CompTIA A+ Core 1 220-1101 Notes

Exam Overview

  • Time Limit: 90 minutes.
  • Questions: Maximum of 90 (multiple choice, drag & drop, performance-based).
  • Passing Score: 675 (out of 900).
  • Exam Fee: $239.

Exam Domains

  • Mobile Devices: 15%
  • Networking: 20%
  • Hardware: 25%
  • Virtualization and Cloud Computing: 11%
  • Hardware and Network Troubleshooting: 29%

Mobile Devices

  • Hardware Replacement:
    • Battery, keyboard/keys, RAM, HDD/SSD.
    • Wireless cards.
  • Display Components: LCD (with backlight), OLED (no backlight needed).
    • LCD types: TN, IPS, VA.
  • Digitizer: Converts analog input to digital images.
  • Connection Methods: USB (C/micro/mini), Lightning, NFC, Bluetooth, Hotspot.
  • Accessories: Touch pens, trackpads, headsets, speakers, webcams.
  • Port Replicator: Reproduces ports.
  • Docking Station: More functionality than port replicator (drive bays, expansion slots).

Cellular Networking Standards

  • 2G: Phone calls, SMS, limited data. GSM and CDMA (incompatible).
  • 3G: Mobile internet, video calls, mobile TV.
  • 4G: LTE (faster than 3G, up to 300 Mbps down, 75 Mbps up). One standard.
  • 5G: Much faster than 4G (up to 100x, potential speeds of 20Gbps), low latency.

Mobile Device Management (MDM)

  • Corporate email configuration.
  • Two-factor authentication.
  • Corporate applications.

Mobile Device Synchronization

  • Account setup (Microsoft 365, Google Workspace, iCloud).
  • Data to synchronize (mail, photos, calendar, contacts).
  • Data caps.

Networking Fundamentals

  • LANs, SOHO networks, enterprise/corporate networks, WLANs.
  • Protocol Suite: TCP/IP (includes HTTP, FTP).
  • TCP: Reliable, connection-oriented, sequenced, acknowledgements, high overhead (24-60 bytes).
  • UDP: Unreliable, connectionless, un-sequenced, no acknowledgments, lightweight (8 bytes).

File Transfer Protocols

  • FTP: TCP ports 20, 21. Unencrypted.
  • TFTP: UDP port 69. No authentication. Unencrypted.
  • SFTP: TCP port 22. Secure implementation of FTP (over SSH).

Mail Protocols

  • SMTP: TCP port 25. Sends outgoing mail.
  • POP3: TCP port 110. Downloads incoming mail.
  • IMAP: TCP port 143. Synchronizes incoming mail.

Remote Access Protocols

  • Telnet: TCP port 23. Insecure, use SSH instead.
  • SSH: TCP port 22. Encrypted remote command line access.

Other Networking Protocols

  • DNS: TCP/UDP port 53. Name to IP address resolution.
  • DHCP: UDP ports 67 (server), 68 (client). Automatic IP configuration.
  • HTTP: TCP port 80. Webpage transfer.
  • HTTPS: TCP port 443. Secure webpage transfer (SSL/TLS).
  • NetBIOS: TCP/UDP ports 137/139. Windows network communication.
  • SNMP: UDP ports 161/162. Network monitoring and configuration.
  • LDAP: TCP/UDP port 389. Directory access.
  • SMB: TCP port 445. File sharing, network browsing, printing.
  • RDP: TCP port 3389. Remote Windows desktop access.

Network Devices

  • NIC: Connects devices to a network, MAC address.
  • Hub: Legacy, broadcasts communications, uses CSMA/CD.
  • Switch: Connects and manages wired communications, forwards based on MAC addresses.
    • Managed (configurable) vs. Unmanaged (not configurable).
  • Router: Connects different broadcast domains, forwards based on IP addresses, DHCP.
  • Firewall: Prevents unauthorized access.
    • DMZ: Network segment intentionally exposed to the Internet.
  • Access Point (AP): Manages wireless communications.
  • SOHO Router: Multifunction device (wireless, switching, firewall, DHCP).
  • PoE: Power over Ethernet, requires PoE switch or injector.
  • DSL modem: Use telephone lines
  • Optical Network Terminal (ONT): Converts optical signal for TV, voice, and data.

Software-Defined Networking (SDN)

  • Dynamic, programmable network configuration.
  • Separates data plane from control plane.
  • Uses a controller to manage network traffic.

Wireless Networking

  • 2.4 GHz: Long range, slower data rates, higher interference (channels 1, 6, 11).
  • 5 GHz: Short range, faster data rates, lower interference.

Wireless Standards

  • 802.11a/b/g/n/ac/ax (Wi-Fi 1/2/3/4/5/6) - various speeds and frequencies.

Access Point Configurations

  • SSID (change default), IP address (static for admin), password (change default), wireless channel.

Wireless Signal Degradation Factors

  • Distance, walls/barriers, interference.

Additional Wireless Technologies

  • Long-range fixed wireless: Point-to-point directional antennas.
  • Bluetooth: Short-range device connections (mice, keyboards, headsets).
  • Near-Field Communication (NFC): Short-distance communication (payments, access).
  • Radio-Frequency Identification (RFID): Object tracking and identification.

Server Roles

  • DNS, DHCP, fileshare, print servers, mail servers, syslog, web servers.

Network Security

  • Authentication, authorization, accounting.

Internet Appliances

  • Spam gateways, unified threat management (UTM), load balancers, proxy servers.

Legacy/Embedded Systems

  • SCADA systems, may require network segmentation.

Internet of Things (IoT)

  • Devices using wireless protocols (Z-Wave, Zigbee, Bluetooth, NFC, IR, RFID, 802.11).

DNS Details

  • Hostnames, domain names, FQDNs.

DNS Record Types

  • A, AAAA, TXT (SPF, DKIM, DMARC), CNAME, MX.

DHCP Details

  • Scope, exclusion range, reservations, lease time.

VPN

  • Secure tunnel to a private network.

VLAN

  • Segmented and isolated network.

Network Types

  • LAN, MAN, WAN, CAN, PAN, SAN.

Internet Connection Types

  • DSL, Cable, Fiber, Satellite, Cellular, WISP.

Networking Tools

  • Crimper, cable stripper, WiFi analyzer, toner probe, punch-down tool, cable tester, loopback plugs, network tap.

Network Cables

  • Copper (up to 40 Gbps), Fiber (above 100 Gbps)

Cable Characteristics

  • Attenuation, Noise Immunity

Coaxial Cable

  • Shielding protects against EMI.
  • Long transmission distance (1100 meters).
  • RG-6, BNC, F-connector.

Twisted Pair Cables

  • STP (shielded), UTP (unshielded), RJ45.

Twisted Pair Categories

  • Cat 5 (100 Mbps), Cat 5e (1 Gbps), Cat 6 (10 Gbps at 55m), Cat 6a (10 Gbps at 100m).

Wiring Standards

  • T568A, T568B.

Fiber Optic Cables

  • Not susceptible to EMI.
  • Longest transmission distance (up to 40km).
  • Fastest speeds (up to 255 Tbps).
  • ST, SC, LC connectors.

USB

  • Supports various devices (keyboards, mice, storage).
  • USB Versions
    • Speeds range from 1.5 Mbps (USB 1.0) to 40 Gbps (USB4).
  • USB Connectors
    • Type A, Type B, Type C.

Thunderbolt

  • Fastest and most capable connector, compatible with DisplayPort and USB.
  • Daisy-chain up to 6 devices.
  • Mini Display Port, USB Type-C port types

Legacy Ports

Serial Port (RS-232/DB9)

  • Oldest ports still in use. Used to manage enterprise class network devices, or Robotic equipment.

Audio/Video Interfaces

  • HDMI, DisplayPort, VGA, DVI.

Hard Drive Cables

  • SATA (replaced PATA/IDE).
  • mSATA (Mini SATA) is a smaller version found in SFF systems.

Older Drive Cables

  • SCSI, IDE/PATA.

Adapters

  • Video adapters change video connector types.

Memory (RAM)

  • SRAM (cache), DRAM (installable).
  • DIMM (desktops/servers), SODIMM (notebooks/SFF).
  • DDR types (DDR, DDR2, DDR3, DDR4, DDR5) - not cross-compatible.
  • Memory Channeling: Allows system to access more RAM simultaneously for better performance.
  • ECC RAM: Detects and fixes errors.

Storage Terminology

  • Capacity, performance, interface, form factor.

Hard Disk Drive (HDD)

  • Magnetic head, spinning platters, SATA interface.
  • Sizes measured in RPMs Laptop/Notebooks 5,400RPMs, Desktops 7,200 RPMs, Gamming and Servers 10,000 RPMs.

Solid State Drive (SSD)

  • Flash chips, SATA and M.2 form factors.

SSD Connectors

  • M.2 replaced mSATA

NVMe

  • PCle based SSD for best performance.

Hybrid Drives

  • Combination of SSD and HDD

External Drives

  • Available in HDD or SSD

Flash Memory

  • Flash Drives:
  • Faster, larger, and more durable than floppy disks or optical media. Meant to be used to transport data,
  • Memory/Storage Cards:
  • Used in portable devices like smartphones, cameras, tablets, and game consoles. SD, miniSD, microSD, CompactFlash.

Optical Drive Comparisons

  • CD/DVD/Bluray
    • CD-R:700MB, SS/SL: 4.7GB, SS/DL: 8.5GB, 25GB,50GB, 200GB (BDXL)

RAID

  • Combines drives for capacity/performance/protection.
  • Hardware RAID, Software RAID, JBOD (Just a Bunch of Disks).
  • RAID 0 (striping - no protection), RAID 1 (mirroring - protection), RAID 5 (striping with parity), RAID 10 (RAID 1+0).

Motherboards and Chipsets

  • Motherboards serve as the basis of the entire computer system.
  • ATX,Micro-ATX,Mini-ITX Motherboards

PCI and PCIE

  • PCI (legacy, slower), PCIe (latest, faster).
  • PCIe sizes (x1, x4, x8, x16, x32).

CPU (Central Processing Unit)

  • Motherboard chipset and socket define CPU compatibility.

  • CPU Architecture - X86/X64 and ARM.

  • PGA and LGA Socket
    Socket and Processors

  • Generation

  • Intel CPUs LGA 1155, 1150,2011,1151,1200,1700.

  • AMD CPUs AM3+,FM2,FM2+,AM4,TR4,sTRX4.

CPU Technology

  • 32 Bit handles 4 Gigabytes of RAM

  • 64 Bit handles 16 Terabytes of RAM

    Cooling

    • Throttling : Reduces power consumption
    • OverClocking : Increase the CPU Frequency.
      *Passive Cooling: Thermal Compounds ,Thermal pads, Heat Sinks.
      *Active Cooling: CPU Fan/CPU Cooler, case Fan.
      *Liquid Cooling: Water or coolant to transfer heads as quickly as possible.

Expansion cards

Sound Card:

Video Card:

Capture card:

NIC:

Boot Process

A BIOS (Basic Input Output System) or a UEFI (Unified Extensible Firmware) is included on every motherboard

The CMOS is used to store configuration changes done to the BIOS/UEFI.
Common CMOS setting,

Boot Device Priority

# Control which storage device the computer will first boot from

Boot Time Passwords

Enable/Disable access to ports

USB, Thunderbolt, Serial, and Network interfaces

Wake-on-LAN (WoL)

Virtualization Support

CPU multipliers and voltages
RAM timing and voltages.

Trusted Platform Module (TPM)

Hardware encryption

Stores cryptographic key generally for hard drive encryption
HSM
Usually an external appliance or add on card

Power Supply

  • A Power supply unit (PSU) is a critical component since they provide power to the motherboard and all other components attached to it.
    • Power Supplies ATX and ATX12V
    • Molex, SATA, and PCle Power connectors

Printers

  • All Printers have USB, Ethernet, and Wireless

  • Duplex, Orientation, Tray settings and Quality

    • A Printer share, Computer has to be on
    • Print server:
      A dedicated computer used to share printers.
      *Badgin, Audit logs,Secured prints.

  • Automatic document feeder - ADF Scanner has Simplex and Duplex. Collator/Separator properly orders the pages, Stapler, and Binder.
    Finisher - Paper trays

Different Printer Types

Laserjet:

Most Important toner the powered ink must avoid inhaling while working on the machine

  • When a new toner or maintenance kit is applied you will need to calibrate it within the printer software - Clean the printer according the manufactured specifications
    Toner Cartridge
    . Imaging Drum
    . Transfer Belt
    . Erase Lamp
    .Primary Corona and transfer Corona
    . Duplexing Assembly

    • Inkjet Printer Components - Ink cartridge, print head, roller, feeder, duplexing assembly, carriage belt

Impact Printer:

  • Most Important. Can print on carbon backed paper.
    Print head, ribbon, tractor feed,Impact paper Replace paper Replace ribbon.
  • Replace print-Impact Printer paper

Thermal printers

Thermal printers are the only printer that does not use ink to print. It prints on heat sensitive paper.

  • Special thermal paper - Replace paper

    Thermal Printers heating element

3D Printers:

-Liquid resin is hardened by light as the object is attachedto a rising print bed (SLA)
-Most Important. Plastic filament is melted out of an extruder (hot end)onto a print bed.

Virtualization

#RAM Each virtual machine will require the same resources as an actual physical machine
VM Storage Types VMStorage
#Hypervisor:The software that is used to create, run, and manage the VMs is the hypervisor
-Prioritizes resources for the VMs -Also known as bare metal virtualization

Public Cloud and Private Cloud

Cloud

#IaaS, PaaS, and SaaS - (1) Customer application

  • The software does NOT require installation instead is accessed via a web browser- the customer only manages user access
    -(2) Operating system the customer only manages user access
    -Customers can develop their ownapplications and services withoutneeed to manage any Infrastructure or operrating system
    the Access to it.

(3) HardWare Customer manages the operating system, the applications installed, and the Access to it.

  • CompTIA Troubleshooting Steps Power-on self-test (POST) beeps

Troubleshooting:

  • Gather information from the user. Establish a theory of probable cause. Test the theory to determine the cause. Establish a plan of action. Verify full system functionality. Document findings.

  • Light-emitting diode (LED) status indicators
    • Use to help you diagnose issues- Can tell you if drives are functioning-On most RAID systems the lights should be-a blinking green, if it is amber it may be a dead drive.- Grinding Noises and Clicking Sounds

Video, Projector, and Display Issues

  • Check the cable to see if its plugged into the correct port, Monitor is set to the correctsource. Replaced Burned Out Bulbs with new - Fuzzy image - Display burn-in - Dead pixels - Flashing screen - Incorrect color display - Audio issues - Dim image
  • Intermittent projector shutdow
  • Common issues with mobile devices.
  • Poor battery health, Swollen battery, Broken screen, Improper charging.
    Replace drum on laser Inspect the print heads on inject Printer issues.
  • Incorrect Color Check - the printer to see what size its- supports
  • Check the printer to see what size it supports ensure that correct drivers