CompTIA A+: key terms

Flashcards for this exam CompTIA A+ guide Class dates

• /etc/hostsA local Linux file mapping hostnames to IP addresses, checked before or instead of DNS according to nsswitch.conf.Foundational
• 10 Gigabit Ethernet (10GbE)Ethernet at 10 Gbps over copper, twinax or fiber, defined in 802.3ae (fiber) and 802.3an (copper).Foundational
• 1000BASE-TGigabit Ethernet over all four pairs of Cat 5e or better twisted-pair copper, up to 100 meters.Foundational
• 100BASE-TXFast Ethernet over two pairs of Cat 5 or better UTP at 100 Mbps, up to 100 meters.Foundational
• 10BASE-TThe original twisted-pair Ethernet standard: 10 Mbps over two pairs of Cat 3 or better UTP, up to 100 meters.Foundational
• 10GBASE-T10 Gbps Ethernet over four-pair twisted-pair copper with RJ45 connectors, up to 100 m on Cat 6a.Intermediate
• 2.4 GHz BandThe 2.400-2.4835 GHz ISM band used by 802.11b/g/n/ax, with only three non-overlapping 20 MHz channels in North America.Foundational
• 24-Pin ATX Power ConnectorThe main power connector from the PSU to the motherboard, supplying 3.3 V, 5 V, and 12 V.Foundational
• 3-2-1 Backup RuleA backup guideline: keep three copies of data on two different media types with one copy offsite.Foundational
• 32-bit vs 64-bitThe register and addressing width of a CPU or OS, which determines addressable memory and software compatibility.Foundational
• 3D PrinterA device that builds physical objects layer by layer from plastic filament or liquid resin.Foundational
• 5 GHz BandWi-Fi spectrum from about 5.150 to 5.895 GHz divided into U-NII sub-bands, offering many non-overlapping channels.Foundational
• 80 PLUS CertificationAn efficiency rating program for power supplies, with tiers from Standard to Titanium.Foundational
• A RecordA DNS record that maps a host name to an IPv4 address.Foundational
• AAAA RecordA DNS record that maps a host name to an IPv6 address.Foundational
• Access Control VestibuleSmall space with two interlocking doors where only one opens at a time, preventing tailgating; formerly called a mantrap.Foundational
• Account LockoutDisabling an account temporarily or permanently after a set number of failed login attempts.Foundational
• Acknowledgment NumberThe TCP field indicating the next byte the receiver expects, implicitly acknowledging all prior bytes.Intermediate
• Activation LockAn Apple security feature that ties a device to an Apple Account so it cannot be reused after a wipe without credentials.Intermediate
• Active Directory (AD)Microsoft's on-premises directory service for Windows domains, using LDAP, Kerberos, and DNS.Foundational
• Active Directory Domain Services (AD DS)Microsoft's on-premises directory service that stores users, computers and groups and provides authentication and policy for Windows domains.Foundational
• Active Directory Users and Computers (ADUC)The classic MMC console for managing AD users, groups, computers and OUs.Foundational
• Active ListeningA communication skill of fully focusing on, understanding, and confirming what the user says.Foundational
• Activity MonitorThe macOS app that shows CPU, memory, energy, disk, and network usage by process.Foundational
• Address Resolution Protocol (ARP)The protocol (RFC 826) that resolves a known IPv4 address to the corresponding MAC address on the local network.Foundational
• Administrative ShareA hidden default Windows share, such as C$ or ADMIN$, used for remote administration.Intermediate
• Advanced Encryption Standard (AES)NIST-standard symmetric block cipher (Rijndael) with a 128-bit block and 128-, 192-, or 256-bit keys.Foundational
• Advanced Host Controller Interface (AHCI)The storage controller mode that enables SATA features like native command queuing and hot-plugging.Intermediate
• Advanced Technology Extended (ATX)The most common desktop motherboard and power supply form factor, measuring 12 x 9.6 inches.Foundational
• AdwareSoftware that displays unwanted advertisements, often bundled with free applications.Foundational
• Airplane ModeA device setting that disables cellular, Wi-Fi, and Bluetooth radios.Foundational
• AirPrintApple's driverless printing technology for macOS and iOS devices on the local network.Intermediate
• All-Nodes Multicast AddressThe link-local multicast group ff02::1, which every IPv6 node joins and which functions like a link broadcast.Intermediate
• All-Routers Multicast AddressThe link-local multicast group ff02::2, which every IPv6 router joins.Intermediate
• AndroidGoogle's Linux-based open-source mobile operating system used by many device manufacturers.Foundational
• Android EnterpriseGoogle's framework for managing Android devices in work profile, fully managed, and dedicated modes.Intermediate
• Antistatic BagA shielding bag used to store and transport static-sensitive components.Foundational
• Antistatic Wrist StrapA strap worn on the wrist and clipped to ground to keep a technician at the same potential as equipment.Foundational
• AnycastOne-to-nearest communication in which the same address is assigned to multiple nodes and routing delivers traffic to the closest one.Intermediate
• Apple Business Manager (ABM)Apple's web portal for organizations to buy apps, manage Apple IDs, and assign devices to MDM for Automated Device Enrollment.Intermediate
• Apple File System (APFS)Apple's modern file system for macOS, iOS, and iPadOS, optimized for SSDs and encryption.Foundational
• Apple SiliconApple's family of ARM-based SoCs (M-series for Macs, A-series for iPhone) with unified memory.Intermediate
• Application Compatibility ModeA Windows setting that runs older programs using behaviors of earlier Windows versions.Foundational
• Application Layer (L7)OSI Layer 7 (and top layer of TCP/IP), which provides network services directly to user applications.Foundational
• ARM ArchitectureA reduced instruction set (RISC) processor architecture used in phones, tablets, Apple Silicon Macs, and Windows on Arm PCs.Foundational
• ARP CacheThe table a host or router keeps of recently resolved IPv4-to-MAC mappings.Foundational
• ARP CommandA command that displays and modifies the ARP cache on Windows, Linux and macOS.Foundational
• Aspect RatioThe proportional relationship between a display's width and height, such as 16:9.Foundational
• Asset LifecycleProgression of an asset through states such as on order, in stock, in use, in maintenance and retired, with substates.Intermediate
• Asset TagA label with a unique identifier attached to IT equipment for inventory tracking.Foundational
• AttenuationThe loss of signal strength as it travels through a medium, measured in decibels.Foundational
• AuthenticationVerifying that a user, device, or process is who or what it claims to be.Foundational
• Authentication FactorCategory of evidence used to prove identity: something you know, have, or are, plus contextual attributes.Foundational
• Authenticator AppMobile application that generates TOTP codes or approves push sign-ins as a possession factor.Foundational
• Authoritative Name ServerA DNS server that holds the official records for a zone and answers queries for it with authority.Intermediate
• Automatic Document Feeder (ADF)A scanner or copier mechanism that feeds multiple pages automatically.Foundational
• Automatic Medium-Dependent Interface Crossover (Auto-MDIX)A port feature that detects the cable type and swaps transmit and receive pairs automatically, so either straight-through or crossover cable works.Foundational
• Automatic Private IP Addressing (APIPA)A Windows feature that self-assigns an address from 169.254.0.0/16 when a DHCP server cannot be reached.Foundational
• AutonegotiationAn Ethernet mechanism through which connected devices exchange capabilities and select the highest common speed and duplex.Foundational
• BackdoorA hidden method of bypassing normal authentication or security controls to access a system.Foundational
• BacklightThe light source behind an LCD panel that makes the image visible.Foundational
• Backout PlanDocumented steps to reverse a change and restore the previous state if it fails.Foundational
• Backup TypesThe main backup methods: full, incremental and differential, plus snapshots and synthetic full backups.Foundational
• BaitingA social engineering attack that leaves an enticing item, such as an infected USB drive, for a victim to use.Foundational
• BandwidthThe maximum data rate a link or path can carry, expressed in bits per second.Foundational
• Barcode ScannerAn input device that reads 1D barcodes or 2D codes such as QR codes and translates them into text.Foundational
• Basic Input/Output System (BIOS)Legacy PC firmware that tests hardware at power-on and loads the boot loader.Foundational
• Batch FileA Windows script file (.bat or .cmd) containing Command Prompt commands run in sequence.Foundational
• Battery DisposalProper handling and recycling of batteries to prevent fires and environmental harm.Foundational
• Bidirectional TransceiverA transceiver that sends and receives on a single fiber strand using two different wavelengths.Intermediate
• Binary-to-Decimal ConversionTranslating between base-2 and base-10 values, an essential skill for IP subnetting.Foundational
• Biometric AuthenticationVerifying identity using unique physiological or behavioral characteristics.Foundational
• BitLockerMicrosoft Windows full-volume encryption feature that can use a TPM to protect keys.Foundational
• Bits per Second (bps)The unit for data rate on networks, scaled as Kbps, Mbps, Gbps and Tbps using powers of 1000.Foundational
• BloatwareUnnecessary software preinstalled by a manufacturer that consumes resources and expands the attack surface.Foundational
• Block SizeThe increment between consecutive subnet addresses in the interesting octet, equal to 256 minus the mask value in that octet.Foundational
• BluesnarfingUnauthorized access to data on a Bluetooth-enabled device, such as contacts, messages or files.Foundational
• BluetoothA short-range 2.4 GHz wireless personal area network technology standardized by the Bluetooth SIG.Foundational
• Bluetooth PairingThe process of establishing a trusted connection between two Bluetooth devices.Foundational
• BNC ConnectorA bayonet-style coaxial connector with a quarter-turn twist lock, used for video, test equipment, T-carrier and legacy 10BASE2 Ethernet.Foundational
• BonjourApple's zero-configuration service discovery using mDNS and DNS-SD on UDP 5353.Intermediate
• Boost ClockThe maximum frequency a CPU or GPU automatically reaches under load when power and thermal limits allow.Intermediate
• Boot CampApple's utility for dual-booting Windows on Intel-based Macs.Intermediate
• Boot Configuration Data (BCD)The Windows database that stores boot loader settings and OS entries.Intermediate
• bootrecA WinRE command used to repair the master boot record, boot sector, and Boot Configuration Data.Intermediate
• BotnetA network of compromised devices remotely controlled by an attacker to perform coordinated tasks.Foundational
• BridgeA Layer 2 device that connects network segments and forwards frames based on MAC addresses, separating collision domains.Foundational
• Bring Your Own Device (BYOD)A policy allowing employees to use personal devices to access corporate resources.Foundational
• BroadcastOne-to-all communication in which a single frame or packet is delivered to every host on the local segment.Foundational
• Broadcast AddressThe last address in an IPv4 subnet, with all host bits set to 1, used to send a packet to all hosts on that subnet.Foundational
• Broadcast DomainThe set of devices that receive each other's Layer 2 broadcasts; bounded by routers or by VLANs.Foundational
• Broadcast MAC AddressThe all-ones MAC address ff:ff:ff:ff:ff:ff, which sends a frame to every device in the broadcast domain.Foundational
• BrownoutA sustained reduction in line voltage below normal levels.Foundational
• Brute Force AttackSystematically trying all possible passwords or keys until the correct one is found.Foundational
• Burn-InPermanent ghost images on a display caused by static content shown for long periods.Foundational
• Burned-In Address (BIA)The factory-assigned MAC address stored in a network interface's hardware.Foundational
• Bus TopologyA topology in which all devices share a single backbone cable terminated at both ends.Foundational
• Cable CertifierA test instrument that measures a cabling link against TIA/ISO category standards and produces pass/fail reports.Intermediate
• Cable ModemA modem that provides broadband Internet over a cable TV provider's coaxial network using DOCSIS.Foundational
• Cable TesterA tool that verifies continuity and correct pinouts on copper cables, detecting opens, shorts and miswires.Foundational
• Canonical Name Record (CNAME)A DNS record that makes one name an alias of another canonical name.Foundational
• Capture CardAn expansion card or external device that records or streams video from an external source.Foundational
• Carrier Sense Multiple Access with Collision Detection (CSMA/CD)The media access method used by half-duplex Ethernet: listen before sending, detect collisions, and retry after a random backoff.Foundational
• Carrier-Grade NAT (CGNAT)Large-scale NAT performed by an ISP so many subscribers share a small pool of public IPv4 addresses.Intermediate
• CAS Latency (CL)The number of clock cycles between a memory read command and the data becoming available.Advanced
• Case FanA fan mounted in a computer chassis to move air through the system and remove heat.Foundational
• cat CommandA Linux/macOS command that displays or concatenates file contents.Foundational
• Category 5e Cable (Cat 5e)Enhanced Category 5 UTP rated to 100 MHz, supporting 1000BASE-T and 2.5GBASE-T up to 100 meters.Foundational
• Category 6 Cable (Cat 6)UTP or STP rated to 250 MHz, supporting 1 Gbps to 100 m and 10GBASE-T up to about 55 m.Foundational
• Category 6A Cable (Cat 6a)Augmented Category 6 cable rated to 500 MHz, supporting 10GBASE-T to the full 100 meters.Foundational
• Category 8 Cable (Cat 8)Shielded twisted-pair cable rated to 2000 MHz, supporting 25GBASE-T and 40GBASE-T up to 30 meters.Intermediate
• cd CommandA command that changes the current working directory in Linux, macOS, and Windows shells.Foundational
• Central Processing Unit (CPU)The main processor that fetches, decodes, and executes program instructions in a computer.Foundational
• Certificate Manager (certmgr.msc)A Windows console for viewing and managing the current user's certificates.Intermediate
• Certificate of DestructionA document from a disposal vendor confirming that media or devices were destroyed or sanitized.Foundational
• Change Advisory Board (CAB)Group that reviews and advises on authorizing changes; ServiceNow provides a CAB Workbench to manage meetings.Foundational
• Change EnablementThe ITIL 4 practice (formerly change management) of maximizing successful IT changes by assessing risk, authorizing, and scheduling them.Foundational
• ChecksumA value calculated over data so the receiver can detect corruption in transit.Foundational
• ChipsetMotherboard logic that manages communication between the CPU and peripherals such as storage, USB, and expansion slots.Intermediate
• chkdskA Windows command that checks a volume's file system and can repair errors and locate bad sectors.Foundational
• chmodThe Linux command that changes file and directory permission bits using symbolic or octal notation.Foundational
• ChromeOSGoogle's lightweight, cloud-focused operating system for Chromebooks.Foundational
• Circuit SwitchingA method that reserves a dedicated communication path for the duration of a session.Foundational
• Class A AddressAn IPv4 address with first octet 1-126 (leading bit 0) and a default mask of 255.0.0.0 (/8).Foundational
• Class B AddressAn IPv4 address with first octet 128-191 (leading bits 10) and a default mask of 255.255.0.0 (/16).Foundational
• Class C AddressAn IPv4 address with first octet 192-223 (leading bits 110) and a default mask of 255.255.255.0 (/24).Foundational
• Class D AddressAn IPv4 address in the 224.0.0.0-239.255.255.255 range (224.0.0.0/4), reserved for multicast groups.Foundational
• Classful AddressingThe original IPv4 scheme that divided the address space into fixed classes A through E based on the leading bits.Foundational
• Classless Inter-Domain Routing (CIDR)The addressing scheme (RFC 4632) that replaced classful addressing by allowing any prefix length and route aggregation.Foundational
• Clean BootStarting Windows with only Microsoft services and no third-party startup items to isolate software conflicts.Intermediate
• Clean InstallInstalling an operating system on a freshly formatted drive without preserving existing apps or settings.Foundational
• Clear CMOSResetting stored firmware settings to factory defaults, usually by jumper, button, or removing the battery.Intermediate
• Client-Server ModelA model in which centralized servers provide resources and services to client devices.Foundational
• Clock SpeedThe rate at which a CPU core executes cycles, measured in gigahertz (GHz).Foundational
• CMOS BatteryA coin-cell battery (usually CR2032) on the motherboard that powers the real-time clock and firmware settings.Foundational
• Coaxial CableA cable with a central conductor, dielectric insulator, metallic shield and outer jacket, used for cable TV, cable Internet and legacy Ethernet.Foundational
• CollisionTwo devices transmitting on a shared medium at the same time, corrupting both signals.Foundational
• Collision DomainA network segment where frames can collide with one another; every switch port is its own collision domain.Foundational
• Command Prompt (cmd)The traditional Windows command-line interpreter.Foundational
• Community StringA shared password-like string used for access control in SNMPv1 and SNMPv2c, sent in clear text.Intermediate
• Complementary Metal-Oxide Semiconductor (CMOS)Battery-backed memory that stores BIOS/UEFI settings and keeps the real-time clock running.Foundational
• Compliance PolicyAn MDM rule set that evaluates whether a device meets security requirements such as encryption, OS version, and passcode.Intermediate
• Compressed AirCanned or electric blower air used to remove dust from computers and peripherals.Foundational
• CompTIA Troubleshooting MethodologyCompTIA's six-step process: identify the problem, theorize, test, plan and implement, verify, and document.Foundational
• Computer ManagementA Windows console (compmgmt.msc) that groups Event Viewer, Device Manager, Disk Management, Services, and more.Foundational
• Configuration ProfileA set of settings pushed by an MDM to configure features like Wi-Fi, VPN, email, restrictions, and certificates.Intermediate
• Congestion ControlTCP algorithms that adjust the sending rate based on signs of network congestion such as packet loss or delay.Intermediate
• Connection-Oriented CommunicationCommunication in which a session is established before data transfer and delivery is tracked with acknowledgments.Foundational
• Connectionless CommunicationCommunication in which each message is sent independently with no session setup, acknowledgments or delivery guarantee.Foundational
• Control PanelThe legacy Windows settings interface with applets for system configuration.Foundational
• copy CommandA Windows command that copies one or more files to another location.Foundational
• Corporate-Owned, Personally Enabled (COPE)A deployment model where the organization owns the device but allows reasonable personal use.Foundational
• cp CommandA Linux/macOS command that copies files and directories.Foundational
• CPU CacheSmall, very fast memory on the CPU that holds frequently used data and instructions to reduce RAM access.Intermediate
• CPU CoreAn independent processing unit within a CPU that can execute its own instruction stream.Foundational
• CPU SocketThe motherboard connector that holds a CPU and links it to power, memory, and the chipset.Foundational
• CRC ErrorAn interface error counted when a received frame's FCS does not match the computed CRC, indicating corruption.Foundational
• CrimperA hand tool that compresses a connector onto a cable so its contacts pierce the conductors, used for RJ45 and RJ11 plugs and coax.Foundational
• Crossover CableA twisted-pair cable with T568A on one end and T568B on the other, swapping transmit and receive pairs to connect like devices.Foundational
• CrosstalkInterference in which a signal on one wire pair couples onto an adjacent pair, degrading signal quality.Foundational
• Customer Premises Equipment (CPE)Equipment located at the customer's site that connects to the provider's network, such as modems, ONTs, routers and set-top boxes.Foundational
• Cyclic Redundancy Check (CRC)An error-detecting code based on polynomial division, used in Ethernet's FCS and in storage systems.Foundational
• Data Link Layer (L2)OSI Layer 2, which delivers frames between nodes on the same local network using physical (MAC) addresses.Foundational
• Data Over Cable Service Interface Specification (DOCSIS)The CableLabs standard for delivering broadband data over cable TV coaxial networks.Intermediate
• DatagramA self-contained, independently routed unit of data sent without a prior connection, commonly the UDP PDU.Foundational
• DDR3 SDRAMThird-generation DDR memory using 240-pin DIMMs at 1.5 V (1.35 V for DDR3L).Foundational
• DDR4 SDRAMFourth-generation DDR memory using 288-pin DIMMs at 1.2 V with JEDEC speeds up to 3200 MT/s.Foundational
• DDR5 SDRAMFifth-generation DDR memory with on-module power management, two subchannels per DIMM, and speeds from 4800 MT/s.Foundational
• Dead PixelA display pixel that stays black, or a stuck pixel that stays one color, due to a panel defect.Foundational
• Debug LEDMotherboard indicator lights or a two-digit display that show which POST stage failed.Intermediate
• DecapsulationThe reverse of encapsulation, in which each layer on the receiver removes and processes its header before passing data up.Foundational
• Dedicated Graphics Card (dGPU)A separate expansion card or chip with its own GPU and video memory (VRAM) for graphics and compute.Foundational
• Default GatewayThe router address a host sends traffic to when the destination is on a different subnet.Foundational
• Default RouteThe route 0.0.0.0/0 (or ::/0 in IPv6) that matches any destination not covered by a more specific route.Intermediate
• DefragmentationReorganizing file fragments on a hard drive so they are stored contiguously to improve read speed.Foundational
• Demarcation PointThe point where the service provider's network responsibility ends and the customer's begins.Foundational
• Demilitarized Zone (DMZ)A network segment between an organization's internal network and the Internet that hosts public-facing services.Foundational
• Denial of Service (DoS)An attack that makes a system or network unavailable to legitimate users by exhausting resources or crashing services.Foundational
• Deployment Image Servicing and Management (DISM)A Windows command-line tool for servicing Windows images and repairing the component store.Intermediate
• Destination UnreachableICMP type 3 message indicating a packet could not be delivered, with codes giving the reason.Intermediate
• Developer ModeA mobile or OS setting that unlocks advanced options such as USB debugging.Intermediate
• Device ManagerA Windows console (devmgmt.msc) for viewing hardware and managing device drivers.Foundational
• DHCP Exclusion RangeAddresses within a scope that the DHCP server will not assign, reserved for statically configured devices.Foundational
• DHCP LeaseThe period during which a client may use an address assigned by DHCP.Foundational
• DHCP OptionsAdditional configuration parameters a DHCP server sends to clients, identified by number.Intermediate
• DHCP Relay AgentA router or Layer 3 switch function that forwards DHCP broadcasts from clients to a DHCP server on another subnet as unicast.Intermediate
• DHCP ReservationA DHCP configuration that always assigns the same IP address to a specific client, identified by its MAC address or client ID.Foundational
• DHCP ScopeThe range of IP addresses and associated settings a DHCP server can assign on a particular subnet.Foundational
• Dictionary AttackA password attack that tries words from a list of common passwords and dictionary terms.Foundational
• Differential BackupA backup that copies all data changed since the last full backup, growing each day until the next full.Foundational
• Digital CertificateElectronic document signed by a CA that binds a public key to an identity such as a domain, person, or device.Foundational
• Digital Subscriber Line (DSL)Broadband Internet over telephone copper pairs, using frequencies above voice so phone service can share the line.Foundational
• Digital Visual Interface (DVI)A legacy video interface that can carry digital (DVI-D), analog (DVI-A), or both (DVI-I) signals.Foundational
• DigitizerThe touch-sensing layer of a screen or tablet that converts touch or pen input into coordinates.Foundational
• dir CommandA Windows command that lists files and folders in a directory.Foundational
• Direct Attach Copper (DAC)A fixed-length twinax cable with transceiver connectors (such as SFP+ or QSFP28) permanently attached on both ends.Intermediate
• Direct-Attached Storage (DAS)Storage connected directly to a single server, such as internal drives or an external SAS enclosure, without a network.Foundational
• Directed BroadcastA packet sent to the broadcast address of a specific remote subnet, which a router could forward to that subnet.Intermediate
• DirectX Diagnostic Tool (dxdiag)A Windows tool that reports display, sound, and input device information and DirectX status.Foundational
• Disk Cleanup (cleanmgr)A Windows utility that frees space by removing temporary files, update leftovers, and other unneeded data.Foundational
• Disk ManagementA Windows console (diskmgmt.msc) for initializing disks and creating, formatting, and resizing partitions.Foundational
• Disk UtilityThe macOS tool for managing disks, volumes, formatting, and running First Aid repairs.Foundational
• diskpartA Windows command-line utility for managing disks, partitions, and volumes.Intermediate
• Display ResolutionThe number of pixels a display shows horizontally and vertically, such as 1920 x 1080.Foundational
• DisplayPort (DP)A digital display interface common on PCs and monitors that supports high refresh rates and daisy-chaining.Foundational
• DisplayPort Alternate Mode (DP Alt Mode)A USB-C feature that carries native DisplayPort video over the USB-C connector.Intermediate
• Distributed Denial of Service (DDoS)A denial-of-service attack launched from many sources, often a botnet, to overwhelm a target.Foundational
• DNS CacheTemporary storage of DNS answers on clients and resolvers for the duration of each record's TTL.Foundational
• DNS ZoneA portion of the DNS namespace managed as a unit, with its records stored in a zone file or directory.Intermediate
• Docking StationA device that connects a laptop to monitors, network, power, and peripherals through one connection.Foundational
• Domain Information Groper (dig)A Linux/macOS DNS query tool that shows detailed responses, including flags, TTLs and authority sections.Intermediate
• Domain JoinAdding a computer to an Active Directory domain so it trusts the domain for authentication and receives Group Policy.Foundational
• Domain Name System (DNS)The hierarchical, distributed system that translates domain names into IP addresses and other records, using UDP and TCP port 53.Foundational
• DORA ProcessThe four-message DHCP exchange: Discover, Offer, Request, Acknowledge.Foundational
• Dotted-Decimal NotationThe format for writing IPv4 addresses as four decimal numbers (0-255) separated by periods.Foundational
• Double Data Rate SDRAM (DDR SDRAM)Synchronous DRAM that transfers data on both the rising and falling edges of the clock signal.Foundational
• Drive EnduranceThe rated amount of data an SSD can write over its life, given as TBW or DWPD.Intermediate
• Drive Form FactorThe physical size standard for storage devices, such as 3.5-inch, 2.5-inch, M.2, and U.2.Foundational
• Drive-by DownloadAn unintended download of malicious code that occurs simply by visiting a compromised or malicious website.Foundational
• Driver RollbackRestoring the previously installed version of a device driver.Foundational
• Dual BootInstalling two operating systems on one computer and choosing which to start at boot.Intermediate
• Dual In-Line Memory Module (DIMM)The standard desktop memory module with separate contacts on each side of the board.Foundational
• Dual-Channel MemoryA memory configuration that uses two channels simultaneously to increase bandwidth.Foundational
• Dumpster DivingSearching trash for discarded information or media that can aid an attack.Foundational
• Duplex MismatchA misconfiguration where one end of a link runs full duplex and the other half duplex, causing poor performance.Foundational
• Duplexing AssemblyThe printer component that flips paper to enable automatic double-sided printing.Foundational
• Duplicate Address Detection (DAD)An IPv6 process that checks whether an address is already in use on the link before assigning it.Intermediate
• Dynamic Host Configuration Protocol (DHCP)A protocol that automatically assigns IP addresses and other configuration to hosts, using UDP ports 67 (server) and 68 (client).Foundational
• Dynamic IP AddressAn IP address automatically assigned to a device, usually by DHCP, for a limited lease period.Foundational
• Dynamic RAM (DRAM)Memory that stores each bit in a capacitor and must be refreshed constantly; used for system RAM.Intermediate
• E-WasteDiscarded electronic equipment that requires proper recycling and data sanitization.Foundational
• EFI System Partition (ESP)A small FAT32 partition on GPT disks that stores UEFI boot loaders.Advanced
• Electromagnetic Interference (EMI)Unwanted electrical noise from external sources, such as motors, fluorescent lights and power lines, that disrupts signals on copper cabling.Foundational
• Electrostatic Discharge (ESD)The sudden flow of static electricity between objects that can damage electronic components.Foundational
• Embedded SIM (eSIM)A programmable SIM built into a device that can download carrier profiles without a physical card.Foundational
• EncapsulationThe process of each layer wrapping data from the layer above with its own header (and sometimes trailer) as it moves down the stack.Foundational
• Encrypting File System (EFS)Windows NTFS feature that encrypts individual files and folders using certificate-protected keys.Intermediate
• EncryptionConverting plaintext into ciphertext using an algorithm and key so only authorized parties can read it.Foundational
• End-of-Life (EOL)The point at which a vendor stops selling, supporting, or patching a product.Foundational
• Ephemeral PortsShort-lived client-side source ports assigned by the operating system for outgoing connections, typically 49152-65535.Foundational
• EPS 12V ConnectorA 4-pin or 8-pin power connector that provides dedicated 12 V power to the CPU voltage regulators.Foundational
• Error-Correcting Code Memory (ECC)Server RAM that detects and corrects single-bit memory errors and detects multi-bit errors, improving reliability.Foundational
• Establish a Theory of Probable CauseStep two of the troubleshooting methodology: form a hypothesis about the cause, questioning the obvious.Foundational
• EthernetThe dominant wired LAN technology, standardized as IEEE 802.3, defining framing, MAC addressing and physical media from 10 Mbps to 800 Gbps.Foundational
• Ethernet FrameThe Layer 2 unit Ethernet uses, containing destination MAC, source MAC, EtherType or length, payload and FCS.Foundational
• Ethernet Naming ConventionThe IEEE format rate-BASE-medium (for example 1000BASE-T) that describes an Ethernet physical layer.Foundational
• EtherTypeA 2-byte Ethernet II field identifying the protocol carried in the frame's payload.Intermediate
• Event ViewerThe Windows console for viewing System, Application, Security and other event logs.Foundational
• Evil TwinA malicious wireless access point that impersonates a legitimate SSID to lure clients into connecting.Foundational
• Exchange ActiveSync (EAS)A Microsoft protocol for synchronizing email, contacts, and calendars to mobile devices.Intermediate
• exFATA Microsoft file system for flash media that supports large files and works on Windows and macOS.Foundational
• Expansion CardA circuit board installed in a motherboard slot to add capabilities such as graphics, networking, or storage.Foundational
• Extended Security Updates (ESU)A paid Microsoft program that provides critical security patches for products past end of support.Intermediate
• External SATA (eSATA)A SATA variant with a shielded connector for attaching external drives.Foundational
• Extreme Memory Profile (XMP)Intel's firmware profile stored on RAM modules that sets rated overclocked speed, timings, and voltage.Intermediate
• F-Type ConnectorA threaded screw-on coaxial connector used for cable TV, cable modems and satellite equipment.Foundational
• Fast StartupA Windows feature that hibernates the kernel session at shutdown to speed the next boot.Intermediate
• Fiber Optic CableCable that transmits data as pulses of light through glass or plastic fibers, offering high bandwidth, long distance and immunity to EMI.Foundational
• Fiber to the Premises (FTTP)Broadband access in which optical fiber runs all the way to the home or business, also called FTTH for homes.Foundational
• File Allocation Table 32 (FAT32)A legacy file system with broad compatibility but a 4 GB maximum file size.Foundational
• File HistoryA Windows backup feature that periodically saves copies of user files to an external or network drive.Foundational
• File Transfer Protocol (FTP)A protocol for transferring files that uses TCP port 21 for control and port 20 (active mode) or a negotiated port (passive mode) for data.Foundational
• File Transfer Protocol Secure (FTPS)FTP secured with TLS, either explicitly via AUTH TLS on port 21 or implicitly on ports 990 (control) and 989 (data).Intermediate
• FileVaultApple macOS full disk encryption feature using XTS-AES-128 with a 256-bit key.Foundational
• FinderThe macOS file manager used to browse, organize, and search files and connect to servers.Foundational
• FirewallA device or software that permits or denies traffic between networks or hosts according to a security policy.Foundational
• FirmwareLow-level software stored in non-volatile memory that controls hardware and initializes devices.Foundational
• Flash DriveA portable USB storage device that uses NAND flash memory.Foundational
• Flatbed ScannerA scanner with a glass surface where a document is placed face down and scanned by a moving sensor.Foundational
• Flow ControlMechanisms that prevent a fast sender from overwhelming a slow receiver.Intermediate
• Folder RedirectionA Group Policy feature that stores user folders such as Documents on a network share.Intermediate
• Force QuitEnding an unresponsive app on macOS with Cmd+Option+Esc or from the Apple menu.Foundational
• format CommandA Windows command that creates a new file system on a volume, erasing its contents.Foundational
• FragmentationSplitting an IP packet into smaller pieces so it can cross a link with a smaller MTU, then reassembling it at the destination.Intermediate
• FrameThe Layer 2 PDU, consisting of a header with MAC addresses, a payload, and usually a trailer for error checking.Foundational
• Frame Check Sequence (FCS)The 4-byte Ethernet trailer containing a CRC-32 value used to detect frame corruption.Foundational
• Front Panel ConnectorsSmall motherboard header pins that connect the case power button, reset button, LEDs, USB, and audio jacks.Foundational
• Full BackupA backup that copies all selected data regardless of when it last changed.Foundational
• Full Disk Encryption (FDE)Encrypting an entire storage device, including the OS and free space, so data is unreadable without authentication.Foundational
• Full MeshA topology in which every node has a direct link to every other node.Intermediate
• Full-DuplexCommunication in which a device sends and receives at the same time over separate paths, eliminating collisions.Foundational
• Fully Qualified Domain Name (FQDN)A complete domain name that specifies a host's exact location in the DNS hierarchy, including all labels up to the root.Foundational
• Function Key (Fn)A laptop modifier key that enables secondary functions such as brightness, volume, and wireless toggles.Foundational
• Functional EscalationTransferring a ticket to a team with greater technical expertise or the right specialty.Foundational
• Fuser AssemblyThe heated rollers in a laser printer that melt and press toner onto paper.Foundational
• GatekeeperA macOS security feature that only allows apps from the App Store or identified, notarized developers by default.Intermediate
• Ghost ImageA faint duplicate of a previous image appearing elsewhere on a laser-printed page.Intermediate
• GiantAn Ethernet frame larger than the maximum allowed size on an interface, normally 1518 bytes untagged.Intermediate
• Gigabit Ethernet (GbE)Ethernet at 1000 Mbps, defined in 802.3z (fiber) and 802.3ab (copper).Foundational
• Global Unicast Address (GUA)A globally routable IPv6 address, currently allocated from 2000::/3.Foundational
• gpresultA Windows command that displays the Resultant Set of Policy applied to a user and computer.Intermediate
• gpupdateA Windows command that refreshes Group Policy settings on a computer.Foundational
• Grandfather-Father-Son Rotation (GFS)A backup retention scheme using daily (son), weekly (father) and monthly (grandfather) backup sets.Foundational
• Graphics Power ConnectorPSU connectors (6-pin, 8-pin, or 16-pin 12V-2x6) that supply supplemental power to graphics cards.Intermediate
• Gratuitous ARP (GARP)An unsolicited ARP message in which a host announces its own IP-to-MAC mapping.Intermediate
• Group PolicyWindows Active Directory feature for centrally applying security and configuration settings to users and computers.Intermediate
• Group Policy Object (GPO)A collection of settings in Active Directory that configures users and computers when linked to sites, domains or OUs.Foundational
• GRUBThe GRand Unified Bootloader, the standard Linux boot loader that loads the kernel and can chain-load other OSes.Intermediate
• GUID Partition Table (GPT)A modern disk partitioning scheme, part of the UEFI specification, supporting disks over 2 TiB and up to 128 partitions by default.Foundational
• Half-DuplexCommunication in which a device can either send or receive at any moment, but not both at once.Foundational
• Hard Disk Drive (HDD)A storage device that records data magnetically on spinning platters read by moving heads.Foundational
• HardeningReducing a system's attack surface by removing unnecessary functions and applying secure configurations.Foundational
• Hardware-Assisted VirtualizationCPU extensions, such as Intel VT-x and AMD-V, that let hypervisors run guests efficiently and securely.Foundational
• Hash FunctionOne-way function that maps input of any size to a fixed-size digest, used to verify integrity.Foundational
• HeaderControl information a protocol adds in front of the payload, such as addresses, ports, sequence numbers and flags.Foundational
• Heat SinkA passive metal component with fins that draws heat away from a chip and dissipates it into the air.Foundational
• Help DeskThe front-line IT support function that receives, logs, and resolves user technical issues.Foundational
• HibernationA power state that saves memory contents to disk and powers off completely.Foundational
• Hidden SSIDConfiguring an AP not to include its SSID in beacons, also called SSID cloaking.Foundational
• Hierarchical EscalationRaising an issue to higher management because of impact, SLA risk, or need for authority or resources.Intermediate
• High-bandwidth Digital Content Protection (HDCP)Copy protection that encrypts digital video between a source and display over HDMI, DisplayPort, or DVI.Intermediate
• High-Definition Multimedia Interface (HDMI)A digital audio/video interface standard for TVs, monitors, projectors, and computers.Foundational
• Home FolderA personal network folder assigned to a user account for storing files.Intermediate
• HomebrewA popular open-source package manager for macOS (and Linux) that installs command-line tools and apps.Intermediate
• Hop LimitThe 8-bit IPv6 header field, equivalent to the IPv4 TTL, decremented by each router and discarded at zero.Foundational
• Host PortionThe trailing bits of an IP address that identify a specific interface within a subnet.Foundational
• Host-Based FirewallSoftware firewall running on an individual endpoint that filters traffic to and from that host.Foundational
• hostname CommandA command that displays the computer's host name on Windows, macOS, and Linux.Foundational
• Hosts FileA local text file that maps host names to IP addresses and is checked before DNS on most systems.Foundational
• Hot Aisle/Cold AisleA rack layout in which rows face alternately so equipment intakes share cold aisles and exhausts share hot aisles.Foundational
• Hot-SwappableA component that can be removed and replaced while the system is running without powering it down.Foundational
• HubA legacy Layer 1 device that repeats incoming signals out every other port, creating a single shared collision domain.Foundational
• Hub-and-Spoke TopologyA WAN topology in which branch sites (spokes) connect to a central site (hub), and traffic between spokes passes through the hub.Foundational
• Human Interface Device (HID)A USB device class for input peripherals such as keyboards, mice, and game controllers.Intermediate
• Hybrid CPU ArchitectureA processor design that combines high-performance cores with power-efficient cores on the same chip.Intermediate
• Hyper-Threading (HT)Intel's implementation of simultaneous multithreading that presents one physical core as two logical processors.Intermediate
• Hyper-VMicrosoft's Type 1 hypervisor built into Windows Server and Windows client editions.Foundational
• Hypertext Transfer Protocol (HTTP)The Application-layer request-response protocol for the web, using TCP port 80 by default.Foundational
• Hypertext Transfer Protocol Secure (HTTPS)HTTP carried inside TLS encryption, using TCP port 443 by default (and UDP 443 for HTTP/3).Foundational
• HypervisorSoftware that creates and runs virtual machines by abstracting physical CPU, memory, storage and network resources.Foundational
• ICMP Echo ReplyICMP type 0 message returned in response to an echo request, confirming reachability and providing round-trip time.Foundational
• ICMP Echo RequestICMP type 8 message sent by ping to test whether a destination is reachable.Foundational
• IEEE 802.11The IEEE family of standards defining wireless LAN PHY and MAC layers, commonly known as Wi-Fi.Foundational
• IEEE 802.3The IEEE working group and family of standards that define wired Ethernet physical layers and MAC.Foundational
• Image DeploymentInstalling a preconfigured OS image on multiple computers.Intermediate
• Imaging DrumThe photosensitive cylinder in a laser printer that holds the electrostatic image and attracts toner.Intermediate
• Impact PrinterA printer that strikes an inked ribbon against paper, such as a dot matrix printer.Foundational
• In-Place UpgradeUpgrading or repairing an operating system while keeping user files, settings, and applications.Foundational
• In-Plane Switching (IPS)An LCD panel technology offering wide viewing angles and accurate color reproduction.Foundational
• Incident ManagementITSM process and ServiceNow application for restoring normal service as quickly as possible after an unplanned interruption.Foundational
• Incremental BackupA backup that copies only data changed since the last backup of any type, minimizing backup time and storage.Foundational
• Infrastructure ModeWLAN operation in which clients connect through an access point.Foundational
• Ink CartridgeA replaceable container of liquid ink for inkjet printers, sometimes including the printhead.Foundational
• Inkjet PrinterA printer that sprays tiny droplets of liquid ink from a printhead onto paper.Foundational
• Input Voltage SelectionConfiguring or relying on a PSU to accept regional AC voltages such as 115 V or 230 V.Foundational
• Institute of Electrical and Electronics Engineers (IEEE)A professional organization whose standards association publishes the 802 family of LAN and MAN standards.Foundational
• Integrated Graphics (iGPU)A graphics processor built into the CPU or SoC that uses shared system memory.Foundational
• Interface Configuration Command (ifconfig)A legacy Unix/Linux command for viewing and configuring network interfaces, replaced on Linux by the ip command.Foundational
• Interface ErrorsCounters on network interfaces that track problems such as CRC errors, runts, giants, collisions, drops and discards.Foundational
• Interface Identifier (IID)The host portion of an IPv6 address, normally the last 64 bits.Intermediate
• Intermediate Distribution Frame (IDF)A secondary telecommunications room that serves a floor or area, connecting horizontal cabling to access switches and backbone links to the MDF.Foundational
• International Mobile Equipment Identity (IMEI)A unique 15-digit number that identifies a mobile device's hardware.Intermediate
• International Mobile Subscriber Identity (IMSI)A unique number stored on the SIM that identifies the subscriber on a cellular network.Intermediate
• Internet Assigned Numbers Authority (IANA)The function, operated by PTI under ICANN, that coordinates global IP address allocation, DNS root zone management and protocol number registries.Foundational
• Internet Control Message Protocol (ICMP)The Layer 3 protocol (IP protocol 1) used for error reporting and diagnostics, such as ping and traceroute.Foundational
• Internet Group Management Protocol (IGMP)The IPv4 protocol hosts use to join and leave multicast groups with their local router (IP protocol 2).Intermediate
• Internet LayerThe TCP/IP model layer that handles logical addressing and routing, equivalent to OSI Layer 3.Foundational
• Internet Message Access Protocol (IMAP)An email retrieval protocol that keeps messages on the server and synchronizes them across clients, using TCP 143 (or 993 with TLS).Foundational
• Internet Options (inetcpl.cpl)A Control Panel applet for system-wide web settings such as proxy, security zones, and certificates.Intermediate
• Internet Printing Protocol (IPP)A standard protocol for submitting and managing print jobs over a network, using TCP port 631.Intermediate
• Internet Protocol (IP)The connectionless Layer 3 protocol that addresses and routes packets across interconnected networks.Foundational
• Internet Protocol version 4 (IPv4)The fourth version of IP, using 32-bit addresses written in dotted-decimal notation, defined in RFC 791.Foundational
• Internet Protocol version 6 (IPv6)The successor to IPv4, using 128-bit addresses written in hexadecimal, defined in RFC 8200.Foundational
• Internet Service Provider (ISP)A company that provides Internet access and related services to customers.Foundational
• Internet Small Computer Systems Interface (iSCSI)A protocol that carries SCSI block storage commands over TCP/IP, using TCP port 3260.Intermediate
• InverterA board that converts DC to high-voltage AC to power CCFL backlights in older LCDs.Foundational
• iOSApple's mobile operating system for iPhone, with iPadOS as a tablet-focused variant.Foundational
• IP AddressA logical Layer 3 address that identifies a network interface and its network for routing purposes.Foundational
• IP Address ConflictA condition in which two devices on the same network use the same IP address, causing intermittent connectivity for both.Foundational
• IP Address Management (IPAM)Software and processes for planning, tracking and managing IP address space together with DHCP and DNS.Intermediate
• IP CommandThe Linux iproute2 utility for managing addresses, links, routes and neighbors.Foundational
• IP Configuration Command (ipconfig)The Windows command that displays and manages IP configuration.Foundational
• IP Protocol NumberThe value in the IPv4 Protocol field (or IPv6 Next Header) that identifies the encapsulated upper-layer protocol.Intermediate
• iPerfAn open-source tool that measures network throughput between a client and server using TCP or UDP streams.Intermediate
• IPv4 HeaderThe 20- to 60-byte header at the front of every IPv4 packet carrying addressing and control fields.Intermediate
• IPv6 Address CompressionRules for shortening IPv6 addresses: omit leading zeros in each hextet and replace one longest run of all-zero hextets with ::.Foundational
• IPv6 Address NotationIPv6 addresses are written as eight groups of four hexadecimal digits separated by colons, with a /prefix length.Foundational
• IPv6 Link-Local Address (LLA)An IPv6 address in fe80::/10, automatically configured on every IPv6 interface and valid only on the local link.Foundational
• IPv6 Loopback AddressThe IPv6 address ::1/128, used by a host to send packets to itself.Foundational
• IPv6 Multicast AddressIPv6 addresses in ff00::/8 that identify groups of interfaces, replacing the role of IPv4 broadcast.Intermediate
• IPv6 Unspecified AddressThe all-zeros IPv6 address ::/128, used as a source address before a host has an address.Intermediate
• IT Asset Management (ITAM)The practice of tracking IT assets across their lifecycle to maximize value, control costs, and manage risk.Intermediate
• Iterative DNS QueryA DNS query in which the server returns the best answer it has, often a referral to another server, rather than resolving fully.Intermediate
• JailbreakingRemoving iOS restrictions to gain root access and install unauthorized software.Foundational
• Jamf ProA widely used Apple-focused device management platform for macOS, iOS, iPadOS, and tvOS.Intermediate
• JitterThe variation in packet delay over time, which disrupts real-time traffic such as voice and video.Foundational
• Journaling File SystemA filesystem that records pending changes in a journal before committing them, enabling fast and consistent recovery after a crash.Foundational
• Jumbo FrameAn Ethernet frame with a payload larger than 1500 bytes, commonly up to 9000 bytes.Intermediate
• Keyboard Video Mouse Switch (KVM)A device that lets one keyboard, monitor, and mouse control multiple computers.Foundational
• Keychain AccessThe macOS app for managing stored passwords, certificates, and secure notes.Foundational
• KeyloggerSoftware or hardware that records keystrokes to capture passwords and other sensitive input.Foundational
• Keystone JackA modular snap-in jack, typically RJ45 with 110-style IDC terminations, mounted in wall plates or modular patch panels.Foundational
• kill CommandA Linux/macOS command that sends a signal to a process, typically to terminate it.Foundational
• Knowledge BaseContainer of knowledge articles with its own managers, workflows and access criteria.Foundational
• Known-Good ComponentA part confirmed to work that is swapped in to isolate whether the original component is faulty.Foundational
• Land Grid Array (LGA)A CPU socket design where the contact pins are in the motherboard socket and the CPU has flat pads.Foundational
• Laptop DisassemblyOpening a laptop to replace components using documented, careful procedures.Foundational
• Laptop Display Output SwitchingChanging how a laptop sends video to internal and external displays: duplicate, extend, or second screen only.Foundational
• Laptop Keyboard ReplacementRemoving and replacing a laptop's integrated keyboard, often via ribbon cable or top-case assembly.Intermediate
• Laser Imaging ProcessThe seven-step sequence a laser printer follows: processing, charging, exposing, developing, transferring, fusing, and cleaning.Intermediate
• Laser PrinterA printer that uses a laser, photosensitive drum, toner, and heated fuser to produce prints.Foundational
• Late CollisionA collision detected after the first 64 bytes of a frame have been transmitted.Intermediate
• LatencyThe time it takes for data to travel from source to destination, usually measured in milliseconds.Foundational
• Leased LineA dedicated, private telecommunications circuit between two locations, rented from a carrier with guaranteed bandwidth.Foundational
• Lightning ConnectorApple's proprietary 8-pin reversible connector used on older iPhones, iPads, and accessories.Foundational
• Lightweight Directory Access Protocol (LDAP)A protocol for querying and modifying directory services such as Active Directory, using TCP/UDP port 389.Foundational
• Limited BroadcastThe address 255.255.255.255, which reaches all hosts on the local segment and is never forwarded by routers.Intermediate
• Line ConditionerA device that smooths voltage fluctuations, filters noise, and regulates sags and swells in AC power.Intermediate
• Linear Tape-Open (LTO)An open magnetic tape standard for high-capacity, low-cost, long-term backup and archive storage.Foundational
• Link LayerThe lowest layer of the TCP/IP model (also called Network Access or Network Interface) covering OSI Layers 1 and 2.Foundational
• Link-Local AddressAn address valid only on the local network segment and never forwarded by routers.Intermediate
• Linux DistributionA complete operating system built on the Linux kernel with packaging, tools, and desktop environments.Foundational
• Linux File PermissionsThe read, write and execute (rwx) access bits that Linux assigns separately to a file's owner, group and others.Foundational
• Liquid CoolingA cooling method that pumps coolant through a block on the CPU or GPU to a radiator with fans.Intermediate
• Liquid Crystal Display (LCD)A flat-panel display that uses liquid crystals and a backlight to produce images.Foundational
• Lithium-Ion Battery (Li-ion)The rechargeable battery chemistry used in laptops, phones, and tablets.Foundational
• Local AccountA user account stored only on one computer's Security Accounts Manager (SAM) database.Foundational
• Local Area Network (LAN)A network covering a limited area such as a home, office or building, usually owned and managed by one organization.Foundational
• Local Security Policy (secpol.msc)A Windows console for configuring security settings such as password, lockout, and audit policies on a single computer.Intermediate
• Local Users and Groups (lusrmgr.msc)A Windows console for managing local user accounts and group memberships.Foundational
• LocalhostThe hostname that resolves to the local machine's loopback address, 127.0.0.1 or ::1.Foundational
• Locator ApplicationA service that shows a lost device's location and can lock, ring, or wipe it.Foundational
• Logic BombMalicious code that lies dormant until a specific condition, such as a date or event, triggers its payload.Foundational
• Logical TopologyThe way data flows through a network and how devices communicate, independent of physical cabling.Foundational
• Long-Term Servicing Channel (LTSC)A Windows Enterprise release that receives security updates for years without feature updates.Advanced
• Loopback AddressAn address that refers to the local host itself; 127.0.0.0/8 in IPv4 (usually 127.0.0.1) and ::1 in IPv6.Foundational
• Loopback PlugA connector that routes a port's transmit pins back to its receive pins to test the port itself without a network.Foundational
• Low-Power DDR (LPDDR)A low-voltage variant of DDR memory used in phones, tablets, and thin laptops, usually soldered.Intermediate
• ls CommandA Linux/macOS command that lists directory contents.Foundational
• Lucent Connector (LC)A small form-factor fiber connector with a 1.25 mm ferrule and push-pull latch, usually used as a duplex pair.Foundational
• M.2A small form factor connector and card standard used mainly for SSDs, Wi-Fi, and Bluetooth modules.Foundational
• MAC AddressA 48-bit Layer 2 address that identifies a network interface on a local network, written as 12 hexadecimal digits.Foundational
• Mac OS Extended (HFS+)Apple's legacy file system used before APFS, still used for some external and Time Machine drives.Foundational
• macOSApple's desktop operating system for Mac computers, built on a Unix-based (Darwin) foundation.Foundational
• macOS App InstallationInstalling Mac software via the App Store, .dmg disk images, or .pkg installer packages.Foundational
• macOS RecoveryA built-in recovery environment for reinstalling macOS, restoring backups, and repairing disks.Foundational
• Macro VirusA virus written in a macro language, such as VBA, embedded in documents and executed when the document is opened.Foundational
• Mail Exchanger Record (MX)A DNS record that identifies the mail servers that accept email for a domain, with preference values.Foundational
• Main Distribution Frame (MDF)The primary telecommunications room where the building's backbone cabling converges and where carrier circuits typically connect.Foundational
• Maintenance KitA manufacturer bundle of wear parts, such as fuser and rollers, replaced at a set page count.Foundational
• Maintenance WindowAgreed period when changes are permitted for a CI, used in conflict detection.Intermediate
• MalwareMalicious software designed to damage, disrupt, spy on or gain unauthorized access to systems or data.Foundational
• Malware Removal ProcessCompTIA's seven-step procedure for removing malware from a system.Intermediate
• Management Information Base (MIB)A hierarchical database definition describing the objects an SNMP agent exposes, such as interface counters and CPU usage.Intermediate
• Mapped Network DriveA drive letter assigned to a shared network folder for easy access.Foundational
• Master Boot Record (MBR)A legacy partitioning scheme storing the boot loader and partition table in the first 512-byte sector of a disk.Foundational
• Maximum Segment Size (MSS)The largest amount of TCP payload data a host will accept in one segment, advertised in the SYN.Intermediate
• Maximum Transmission Unit (MTU)The largest Layer 3 packet, in bytes, that a link can carry without fragmentation; 1500 bytes on standard Ethernet.Foundational
• Media ConverterA Layer 1 device that converts signals between different media types, such as copper twisted pair to fiber.Foundational
• Media SanitizationRemoving data from storage so it cannot be recovered, using clear, purge, or destroy methods.Intermediate
• Memory SpeedThe data transfer rate of RAM, expressed in mega-transfers per second (MT/s) or as a PC module rating.Intermediate
• Mesh TopologyA topology in which devices have multiple interconnections, providing redundant paths.Foundational
• Metro EthernetA carrier service that delivers Ethernet connectivity between sites across a metropolitan area or wider WAN.Intermediate
• Metropolitan Area Network (MAN)A network spanning a city or metropolitan area, larger than a campus but smaller than a WAN.Foundational
• Micro-USBA small USB connector used on older Android phones, accessories, and peripherals.Foundational
• microATX (mATX)A smaller motherboard form factor (9.6 x 9.6 inches) with up to four expansion slots.Foundational
• Microsoft Account (MSA)A personal Microsoft identity used to sign in to Windows, Outlook.com, OneDrive, and Xbox.Foundational
• Microsoft Defender AntivirusThe built-in antimalware engine in Windows that provides real-time and cloud-delivered protection.Foundational
• Microsoft Entra JoinJoining a Windows device directly to Microsoft Entra ID (formerly Azure AD) instead of on-premises AD.Intermediate
• Microsoft IntuneMicrosoft's cloud-based endpoint management service for Windows, macOS, iOS/iPadOS, Android, and Linux.Intermediate
• Microsoft Management Console (MMC)The Windows framework that hosts administrative snap-ins in customizable consoles.Intermediate
• Microsoft Universal PrintA Microsoft 365 cloud print service that removes the need for on-premises print servers.Intermediate
• Mini-ITXA compact motherboard form factor measuring 6.7 x 6.7 inches with a single expansion slot.Foundational
• Mini-LEDAn LCD backlight technology using thousands of tiny LEDs grouped in local dimming zones.Intermediate
• MirroringWriting identical copies of data to two or more drives or systems for redundancy.Foundational
• Mobile App TroubleshootingSteps to resolve app crashes, freezes, or misbehavior on mobile devices.Foundational
• Mobile Application Management (MAM)Managing and protecting corporate apps and data on a device without managing the whole device.Intermediate
• Mobile DeviceA portable computing device such as a smartphone, tablet, or wearable.Foundational
• Mobile Device Battery HealthThe remaining capacity and performance of a mobile device battery relative to when new.Foundational
• Mobile Device Management (MDM)Centralized management of phones, tablets, and computers to enforce policies, deploy apps, and secure data.Foundational
• Mobile Device OverheatingExcess heat in a phone or tablet caused by heavy use, charging, environment, or failing batteries.Foundational
• Mobile Device SynchronizationKeeping data such as contacts, calendar, email, and files consistent between a mobile device and other systems.Foundational
• Mobile OS UpdateInstalling new versions or security patches of iOS, iPadOS, or Android on mobile devices.Foundational
• ModemA device that modulates digital data onto an analog carrier and demodulates it back, connecting a customer network to a provider medium.Foundational
• Modular Power SupplyA PSU with detachable cables so only the needed connectors are installed.Foundational
• Molex ConnectorA legacy 4-pin peripheral power connector supplying 5 V and 12 V, used for older drives and fans.Foundational
• MotherboardThe main circuit board that connects the CPU, memory, storage, expansion cards, and I/O.Foundational
• Motherboard Form FactorA standard that defines a motherboard's dimensions, mounting holes, and I/O placement.Foundational
• MulticastOne-to-many communication delivered only to hosts that have joined a particular group.Foundational
• Multicast DNS (mDNS)A zero-configuration protocol that resolves .local names on the local link using multicast queries to UDP port 5353.Intermediate
• Multicast MAC AddressA MAC address with the least significant bit of the first byte set to 1, used to deliver frames to a group of interfaces.Intermediate
• Multifunction Device (MFD)A device combining printing, scanning, copying, and often faxing in one unit.Foundational
• Multigigabit Ethernet (NBASE-T)2.5GBASE-T and 5GBASE-T Ethernet (802.3bz), which deliver more than 1 Gbps over existing Cat 5e and Cat 6 cabling.Intermediate
• Multilayer SwitchA switch that can also perform Layer 3 routing (and sometimes higher-layer functions) in hardware.Foundational
• MultimeterA handheld meter that measures voltage, current, resistance, and continuity.Foundational
• Multimode Fiber (MMF)Fiber with a larger core (50 or 62.5 microns) that carries multiple light paths, used for shorter distances inside buildings and data centers.Foundational
• MultiplexingCombining multiple signals or data streams over a single shared medium.Intermediate
• mv CommandA Linux/macOS command that moves or renames files and directories.Foundational
• Name Server Lookup (nslookup)A command-line tool on Windows, Linux and macOS for querying DNS servers.Foundational
• Name Server Record (NS)A DNS record that lists the authoritative name servers for a zone.Foundational
• NAND Flash Cell TypesClasses of flash memory (SLC, MLC, TLC, QLC) defined by how many bits each cell stores.Intermediate
• nanoA simple terminal-based text editor common on Linux and macOS.Foundational
• Near Field Communication (NFC)Very short-range (about 4 cm) 13.56 MHz wireless communication used for payments, access badges, and pairing.Foundational
• Near-End Crosstalk (NEXT)Crosstalk measured at the same end of the cable as the transmitter, usually caused by poor terminations.Intermediate
• net use CommandA Windows command that connects, lists, or removes mapped network drives and shares.Foundational
• net user CommandA Windows command for creating, modifying, and viewing user accounts.Foundational
• NetBIOSA legacy API and set of services for name resolution and sessions on Windows networks, using UDP 137, UDP 138 and TCP 139.Intermediate
• NetFlowA Cisco-originated technology that exports metadata about traffic flows, such as addresses, ports and byte counts, to a collector.Intermediate
• netshA Windows command-line tool for viewing and configuring network settings, including Wi-Fi, firewall, and proxies.Intermediate
• Network AddressThe first address in a subnet, with all host bits set to 0, which identifies the subnet itself.Foundational
• Network Address Translation (NAT)A function that rewrites IP addresses (and often ports) in packet headers as traffic passes through a router or firewall.Foundational
• Network BaselineA record of normal network performance and behavior used to identify anomalies.Foundational
• Network DiscoveryA Windows setting that lets a PC find and be found by other devices on the network.Foundational
• Network File System (NFS)A file-sharing protocol common in Unix and Linux environments, using TCP and UDP port 2049.Intermediate
• Network Interface Card (NIC)The hardware that connects a device to a network, providing a physical connection and a MAC address.Foundational
• Network Layer (L3)OSI Layer 3, which provides logical addressing and routing of packets between different networks.Foundational
• Network Location ProfileThe Windows classification of a network as Public or Private (or Domain) that sets firewall and discovery behavior.Foundational
• Network PortionThe leading bits of an IP address, identified by the subnet mask, that specify which network or subnet the address belongs to.Foundational
• Network Statistics Command (netstat)A command that shows active connections, listening ports, routing tables and interface statistics.Foundational
• Network Time Protocol (NTP)A protocol that synchronizes clocks across network devices and hosts, using UDP port 123.Foundational
• Network TopologyThe arrangement of nodes and links in a network, described physically (cabling) or logically (data flow).Foundational
• Network Troubleshooting MethodologyThe structured seven-step process: identify the problem, establish a theory, test it, plan, implement, verify functionality and document.Foundational
• Network-Attached Storage (NAS)A storage device connected to a network that provides file-level access using protocols such as SMB and NFS.Foundational
• NIC TeamingCombining multiple NICs on a host into one logical interface for redundancy, load balancing or both.Intermediate
• NmapA widely used open-source network scanner for host discovery, port scanning, service detection and OS fingerprinting.Intermediate
• Non-Volatile Memory Express (NVMe)A storage protocol designed for flash that connects SSDs over PCIe with deep parallel queues and low latency.Foundational
• Northbridge and SouthbridgeLegacy two-chip chipset design where the northbridge handled fast components and the southbridge handled slower I/O.Intermediate
• NTFSThe New Technology File System, the standard journaling filesystem for Windows with permissions, encryption, compression and quotas.Foundational
• NTFS PermissionsFile and folder access controls on NTFS volumes, such as Full Control, Modify, Read and Execute, applying both locally and over the network.Foundational
• Number of Subnets FormulaThe calculation 2^s, where s is the number of borrowed subnet bits, giving how many subnets are created.Foundational
• Object Identifier (OID)A dotted numeric identifier that uniquely names an object in the SNMP MIB tree.Intermediate
• OctetA group of 8 bits; an IPv4 address contains four octets.Foundational
• On-Path AttackAn attack in which the adversary positions themselves between two communicating parties to intercept or alter traffic.Foundational
• One-Time Password (OTP)Password valid for only one login session or transaction, generated by a token, app, or service.Foundational
• OneDrive Known Folder Move (KFM)A OneDrive feature that redirects Desktop, Documents, Pictures, and other known folders to OneDrive.Intermediate
• Open Systems Interconnection Model (OSI model)A seven-layer ISO reference model that describes how data moves from an application on one host to an application on another.Foundational
• Optical DriveA drive that reads and writes CDs, DVDs, or Blu-ray discs using a laser.Foundational
• Optical Network Terminal (ONT)The customer-premises device that terminates a fiber-to-the-premises connection and converts optical signals to Ethernet.Intermediate
• Optimize Drives (dfrgui)The Windows tool that defragments HDDs and sends TRIM to SSDs on a schedule.Foundational
• Organic Light-Emitting Diode (OLED)A display technology where each pixel emits its own light, giving perfect blacks and high contrast.Foundational
• Organizationally Unique Identifier (OUI)The first 24 bits of a MAC address, assigned by the IEEE to identify the device manufacturer.Foundational
• OverclockingRunning a CPU, GPU, or memory faster than its rated specification to gain performance.Intermediate
• PacketThe Layer 3 PDU, consisting of an IP header plus a transport-layer payload.Foundational
• Packet Capture (pcap)The recording of network packets for analysis, and the file format (pcap/pcapng) that stores them.Foundational
• Packet Internet Groper (ping)A command that tests IP reachability and round-trip time by sending ICMP Echo Requests and waiting for Echo Replies.Foundational
• Packet LossThe percentage of packets that fail to reach their destination.Foundational
• Packet SwitchingA method in which data is divided into packets that are forwarded independently and share network links with other traffic.Foundational
• Paging FileDisk space used by the OS as virtual memory when physical RAM is full (pagefile.sys on Windows).Intermediate
• Paper JamA printer error where paper becomes stuck in the paper path.Foundational
• Parity MemoryMemory that stores one parity bit per byte to detect, but not correct, single-bit errors.Intermediate
• Partial MeshA topology in which some nodes have multiple connections but not every node connects to every other.Intermediate
• Passive Optical Network (PON)A point-to-multipoint fiber network that uses unpowered optical splitters to serve multiple customers from one provider port.Intermediate
• passwd CommandA Linux/macOS command that changes a user's password.Foundational
• Password ManagerApplication that generates, stores, and autofills strong unique passwords in an encrypted vault.Foundational
• Password PolicyRules governing password creation, storage, and use, now guided by NIST SP 800-63B.Foundational
• Patch CableA short, flexible, factory-terminated cable that connects devices to jacks or patch panels to switches.Foundational
• Patch ManagementThe process of acquiring, testing, deploying and verifying software updates to fix vulnerabilities and defects.Foundational
• Patch PanelA panel of ports in a rack where permanent cabling terminates, allowing short patch cables to connect runs to switches.Foundational
• PathpingA Windows command that combines traceroute and ping to show loss and latency at each hop over a period of time.Intermediate
• PCI Express (PCIe)A high-speed serial expansion bus connecting graphics cards, NVMe SSDs, and other cards to the motherboard.Foundational
• PCIe LanesIndividual full-duplex serial links that make up a PCIe connection; more lanes provide more bandwidth.Intermediate
• Peer-to-PeerDirect communication between wireless client devices.Intermediate
• Peer-to-Peer Network (P2P)A network in which devices share resources directly with each other without a dedicated central server.Foundational
• Performance MonitorA Windows tool for real-time and logged collection of performance counters for CPU, memory, disk and network.Intermediate
• Permission InheritanceThe default behavior where files and subfolders receive permissions from their parent folder.Intermediate
• Personal Protective Equipment (PPE)Safety gear such as gloves, eye protection, and masks used to reduce injury risk.Foundational
• PhishingA social engineering attack using fraudulent messages, typically email, to steal credentials, deliver malware or induce payments.Foundational
• Physical Layer (L1)OSI Layer 1, which transmits raw bits as electrical, optical or radio signals over a medium.Foundational
• Physical TopologyThe actual layout of cables, devices and connections in a network.Foundational
• Pickup RollerA rubber roller that grabs the top sheet from the paper tray and feeds it into the printer.Foundational
• PiggybackingEntering a secure area with the consent of an authorized person who lets the intruder in.Foundational
• Pin Grid Array (PGA)A CPU package design where the pins are on the underside of the processor and fit holes in the socket.Foundational
• Plan of ActionStep four of troubleshooting: plan the fix, consider impacts, and implement the solution or escalate.Foundational
• Plenum-Rated Cable (CMP)Cable with a fire-resistant, low-smoke jacket required for installation in plenum spaces used for air circulation.Foundational
• PoE InjectorA midspan device that adds PoE power to an Ethernet cable when the switch does not provide PoE.Foundational
• PoE Plus (PoE+)IEEE 802.3at, which delivers up to 30 W per port at the switch (25.5 W at the device) over two pairs.Foundational
• PoE Plus Plus (PoE++)IEEE 802.3bt, delivering up to 60 W (Type 3) or 90 W (Type 4) at the source using all four pairs.Intermediate
• Point-to-Point Protocol over Ethernet (PPPoE)A protocol that encapsulates PPP frames in Ethernet, used by many DSL and some fiber ISPs to authenticate subscribers.Intermediate
• Point-to-Point TopologyA direct link between exactly two endpoints.Foundational
• Pointer Record (PTR)A DNS record that maps an IP address to a host name, used for reverse lookups.Foundational
• Port Address Translation (PAT)NAT that maps many inside addresses to one (or a few) public addresses by tracking unique source port numbers; also called NAT overload.Foundational
• Port ForwardingA NAT rule that maps a public IP and port to an internal host and port so outside clients can reach an internal service.Foundational
• Port NumberA 16-bit number (0-65535) that identifies a specific application or service on a host at Layer 4.Foundational
• Port ScannerA tool that probes a host for open TCP and UDP ports to identify running services.Intermediate
• POST Beep CodesAudible patterns from the motherboard that indicate which hardware failed during POST.Foundational
• Post Office Protocol 3 (POP3)An email retrieval protocol that downloads messages from a server to a client, using TCP 110 (or 995 with TLS).Foundational
• PostScript (PS)Adobe's device-independent page description language used for high-fidelity graphics printing.Intermediate
• Potentially Unwanted Program (PUP)Software that is not clearly malicious but is unwanted, often installed through bundling, such as toolbars or adware.Foundational
• Power Factor Correction (PFC)PSU circuitry that aligns current with voltage to improve power usage and enable wide input range.Advanced
• Power OptionsWindows settings for power plans, sleep, hibernation, lid actions, and button behavior.Foundational
• Power over Ethernet (PoE)Delivering DC power and data together over twisted-pair Ethernet cabling, standardized in IEEE 802.3af, 802.3at and 802.3bt.Foundational
• Power Sourcing Equipment (PSE)The device that supplies PoE power, such as a PoE switch (endpoint PSE) or a midspan injector.Intermediate
• Power Supply TesterA device that checks a PSU's output voltages on each connector without a motherboard.Foundational
• Power Supply Unit (PSU)The component that converts AC wall power to regulated DC voltages for computer components.Foundational
• Power-On Self-Test (POST)Firmware diagnostics run at startup that check the CPU, memory, video, and other core hardware.Foundational
• Powered Device (PD)A device that receives operating power over Ethernet cabling, such as an IP phone, camera or access point.Intermediate
• PowerShellMicrosoft's cross-platform, object-based command shell and scripting language for automating Windows Server and cloud administration.Foundational
• PowerShell Execution PolicyA PowerShell safety setting that controls whether scripts can run and whether they must be signed.Intermediate
• Pre-Shared Key (PSK)Secret shared in advance between parties and used for authentication or key derivation.Foundational
• Preboot Execution Environment (PXE)A standard that lets a computer boot from the network, using DHCP to find a boot server and TFTP to download a boot image.Intermediate
• Preferred Roaming List (PRL)A carrier database on CDMA devices that told phones which towers to use while roaming.Intermediate
• Prefix LengthThe number of leading network bits in an address, written after a slash, as in /24 or /64.Foundational
• Presentation Layer (L6)OSI Layer 6, which translates, formats, compresses and encrypts data so the receiving application can read it.Foundational
• Previous VersionsA Windows feature that restores earlier copies of files or folders from shadow copies or File History.Foundational
• Print ServerA system that manages shared printers, queues, and drivers for network clients.Intermediate
• Print SpoolerThe OS service that queues print jobs and sends them to printers.Foundational
• Printer CalibrationAdjusting a printer's color or alignment settings so output matches expectations.Foundational
• Printer Control Language (PCL)HP's page description language widely supported by laser printers.Intermediate
• Printer DriverSoftware that translates application print data into a language the printer understands.Foundational
• Printer SharingMaking a locally connected or network printer available to other users on the network.Foundational
• PrintheadThe inkjet component with microscopic nozzles that deposit ink onto paper.Foundational
• Priority MatrixA table that derives ticket priority from impact and urgency.Foundational
• Privacy ExtensionsIPv6 features that generate random, temporary interface IDs so a host's address does not reveal a stable hardware identifier.Advanced
• Private IP AddressIPv4 addresses reserved by RFC 1918 for internal use: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16.Foundational
• Problem ManagementITSM process to identify and manage root causes of incidents and reduce their recurrence.Foundational
• Product ActivationVerifying that an operating system or software is properly licensed.Foundational
• Professional CommunicationCustomer service behavior expected of IT support staff, including punctuality, respect, and clear language.Foundational
• ProjectorA display device that projects images onto a surface, rated by brightness in lumens.Foundational
• Protocol AnalyzerA tool that captures and decodes network traffic so it can be examined protocol by protocol.Foundational
• Protocol Data Unit (PDU)The name for the unit of data at a given layer, such as bits, frame, packet, segment or data.Foundational
• Proximity CardContactless access card read by radio frequency when held near a reader, commonly used for badge entry.Foundational
• Proxy ServerA server that acts as an intermediary for requests between clients and other servers.Foundational
• Public IP AddressA globally unique, Internet-routable IP address assigned by an ISP or registry.Foundational
• Punchdown BlockA terminal block where individual wires are terminated by pressing them into insulation-displacement slots.Foundational
• Punchdown ToolA hand tool that seats wires into IDC terminals and trims the excess conductor.Foundational
• pwd CommandA Linux/macOS command that prints the current working directory.Foundational
• Quad Small Form-Factor Pluggable (QSFP)A larger hot-swappable module with four lanes, used for 40G (QSFP+), 100G (QSFP28) and, in QSFP-DD and OSFP forms, 400G and 800G.Intermediate
• Question the ObviousA troubleshooting principle of checking simple causes first, such as power, cables, and settings.Foundational
• QUICA UDP-based, encrypted, multiplexed transport protocol (RFC 9000) that underlies HTTP/3.Intermediate
• Quick AssistA built-in Windows app that lets a helper view or control a user's PC remotely with a security code.Foundational
• Rack UnitThe standard unit of vertical height for rack-mounted equipment, equal to 1.75 inches (44.45 mm).Foundational
• Radio Frequency (RF)Electromagnetic energy in the roughly 3 kHz to 300 GHz range used to carry data wirelessly.Foundational
• RAID 0Disk striping across two or more drives for maximum performance and capacity with no redundancy.Foundational
• RAID 1Disk mirroring, writing identical data to two drives so the array survives one drive failure.Foundational
• RAID 10A nested level that stripes data across mirrored pairs, combining RAID 1 redundancy with RAID 0 performance.Foundational
• RAID 5Striping with distributed single parity across three or more drives, tolerating one drive failure.Foundational
• RAID 6Striping with dual distributed parity across four or more drives, tolerating two simultaneous drive failures.Foundational
• Random Access Memory (RAM)Volatile working memory that holds the OS, running programs, and active data for fast CPU access.Foundational
• RansomwareMalware that encrypts or locks a victim's data or systems and demands payment for restoration.Foundational
• Read-Only Memory (ROM)Non-volatile memory that retains data without power; on PCs it historically stored firmware.Foundational
• Real-time Transport Protocol (RTP)A protocol that carries real-time audio and video over UDP, with sequence numbers and timestamps for playback timing.Intermediate
• Recursive DNS ResolverA DNS server that accepts queries from clients and performs the full lookup process on their behalf, caching results.Intermediate
• Redundant Array of Independent Disks (RAID)A technique combining multiple drives into one logical unit for performance, redundancy or both, using striping, mirroring or parity.Foundational
• Redundant Power SupplyTwo or more power supply units in a server, each able to carry the load alone so one can fail without downtime.Foundational
• Refresh RateHow many times per second a display redraws its image, measured in hertz (Hz).Foundational
• Registered Jack 11 (RJ11)A six-position modular connector, usually wired with two or four contacts, used for analog telephone lines and DSL.Foundational
• Registered Jack 45 (RJ45)The common name for the eight-position, eight-contact (8P8C) modular connector used on Ethernet twisted-pair cables.Foundational
• Registered Memory (RDIMM)Server memory with a register that buffers command and address signals, allowing more modules per channel.Intermediate
• Registered PortsPorts 1024-49151, which IANA registers for specific applications and vendors on request.Foundational
• Registry Editor (regedit)The Windows tool for viewing and editing the registry database.Foundational
• ReimagingRestoring a system from a known-good image to remove compromise rather than attempting to clean it.Foundational
• Reliability MonitorA Windows tool that charts system stability over time with application failures, Windows failures, and updates.Intermediate
• Remote Desktop Protocol (RDP)Microsoft's protocol for remote graphical access to Windows systems, using TCP and UDP port 3389.Foundational
• Remote Monitoring and Management (RMM)Software used by IT teams and MSPs to monitor, patch, script, and remotely support endpoints.Intermediate
• Remote Procedure Call (RPC)A mechanism that lets a program execute code on a remote system as if it were local; Microsoft RPC uses TCP port 135 for its endpoint mapper.Intermediate
• Remote WipeErasing data on a lost or stolen device remotely through MDM or a vendor service.Foundational
• RepeaterA Layer 1 device that regenerates and retransmits a signal to extend the distance a network can cover.Foundational
• Reset This PCA Windows recovery option that reinstalls Windows while keeping or removing personal files.Foundational
• Resource ConsumptionAn indicator of malicious activity shown by unusual CPU, memory, disk, or bandwidth usage.Foundational
• Resource MonitorA Windows tool (resmon) that gives detailed real-time CPU, memory, disk, and network usage per process.Intermediate
• Response TimeHow quickly a display pixel changes from one color to another, measured in milliseconds.Foundational
• Restore PointA snapshot of Windows system settings and files used by System Restore.Foundational
• RetransmissionResending TCP data that was not acknowledged within a timeout or was reported missing by duplicate ACKs.Intermediate
• Reverse DNS Lookup (rDNS)Resolving an IP address back to a host name by querying PTR records.Intermediate
• RG-6A 75-ohm coaxial cable with a thicker conductor and better shielding than RG-59, the standard for cable TV and broadband.Foundational
• Ribbon CableA flat multi-conductor cable used to connect internal laptop and device components.Foundational
• Ring TopologyA topology in which each device connects to two neighbors, forming a closed loop through which data travels.Foundational
• Riser-Rated Cable (CMR)Cable rated to resist vertical fire spread, used in vertical shafts between floors that are not air-handling spaces.Intermediate
• rm CommandA Linux/macOS command that deletes files and, with -r, directories.Foundational
• Roaming ProfileA Windows user profile stored on a server and downloaded to whichever domain computer a user signs in to.Intermediate
• Robust File Copy (robocopy)A Windows command-line tool for reliable, resumable file and folder copying with mirroring.Intermediate
• Rogue Access PointAn unauthorized wireless access point connected to a network, bypassing perimeter security.Foundational
• Rollover CableA cable with pins reversed end to end (1 to 8, 2 to 7 and so on), used to connect a computer serial port to a network device console port.Foundational
• Root Name ServerThe servers at the top of the DNS hierarchy that answer queries with referrals to top-level domain servers.Intermediate
• RootingGaining superuser (root) access on an Android device, bypassing built-in restrictions.Foundational
• RootkitMalware that hides its presence and other malicious activity by subverting the operating system at a deep level.Intermediate
• Round-Trip Time (RTT)The time for a packet to travel to a destination and for the response to return.Foundational
• RouterA Layer 3 device that forwards packets between different IP networks based on destination IP address and its routing table.Foundational
• RST FlagThe TCP reset flag that immediately aborts a connection or rejects a connection attempt to a closed port.Intermediate
• RuntAn Ethernet frame smaller than the 64-byte minimum, usually the result of collisions or faults.Intermediate
• Safe ModeA Windows startup mode that loads only essential drivers and services for troubleshooting.Foundational
• Safety Data Sheet (SDS)A document describing a material's hazards, safe handling, storage, PPE, first aid, and disposal requirements.Foundational
• SambaOpen-source software that provides SMB file and print sharing for Linux and macOS.Intermediate
• SATA Power ConnectorA 15-pin L-shaped PSU connector that supplies 3.3 V, 5 V, and 12 V to SATA drives.Foundational
• Satellite InternetInternet access delivered via communication satellites, useful in remote areas without terrestrial service.Foundational
• ScarewareSoftware or pop-ups that use fear of infection to trick users into buying fake security products or installing malware.Foundational
• Screen LockA device setting that requires authentication to unlock after inactivity or on demand.Foundational
• Script File TypesCommon script file extensions tested at the A+ level: .bat, .ps1, .vbs, .sh, .js, and .py.Foundational
• Secure BootUEFI feature that allows only cryptographically signed bootloaders and OS components to run at startup.Intermediate
• Secure Digital Card (SD)A removable flash memory card format used in cameras, drones, and some laptops and phones.Foundational
• Secure EraseA drive firmware command that erases all user data on SSDs or HDDs, including remapped areas.Intermediate
• Secure Print ReleaseA printing feature that holds jobs until the user authenticates at the printer.Foundational
• Secure Shell (SSH)An encrypted protocol for remote command-line access, tunneling and file transfer, using TCP port 22.Foundational
• Security Group (SG)Stateful virtual firewall attached to instances or network interfaces that allows specified inbound and outbound traffic.Foundational
• SegmentThe Layer 4 PDU produced by TCP, consisting of a TCP header and a chunk of application data.Foundational
• Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T.)Built-in drive health monitoring that tracks attributes such as reallocated sectors and wear level.Intermediate
• Self-Signed CertificateCertificate signed with its own private key rather than by a trusted CA.Foundational
• Separation PadA friction pad that ensures only one sheet of paper feeds at a time.Foundational
• Sequence NumberA 32-bit TCP header field that numbers the bytes in a stream so the receiver can reorder data and detect loss.Intermediate
• Serial ATA (SATA)A common serial interface for hard drives and SSDs, with a 6 Gb/s maximum in SATA III, used in desktops and lower-tier servers.Foundational
• Serial Attached SCSI (SAS)A point-to-point serial interface for enterprise drives, offering dual-porting, higher reliability and compatibility with SATA drives.Foundational
• Serial PortA legacy RS-232 interface (DB-9) used for console connections and older peripherals.Foundational
• Serial Presence Detect (SPD)A small EEPROM on a memory module that stores its size, speed, timings, and voltage.Advanced
• Server Message Block (SMB)The Windows file and printer sharing protocol, running directly over TCP port 445.Foundational
• Service Record (SRV)A DNS record that specifies the host and port for a particular service, with priority and weight.Intermediate
• Service Set Identifier (SSID)The human-readable name of a wireless network, up to 32 octets.Foundational
• Services ConsoleThe Windows tool (services.msc) for starting, stopping, and configuring background services.Foundational
• Session Initiation Protocol (SIP)A signaling protocol that sets up, modifies and tears down VoIP and video sessions, using port 5060 (unencrypted) and 5061 (TLS).Foundational
• Session Layer (L5)OSI Layer 5, which establishes, manages and terminates sessions (dialogs) between applications.Foundational
• Share PermissionsPermissions on an SMB shared folder (Full Control, Change, Read) that apply only when accessed over the network.Foundational
• Shared Address SpaceThe 100.64.0.0/10 block reserved by RFC 6598 for carrier-grade NAT between an ISP and customer routers.Intermediate
• Shielded Twisted Pair (STP)Twisted-pair cable with foil or braided shielding around pairs or the whole cable to reduce EMI and crosstalk.Foundational
• Shoulder SurfingObserving someone's screen or keyboard to obtain sensitive information such as passwords or PINs.Foundational
• shutdown CommandA Windows command to shut down, restart, or log off local or remote computers.Foundational
• SideloadingInstalling apps on a mobile device from outside the official app store.Foundational
• Simple Mail Transfer Protocol (SMTP)The protocol for sending email and relaying it between mail servers, using TCP port 25 (server-to-server) and 587 (client submission).Foundational
• Simple Network Management Protocol (SNMP)A traditional UDP-based protocol for monitoring and managing network devices using MIBs, polling (ports 161) and traps (port 162).Foundational
• Simultaneous Multithreading (SMT)A CPU feature that lets each physical core run two hardware threads, presenting more logical processors to the OS.Intermediate
• Single-Mode Fiber (SMF)Fiber with a very small core (about 9 microns) that carries a single light path, supporting distances of tens to hundreds of kilometers.Foundational
• Sleep ModeA low-power state that keeps memory powered so the system resumes quickly.Foundational
• Sliding WindowA TCP mechanism that lets a sender transmit multiple segments before needing an acknowledgment, with the allowed amount adjusting dynamically.Intermediate
• Small Form Factor PC (SFF)A compact desktop design that uses smaller boards, low-profile cards, and limited internal space.Foundational
• Small Form-Factor Pluggable (SFP)A hot-swappable transceiver module, typically 1 Gbps, that plugs into a switch or router port to provide fiber or copper connectivity.Foundational
• Small Form-Factor Pluggable Plus (SFP+)An enhanced SFP module supporting 10 Gbps, physically compatible with SFP ports.Foundational
• Small Outline DIMM (SO-DIMM)A smaller memory module used in laptops, mini PCs, and some all-in-ones.Foundational
• Smart CardCredit-card-sized card with an embedded chip that securely stores certificates and private keys for authentication.Foundational
• Smart Card ReaderA device that reads chip-based cards used for authentication, such as PIV and CAC cards.Foundational
• Smart JackAn intelligent network interface device at the demarc that lets the carrier run remote diagnostics, such as loopback tests, on a circuit.Intermediate
• Smartphone TetheringSharing a phone's cellular data connection with another device via USB, Bluetooth, or Wi-Fi hotspot.Foundational
• SmartScreenA Microsoft reputation-based protection that warns about malicious sites and untrusted downloads.Intermediate
• SmishingPhishing conducted through SMS or other text messaging.Foundational
• SMS-Based AuthenticationSending one-time codes by text message as a second factor; convenient but weak.Foundational
• SNMP TrapAn unsolicited message an SNMP agent sends to a manager on UDP 162 when a significant event occurs.Intermediate
• SNMPv3The secure version of SNMP, providing user-based authentication, message integrity and encryption.Intermediate
• Social EngineeringManipulating people into revealing information, granting access or performing actions that compromise security.Foundational
• SocketThe combination of an IP address, transport protocol and port number that identifies one endpoint of a connection.Intermediate
• Socket Statistics Command (ss)The modern Linux command that displays socket information, replacing netstat.Intermediate
• Software DeploymentDistributing and installing applications to many endpoints with management tools.Intermediate
• Software LicensingThe legal terms governing how software can be installed and used.Foundational
• Solid-State Drive (SSD)A storage device using NAND flash memory with no moving parts, offering fast access and low latency.Foundational
• Solid-State Hybrid Drive (SSHD)A hard drive with a small built-in flash cache that stores frequently accessed data.Foundational
• Sound CardA device that converts digital audio to analog output and analog input to digital, via expansion card or onboard chip.Foundational
• Spindle SpeedThe rotational speed of a hard drive's platters in revolutions per minute (RPM).Foundational
• Split PairA wiring fault in which wires from two different pairs are used together as a pair, so pin-to-pin continuity is correct but twisting is broken.Intermediate
• SpotlightThe macOS system-wide search tool for finding files, apps, settings, and information.Foundational
• SpywareMalware that secretly monitors user activity and collects information without consent.Foundational
• SSH File Transfer Protocol (SFTP)A secure file transfer protocol that runs as a subsystem of SSH over TCP port 22.Foundational
• Star TopologyA topology in which every node connects to a central device such as a switch.Foundational
• Start of Authority Record (SOA)The DNS record at the top of every zone that names the primary server, administrator email, serial number and timers.Intermediate
• Startup RepairA WinRE tool that automatically diagnoses and fixes problems that prevent Windows from booting.Foundational
• Stateless Address Autoconfiguration (SLAAC)An IPv6 method in which hosts build their own addresses from a router-advertised /64 prefix plus a self-generated interface ID.Foundational
• Static IP AddressAn IP address manually configured on a device that does not change unless an administrator changes it.Foundational
• Static RAM (SRAM)Fast memory that holds data in flip-flop circuits without needing refresh; used for CPU cache.Intermediate
• Stop ErrorA critical Windows error that halts the system with a stop code, commonly called a blue screen of death (BSOD).Foundational
• Storage Area Network (SAN)A dedicated high-speed network that gives servers block-level access to shared storage.Intermediate
• Storage SenseA Windows Settings feature that automatically frees disk space by deleting temporary files and offloading cloud files.Foundational
• Straight Tip ConnectorA round fiber connector with a 2.5 mm ferrule and a bayonet twist-lock, common in legacy multimode installations.Foundational
• Straight-Through CableA twisted-pair cable with the same pinout (both T568A or both T568B) on each end, used to connect unlike devices.Foundational
• StripingSplitting data into blocks written sequentially across multiple drives so they can be accessed in parallel.Foundational
• Structured CablingA standardized, hierarchical approach to building cabling that organizes entrance facilities, equipment rooms, backbone and horizontal cabling, and work areas.Foundational
• SubnetA logical subdivision of an IP network defined by a network address and prefix length.Foundational
• Subnet MaskA 32-bit value with contiguous 1 bits marking the network portion of an IPv4 address and 0 bits marking the host portion.Foundational
• SubnettingDividing a larger IP network into smaller subnets by borrowing host bits for the network portion.Foundational
• Subscriber ConnectorA square fiber connector with a 2.5 mm ferrule and push-pull latching, common in older enterprise and FTTH installations.Foundational
• Surge ProtectorA power strip or device that diverts voltage spikes away from connected equipment.Foundational
• Swap SpaceDisk space used as overflow for physical RAM, where the kernel moves inactive memory pages when memory is under pressure.Foundational
• SwitchA Layer 2 device that forwards frames to specific ports based on destination MAC addresses it has learned.Foundational
• SyslogA standard for sending event log messages to a central collector, traditionally over UDP port 514.Foundational
• Syslog Severity LevelsThe eight syslog message levels from 0 (Emergency) to 7 (Debugging).Intermediate
• SysprepThe Microsoft System Preparation tool that generalizes a Windows installation by removing machine-specific data before imaging.Intermediate
• System Configuration (msconfig)A Windows utility for configuring boot options, services, and diagnostic startup.Foundational
• System File Checker (sfc)A Windows command that scans and repairs protected system files.Foundational
• System Information (msinfo32)A Windows tool that displays detailed hardware, firmware, and software configuration.Foundational
• System on a Chip (SoC)A single chip integrating CPU, GPU, memory controller, and other subsystems, common in mobile devices.Intermediate
• System RestoreA Windows feature that rolls system files, drivers, registry, and installed programs back to an earlier restore point.Foundational
• System SettingsThe macOS app for configuring system preferences, replacing System Preferences since macOS Ventura.Foundational
• T1 LineA North American digital circuit carrying 1.544 Mbps as 24 time-division channels of 64 Kbps.Foundational
• T568AA TIA wiring standard for RJ45 terminations with pin order green-white, green, orange-white, blue, blue-white, orange, brown-white, brown.Foundational
• T568BA TIA wiring standard for RJ45 terminations with pin order orange-white, orange, green-white, blue, blue-white, green, brown-white, brown.Foundational
• TailgatingGaining physical access by following an authorized person through a secured entrance without their knowledge.Foundational
• Task ManagerA Windows utility that shows running processes, performance, startup apps, users, and services.Foundational
• Task SchedulerA Windows tool (taskschd.msc) for running programs or scripts automatically on triggers or schedules.Foundational
• TCP Connection TerminationThe FIN and ACK exchange (usually four segments) that gracefully closes a TCP connection in each direction.Intermediate
• TCP FlagsSingle-bit control fields in the TCP header (SYN, ACK, FIN, RST, PSH, URG, ECE, CWR) that signal connection state and handling.Intermediate
• TCP/IP ModelThe four-layer model of the Internet protocol suite: Link (Network Access), Internet, Transport and Application.Foundational
• tcpdumpA command-line packet capture tool for Unix-like systems.Intermediate
• TelnetA legacy protocol for remote command-line access over TCP port 23 that sends everything, including passwords, in clear text.Foundational
• Temporary ProfileA Windows profile loaded when a user's normal profile cannot be loaded, with changes lost at sign-out.Intermediate
• Text Record (TXT)A DNS record that holds arbitrary text, widely used for domain verification and email authentication (SPF, DKIM, DMARC).Foundational
• Thermal Design Power (TDP)The rated heat output, in watts, a cooling system must dissipate for a processor under typical sustained load.Intermediate
• Thermal PadA soft, pre-formed thermally conductive pad used between components and heat sinks where gaps are larger.Intermediate
• Thermal PasteA thermally conductive compound applied between a processor and heat sink to fill air gaps.Foundational
• Thermal PrinterA printer that uses heat on special heat-sensitive paper (direct thermal) or a ribbon (thermal transfer).Foundational
• Thermal ThrottlingAutomatic reduction of processor speed to prevent damage when temperature limits are reached.Foundational
• Three-Way HandshakeThe SYN, SYN-ACK, ACK exchange TCP uses to establish a connection and synchronize sequence numbers.Foundational
• ThroughputThe actual rate of successful data delivery over a link or path, usually lower than the rated bandwidth.Foundational
• ThunderboltAn Intel-developed interface over USB-C that combines PCIe, DisplayPort, and USB with high bandwidth.Intermediate
• TIA/EIA-568 StandardThe TIA standard family for commercial building telecommunications cabling, defining cable categories, distances, pinouts and installation practices.Foundational
• Ticket TriageAssessing and categorizing new tickets to set priority and route them correctly.Foundational
• Ticketing SystemSoftware that records, tracks, prioritizes, and reports on support incidents and requests.Foundational
• Tiered Support ModelOrganizing IT support into levels (Tier 0-3) by complexity and expertise.Foundational
• Time ExceededICMP type 11 message sent when a packet's TTL reaches zero (code 0) or fragment reassembly times out (code 1).Intermediate
• Time MachinemacOS's built-in backup utility that keeps hourly, daily, and weekly snapshots on an external or network drive.Foundational
• Time to Live (TTL)An 8-bit IPv4 header field decremented by each router; when it reaches zero the packet is discarded to prevent endless looping.Foundational
• Time-Based One-Time Password (TOTP)OTP algorithm (RFC 6238) that generates codes from a shared secret and the current time, typically every 30 seconds.Foundational
• Time-Domain Reflectometer (TDR)An instrument that sends a pulse down a copper cable and times reflections to locate breaks, shorts, kinks and impedance changes.Intermediate
• Tone Generator and ProbeA two-part tool for tracing cables: the generator puts a tone on a wire and the inductive probe detects it at the other end.Foundational
• Toner CartridgeThe replaceable laser printer unit containing powdered toner, often combined with the drum.Foundational
• Top-Level Domain (TLD)The last label in a domain name, such as .com, .org or a country code such as .uk.Foundational
• Top-of-Rack Switch (ToR)A switch installed at the top of each server rack, connecting the rack's servers with short cables and uplinking to aggregation or spine switches.Intermediate
• TouchpadA laptop pointing device that senses finger movement and gestures.Foundational
• TracerouteA tool that discovers the routers along the path to a destination by sending probes with increasing TTL values.Foundational
• TransceiverA device that both transmits and receives signals, typically a pluggable module converting electrical signals to optical or copper media.Foundational
• Transfer RollerThe laser printer component that applies charge to paper so toner moves from the drum to the page.Intermediate
• Transmission Control Protocol (TCP)A connection-oriented Layer 4 protocol that provides reliable, ordered, error-checked delivery of a byte stream.Foundational
• Transport Layer (L4)OSI Layer 4, which provides host-to-host delivery, segmentation, port addressing and optionally reliability.Foundational
• Transport Layer Security (TLS)The cryptographic protocol that secures application traffic with encryption, integrity and certificate-based authentication; successor to SSL.Foundational
• TRIMAn OS command that tells an SSD which blocks are no longer in use so it can erase them in advance.Intermediate
• Trivial File Transfer Protocol (TFTP)A simple, unauthenticated file transfer protocol using UDP port 69.Foundational
• Trojan HorseMalware disguised as legitimate software that performs hidden malicious actions once the user runs it.Foundational
• Trusted Platform Module (TPM)Secure cryptoprocessor chip on a device that stores keys, measures boot integrity, and supports attestation.Foundational
• Twisted Nematic (TN)An LCD panel type with very fast response times but narrow viewing angles and weaker color.Foundational
• Twisted PairCopper cabling in which pairs of insulated wires are twisted together to cancel electromagnetic interference and crosstalk.Foundational
• Type 1 HypervisorA bare-metal hypervisor that runs directly on server hardware without a general-purpose host operating system.Foundational
• Type 2 HypervisorA hosted hypervisor that runs as an application on top of a conventional operating system.Foundational
• Unattended InstallationAn OS installation that runs without user input, using an answer file.Intermediate
• UnicastOne-to-one communication from a single sender to a single receiver.Foundational
• Unified Extensible Firmware Interface (UEFI)Modern system firmware that replaces legacy BIOS, supporting GPT boot disks, Secure Boot and a pre-boot environment.Foundational
• Unified MemoryA memory design where the CPU, GPU, and other processors share one pool of RAM in the same package.Intermediate
• Uninterruptible Power Supply (UPS)A device that provides immediate battery-backed power during utility outages and conditions power for connected equipment.Foundational
• Unique Local Address (ULA)IPv6 addresses in fc00::/7 (in practice fd00::/8) meant for local use within a site or group of sites, similar to IPv4 private addresses.Intermediate
• Universal Plug and Play (UPnP)A set of protocols that let devices discover each other and automatically request port forwards on a home router.Intermediate
• Universal Serial Bus (USB)The standard interface for connecting peripherals, storage, and charging to computers and mobile devices.Foundational
• Unshielded Twisted Pair (UTP)Twisted-pair cable without metallic shielding, relying only on twisting to reject interference; the most common LAN cable.Foundational
• Unspecified AddressThe IPv4 address 0.0.0.0, meaning "this host" or "no address," used as a source before an address is assigned.Intermediate
• Usable Hosts FormulaThe calculation 2^h - 2, where h is the number of host bits, giving the assignable IPv4 addresses in a subnet.Foundational
• USB Power Delivery (USB PD)A USB charging specification that negotiates higher voltages and currents over USB-C, up to 240 W.Intermediate
• USB Type-CA reversible 24-pin USB connector that supports data, video, and high-wattage charging.Foundational
• User Account Control (UAC)A Windows feature that prompts for consent or credentials before actions requiring administrative privileges.Foundational
• User Datagram Protocol (UDP)A connectionless Layer 4 protocol that sends datagrams with minimal overhead and no delivery, ordering or retransmission guarantees.Foundational
• Verify Full System FunctionalityStep five of troubleshooting: confirm the fix works end to end and apply preventive measures.Foundational
• Vertical Alignment (VA)An LCD panel type with high contrast ratios and deep blacks but slower response than IPS or TN.Intermediate
• Video Graphics Array (VGA)A legacy analog video connector (DE-15, three rows of 15 pins) for monitors and projectors.Foundational
• Virtual Desktop Infrastructure (VDI)Hosting desktop operating systems in VMs in the data center or cloud and delivering them to users over a remote display protocol.Foundational
• Virtual Machine (VM)A software-defined computer with virtual hardware that runs its own operating system on top of a hypervisor.Foundational
• Virtual MemoryAn OS technique that gives each process its own address space backed by RAM and disk storage.Intermediate
• Virtual Network Computing (VNC)A cross-platform remote desktop system that uses the RFB protocol, typically on TCP port 5900.Intermediate
• VirusMalware that attaches to a host file or program and replicates when that host is executed, requiring user action to spread.Foundational
• VishingVoice phishing that uses phone calls or voicemail to manipulate victims into revealing information or taking action.Foundational
• Voice over IP (VoIP)Technology that carries voice calls as packets over IP networks instead of traditional circuit-switched lines.Foundational
• Voltage Regulator Module (VRM)Motherboard circuitry that converts 12 V from the PSU into the low voltages needed by the CPU.Advanced
• Wearable DeviceA body-worn smart device such as a smartwatch, fitness tracker, or smart glasses.Foundational
• WebcamA camera built into or attached to a computer for video calls and recording.Foundational
• Well-Known PortsPorts 0-1023, assigned by IANA to common system services such as HTTP, SSH and DNS.Foundational
• whoami CommandA command that displays the currently logged-on user and, on Windows, groups and privileges.Foundational
• Wi-Fi Antenna ConnectorSmall coaxial connectors (U.FL/IPEX) that attach laptop antenna cables to the wireless card.Intermediate
• Wi-Fi DirectWi-Fi Alliance certification for device-to-device connections where one device acts as a soft AP group owner.Intermediate
• Wi-Fi Generation NamesWi-Fi Alliance consumer names mapping standards to generations: Wi-Fi 4 (n), 5 (ac), 6 (ax), 7 (be).Foundational
• Wi-Fi Protected Access 2 (WPA2)Wi-Fi Alliance security certification implementing 802.11i with AES-CCMP, in Personal (PSK) and Enterprise (802.1X) modes.Foundational
• Wi-Fi Protected Access 3 (WPA3)Current Wi-Fi security standard that uses SAE for personal networks and mandates protected management frames.Foundational
• Wi-Fi Protected Setup (WPS)A simplified setup method using a PIN or push button, vulnerable to brute-force and Pixie Dust attacks.Foundational
• Wide Area Network (WAN)A network spanning large geographic areas, connecting LANs across cities, countries or continents, usually over provider services.Foundational
• Window SizeThe TCP header value advertising how many bytes the receiver is currently willing to accept.Intermediate
• Windows 10 End of SupportThe October 14, 2025 date after which Windows 10 stopped receiving free security updates.Foundational
• Windows 11Microsoft's current desktop operating system, requiring TPM 2.0, UEFI Secure Boot capability, and a supported 64-bit CPU.Foundational
• Windows AutopilotA Microsoft service that provisions new Windows devices straight from the OEM using cloud identity and Intune.Intermediate
• Windows Boot Manager (bootmgr)The Windows boot loader component that reads BCD and starts the selected OS loader.Intermediate
• Windows Defender FirewallThe host-based stateful firewall built into Windows, with Domain, Private, and Public profiles.Foundational
• Windows EditionsThe different versions of Windows (Home, Pro, Enterprise, Education) with different features and licensing.Foundational
• Windows Event LogThe structured logging system in Windows that records security, system and application events.Foundational
• Windows Feature UpdateAn annual Windows release that adds new features and resets the support lifecycle.Intermediate
• Windows Imaging Format (WIM)A file-based disk image format (.wim) used for Windows installation and deployment.Advanced
• Windows Installer Package (MSI)The .msi installation package format used to install, repair, and uninstall Windows software.Intermediate
• Windows Memory Diagnostic (mdsched)A built-in Windows tool that tests RAM for errors at the next reboot.Foundational
• Windows Package Manager (winget)A Windows command-line tool for installing, upgrading, and removing applications.Intermediate
• Windows Preinstallation Environment (WinPE)A minimal Windows environment used to install, deploy, and repair Windows.Advanced
• Windows Quality UpdateA monthly cumulative Windows update that delivers security and reliability fixes.Intermediate
• Windows Recovery Environment (WinRE)A recovery OS built on WinPE that provides startup repair, restore, reset, and command-line tools.Foundational
• Windows RegistryThe hierarchical database storing configuration for Windows, its services, hardware and applications.Foundational
• Windows SandboxA lightweight disposable desktop in Windows Pro and Enterprise for safely running untrusted applications.Intermediate
• Windows SecurityThe Windows app that centralizes antivirus, firewall, device security, and account protection status.Foundational
• Windows SettingsThe modern Windows configuration app for system, devices, network, accounts, privacy, and updates.Foundational
• Windows Subsystem for Linux (WSL)A Windows feature that runs Linux distributions directly on Windows.Intermediate
• Windows TerminalA modern Windows terminal application that hosts PowerShell, Command Prompt, and WSL shells in tabs.Foundational
• winverA Windows command that displays the installed Windows version and build number.Foundational
• Wire MapA test that verifies each conductor is connected to the correct pin at both ends of a twisted-pair cable.Foundational
• Wired Equivalent Privacy (WEP)Original, broken 802.11 encryption protocol using RC4 with a 24-bit IV.Foundational
• WiresharkA free, open-source graphical protocol analyzer that captures and decodes network packets.Foundational
• WorkgroupA peer-to-peer Windows network where each computer manages its own accounts and resources.Foundational
• WormSelf-replicating malware that spreads across networks without user interaction by exploiting vulnerabilities.Foundational
• x86-64 Architecture (x64)The 64-bit extension of the x86 instruction set used by most Intel and AMD PC processors.Foundational
• xcopyA legacy Windows command that copies files and directory trees.Foundational
• XProtectApple's built-in signature-based malware detection for macOS.Intermediate
• yumThe legacy package manager for Red Hat-based Linux distributions, replaced by dnf.Foundational
• Zero Insertion Force Socket (ZIF)A CPU socket with a lever that releases clamping pressure so the processor can be inserted without force.Foundational
• Zone TransferReplication of DNS zone data from a primary to secondary servers, as a full transfer (AXFR) or incremental transfer (IXFR), over TCP 53.Intermediate