CompTIA A+ Cheat Sheet (Updated for Latest Exam)

CompTIA A+ Cheat Sheet (Updated for Latest Exam)

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):

CompTIA A+ Domains: Core 1 220-1101: 1.0 Mobile Devices 14% 2.0 Networking 20% 3.0 Hardware 27% 4.0 Virtualization and Cloud Computing 12% 5.0 Hardware and Network Troubleshooting 27%; Core 2 220-1102: 1.0 Operating Systems 27% 2.0 Security 24% 3.0 Software Troubleshooting 26% 4.0 Operational Procedures 23%
CompTIA A+ Exam Domains

Core 1 220-1101 Cheat Sheet

This section covers important concepts for Core 1.

CompTIA A+ Technical Troubleshooting—Best Practice Methodology: Given a scenario, apply the best practice methodology to resolve problems. - Always consider corporate policies, procedures, and impacts before implementing changes 1. Identify the problem - Gather information from the user, identify user changes, and, if applicable, perform backups before making changes - Inquire regarding environmental or infrastructure changes 2. Establish a theory of probable cause (question the obvious) - If necessary, conduct external or internal research based on symptoms 3. Test the theory to determine the cause - Once the theory is confirmed, determine the next steps to resolve the problem - If the theory is not confirmed, re-establish a new theory or escalate 4. Establish a plan of action to resolve the problem and implement the solution - Refer to the vendor’s instructions for guidance 5. Verify full system functionality and, if applicable, implement preventive measures 6. Document the findings, actions, and outcomes
Technical Troubleshooting—Best Practice Methodology

Hardware and Mobile Devices

Revisit these hardware-related concepts often.

ConceptElaboration
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:
• LGA775
• 1150
• 1155
• 1156
• 1366
• 2011

AMD CPUs use these sockets:AM3
• AM3+
• FM1
• FM2
• FM2
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.

Revisions:
• 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)
• SATA
• Peripheral Component Interconnect Express (PCIe): x1, x2, x8, x16

Form factors: M.2, mSATA
Solid-state mediaExamples:
• SSDs
• USB flash drives
• CompactFlash
• 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
IPSIn-plane switching. Possesses wider viewing angle.
TNTwisted nematic
Optical mediaOptical disc drives use changeable media to store and retrieve data.

Versions:
• 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)
LaptopPortable miniaturized versions of desktop computers. Uses M.2, Mini PCIe, and Mini PCI (internal) and ExpressCard /34 and /54 (external).

Replaceable components:
• Keyboards
• Touchpads
• SODIMM RAM
• Screens
• Inverters
• Batteries
• Optical disc drives
• Smart card readers
• Hard drives (SSD, HDD, or hybrid).
Heat sinkWhen 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 cardLinks 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 cardYou link them to motherboards through x16 PCIe or PCI expansion slots.

Video connector types and cables:
• DVI
• VGA
• HDMI
• Mini-HDMI
• DisplayPort
• Mini Display Port
• S-Video
• Component Video/RGB
• Composite

Typical color depths:
• 16-bit
• 24-bit
• 32-bit

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 printing1. Processing
2. Charging
3. Exposing
4.Developing
5. Transferring
6. Fusing
7. Cleaning
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
• Passwords
• Power management
• WOL
• Monitoring
• Clock and bus speeds
• Virtualization support (Intel VT or AMD-V)
• Enable/disable devices
• Diagnostics
• Security
• Intrusion detection

Networking

A+ covers network topologies and the devices connecting them.

ConceptExplanation
LANLocal area network
WANWide area network
MAN Metropolitan area network
PANPersonal area network
SANStorage area network
WLANWireless local area network
Network Address Translation (NAT)Modifying IP address as it crosses a router
Port forwardingForwards outside network port to internal IP address and port
SwitchConnect computers in LAN
RouterConnects ≥2 LANs to the Internet
FirewallSafeguards computers and networks against unauthorized access
IDSIntrusion detection system
IPSIntrusion prevention system
UTMUnified threat management

Network cables: Familiarize yourself with the examples.

TypeExamples/Elaboration
Twisted pairRJ45, RJ11
Fiber opticSC, ST, LC
CoaxialF-connector, BNC
Plenum-ratedFire-resistant cable designed for airways, conduits, and regions where sprinklers cannot reach.

Cabling standards:

CategoryRated for
310 Mb/s
5100 Mb/s
5e100 Mb/s and gigabit networks
6/6agigabit and 10 Gb/s networks
7gigabit and 10 Gb/s networks

Wiring patterns:

StandardExplanation
T568A1. White/green
2. Green
3. White/orange
4. Blue
5. White/blue
6. Orange
7. White/brown
8. Brown
T568BSwap “green” and “orange” in T568A.

Connection methods:

ConceptElaboration
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.
BluetoothShort-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:

ConceptElaboration
IPv4 address32-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.
IPv4 loopback127.0.0.1
APIPA/link-local169.254.x.x
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 address128-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:

ClassRange (1st decimal)Subnet maskPrivate
A1–126255.0.0.010.x.x.x
B128–191255.255.0.0172.16.0.0–172.31.255.255
C192–223255.255.255.0192.168.x.x

Wireless Ethernet:

VersionData transmission rateFrequency modulation (GHz)
802.11a54 Mb/s5
802.11b11 Mb/s2.4
802.11g54 Mb/s2.4
802.11n300/600 Mb/s2.4, 5
802.11ac≥1.7 Gb/s5
802.11ax≤9.6 Gb/s2.4, 5, 6

Ports and Protocols:

PortNetwork protocol 
21File Transfer Protocol (FTP)
22Secure Shell (SSH)
23Telnet
25, 587Simple Mail Transfer Protocol (SMTP)
53Domain Naming System (DNS)
80Hypertext Transfer Protocol (HTTP)
110Post Office Protocol (POP3)
137–139NetBIOS
143Internet Message Access Protocol (IMAP)
443HTTP Secure (HTTPS)
445Server Message Block (SMB)
548Apple Filing Protocol (AFP)
3389Remote Desktop Protocol (RDP)

Remember to check out our Common Ports Cheat Sheet.

Well-Known Ports: Unencrypted vs Encrypted
Well-Known Ports: Unencrypted vs Encrypted

Virtualization and Cloud Computing

Despite its small weighting, we’d like to cover basic concepts in this domain.

AbbreviationExplanation
IaaSInfrastructure as a service
PaaSPlatform as a service
SaaSSoftware as a service
VDIVirtual desktop infrastructure

Virtual machines (VMs) come in these two types:

HypervisorElaboration
Type 1Bare or native metal
Type 2App-like VM on the operating system

Core 2 220-1102 Cheat Sheet

This section covers key ideas for Core 2.

Operating Systems

The following table focuses on the Windows operating system. You can also get our command-line cheat sheets for Linux and Unix (applies to Mac).

ConceptElaboration
Microsoft Management Console (MMC) snap-inExamples: 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 driveSegment of an extended partition
Active partitionComputer boots from here, usually contains operating system
VolumeAny section of a drive with a letter
SambaFile- and printer-sharing service
EOLEnd-of-life
CDFSCompact disc file system
NFSNetwork file system
NTFSNew Technology File System
FAT32File Allocation Table 32
ext3, ext4Third and fourth extended file systems
APFSApple File System
exFATExtensible File Allocation Table

Common system tools in Windows:

ToolPurpose
Command PromptCommand-line program.
For elevated privileges: Click START (bottom left corner) > type “cmd” > select “Run as administrator”.
Control PanelView/change settings
RegistryStore settings
Task ManagerMonitor and start/end processes
Device ManagerMonitor and (dis)connect devices
Remote Desktop softwareView/control a remote computer
User State Migration Tool (USMT)Move user data
System RestoreRevert to earlier system configuration (“restore point”)

Windows upgrade minimum prerequisites:

WindowsCPU (GHz)RAM (GB)Free disk space (GB)
10 (32-bit)1116
10 (64-bit)1220
111; 2 cores464

Security

Know the advantages and vulnerabilities of these protocols.

Wireless encryption protocolExplanation
WPAWi-Fi Protected Access
TKIPTemporal Key Integrity Protocol
AESAdvanced Encryption Standard
RADIUSRemote Authentication Dial-In User Service
TACACS+Terminal Access Controller Access-Control System

Social Engineering:

TechniqueExplanation
PhishingAttack by email; single target
VishingAttack by telephone or voicemail
Shoulder surfingLook over someone’s shoulder, often with a recording device
WhalingPhishing that targets high-ranking people, such as C-suite executives
TailgatingUnauthorized entity follows authorized party into secured premises
ImpersonationAttacks using stolen credentials or personal information
Dumpster divingRecover information from trash
Evil twinSetting up a fake Wi-Fi access point, hoping people choose it over the genuine one.

Threats:

NameExplanation
Denial of service (DoS)Overwhelming a target using a single machine
Distributed denial of service (DDoS)DoS using multiple machines
Zero-day attackVulnerability unbeknownst to developers
SpoofingGain unauthorized access by pretending to be authorized
On-path attackSetting up Wi-Fi networks to trap unsuspecting users
Brute-force attackTrying character combinations
Dictionary attackUsing lists of probable passwords
Insider threatPotential for an insider to use their authorized access or understanding of an organization to harm that organization
Structured Query Language (SQL) injectionManipulating SQL to modify remote database (such as by using sqlmap)
Cross-site scripting (XSS)Injecting malicious scripts into normal websites

Malware:

NameExplanation
VirusRuns on a computer without the user’s knowledge.
Examples: Boot Sector, Macro, Program, Polymorphic, Stealth, and Multipartite.
WormReplicates itself across a network
Trojan HorsePerforms useful functions superficially but runs malicious programs covertly
SpywareSpies on a computer and records its activities.
Examples: keylogger and browser-hijacking adware
RootkitGains administrator-level access to the system core undetected
RansomwareHolds a computer hostage until the user pays
Best practice procedures for malware removal. Details: 1. Investigate and verify malware symptoms 2.Quarantine infected systems 3.Disable System Restore in Windows  4.Remediate infected systems a. Update anti-malware software b.Scanning and removal techniques (e.g., safe mode, preinstallation environment)  5.Schedule scans and run updates 6.Enable System Restore and create a restore point in Windows 7. Educate the end user
Best Practice Procedures for Malware Removal
CompTIA A+ Professionalism for Technicians: 10 Proper Communication Techniques. Details: 1• Professional appearance and attire - Match the required attire of the given environment > Formal > Business casual 2• Use proper language and avoid jargon, acronyms, and slang, when applicable 3• Maintain a positive attitude/ project confidence 4• Actively listen, take notes, and avoid interrupting the customer 5• Be culturally sensitive - Use appropriate professional titles, when applicable 6• Be on time (if late, contact the customer) 7• Avoid distractions - Personal calls - Texting/social media sites - Personal interruptions 8• Dealing with difficult customers or situations - Do not argue with customers or be defensive - Avoid dismissing customer problems - Avoid being judgmental - Clarify customer statements (ask open-ended questions to narrow the scope of the problem, restate the issue, or question to verify understanding) - Do not disclose experience via social media outlets 9• Set and meet expectations/time line and communicate status with the customer - Offer repair/replacement options, as needed - Provide proper documentation on the services provided - Follow up with customer/user at a later date to verify satisfaction 10• Deal appropriately with customers’ confidential and private materials - Located on a computer, desktop, printer, etc.
Proper Communication Techniques and Professionalism for Technicians
CompTIA A+ in StationX's Cyber Security Certification Roadmap: A+ belongs to Essential IT
Location of A+ in the StationX Cyber Security Certification Roadmap

Conclusion

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.

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