCI-X, and AGP, available in x1, x4, x8, and x16 sizes, using point-to-point serial connections for direct access to the motherboard.

Video Cards (Graphics Cards)

Expansion cards that provide better graphics performance than integrated solutions, typically installed in PCIe x16 slots, featuring dedicated GPUs and high-speed memory.

Capture Cards

Expansion cards that move video data into the computer for processing, used for gaming footage, security camera signals, or TV input.

Network Interface Cards (NICs)

Expansion cards that provide wired or wireless network connections, such as Gigabit NICs for RJ45 ports or Wireless NICs for Wi-Fi capabilities.

Thermal Load

The heat generated by computer components like the power supply, processor, memory, and expansion cards, which can cause damage if excessive.

Passive Cooling

Relies on components without moving parts or power, such as heat sinks (finned metal devices) and thermal paste (ensures better heat transfer between components).

Active Cooling

Uses fans powered by electricity to increase airflow and dissipate heat, commonly found on processors, in cases, power supplies, and graphics cards.

Liquid Cooling

Designed for high-performance systems, using liquids as coolants due to their superior heat absorption compared to air. Can be closed-loop (self-contained) or open-loop (customizable).

PSU (Power Supply Unit)

Provides direct current (DC) power to computer components by converting alternating current (AC) from wall outlets into low-voltage DC.

Modular PSU

A type of power supply unit that allows unused cables to be detached, improving airflow and cooling by reducing cable clutter inside the case.

Redundant Power Supplies

Found in critical systems like servers and workstations, providing dual power supplies for continuous operation, allowing one PSU to fail without shutting down the system.

Motherboard/Mainboard Power Connector

Typically a 24-pin connector (or 20+4 pin for compatibility) used in modern power supplies to power most components on the motherboard.

Processor (CPU) Power Connector

Can have 4-pin, 6-pin, or 8-pin configurations, with most modern systems using 8-pin connectors to provide power directly to the CPU.

PCIe (PCI Express) Power Connectors

Provide additional power (beyond the 75 watts supplied by the PCIe slot) to high-performance expansion cards like graphics cards, commonly in 6-pin or 8-pin configurations.

SATA Power Connectors

15-pin L-shaped connectors used for powering SATA devices such as hard drives, SSDs, and optical drives.

Molex Connectors

Legacy 4-pin connectors for older IDE/PATA hard disks and optical drives, rarely used in modern systems but often included in PSUs for backward compatibility.

Input Voltages (AC Power)

AC power standards vary by region: 120 volts AC (60 Hz) in the US and 230 volts AC (50 Hz) in Europe and Asia.

Output Voltages (DC Power)

Key DC voltages provided by a PSU to computer components are +3.3 volts, +5 volts, and +12 volts, with +12 volts being most critical for modern PCs.

Wattage Rating (PSU)

Refers to the power supply unit's output capacity, measured in Watts, which must exceed the total power consumption of all system components for stable operation.

RAM (Random Access Memory)

Temporary storage for data and instructions before processing by the CPU, faster than storage devices but non-persistent (data is lost when powered off).

Memory Addressing (32-bit vs. 64-bit)

32-bit (x86) CPUs can address up to 4 GB of memory, while 64-bit (x64) CPUs can address up to 16 exabytes of memory, supporting higher RAM capacities for better performance.

DIMM (Dual In-line Memory Modules)

Larger memory modules used in desktops.

SODIMM (Small Outline DIMM)

Compact memory modules used in laptops.

DRAM (Dynamic RAM)

A type of RAM that requires constant refreshing to retain data.

SRAM (Static RAM)

A faster but more expensive type of RAM, typically used in CPU caches (L1, L2, L3).

DDR SDRAM (Double Data Rate Synchronous DRAM)

A type of SDRAM that transfers data twice per clock cycle, with sequential advancements in speed, efficiency, and capacity across versions (DDR2, DDR3, DDR4, DDR5).

Multi-Channel Memory

Allows multiple memory modules (e.g., two for Dual-Channel, three for Triple-Channel) to work together to increase data pathway width and enhance performance.

Interleaving (Memory)

A process where multiple memory modules work together to enhance data transfer speed, improving performance beyond simple addition.

Parity Memory

Performs basic error checking using an extra parity bit to detect single-bit errors but cannot correct them. Slower and more expensive than non-parity memory.

ECC (Error Correcting Code) Memory

An advanced memory type that can both detect and correct single-bit memory errors, primarily used in high-end workstations and servers for higher reliability, but is slower than parity memory.

Buffered/Registered Memory

Includes additional hardware called a register (buffer) between memory and CPU to reduce electrical load in systems with many memory modules, often paired with ECC for enhanced reliability.

Virtual Memory

Also known as a page file (Windows) or swap space (Linux/Unix/Mac), it allocates a block of hard drive or SSD space to act as system memory (RAM) when physical RAM is insufficient.

Page File/Swap Space

The specific terms for virtual memory in Windows (Page File) and Linux/Unix/Mac (Swap Space), extending RAM capacity by using disk space.

BIOS (Basic Input/Output System)

A legacy program used by a computer's microprocessor to initialize and boot the system after power-on, managing data flow between the operating system and hardware devices. Stored in ROM and can be updated via flashing.

UEFI (Unified Extensible Firmware Interface)

A modern replacement for BIOS with a graphical user interface (GUI), 64-bit support, support for storage devices larger than 2.2 TB using GUID Partition Table (GPT), and faster boot times.

CMOS (Complementary Metal-Oxide Semiconductor)

Battery-powered memory that stores BIOS/UEFI settings. Failure of the CR2032 battery causes loss of settings like system time and date.

POST (Power-On Self-Test)

A diagnostic sequence performed at startup to verify the functionality of essential hardware components. It issues errors via text messages or beep codes if problems are detected.

Boot Order

Determines the sequence in which the system checks devices for an operating system (e.g., hard drives, optical drives, USB devices, network adapters).

Flashing (Firmware)

The process to update BIOS/UEFI firmware for fixes, security patches, or new features, typically done by downloading the latest firmware from the manufacturer's website.

Secure Boot

A UEFI security feature that verifies the integrity of firmware, OS loaders, and boot-critical drivers during the boot process to protect against rootkits and ensure the OS has not been tampered with.

USB Port Permissions (BIOS/UEFI)

BIOS/UEFI options to enable/disable USB ports or restrict their usage for specific devices (e.g., block mass storage devices) to protect against malware and data exfiltration.

Root of Trust (RoT)

The foundational component for secure operations of a computing system, containing cryptographic keys and ensuring a secure boot process by verifying firmware and boot settings.

TPM (Trusted Platform Module)

A hardware-based Root of Trust embedded in modern systems, used for storing digital certificates, keys, and password hashes, attesting to system integrity, and enabling secure encryption like BitLocker.

HSM (Hardware Security Module)

A specialized appliance for secure generation and storage of cryptographic keys, less susceptible to tampering than software solutions, used in high-security environments.

NTP (Network Time Protocol) Servers

Dedicated systems that synchronize the time of devices across a network, ensuring consistency and accuracy. Operates using a hierarchical structure to distribute Coordinated Universal Time (UTC).