CompTIA A+ Core Certification: Glossary of Important Concepts

Numerics

3-2-1 backup rule: The 3-2-1 backup rule/scheme is an easy way to define the practice of keeping: (3) 1 primary plus 2 backup copies of data; (2) 2 methods of storage for the data (for example, local and cloud); (1): 1 local backup offsite, in case of fire or storm damage to a facility.

3D printer Commonly known as additive manufacturing (AM), a 3D printer comes in two flavors: fused deposition modeling (FDM), which is 3D printing in a tabletop environment, and stereolithography (SLA), which is a newer 3D tabletop process that involves photopolymer resins and lasers.: The most common material used with 3D printers is a strand of plastic filament that is fed from a spool to a moving printer head.: The printer head heats the plastic and thinly layers it on the printing platform in cross-sections that eventually build up into the 3D object that has been designed on the computer.

802.11a: A wireless Ethernet standard that uses 5GHz radio signals and provides performance at rates from 6Mbps up to 54Mbps. It is not compatible with other 802.11-based wireless networks unless dual-band access points are used.

802.11ac (Wi-Fi 5): A wireless Ethernet standard that uses 5GHz radio signaling for performance up to 1300Mbps. It uses MU-MIMO antenna technology.

802.11ax (Wi-Fi 6): A wireless Ethernet standard that uses both 2.4GHz and 5GHz bands, with increased speeds up to 9.6Gbps. Wi-Fi 6E improves upon Wi-Fi 6 by supporting the 6GHz band.

802.11b: A wireless Ethernet standard that uses 2.4GHz radio signaling for performance from 2Mbps to 11Mbps. It is compatible with 802.11g-based wireless networks but not with 802.11a-based networks unless dual-band access points are used.

802.11g: A wireless Ethernet standard that uses 2.4GHz radio signaling for performance up to 54Mbps. It is compatible with 802.11b-based wireless networks but not with 802.11a-based networks unless dual-band access points are used.

802.11n (Wi-Fi 4): A wireless Ethernet standard that uses 2.4GHz and 5GHz radio signaling for performance up to 600Mbps. It uses MIMO antenna technology.



A

A records DNS stores 32-bit IPv4 address data in: A records, and DNS accesses: A records when resolving IPv4 address requests.

AAAA records: DNS stores 128-bit IPv6 address data in AAAA records, and DNS accesses AAAA records when resolving IPv6 address requests.

acceptable use policy (AUP): A company’s policy for employees that pertains to user safety, security procedures, and computer best practices within a company.: The policy is designed to keep the network safe.

access control list (ACL): A list of permissions or restriction rules for access to an object such as a file or folder.

access control vestibule: Formerly known as a mantrap, an access control vestibule is an area with two locking doors that is used to enforce physical security and monitor for unauthorized access to a building entrance.

access point: A piece of hardware that extends a wired network to wireless connections.

Active Directory: A Microsoft solution for managing users, computers, and information access in a network.

ad blocker: A tool that integrates with a web browser and uses filtering to block specific advertisements. Ad blockers assist with online privacy and help to avoid spyware-infected ads.

Advanced Encryption Standard (AES): A protocol that is similar to TKIP. AES is more secure and is used with the WPA2 wireless encryption standard.

Advanced RISC Machine (ARM): A processor architecture that is based on Reduced Instruction Set Computer (RISC). ARM is the most widely used instruction set architecture. ARM processors are low cost, have minimal power consumption, and generate lower heat, making them ideal for devices such as smartphones, tablets, laptops, and other embedded systems.

Advanced Technology eXtended (ATX): A family of motherboards that has dominated desktop computer designs since the late 1990s.: An ATX motherboard has the following characteristics: a rear port cluster for I/O ports, expansion slots that run parallel to the short side of the motherboard, and a left-side case opening (as viewed from the front of a tower PC).

Android: An open-source operating system based on the Linux kernel and used mostly on smartphones and tablet computers. Android is developed by the Open Handset Alliance, a group directed by Google.

Android Package (APK) source: Format for applications to run on the Android OS.

anti-malware software: Software that scans for infections that antivirus software might have missed.

antivirus software: Software that provides real-time protection against threats from local files, websites, and email.

.app files: In macOS, the application bundle files that contain all the files and folders that make up the application.

Apple File System (APFS): The Apple file allocation system designed to work with SSD and flash drives.

application spoofing: The act of a malicious application imitating a legitimate application and tricking the user into revealing passwords or other sensitive information as they interact with the false app. This process is very similar to a phishing attack.

application virtualization: Allows users to access applications from a different computer than the one where the application is installed.

apt-get: A Linux command used to install or manage APT (Advanced Packaging Tool) software packages. It is common in Debian-based distributions such as Ubuntu.

authentication: The process of verifying user identity.

authentication, authorization, and accounting (AAA) server: An AAA server is used to examine and either verify or deny credentials to a user who is attempting to log into secured networks.

automatic document feeder (ADF): A feature found in printers, photocopiers, and scanners that automatically feeds a single sheet of paper from a stack of paper into the machine. This allows the user to print, scan, or copy without needing to manually feed paper into the machine one sheet at a time.

Automatic Private IP Addressing (APIPA) Most IP networks use addresses provided automatically by DHCP; however, if the DHCP server becomes unavailable and an alternate IP address has not been set up, devices on the network assign themselves APIPA/link local addresses. These addresses are in the IPv4 address range 169.254.0.1 to 169.254.255.254 (with the subnet mask 255.255.0.0).: The IPv6 version is called a link local address and has the FE80::/64 prefix.: A device with an APIPA address cannot connect to the Internet.



B

.bat script files: .bat files are script files that are strictly Windows based. They are text files that contain commands or instructions for the command-line interpreter to execute.

biometrics: The use of a person’s biological information, such as fingerprints, retina scans, or facial recognition, to authenticate a potential user of a secure area.

BitLocker: Full disk encryption software by Microsoft that can encrypt the entire disk. After encryption is completed, authentication is required to access the drive.

BitLocker To Go: BitLocker functionality that is extended to removable drives.

black screen: The absence of video output during the boot sequence. It can indicate cable or software issues.

blue screen of death (BSOD): An error in which the screen background is blue (or sometimes black), with the error message in white text. Such errors can occur either during startup or after a system is running, and they halt a system by default.

Bluetooth: A short-range wireless network used primarily by mobile devices.

bollards: Short wood, metal, or concrete posts installed in sidewalks and driveways to allow pedestrian and bike traffic to pass, while keeping larger vehicles away.

boot methods: The methods used to load OS files into RAM. Examples are using HD, a thumb drive, a CD, or a network boot.

boot sector virus: Similar to a root kit virus, in that the virus is embedded deep into the computer. In this case, the virus embeds itself into the initial code of the boot sector on a hard drive.

bootleg: Unauthorized copies of software; also files with unauthorized changes.

brute-force attack: A method of cracking passwords by calculating and using every possible combination of characters until the correct password is discovered.



C

cable Broadband: Internet service that is provided by a cable TV company. Broadband can deliver voice, data, and video at one time.

cable modem: A device that encodes and decodes cable Internet network signals. It can be connected to a single computer or to a wired or wireless router.

cable stripper: A tool used to strip a portion of the plastic jacket off a cable to expose the individual wires.

cable tester: A tool that tests each wire in a cable and makes sure each one is wired properly.

capacitor swelling: Capacitors are used as part of the voltage step-down circuits that provide power to the processor. From 2002 to 2007, many motherboards were built using faulty capacitors that became swollen and leaked, causing system failure and sometimes physical damage to the motherboard.

capture card: A video capture card is equipped to receive HDTV or higher-quality signs via HDMI, DVI, or component. Video capture cards have built-in hardware support for MPEG-4 recording and can be used to capture video for training, game recording, YouTube, or broadcast purposes. Some video capture devices connect to a USB port.

cat: A Linux utility command for writing text into files and printing file content.

Cat 5: Category 5 TP cable. Supports Fast Ethernet (up to 100Mbps) and uses 24-gauge wires.

Cat 5e: Category 5e TP cable. Supports Gigabit Ethernet (10/100/1000Mbps).

Cat 6: Category 6 TP cable. Supports 10G Ethernet (10/100/1000/10000Mbps) and reduces crosstalk for more reliable connections at gigabit speeds.

Cat 6a: Category 6a TP cable. Supports 10BASE-T, 100BASE-T, 1000BASE-T, and 10GBASE-T (10Gbps Ethernet).

cd: A Linux command used to change directories (folders).

cellular: A data network that enables mobile devices to offer many ways to connect to other devices, including sharing their Wi-Fi or cellular connections with one or more computers.

Certificate Manager (certmgr.msc): Allows the import, export, modification, or deletion of root certificates that manage authentication when sending and receiving information in Windows.

certification of destruction/recycling: Offered by a certified third-party material destruction company that verifies the destruction and recycling of material.

chain of custody: Chronological documentation or paper trail of evidence.

change management: The process of preparing for changes in a network, including planning, staffing, organizing, and getting feedback from impacted stakeholders.

channel: The wireless spectrum is divided into 11 channels. Part of installing a router on a 2.4GHz wireless network is selecting an appropriate channel for the signal.

charging: Step 2 of the laser printing process, in which the cylinder-shape imaging drum receives an electrostatic charge of –600Vdc (DC voltage) from a conditioning roller.

chkdsk: A Windows command that scans a specified drive for errors and repairs them.

chmod: A Linux command used to change permissions on files and directories.

chown: A Linux command used to change file ownership.

Chrome OS: Google open-source mobile operating system, which is chiefly designed to run on web-based applications and is installed on Chromebooks, which are an inexpensive laptop option.

CIFS: Common Internet File System, an early standard method for sharing files across corporate intranets and the Internet. It has largely been replaced by updated versions of Server Message Block (SMB).

clean install: A fresh installation of the Windows OS as an upgrade or to free up space on the disk.

cleaning: Step 7 of the laser printing process, which involves preparing the drum for a new page by removing the preceding page from the drum by using a discharge lamp. Toner that is not adhering to the surface of the drum is scraped from the drum’s surface for reuse.

coaxial: A type of cable that consists of a solid center copper core, insulation, a metal braided jacket for grounding, and a vinyl or plastic outer jacket. It is commonly used for cable TV, cable Internet, and satellite Internet.

[command name] /?: A Windows command that displays help for the specified command.

community cloud computing: A type of cloud computing in which organizations with common concerns or goals share a cloud infrastructure.

connection oriented: Transmission Control Protocol (TCP) sessions are known as connection-oriented sessions. This means that every packet that is sent is checked for delivery. If the receiving computer does not receive a packet, it cannot assemble the message and must ask the sending computer to transmit the missing packet again. No packet is left behind.

connectionless: User Datagram Protocol (UDP) sessions are known as connectionless sessions. This means the messages are sent without an expectation of communication from the receiver. UDP does its best to send a message, but errors are not accounted for.

content filtering: Blocking content into a local network or group of users, filtering by web address or inappropriate terms in the content.

copy: A Windows command that copies one or more files to another folder or drive.

corporate use license: A license that covers the use of software by workers in a company or another organization.

cp: A Linux command used to copy files to a specified location.

crimper: A tool used to attach a connector to the end of a raw twisted pair (TP) or coaxial cable.

cross-platform virtualization: A type of application virtualization that can involve different underlying virtualization technologies.

cross-site scripting (XSS): Involves tricking a user, often with a link in an email or some other ruse. When an unsuspecting user clicks, the attacker can inject malicious code into a web-based app.

cryptominers: Viruses that take over resources of an infected computer for the purpose of mining cryptocurrency (usually Bitcoin). This practice is also known as cryptojacking.

cursor drift: When a screen cursor unintentionally moves across the screen, typically caused by accidentally swiping or pressing on the device’s touchpad, or by a problem with the device’s integrated pointing stick.



D

data-at-rest encryption: Encryption of backup data that is “at rest,” usually archived in data centers and not in current use.

DB9: A nine-pin D-shell connector.

Defender Antivirus: The antivirus application built into Windows Defender. This can work in place of or along with third-party antivirus applications.

degaussing: The process of removing magnetic content from hard drives, magnetic tapes, or other magnetic digital storage.

denial of service (DoS): An attack in which one computer sends an overwhelming number of service requests to a specific target.

desktop virtualization: The creation of a user interface to a computer that is hosted on a central server on the premises or in the cloud.

Device Manager (devmgmt.msc): A Microsoft Windows utility that displays detailed information about the computer hardware in a system, including status and driver information.

df: Linux command used to display used and free space on disks.

DHCP: Dynamic Host Configuration Protocol; a protocol used to automatically assign IP addresses to hosts. DHCP uses ports 67 and 68.

DHCP lease: A device is leased an IP address for a certain amount of time and can renew a leased IP address before the lease expires. If the lease expires, the device must request an IP address again.

DHCP reservation: A permanent lease that is assigned to a DHCP client.

DHCP scope: A pool or range of IP addresses that the DHCP server can assign or lease to devices.

dictionary attack: An attempt to crack passwords by trying all the words in a list, such as a dictionary.: A simple list might include commonly used passwords such as 12345678 and password.

differential backup: These backups record data that has changed since the last full backup. They can be done often to ensure that data backups are very current.

dig: Domain Information Grouper; a Linux command that provides information on DNS servers for troubleshooting DNS issues.

digital rights management (DRM): The general term for software or service mechanisms that limit the end user’s rights to copy, transfer, or use software or digital media.

Digital Visual Interface (DVI): A standard that replaced DFP for the support of LCD displays on desktop computers. DVI-D is for digital displays only, DVI-I supports digital and analog displays, and DVI-A supports analog displays only.

digitizer: A touchscreen display differs from a standard laptop display, in that it has a digitizer layer on top of the display panel.: The digitizer detects and transmits touches to the laptop processor. Digitizers are also used on touchscreen smartphones, tablets, fitness monitors, smart watches, phablets, e-readers, and smart cameras.

dir: A Windows command that displays a list of a folder’s files and subfolders.

direct burial: Versions of UTP and STP cables designed with enough protection on the outer jacket, commonly known as a CMX jacket, to withstand weather, ground moisture, and even direct placement in water.

Disk Cleanup (cleanmgr.exe): A Windows command-line command that brings up disk cleanup and management utilities.

Disk Defragment (dfrgui.exe): A Windows command-line utility for defragmenting a drive.

Disk Management (diskmgmt.msc): A snap-in of the Computer Management Console that is a GUI-based application for analyzing and configuring hard drives.

Disk Utility: Utility in macOS for managing disk images.

diskpart: A Windows command that creates, removes, and manages disk partitions.

DisplayPort: A cable and port that is primarily used to transmit video that can also send audio and USB signals. It was designed as a replacement for VGA and DVI.

distributed denial of service (DDoS): An attack in which the perpetrator uses multiple computers to disrupt the target computer’s access to the Internet.

.dmg files: Disk Image files in the macOS. Similar to ISO files in Windows.

DNS: Domain Name System; a service that translates domain names into IP addresses. DNS uses port 53.

Dock: A macOS feature for launching and switching applications that displays app icons across the bottom of the desktop.

docking station: A device where laptops, smartphones, tablets, or other mobile devices can be placed to be charged and connected to various peripherals.

domain: A computer network or group of computer networks under the same administration.

domain access: Accessing the domain to manage computers on the domain.

Domain Name System (DNS): Domain Name System; a service that translates domain names into IP addresses. DNS uses port 53.

Domain-based Message Authentication, Reporting, and Conformance (DMARC): A mail authentication process that builds on DKIM and SPF to further enhance security from fraudulent spam.

DomainKeys Identified Mail (DKIM): A process that enables a receiving mail system to check that the message was authorized by the sending party and was not used for spam or phishing.

Double Data Rate 3 (DDR3): DDR3 SDRAM; the successor to DDR2 SDRAM, which runs its external data bus at twice the speed of DDR2 SDRAM, enabling faster performance. DDR3 SDRAM also uses lower voltages than DDR2 and supports higher memory capacities.

Double Data Rate 4 (DDR4): DDR4 SDRAM; the successor to DDR3 SDRAM, which runs its external data bus at twice the speed of DDR3 SDRAM, enabling faster performance. DDR4 SDRAM also uses lower voltages than DDR3 and supports higher memory capacities.

Double Data Rate 5 (DDR5): DDR5 SDRAM was released in 2020 and is the fifth generation of DDR memory. Although DDR5 DIMMs has the same number of pins as DDR4 (288 pins), they are not compatible because the alignment key is located in a different area on the RAM stick. Compared to DDR4, DDR5 reduces power consumption (1.1V vs. 1.2V), offers twice the data transfer rate (6.4Gbps vs. 3.2Gbps), and has four times the memory density per chip (64GB vs. 16GB). DDR5 can include an onboard voltage regulator to gain higher speeds. In addition, the burst length in DDR5 is increased from DDR4’s 8 to 16.

DSL: Digital Subscriber Line; a type of broadband Internet service that uses telephone lines to carry Internet traffic at speeds up to 1.5Mbps or more while allowing you to use your phone for normal functions at the same time. Two major types of DSL are ADSL and SDSL.

dual channel: A motherboard feature in which two identical memory modules are treated as a single logical unit for faster access.

dumpster diving: The process of going through the trash, seeking information about a network or a person with access to the network.

duplexing assembly: A printer component that switches paper from the front to the back side so that the printer can print on both sides of the paper.

Dynamic Host Configuration Protocol (DHCP) reservations: A protocol that allows a computer, router, or other DHCP-enabled device to assign IP addresses to hosts on a local network.

dynamic IP addresses: Addresses that are assigned by a DHCP server and that will likely change each time a device leaves and then rejoins the network or when the address is used beyond its lease time and expires.



E

Ease of Access: Windows app for configuring settings to the user’s needs and tastes.

electrostatic discharge (ESD): Static electricity that discharges to something that has a different electric potential, especially metallic items such as circuit boards. Casually picking up an expensive video card can possibly damage it. This damage can cause a complete failure or can cause intermittent issues that might be difficult to troubleshoot.

embedded system: Dedicated computing devices used for specific tasks such as machine control, point-of-sale systems, or ATMs. Embedded systems are often legacy systems.

Encrypting File System (EFS): A feature used to protect sensitive data files and temporary files through encryption that can be applied to individual files or folders.

end-user license agreement (EULA): An agreement that restricts how an app can be used and what the transfer rights are.

error-correction code (ECC): Advanced memory that can correct errors and requires special chipsets. ECC is used primarily in servers.

Event Viewer (eventvwr.msc): A Windows tool that allows an administrator to track all the logs of events logins, security actions, crashes, and so on that have happened in the computer.

evil twin: A type of network attack that involves setting up a fake access point to gather access information from legitimate users.

expansion cards: Onboarded video, audio, and graphics cards that have dedicated memory space to enhance video, audio, and graphics capabilities beyond what most CPUs can do inherently.

exposing: Step 3 of the laser printing process, in which a moving mirror moves the laser beam across the surface of the drum. As it moves, the laser beam temporarily records the image of the page to be printed on the surface of the drum by reducing the voltage of the charge applied by the charger corona to –100VDC.

Extensible File Allocation Table (exFAT): Also known as FAT64; a file system designed to enable mobile personal storage media to be used seamlessly on mobile and desktop computers.

External SATA (eSATA): External SATA cables enable external drives to be mounted at the same data rate. eSATA has better shielding to protect the cable and the data than regular SATA.



F

F type: A connector used for cable, satellite, and fixed wireless Internet and TV service. It can be crimped or attached via compression to the coaxial cable.

fiber: Abbreviation for fiber optic. Network cable that uses glass fibers to transmit photons to carry data.

fiber-optic cabling: Network cable that uses glass fibers to transmit photons to carry data.

filament: The (usually) plastic material that is fed from a spool, which is basically the “ink” for a 3D printer.: The two most common types of filament are polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS).

File Allocation Table 32 (FAT32): The Windows file system introduced in 1995 that has a 32-bit file allocation table, which allows for 268,435,456 entries (232) per drive.

file server: Typically a computer with a single large drive or a RAID array for shared storage on a network.

file synchronization: The process of ensuring that one or more files that are stored in different locations are updated and identical.

FileVault: A disk encryption app in macOS.

find: A Linux command for searching for files and folders.

Finder: Application on Apple computers for searching for files or apps.

firewall: A hardware appliance or software application that protects a computer from unwanted intrusion.

firmware update: Solves operational problems and adds features that enhance Wi-Fi interoperability, security, and ease of use on devices.

flash drive: A small electronic device (typically a USB drive) that contains flash memory that is used for storing data or transferring it to or from a computer, digital camera, or similar device.

Force Quit: A Linux and macOS option to shut down an unresponsive app or program.

format: A Windows command-line command that prepares a hard drive with a file system in order to install an operating system.

Fourth Extended Filesystem (ext4): Linux OS journaling system of events to minimize the impact of a system failure. It is the replacement for ext3.

frequencies: The frequency ranges in the wireless spectrum that carry the 2.4GHz and 5GHz Wi-Fi bands.

FTP: File Transfer Protocol; a protocol that both web browsers and specialized FTP programs use to access dedicated file transfer servers for file downloads and uploads. FTP uses port 21.

full backup: A backup of the entire contents of the computer or selected drive to another local or network location. Because every file is copied, a full backup takes the longest and uses the most storage of the backup types.

fuser assembly: A laser printer component that fuses the page image to the paper.

fusing Step 6 of the laser printing process, in which the printed sheet of paper is pulled through fuser rollers, using high temperatures (approximately 350° Fahrenheit) to heat the toner and press it into the paper. The printed image is slightly raised above the surface of the paper.



G

gateway: Identifies the IP address of a device that connects the computer to the Internet or another network.

gestures: Finger movements made across a macOS trackpad or Magic Mouse surface, or across a touchscreen on another OS to perform specific tasks.

gpedit.msc: See Group Policy Editor.

gpresult: A Windows command that displays the resultant set of policy for the specified computer and user.

gpupdate: A Windows command that refreshes the Group Policy on local or Active Directory systems.

grandfather-father-son (GFS): A backup rotation method that describes keeping three different generations, or types of backups, in various places.: The name is simply an easy way to remember that full backups (grandfather—perhaps a monthly backup stored redundantly offsite) can be combined with a weekly backup (father—also sent offsite) and a daily incremental backup (son).

grep: A Linux command used to perform text searches.

Group Policy Editor (gpedit.msc): Utility in Windows that is a graphic interface for editing items in the Registry.

GUID [globally unique identifier] Partition Table (GPT): The table that describes the partitions on a physical HD so that they are recognized by the OS.



H

hard disk drive (HDD): A mass storage device. This term can also refer to a hybrid drive or a solid-state drive (SSD).

hard token: Any physical device that a user must carry to gain access to a specific system. Examples are smart cards, RFID cards, USB tokens, and key fobs.

hardware security module (HSM): A module or external device that can be added to store security keys for general use.

hashing Method of verifying that the contents of files are unaltered.: A hash is often created on a file before it is downloaded and then hashed after the download; the two values then are compared to make sure that the contents are the same.

headers: Refers to the pin headers that the connectors plug into on a motherboard.

heat sink: A finned metal device that radiates heat away from the processor.

high availability Ensuring that resources are always up and available to users.

high latency: An escalated amount of data delay between sender and receiver, which can be caused by router overloads or high demand on a key bottleneck of a network.

High-Definition Multimedia Interface (HDMI): A compact audio/video interface for transmitting uncompressed digital data.

hostname: The name given to a device on the network, making it distinguishable from other devices.

hotspot: A method for sharing a smartphone’s Internet access via Wi-Fi.

HTTP: Hypertext Transfer Protocol; a protocol used by web browsers, such as Internet Explorer, Microsoft Edge, Firefox, and Chrome, to access websites and content. HTTP uses port 80.

HTTPS: Hypertext Transfer Protocol over Secure Sockets Layer; a protocol that is often used for payment transactions on the World Wide Web and for sensitive transactions in corporate information systems. HTTPS uses port 443.

hub: A simple device used on an Ethernet network for connecting devices to each other.

hybrid cloud computing: A type of computing that shares characteristics of both private and public clouds.: A hard disk drive with a small solid-state drive (SSD) onboard is used to improve disk access time.



I

IaaS: Infrastructure as a Service; a type of cloud computing in which users can lease cloud-based network services, servers, storage space, and other resources.

iCloud: The iOS cloud backup service.

image deployment: The process of installing Microsoft Windows from an image. It is also known as disk cloning.

imaging drum: A printer component that applies the page image to the transfer belt or roller. It is frequently combined with the toner supply in a toner cartridge.

IMAP Internet Message Access Protocol; an email protocol that enables messages to remain on the email server so that they can be retrieved from any location. IMAP uses port 143.

impact printer: A printer that uses a mechanical print head that presses against an inked ribbon to print characters and graphics. Impact printers are the oldest printer technology, and they are primarily used today in industrial and point-of-sale applications.

impersonation: A type of social engineering similar to phishing, in which a hacker sends an email pretending to be someone the victim trusts.

Incident reports: When a rule or law has been broken, an incident report is necessary so that the company can track its legal responsibilities. This allows the company to plan for training and to comply with laws as necessary.

incremental backup: These backups copy only data that has changed since the last backup. If a full backup is performed every Saturday, an incremental backup could be run each day of the week, recording one day of activity each time. This way, backups are current but a full backup does not have to be run each day.

Information Technology eXtended (ITX): A family of motherboards that was originally developed by VIA Technologies in 2001 for use with its low-power x86 C3 processors.

injectors: Power over Ethernet (PoE) devices installed between a standard Ethernet switch and a PoE device to provide power only.

inkjet printer: A print technology that sprays fine droplets of ink onto the page.

in-place upgrade: A type of upgrade that involves updating an installation to the new version with the existing configuration. It is another name for a repair installation in Windows.

in-plane switching (IPS): An active matrix LCD technology that holds liquid crystal cells horizontally between two glass layers. When electric current is applied, the cells rotate, allowing light and color to display on the screen.

input/output operations per second (IOPS): The standard way to measure the performance of hard disk drives (HDDs) and solid-state drives (SSDs) in a computer.

Integrated Drive Electronics (IDE): The interface that connects the motherboard to drives such as a CD-ROM/DVD or a hard drive.

Internet appliances: A single-purpose device used to perform specific tasks on an IP network.

Internet of Things (IoT): A catch-all term referring to devices that have embedded Internet communication capabilities. These devices include phones, cars, home appliances, door locks, wall outlets, lights, and video-enabled doorbells, among many others. IoT devices communicate data without human interaction.

Internet Protocol (IP) addressing scheme: Refers to the pattern of IP addresses for hosts on a local network or subnetworks.

iOS: The closed source mobile OS for Apple devices, used by iPod Touch, iPad, and iPhone devices.

IP: Internet Protocol; the common protocol for communications on networks and over the Internet.

IP addresses: Changeable, logical addresses that are assigned to devices for communicating outside their local networks.

IP filtering: Method of controlling which Internet Protocol (IP) traffic will be allowed into and out of your network.

iPadOS: Mobile OS developed by Apple for tablets.

ipconfig: Command that returns IP configurations on local network adapters (virtual and physical) on a computer.

IPv4: An IP version 4 (IPv4) address consists of a group of four numbers that each range from 0 to 255 (for example, 192.168.5.1).: An IP address is divided into two sections: the network portion, which is the number of the network the computer is on, and the host portion, which is the individual number of the computer.

IPv6: IP version 6 (IPv6) greatly increases the number of available IP addresses for computers, smartphones, and other mobile devices. IPv6 uses 128-bit source and destination IP addresses (compared to 32-bit addresses for IPv4), theoretically enabling up to 340 undecillion addresses (3.4×1038).



J

jailbreaking: “Breaking into” the root access of a phone to change settings or portability.

jitter: The presence of variations of a network’s latency, which can cause problems for end users on a network.

.js script files: JavaScript is a programming language that has many uses today. It is valuable for creating scripts because it can be run on any operating system. It is usually written into web pages to create client interactions; JavaScript is read by the browser. Creating and running command-line JavaScript requires installing Node.js.

K

Kerberos: An open standard authentication protocol that is used between two clients (or a client and a server) and a third-party Kerberos Key Distribution Center server.: The clients acquire a Kerberos key and can mutually authenticate across an unsecure network or the Internet.

keyboard: An alphanumeric data entry device with a typewriter-style keyboard and additional functional, numeric, directional, and text-editing keys. It connects via a USB or PS/2 keyboard port.: The keyboard also includes Fn keys for special functions.

Keychain: A macOS password-management system.

keylogger: A hardware device or software program (often a virus) that can track keystrokes and capture the usernames and passwords of unwitting users.

L

LAN: Local area network; a group of computers and other devices that are usually located in a small area such as a house, a small office, or a single building.

laser printer: A page printer that stores the entire contents of a page to be printed in its memory before printing it. By contrast, inkjet, thermal, and impact printers print a page as a series of narrow bands.

LDAP: Lightweight Directory Access Protocol; a protocol used to access and maintain distributed directories of information, such as the kind involved with Microsoft domains. LDAP uses port 389.

legacy software and operating systems: An outdated operating system, programming language, application, or hardware.

light-emitting diode (LED): status indicators LED lights that technicians use to evaluate a computer’s health at a glance. Computers, NICs, switches, routers, and other devices all use LEDs to visually communicate their activity status or problems with communication.

Lightning: The proprietary, reversible Apple iOS sync/charging USB 2.0 connector and port. It is used on older iOS devices.

Linux: An open-source operating system derived from the UNIX OS.

liquid crystal display (LCD): A flat-panel screen that applies electrical currents to a layer of liquid crystal cells to modulate its optical properties.

load balancer: Increases redundancy and performance by distributing the load to multiple servers. Network load balancers are often reverse proxy servers configured in a cluster to provide scalability and high availability.

Local Users and Groups (lusrmgr.msc): The lusrmgr.msc command opens the Local Users and Groups Manager on Windows 10/11 for user/group configuration.

long-range fixed wireless: A solution for providing Internet connectivity where physical access to an Internet service provider (ISP) is not possible, such as in rural areas. Fixed wireless providers send a signal from a wireless tower to customers who have a small antenna in their home or business.

loopback plug: A plug that routes output to input wires, to enable a port to be tested for proper send/receive functions. Loopback plugs are widely available for testing Ethernet ports as well as legacy COM and LPT ports. Some BIOS/UEFI and third-party vendors also offer USB loopback plugs.

Lucent connector (LC): A square connector type used in fiber-optic devices and cables.



M

M.2: A solid-state drive (SSD) that can mount directly onto a motherboard or an expansion card, giving the drive more direct access to the CPU, for much faster reading than with an SSD.

macOS: The operating system on Apple computers.

magnetometers: Another name for a metal detector, common in all airports and many public areas.

mail exchanger (MX) records: A DNS record that efficiently maps email addresses to the destination email servers.

mail servers: A server that sends or receives email.

malware: Malicious software; software designed to infiltrate a computer system and possibly damage it without the user’s knowledge or consent. Malware is a broad term that includes viruses, worms, Trojan horses, spyware, rootkits, adware, and other types of unwanted software.

MAN: Metropolitan area network; a type of network that results when a company has two offices in the same city and makes a high-speed connection between them.

man: Linux command to view the distribution’s manual (manpages).

managed switch: Switch that is common in corporate and enterprise networks. Managed switches also support SNMP, for diagnostics and performance measurement; virtual LANs (VLANs), to enable multiple workgroups to use the same physical switch but keep their traffic separate; and redundancy.

master boot record (MBR): Partition supported by BIOS/UEFI with boot settings.

material safety data sheet (MSDS): Also known as a safety data sheet (SDS), a document that provides information about a particular substance or device, such as the toner in a laser printer’s toner cartridge.

md: Windows command-line tool for making a directory, used for creating folders and subfolders.

metered connections/metered utilization Terms describing cloud services that are priced by the time or capacity used.: The client pays only for what is used.

metered utilization: A term describing cloud services that are priced by the time or capacity used.: The client pays only for what is used.

MicroATX (mATX): A smaller version (24cm × 24cm) of the ATX motherboard commonly used in mini tower computers.

Microsoft Management Console (MMC) snap-in: A blank console that uses various snap-in console windows.: The MMC saves the consoles you snap in and remembers the last place you were working, which makes it a valuable, time-saving tool.

Microsoft Remote Assistance (MSRA): The Windows utility for offering or accepting remote assistance.

micro-USB: Smallest of the USB connector types. This is the USB type for many non-Apple phones.

mini-USB: A Type B USB cable (USB 1). It is used in cameras, phones, and similar devices.

Mission Control: A visual setting in macOS that allows for simultaneous viewing of all open apps.

mobile application management (MAM): Software that enables an organization to manage software on devices across its enterprise network.

mobile device management (MDM): A way to manage the mobile devices within an enterprise—for example, to ensure that all mobile users on the network have updated security files.

modular power supply: A power supply that uses modular connections so that you can customize the power supply connections needed for your hardware.: An advantage of such a power supply is that the cables can detach from the power supply. Cable management also is much easier.

Molex: A four-pin power connector used for desktop PATA drives and some add-on cards. Molex connectors can be adapted to SATA drives, case fans, and Bern connectors (used for floppy drive power).

mSATA: A miniPCIe form factor used by some high-performance laptops and desktops.

multicore: A processor with two or more cores; some desktop processors have as many as eight cores.

multifactor authentication: A security system that uses two or more authentication methods and is far more secure than single-factor authentication.: An example is a person using a digital code from a fob and typing a username and password to gain access to a system.

multithreading: As CPUs developed and added cores, multithreading was developed as a method to allow multiple threads on each core. This works differently from hyperthreading because multithreading breaks each core into logically smaller CPUs to handle more sets of operating instructions, resulting in higher CPU performance.

mv: A Linux command used to move files to a specified location.



N

nano: A command-line text editor with keyboard shortcuts and functions for editing files.

near-field communication (NFC): A feature included in many mobile devices, such as tablets, for data transfer and shopping. When NFC is enabled and a suitable payment system (such as Apple Pay or Android Pay) is installed on a mobile device, it can be used for secure payments at any retailer that supports NFC payments.

net use: A Windows command that connects to shared folders; it works similarly to mapping a network drive.

net user: A Windows command used to manage user accounts (for adding, removing, or changing).

NetBIOS/NetBIOS over TCP/IP (NetBT): Also known as NetBT (RFC 1001), this protocol allows some legacy applications that were developed in the 1980s, before the TCP/IP environment had become the standard, to work on larger networks and the Internet. NetBIOS/NetBT uses ports 137–139.

netstat: A Windows command that displays a list of active TCP connections on a local network.

network tap: A device that is inserted into the network cable and makes an exact duplicate of network traffic, allowing network managers to “tap” into the data flowing through a network.

network topology diagram: A map of a network that shows how equipment is physically arranged in the building and logically connected as a network.

New Technology File System (NTFS): The native secure file system of Windows 10 and 11, as well as some previous versions.

NFC: Near-field communication; a feature included in many mobile devices such as tablets for data transfer and shopping. When NFC is enabled and a suitable payment system (such as Apple Pay or Android Pay) is installed on a mobile device, it can be used for secure payments at any retailer that supports NFC payments.

NIC: Network interface card; an interface on a computer (or other device) that connects to a LAN.

Non-Volatile Memory Express (NVMe): A protocol designed to allow solid-state drives (SSDs) to transfer data between the motherboard and the SSDs at staggeringly high rates.

nslookup: A Windows command that gathers a network’s Domain Name System (DNS) information.

NTFS: New Technology File System; the native secure file system of Windows 10.



O

on-demand: A characteristic of cloud computing in which users can purchase access to additional resources as needed.

on-path attack: Involves the attacker intercepting a connection while fooling the endpoints into thinking that they are communicating directly with each other.

open-source license: License for software that can be freely accessed, used, changed, and shared (in modified or unmodified form) by anyone.

optical drive: Drive that stores data in a continuous spiral of indentations called pits and lands that are burned into the nonlabel side of a disc from the middle outward to the edge. Optical drives use a laser to read the data.

optical network terminal (ONT): An optical network device similar to a modem in purpose: It connects the end user to the ISP, but because the communication is light pulses instead of electrical signals, no modulating/demodulating takes place. Therefore, an ONT is technically different than a modem.

organic LED (OLED): A type of display that uses organic compounds that emit light.



P

PaaS: Platform as a Service; a cloud computing category designed for developing and deploying apps.

PAN: Personal area network; a network that is larger than a LAN and smaller than a WAN.

partitioning: The process of creating separate portions on a hard disk. These can be assigned drive letters and can be bootable sectors.

patch panel: A box designed as a junction point for twisted pair (TP) cable and fiber cable used in networks.

pathping: Command-line command that returns latency data for the path across the network or Internet.

Performance Monitor (perfmon.msc): A Windows Computer Management node that enables the customized logging of system performance factors, including processor performance, memory transfers, and network performance.

Peripheral Component Interconnect (PCI) (1): A 32-bit I/O bus that provides a shared 33MHz or 66MHz data path between the CPU and peripheral controllers. (2) Payment Card Industry; standards that protect a cardholder’s data.

Peripheral Component Interconnect Express (PCIe): A high-speed set of serial bus communication channels used by adapter cards.

personal license: A software license provided for a computer purchased at a retail or online store, and for downloaded or packaged apps designed for use by individuals.

phishing: The process of creating bogus websites or sending fraudulent emails in an attempt to trick users into providing personal, bank, or credit card information.

pickup rollers: Printer component that picks up paper.

PII: Personally identifiable information; information such as a person’s name and social security number.

ping: A Windows command that sends IP packets to check network connectivity.

pinwheel: A macOS spinning icon that is caused by an application failing, but that can also indicate that the system is locked up and needs a hard reboot. It is also referred to as the “spinning rainbow” or “beachball of death.”

.pkg files: In macOS, these are compressed application files.

plenum: An air space in a building, such as HVAC ductwork or a suspended ceiling. Plenum cable, which produces very little smoke when burned, is required when a plenum is being used for cabling.

PoE: Power over Ethernet; a switch with added capability (a built-in end span) to send power out a port using Cat 5 or better grades of twisted pair cable.

pointing device: A general term for any mouse-type device.

POP3 Post Office Protocol version 3; an email protocol used by client computers to download or receive email. POP3 uses port 110.

port: A number or range of numbers assigned to a particular connection session or connection type.

port flapping Condition that occurs when the physical port on a device turns on and off intermittently, usually very rapidly.

port forwarding/mapping: A method of allowing inbound traffic on a particular TCP or UDP port or range to go to a particular IP address instead of to all devices on a network. It is used to forward external visitors through the router to a specific computer. Instead of opening up the entire LAN, port forwarding directs particular traffic where you want it to go.

port replicator: A device that allows a laptop to expand the number of ports so that additional devices can be attached.

PostScript: A printer driver that does not depend on the printer for processing the print job, so the printing might be slower than with PCL printers. However, the advantage is that the print jobs will be consistent, no matter where they are printed in the network.

power surges: Overvoltage events that last no more than 50ms and that can reach voltage levels as high as 6000V and 3000A.

power-on self-test (POST): beeps Sounds used by many BIOS versions to indicate either fatal or serious errors.

Preferred Roaming List (PRL): A database created by the mobile service provider that contains a priority list of radio frequencies and service provider IDs that the device needs to connect to the right tower in various geographical areas.

principle of least privilege: Giving a user access to only what is required to do his or her job.

print bed: With 3D printing, the platform on which the object is created.

print server: A device that manages the printing tasks for multiple users who share one or more printers in an office.

Printer Control Language (PCL): A common printer driver language used by many different printer companies that works with many different operating systems. PCL uses the printer hardware to process the print job data. This can take work off the computer and speed up the printing process; however, because the printer does the processing work, the print job output can vary, depending on the brand of printer.

private cloud computing: Use of a privately owned cloud that is accessible only to authorized users. Private cloud services are more secure than public cloud services.

product life cycle: Expected time for a product such as a CPU to be considered standard before it is replaced with a newer version.

protocol: A set of rules used to enable communication between network devices.

proxy server: A server that caches Internet page requests, enabling a single page to be viewed by all the devices requesting it.: A proxy server reduces outbound traffic to the Internet and can also be used for filtering content.

proxy settings: Specific settings for the types of content using a proxy server and its IP address and port numbers.

ps: A Linux command used to list current processes.

.ps1 script files: Windows PowerShell is a tool to help technicians and network administrators automate support functions through the use of scripts and snippets. Windows 10 and 11 ship with PowerShell.

public cloud computing: Use of cloud services provided over the public Internet.

punchdown tool: A tool that punches down the individual wires into the 110 IDC clips of an RJ-45 jack and a patch panel.

pwd: A Linux command used to display the name of the current/working directory.

.py script files: Python is often a good choice for those beginning to learn programming. It is relatively easy to learn, and Python scripts can run on most operating systems. For example, Windows Shell is known as Python Interactive Shell.



Q–R

quad-channel: A type of RAM designed to quadruple the speed of the RAM bandwidth using two sets of four sockets.

RAID Level 0 (RAID 0): A type of RAID in which two drives are treated as a single drive, with both drives used to simultaneously store different portions of the same file.

RAID Level 1 (RAID 1): A type of RAID in which two drives are treated as mirrors of each other; changes to the contents of one drive are immediately reflected on the other drive.

RAID Level 1+0 (RAID 10): A type of RAID in which four drives combine striping plus mirroring, for extra speed plus better reliability. RAID 10 is suitable for use with program and data drives. RAID 10 is a striped set of mirrors.

RAID Level 5 (RAID 5): A type of RAID in which three or more drives are treated as a logical array, and parity information (used to recover data in case a drive fails) is spread across all drives in the array. RAID 5 is suitable for use with program and data drives.

RAM: Random Access Memory; the main memory in a computer, where the operating system (OS), application programs, and data reside so that they can be quickly reached by the device's processor.

ransomware: A virus that takes over a computer or network until a ransom is paid.

rapid elasticity: A characteristic of cloud computing that refers to how quickly and easily more or fewer cloud resources can be used or set aside, as needed.

RDP: Remote Desktop Protocol; a protocol used by Remote Desktop Services (RDS), which is the Windows Server–based companion of Remote Desktop Connection. RDP uses port 3389.

read/write failure: A hard drive error caused by a failure to read data on the drive or write new data to the drive.

recovery mode: The mode of a computer (or other device) that provides access to core functions of the computer for repair or reset purposes after a system failure.

recovery partition: A space on the hard drive that holds the Windows Recovery Environment (WinRE) during a clean install.

Redundant Array of Independent (or Inexpensive) Disks: A method for creating a faster or safer single logical hard disk drive from two or more physical drives.

Registry Editor (regedit.exe): The Windows Registry Editor.

Remote Authentication Dial-In User Service (RADIUS): Software and a protocol that allows remote authentication via a central server.

Remote Desktop Protocol (RDP): A protocol used by Remote Desktop Services (RDS), which is the Windows Server–based companion of Remote Desktop Connection. RDP uses port 3389 and enables a user to securely connect to a remote computer in order to perform services or support another user.

Remote Disc: A feature that enables a macOS computer that lacks an optical disc drive to use another computer’s optical disc drive.

Remote Monitoring and Management (RMM): Tools that allow technicians to monitor and manage remote networks. This usually involves installing special tools called agents that collect data and report it back to the management team for data analysis.

remote network installation: Installing software via a network connection instead of a physical disk.

remote wipes: A program that can be initiated from a desktop computer to delete all the contents of a remote mobile device that has been lost or stolen.

repair installation: A Windows installation option in which the OS is installed over the same version to fix problems with the previous installation. It is also known as an in-place upgrade.

resin: The liquid medium in 3D printers that is heated and fused to form thin layers of plastic to print an object.

Resource Monitor (resmon.exe): Utility that tracks CPU usage and performance.

RFID: Radio-frequency identification; a technology that consists of an RFID tag that can broadcast information about an item, plus an RFID reader to accept the broadcast information and deliver it to a computer system for use.

risk analysis: A method of identifying risks to a network performed using either qualitative or quantitative analysis methods, with the end goal being a plan to mitigate the impact of risks.

RJ-11: A standard phone jack.

RJ-45: Registered jack function 45; the most common Ethernet cable, which connects network interface cards on PCs to network switches and SOHO routers.

rm: A Linux command used to remove (delete) files from a system.

rmdir Command-line command that removes a directory and the subdirectories within it.

robocopy: A Windows command that is used as a highly configurable file/folder copy-and-move app. It can be configured with various optional GUIs.

rollback plan: A document that lets the change administrators restore the network to the service level that was present before the change.

root access: Accessing root files of an OS to change settings or allow portability between cell providers.

rootkit: A set of hacking tools that finds its way deep into a computer’s operating system or applications and sets up shop to take over the computer.

router: A device that routes data from one network to another. It is often integrated with wireless access points and switches.



S

SaaS: Software as a Service; software programs that can be run from the cloud without downloading an app. Examples include Google Docs, Microsoft Word Online, and Excel Online.

Safe Mode: A mode that loads minimal Windows features, such as low-­resolution graphics and minimal networking. It is helpful in troubleshooting Windows features.

Samba: A utility that allows Linux to operate in a Windows environment.

sandboxing: Creating an isolated machine (or network of machines) where experiments can be run or software can be securely tested without risk to machines on the production network.

SATA (Serial Advanced Technology Attachment): A version of ATA that uses thin data and power cables to transmit data serially at rates of 1.5Gbps, 3.0Gbps, 6.0Gbps, and 16Gbps (SATA Express).

satellite: An Internet provider option that uses dish antennas similar to satellite TV antennas to receive and transmit signals between geosynchronous satellites and computers.

screened subnet Formerly known by CompTIA as a demilitarized zone (DMZ).: A screened subnet allows outside traffic through to a particular IP address on a LAN.

Secure Boot: A setting that blocks the installation of untrusted software during the boot process.

Secure Shell (SSH): A protocol that allows data to be exchanged between computers on a secured channel. SSH is a more secure replacement for FTP and Telnet.

Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T.): A technology that monitors internal hard disks and warns of impending failure.

Sender Policy Framework (SPF): A tool that lets domain owners list the IP addresses that are authorized to send mail, to control spam.

serial: A serial communication physical interface (also known as a COM port) through which information transfers in or out 1 bit at a time.: The RS-232 standard is commonly used to transmit data through DB-9 ports.

sfc: A Windows command that scans system files and replaces damaged or missing files.

.sh script files: A shell script is a text file that contains a sequence of commands for a Linux- or UNIX-based system. Shell scripts might not run correctly on a Windows system. Linux has had several shells; BASH (Bourne-Again Shell) is the most common of them.

share permissions: A set of rules that determine a user’s level of access to a file or folder.

shared resources: Resources such as data files and devices that can be used by multiple users in a cloud environment.

Shell: A macOS or Linux command-line environment.

shielded twisted pair: Ethernet cable with added shielding to protect against electromagnetic interference.

shoulder surfing: Attempting to view physical documents on a user’s desk or electronic documents displayed on a monitor by looking over the user’s shoulder.

shutdown: A Windows command that shuts down a computer.

single channel: A single RAM slot on an earlier motherboard.

single core: An early CPU with only a single processing thread running.

single sign-on (SSO): The use of a single password to authenticate multiple apps in an organization that require authentication.

Small Computer System Interface (SCSI): A flexible interface that can be used for hard drives and optical drives, scanners, and other devices. Narrow SCSI interfaces enable the daisy chaining of seven devices to a single port. Wide SCSI enables the daisy chaining of up to 15 devices to a single port.

Small Outline Dual Inline Memory Module (SODIMM): A compact version of the standard DIMM module, available in various pinouts for use in notebook and laptop computers and laser printers.

smart card: A credit card–size card that contains stored information and might also contain a simple microprocessor or an RFID chip.

SMB: Server Message Block; a protocol that provides access to shared items such as files and printers. SMB uses ports 137–139 for SMB traffic using NetBIOS over TCP (NetBT) and port 445 for SMB hosted on TCP.

SMTP: Simple Mail Transfer Protocol; a protocol that is used to send email from a client system to an email server, which also uses SMTP to relay the message to the receiving email server. SMTP uses port 25.

SNMP: Simple Network Management Protocol; a protocol that is used as the standard for managing and monitoring devices on a network. SNMP uses ports 161 and 162.

social engineering: A type of attack in which hackers trick users into providing passwords or other sensitive information.

soft token: Part of a multifactor authentication process. Software (soft) tokens exist in software and are commonly stored on devices.

software-defined networking (SDN): A network in which a virtual layer created in software controls the data flow over the physical network devices.

software firewalls: A program that examines data packets on a network to determine whether to forward them to their destination or block them.

solid-state drive (SSD): A hard drive that uses flash memory instead of magnetic storage platters.

spam gateways: Email filters that can detect almost all spam coming into a system, which increases email efficiency and network security as well.

splash screens: Display of logos or policies that “welcome” a user at startup or login. These might come with a checkbox requiring the acknowledgment of rules before the user can access the company resources.

spoofing: A general term for malware attacks that purport to come from a trustworthy source. Phishing, spear phishing, and rogue antivirus programs are three examples of spoofing.

Spotlight: A macOS search tool.

spyware: Software that spies on system activities and transmits the details of web searches or other activities to remote computers.

SSH Secure Shell: a protocol that allows data to be exchanged between computers on a secured channel. It is a more secure replacement for FTP and Telnet. SSH uses port 22.

static IP addresses: Assigned to a device by the administrator and not subject to change until reconfigured by the administrator.

static wide area network (WAN) IP Provided by the ISP and applied (usually automatically) to the “Internet” port on the router.: The address is “static” because it does not change and does not expire like a leased dynamic address.

storage area network (SAN): A special network made of computers storing vast amounts of information in blocks of data.: The SAN storage servers reside in data centers both near and far; to the user, however, it can appear to be attached to the local computer.

straight tip (ST): A round connector type used in fiber-optic devices and cables.

Structured Query Language (SQL) injection: Malicious code inserted into strings that are later passed to a database server.

su: A Linux command used to switch between accounts.

subnet mask: An IPv4 network-addressing feature used to specify how much of an IP address is the host address and what part is the extended network address.

subscriber connector (SC): A square connector type used in fiber-optic devices and cables.

sudo: A Linux command used to run a command as another user.

supervisory control and data acquisition (SCADA): SCADA systems are designed to provide centralized control to manage industrial equipment, such as in manufacturing or water and waste treatment plants.

switch: A network device that sets a direct path for data to run from one system to another; it can be combined with a router or a wireless access point.: A switch is faster than a hub because it supports the full bandwidth of the network at each port instead of subdividing the bandwidth among active ports, as a hub does.

synthetic backup These backups are similar to full backups, except they are actually reconstructed in software from a full backup in the past and modified with the incremental backups that have occurred since the full backup.: The benefit is reduced storage needs for backup data.

syslog server: A server that tracks events, such as user logins and crashes, that happen on devices on a network.

System Configuration (msconfig.exe): The MSConfig utility in Windows, which configures startup, boot settings, services, and startup apps, and also provides access to tools.

System Information (msinfo32.exe): The Microsoft System Information utility, which displays information about Windows, the computer, peripherals, and installed applications.

System Restore: A Windows feature that enables a system to be returned to a previous condition using restore points.



T

T568A: A TP wiring standard that uses the following wires from pins 1 to 8: green stripe, green, orange stripe, blue, blue stripe, orange, brown stripe, brown.

T568B: A TP wiring standard that uses the following wires from pins 1 to 8: orange stripe, orange, green stripe, blue, blue stripe, green, brown stripe, brown.

tailgating: A process in which an unauthorized person attempts to accompany an authorized person into a secure area by following closely and grabbing the door before it shuts.

Task Manager: A utility that provides a useful real-time look into the inner workings of Windows and the programs that are running.

Task Scheduler (taskschd.msc): A Windows utility used to run a task on a specified schedule.

Telnet: A protocol that enables a user to make a text-based connection to a remote computer or networking device and then use it as if he or she were a regular user sitting in front of it instead of simply downloading pages and files as the user would with an http:// or ftp:// connection. Telnet uses port 23.

Temporal Key Integrity Protocol (TKIP): An encryption protocol for wireless LANs. TKIP replaced WEP, which had security vulnerabilities.

Terminal: A command-line environment available in macOS, Linux, and Windows for managing computer settings and files.

Terminal Access Controller Access-Control System Plus (TACACS+): An authentication protocol that allows a remote access server to verify a user by communicating with an authentication server.

test development: The process of testing software in various ways to see how the code runs and operates.

tethering: The sharing of a cellular data connection from a smartphone to a laptop, tablet, or other device.

text (TXT) records: Records that enable administrators to enter common text explanations into DNS, usually describing domain ownership or other information. TXT records are also used to counter email spam.

thermal paste/pads Adhesive used to reapply a heat sink, typically applied with a syringe.

thermal printer: A printer that uses heat transfer to create text and graphics on the paper.

Third Extended Filesystem (ext3): Linux feature that journals changes to minimize damage in case of a system failure.

Thunderbolt: A high-speed interface capable of supporting hard disk drives, SSDs, HDTVs up to 4K resolution, and other types of I/O devices.

ticketing systems: A system that enables technical processes to run smoothly and helps the clients, whether customers or coworkers, feel that their needs were addressed and their problems were resolved in a professional manner.

Time Machine: The macOS backup app.

toner probe: A reliable communication protocol that ensures reliable delivery of data to the destination computer.

top: A Linux command that provides summary information on resource use for tasks and processes in the form of a dashboard.

tracert: A Windows command that is similar to ping but returns path information to an IP address destination. traceroute is a similar command used in macOS and Linux.

tractor feed: A printer mechanism used to pull or push the paper past the print head.

transfer belt/roller: A printer component that transfers a page image from the drum to the page.

Transmission Control Protocol (TCP): A communication protocol that is considered reliable; the delivery of network packets to the destination computer is guaranteed.

triple channel: A motherboard technique used to triple RAM speed.

Trivia File Transfer Protocol (TFTP): A protocol used for transporting file packets that do not need a response.

Trojan: A malware program disguised as a “gift” (such as a popular video or website link), to trick the user into downloading the virus.

Trusted Platform Module (TPM): A chip residing on a motherboard that stores encrypted keys.

twisted nematic (TN): An LCD screen technology that uses nematic liquid crystal cells between two glass layers that align in a twisted form when no electric current is applied.

two-factor authentication: An authentication method that requires the user to provide two different forms of verification. Most forms of two-factor authentication are based on something the user knows and something the user possesses, such as a password and a biometric scan or security token.



U

UDP: User Datagram Protocol; a communication protocol that is considered unreliable and does not guarantee delivery of network packets of information to the destination computer.

Universal Plug and Play (UPnP): Designed to allow devices on a home or SOHO local area network (LAN) to easily connect and cooperate with other devices on the LAN.

unmanaged switch: Low-cost switches used in small office/home office (SOHO) networks that cannot be configured to perform complex switching functions.

unshielded twisted pair: Ethernet cables with four pairs of twisted wires inside a sheath.

USB 2.0: Universal Serial Bus version 2; a version of USB with a peak speed of 480Mbps that is compatible with USB 1.

USB 3.0: Universal Serial Bus version 2; it works at 5Gbps. This version of USB supports older USB devices at the native speeds of those devices.

USB-C: The newest reversible USB connector; it should replace other USB types.

User Account Control (UAC) Allows the end user to select a level of notifications concerning changes being made to the computer.: The purpose of this tool is to prevent unauthorized changes to the computer.

UTM: Unified threat management; a device that provides firewall, remote access, and virtual private network (VPN) support, as well as web traffic filtering with anti-malware software and network intrusion prevention.



V

.vbs script: files VBScript, a scripting language developed by Microsoft, is considered a subset of the Visual Basic programming language. It was designed specifically for use with Microsoft Internet Explorer and gives web pages a level of interactivity.

Vertical Alignment (VA): An LCD screen technology that holds liquid crystal cells between two glass layers and aligns them vertically when no electric current is applied.

Video Graphics Array (VGA): The first popular analog video standard, and the basis for all current video cards.

video random access memory (VRAM) RAM dedicated to processing graphic displays.

Virtual desktop infrastructure (VDI) IT infrastructure that allows organizations to offer users remote access to enterprise computer systems.

virtual network computing (VNC): A common desktop support model that allows a support agent to remotely control mouse and keyboard inputs to a client’s computer.

virtual private network (VPN): A private and secure network connection that is carried by an insecure public network, such as the Internet.

virtual RAM: Virtual memory, also known as the paging file, that uses part of the hard drive to expand the RAM. This allows users to run more apps than the RAM could otherwise handle.

virus: A generic term for any malicious software that can spread to other computers and cause trouble.

vishing: Involves leaving deceptive voice messages that appear to come from an internal source or other authority. These messages request providing confidential information, such as payroll or tax information.

VLAN Virtual local area network; a grouping of some computers on a local area network (LAN) that are configured to behave as if they have their own separate LAN.: A VLAN allows users to create an encrypted connection to their home or business network via the Internet when accessing the network remotely.

VPN: A private and secure network connection that is carried by an insecure public network, such as the Internet.



W

WAN Wide area network: A group of one or more LANs over a large geographic area.

wattage rating: A power measurement used to determine the appropriate size of a UPS or a power supply. It is also used to measure the thermal design power of a CPU so that an adequate cooling solution can be used.

web server: A specialized computer that hosts websites and provides various types of content to clients via the Internet.: A web server uses HTTPS to communicate with computers on other networks that are requesting information.

whaling: A specific type of phishing attack that goes after high-level employees (the big fish, or whale) in an organization, especially the CEO.

Wi-Fi analyzer: A device or app that detects Wi-Fi signals and determines signal strength.

Wi-Fi Protected Access 2 (WPA2): Released in 2004 and uses Advanced Encryption Standard (AES) encryption. WPA2’s AES encryption is much stronger than the previous version.

Windows: The commercial OS from Microsoft; currently, Windows versions 10 and 11 are in use.

Windows Defender: Firewall Windows built-in network security program.

winver: A text command that displays the version of Windows OS.

wireless card: A Wi-Fi adapter or a USB-based wireless adapter.

wireless Internet service provider (WISP): An Internet service provider that offers Internet access through a wireless connection to customers in areas where other options are unavailable.

wireless wide area network (WWAN): A wireless network based on cellular connections.: A WWAN requires a SIM card activated by the mobile provider.

WLAN: A network made up of wireless computers and other devices communicating via wireless transmissions, not cables and wires.: A common type of WLAN is a Wi-Fi network in a home or office.: A group of network access points that make up the WLAN can be configured to work together and can be managed with a specialized device called a WLAN controller.

WLAN controller: A configurable device used to manage connectivity between devices in a WLAN.

workgroup: A network that does not use a domain controller. Each computer can share or not share folders or printers with others. Unless password-protected sharing is disabled, anyone who wants to use a different computer’s resources must have an account on that system.

WPA3: Released in January 2018, uses 128-bit encryption (192-bit in an enterprise version), and has a different method for sharing security keys than the other types of encryption. WPA3 is designed to add better privacy and protection against attacks on public Wi-Fi networks.



X–Z

xcopy: A Windows command that copies one or more files and folders to another folder or drive.

yum: An open-source utility for automatic updates and package management in Linux.

zero-day attack: ​​​​​​​ Attack in which hackers exploit software vulnerabilities discovered as a result of notifications put out by users of that software before the company has a chance to create a security patch.