You’ve made an excellent choice aiming for the CompTIA A+ certification. It goes without saying that you want to excel in this exam. As A+ covers many technical topics broadly, it is tricky to remember fine details, especially when troubleshooting the problems described in the exam questions.
A+ is a popular entry point into the IT and cyber security industry. To become a technical support specialist, field service technician, help desk technician, service desk analyst, data support technician, or desktop support administrator, the CompTIA A+ certification will get your foot in the door. It also contains essential IT knowledge for a career in cyber security.
Therefore, we’ve prepared this CompTIA A+ cheat sheet for you as an ongoing revision checklist and provide direction in your exam preparation. Get a copy of this CompTIA A+ cheat sheet for your desk here. When you’re ready, let’s review our must-know concepts below.
About CompTIA A+ Certifications
CompTIA A+ comprises two examinations: Core 1, which focuses on hardware, and Core 2, which is about software. The latest CompTIA A+ exam codes are 220-1101 for Core 1 and 220-1102 for Core 2, and you must pass both to obtain the CompTIA A+ certification.
Each of the Core examinations has at most 90 questions, usually 82–83, and you must complete each exam in 90 minutes. That means you only have 180 minutes to finish the A+ exams. On a scale of 100–900, the passing scores for Core 1 and Core 2 are 675 and 700, respectively.
Here is a chart on CompTIA A+ exam objectives (domains):
Core 1 220-1101 Cheat Sheet
This section covers important concepts for Core 1.
Hardware and Mobile Devices
Revisit these hardware-related concepts often.
|Motherboard||• For connecting all components.|
• Form factors: ATX, microATX, and ITX.
• Types of expansion buses: PCI Express (PCIe) and PCI.
• Intel chipsets link to CPU via DMI or QPI.
• AMD CPU-to-chipset connection is HyperTransport.
|Central processing unit (CPU)||Handles most calculations. Each core contains L1/L2 cache. The entire CPU shares L3 cache.|
Intel CPUs use these sockets:
AMD CPUs use these sockets:AM3
|Random Access Memory (RAM)||• RAM DIMMs include DDR (184 pins), DDR2 (240 pins), DDR3 (240 pins) and DDR4 (288 pins).|
• RAM SODIMMs include DDR (200 pin), DDR2 (200 pin), DDR3 (204 pin), and DDR4 (260 pin).
• Dual-channel: 2× width of 128-bit bus.
• Triple-channel: 3× width of 192-bit bus.
• Quad-channel: 4× width of 256-bit bus.
• Latency measured as CL or CAS.
|Serial Advanced Technology Attachment (SATA)||Consists of a 15-pin power connection and a 7-pin data connector.|
• Rev 1 (1.5 Gb/s),
• Rev 2 (3 Gb/s),
• Rev 3 (6 Gb/s),
• Rev 3.2 (SATA Express) (16 Gb/s),
• Rev 3.2 (SATA Express) (16 Gb/s).
mSATA = mini-SATA.
|Hard disk drive (HDD)||Speeds: 5,400 RPM, 7,200 RPM, 10,000 RPM, 15,000 RPM|
Form factors: 3.5”, 2.5”
|Solid-state drive (SSD)||Communication interfaces:|
• Non-Volatile Memory Express (NVMe)
• Peripheral Component Interconnect Express (PCIe): x1, x2, x8, x16
Form factors: M.2, mSATA
• USB flash drives
• Secure Digital (SD) cards
|Redundant Array of Independent/Inexpensive Disks (RAID)||• RAID 0 = striping; not fault-tolerant.|
• RAID 1 = mirroring. RAID 1 + two disk controllers = disk duplexing.
• RAID 5 = striping with parity.
• RAID 10 = mirrored sets in a striped set.
|Small Computer Systems Interface (SCSI)||Modern SCSI standards:|
• Serial Attached SCSI (SAS)
• Internet SCSI
|IPS||In-plane switching. Possesses wider viewing angle.|
|Optical media||Optical disc drives use changeable media to store and retrieve data.|
• read-only memory (ROM)
• write-once ®
• rewritable/write-many (RW)
|Compact Disc (CD)||Capacity: 650–700 MB|
|Digital video/versatile disc (DVD)||Special formats:|
• DL: dual-layered
• DS: double-sided
Capacity: 4.37 – 17 GB
Recording technologies: DVD+R, DVD-R, DVD+RW, and DVD-RW.
|Blu-ray disc (BD)||For games and HD movies.|
Capacity: 25–128 GB(Mini-disc capacity: 7.8 or 15.6 GB)
|Laptop||Portable miniaturized versions of desktop computers. Uses M.2, Mini PCIe, and Mini PCI (internal) and ExpressCard /34 and /54 (external).|
• SODIMM RAM
• Optical disc drives
• Smart card readers
• Hard drives (SSD, HDD, or hybrid).
|Heat sink||When installing a heat sink, use thermal paste or pads for filling in gaps and increasing thermal conductivity between CPU and heat sink.|
Liquid-based cooling systems have higher thermal transfer capabilities than air cooling.
To minimize overheating, a “dual-rail” power supply unit (PSU) separates and controls the current in each wire.
|Sound card||Links as x1 PCIe (or PCI cards) and will typically have PC 99 color-coded 1/8” mini-jacks for I/O and speakers and optical I/Os known as S/PDIF.|
|Video card||You link them to motherboards through x16 PCIe or PCI expansion slots.|
Video connector types and cables:
• Mini Display Port
• Component Video/RGB
Typical color depths:
Typical resolutions (aspect ratio)
• 1280×720 (720p, 16:9)
• 1920×1080 (1080p, 16:9)
• 1366×786 (16:9)
• 1680×1050 (WSXGA+, 8:5)
• 1920×1200 (WUXGA, 8:5)
• 640×480 (VGA, 4:3)
|Image processing of laser printing||1. Processing|
|Printer configuration settings||• Duplexing: printing on both sides.|
• Collation: printing many jobs in a row.
• Orientation: portrait/landscape.Quality: 600 or 1200 DPI.
|BIOS/UEFI||• Locates, tests, and initializes components and boots to the hard drive, optical disc, USB flash drive, or network by PXE.|
• CMOS stores time/date and passwords.
• A CR2032 lithium battery powers the CMOS.
|BIOS/UEFI configurations||• Time/date|
• Boot device order
• Power management
• Clock and bus speeds
• Virtualization support (Intel VT or AMD-V)
• Enable/disable devices
• Intrusion detection
A+ covers network topologies and the devices connecting them.
|LAN||Local area network|
|WAN||Wide area network|
|MAN||Metropolitan area network|
|PAN||Personal area network|
|SAN||Storage area network|
|WLAN||Wireless local area network|
|Network Address Translation (NAT)||Modifying IP address as it crosses a router|
|Port forwarding||Forwards outside network port to internal IP address and port|
|Switch||Connect computers in LAN|
|Router||Connects ≥2 LANs to the Internet|
|Firewall||Safeguards computers and networks against unauthorized access|
|IDS||Intrusion detection system|
|IPS||Intrusion prevention system|
|UTM||Unified threat management|
Network cables: Familiarize yourself with the examples.
|Twisted pair||RJ45, RJ11|
|Fiber optic||SC, ST, LC|
|Plenum-rated||Fire-resistant cable designed for airways, conduits, and regions where sprinklers cannot reach.|
|5e||100 Mb/s and gigabit networks|
|6/6a||gigabit and 10 Gb/s networks|
|7||gigabit and 10 Gb/s networks|
|T568B||Swap “green” and “orange” in T568A.|
|Thunderbolt||• Version 1 is 10 Gb/s and uses DisplayPort;|
• Version 2 is 20 Gb/s and also uses DisplayPort;
• Version 3 is 40 Gb/s and uses USB-C.
|Universal Serial Bus (USB)||Can support up to 127 devices.|
• USB 1.1 (full speed) runs at 12 Mb/s by a max cable length of 3m.
• USB 2.0 (high-speed) runs at 480 Mb/s by a max cable length of 5m.
• USB 3.0 (SuperSpeed) runs at 5 Gb/s.
• USB 3.1 (SuperSpeed+) runs at 10 Gb/s.
Version 3.x ports are blue.
Desktop/laptop computers use USB-A/B connectors.
Tablets/smartphones use mini- and micro-connectors.
USB-C: one-third size of USB-A plug; compatible with USB 3.1.
|Bluetooth||Short-range technology for simplifying communication and connectivity among network devices|
|Bluetooth transmission range lengths||• Class I: 100m|
• Class II: 10m (most popular)
• Class III: 1m (unpopular)
|Bluetooth maximum data transfer rate||• Version 1: 721 Kb/s|
• Version 2: 2.1 Mb/s
• Version 3: 24 Mb/s
Internet Protocol (IP) addressing:
|IPv4 address||32-bit number, consisting of four decimals from 0 to 255 separated by period (.), e.g., 192.168.1.1|
Manual entry or Dynamic Host Configuration Protocol (DHCP) determines your IPv4 address.
|Classless Inter-Domain Routing (CIDR)||CIDR IPv4 addresses have a prefix; e.g., “/24” in “10.150.23.58/24” denotes a 255.255.255.0 subnet mask.|
|IPv6 address||128-bit hexadecimal number, e.g., 2001:7120:0000:8001: 0000:0000:0000:1F10|
|IPv6 loopback||::1 (unicast)|
|Network speed||• 1000 Mb/s (gigabit Ethernet)|
• 10 Gb/s (10 Gb Ethernet)
IPv4 address classes:
|Class||Range (1st decimal)||Subnet mask||Private|
|Version||Data transmission rate||Frequency modulation (GHz)|
|802.11n||300/600 Mb/s||2.4, 5|
|802.11ax||≤9.6 Gb/s||2.4, 5, 6|
Ports and Protocols:
|21||File Transfer Protocol (FTP)|
|22||Secure Shell (SSH)|
|25, 587||Simple Mail Transfer Protocol (SMTP)|
|53||Domain Naming System (DNS)|
|80||Hypertext Transfer Protocol (HTTP)|
|110||Post Office Protocol (POP3)|
|143||Internet Message Access Protocol (IMAP)|
|443||HTTP Secure (HTTPS)|
|445||Server Message Block (SMB)|
|548||Apple Filing Protocol (AFP)|
|3389||Remote Desktop Protocol (RDP)|
Remember to check out our Common Ports Cheat Sheet.
Virtualization and Cloud Computing
Despite its small weighting, we’d like to cover basic concepts in this domain.
|IaaS||Infrastructure as a service|
|PaaS||Platform as a service|
|SaaS||Software as a service|
|VDI||Virtual desktop infrastructure|
Virtual machines (VMs) come in these two types:
|Type 1||Bare or native metal|
|Type 2||App-like VM on the operating system|
Core 2 220-1102 Cheat Sheet
This section covers key ideas for Core 2.
|Microsoft Management Console (MMC) snap-in||Examples: Computer Management, Performance Monitor|
|Master boot record (MBR)||Hard drive has up to four partitions but only one extended partition.|
|GPT (GUID Partition Table)||Hard drive has 128 partitions and may exceed MBR’s 2 TB limit. Stored in multiple locations. Requires UEFI-compliant motherboard.|
|Logical drive||Segment of an extended partition|
|Active partition||Computer boots from here, usually contains operating system|
|Volume||Any section of a drive with a letter|
|Samba||File- and printer-sharing service|
|CDFS||Compact disc file system|
|NFS||Network file system|
|NTFS||New Technology File System|
|FAT32||File Allocation Table 32|
|ext3, ext4||Third and fourth extended file systems|
|APFS||Apple File System|
|exFAT||Extensible File Allocation Table|
Common system tools in Windows:
|Command Prompt||Command-line program.|
For elevated privileges: Click START (bottom left corner) > type “cmd” > select “Run as administrator”.
|Control Panel||View/change settings|
|Task Manager||Monitor and start/end processes|
|Device Manager||Monitor and (dis)connect devices|
|Remote Desktop software||View/control a remote computer|
|User State Migration Tool (USMT)||Move user data|
|System Restore||Revert to earlier system configuration (“restore point”)|
Windows upgrade minimum prerequisites:
|Windows||CPU (GHz)||RAM (GB)||Free disk space (GB)|
|11||1; 2 cores||4||64|
Know the advantages and vulnerabilities of these protocols.
|Wireless encryption protocol||Explanation|
|WPA||Wi-Fi Protected Access|
|TKIP||Temporal Key Integrity Protocol|
|AES||Advanced Encryption Standard|
|RADIUS||Remote Authentication Dial-In User Service|
|TACACS+||Terminal Access Controller Access-Control System|
|Phishing||Attack by email; single target|
|Vishing||Attack by telephone or voicemail|
|Shoulder surfing||Look over someone’s shoulder, often with a recording device|
|Whaling||Phishing that targets high-ranking people, such as C-suite executives|
|Tailgating||Unauthorized entity follows authorized party into secured premises|
|Impersonation||Attacks using stolen credentials or personal information|
|Dumpster diving||Recover information from trash|
|Evil twin||Setting up a fake Wi-Fi access point, hoping people choose it over the genuine one.|
|Denial of service (DoS)||Overwhelming a target using a single machine|
|Distributed denial of service (DDoS)||DoS using multiple machines|
|Zero-day attack||Vulnerability unbeknownst to developers|
|Spoofing||Gain unauthorized access by pretending to be authorized|
|On-path attack||Setting up Wi-Fi networks to trap unsuspecting users|
|Brute-force attack||Trying character combinations|
|Dictionary attack||Using lists of probable passwords|
|Insider threat||Potential for an insider to use their authorized access or understanding of an organization to harm that organization|
|Structured Query Language (SQL) injection||Manipulating SQL to modify remote database (such as by using sqlmap)|
|Cross-site scripting (XSS)||Injecting malicious scripts into normal websites|
|Virus||Runs on a computer without the user’s knowledge.|
Examples: Boot Sector, Macro, Program, Polymorphic, Stealth, and Multipartite.
|Worm||Replicates itself across a network|
|Trojan Horse||Performs useful functions superficially but runs malicious programs covertly|
|Spyware||Spies on a computer and records its activities.|
Examples: keylogger and browser-hijacking adware
|Rootkit||Gains administrator-level access to the system core undetected|
|Ransomware||Holds a computer hostage until the user pays|
We hope this CompTIA A+ cheat sheet helps you in your studies as a brief recap of key points. Don’t forget to look into our latest CompTIA A+ courses and practice tests for comprehensive exam preparation. Above all, we wish you success in the exam and beyond.