CompTIA Tech+ (FC0-U71) flashcards

Global variables within an operating system that define the environment in which processes run, affecting all users and persisting across system reboots.

• Accessible via 'System Properties > Advanced > Environment Variables' in Windows.
• Used for paths, temporary directories, and other system-wide settings.
• Distinct from user-specific environment variables.

Memory trick: Think of variables as global or local settings for your computer's world.

The primary file system for Windows operating systems, supporting large files, security permissions, journaling, and compression.

• Default for Windows OS drives.
• Supports advanced security features like access control lists (ACLs).
• Includes journaling for data recovery and integrity.
• Supports very large file and partition sizes.

Memory trick: Windows uses NTFS for its core, keeping data secure and more.

Specific 2.4 GHz Wi-Fi channels (1, 6, and 11 in North America) that do not overlap in frequency, allowing multiple access points to operate in proximity without causing significant interference to each other.

• Each 2.4 GHz Wi-Fi channel is 22 MHz wide but spaced 5 MHz apart.
• Using non-overlapping channels prevents co-channel interference.
• Crucial for effective multi-AP deployments in dense environments.

Memory trick: One, Six, Eleven: No Overlap, Heaven!

A compact memory module form factor used in laptops and small-form-factor devices, smaller than desktop DIMM modules.

• Roughly half the length of a DIMM
• Used in laptops, mini PCs, printers
• Not interchangeable with desktop DIMM slots

Memory trick: SODIMM is DIMM's 'So' Small cousin for laptops.

Data-driven decision making is the practice of basing business or operational decisions on the analysis of collected data, such as trends, reports, and dashboards, rather than intuition alone.

• Relies on reports, dashboards, and trend analysis
• Improves accuracy of business decisions
• Common tools: dashboards, KPIs, data visualizations

Memory trick: Data-Driven = 'Drive' decisions using the Data as the steering wheel

The process by which a wireless access point periodically sends out beacons containing its network name (SSID) to allow devices to discover it.

• Enabled by default for easy network discovery.
• Can be disabled for a minor security obscurity measure.
• Hiding SSID does not prevent determined attackers from finding the network.

Memory trick: Hide the name, filter the MAC, encrypt the data, don't turn back.

A nested RAID level that combines RAID 1 (mirroring) for data redundancy with RAID 0 (striping) for performance, offering high read/write speeds and excellent fault tolerance.

• Requires a minimum of 4 drives (even number, 2+ pairs).
• Data is striped across mirrored pairs.
• Provides high performance for both reads and writes.
• Can tolerate multiple drive failures, as long as they are not within the same mirrored pair.

Memory trick: RAID 10: Mirrored speed, striped safety, a database's delight.

A base-16 number system commonly used in computing, often prefixed with '0x' to distinguish it from decimal.

• Uses digits 0-9 and letters A-F to represent values 10-15.
• Each hexadecimal digit corresponds to four binary bits.
• Provides a more compact representation of binary data than decimal or binary itself.

Memory trick: Prefixes Point to the Base!

A digital display interface that carries video and audio and supports connecting multiple monitors via Multi-Stream Transport.

• Supports video and audio in one cable
• Allows daisy-chaining multiple displays
• Common on modern laptops and monitors

Memory trick: 'Display' Port displays it all: video, audio, and daisy-chains.

An incremental backup captures only the data that has changed since the most recent backup of any type (full or incremental), making it faster but requiring the full chain to restore.

• Backs up changes since the LAST backup (any type)
• Faster and smaller than full backups
• Requires full backup plus every incremental since to restore

Memory trick: Incremental = 'Since the Immediately-preceding' backup

An instance of a class, representing a real-world entity or concept. It encapsulates data (attributes/properties) and behaviors (methods/functions) into a single, self-contained unit.

• Bundles data and behavior.
• Instance of a class.
• Represents a real-world entity.

Memory trick: An 'object' is like a 'thing' with properties and actions.

IaaS provides raw infrastructure, PaaS provides a managed platform for app development, and SaaS delivers complete ready-to-use software.

• IaaS: e.g., virtual machines, storage
• PaaS: e.g., app development platforms
• SaaS: e.g., email, office suites
• Responsibility for management decreases from IaaS to SaaS

Memory trick: IaaS = build your own house; PaaS = rent a furnished workshop; SaaS = order takeout.

The WHERE clause in SQL filters query results to only include rows that meet a specified condition.

• Used with SELECT, UPDATE, DELETE statements
• Filters based on column value conditions
• Different from ORDER BY (sorting) and GROUP BY (aggregating)

Memory trick: WHERE = 'Where does this row belong?' filter

A SQL operation that combines rows from two or more tables based on a related column between them.

• Common type is an INNER JOIN, which returns only matching rows from both tables.
• Requires a shared column, often a foreign key referencing a primary key.
• Allows queries to pull related data spread across multiple normalized tables.

Memory trick: JOIN is a zipper connecting two rows of teeth (tables) that match up.

Aggregate functions like COUNT(), SUM(), and AVG() calculate a single value from a group of rows, and GROUP BY organizes rows into those groups based on a shared column value.

• COUNT(*) counts the number of rows in each group
• GROUP BY must include the non-aggregated columns being selected
• Common aggregates: COUNT, SUM, AVG, MIN, MAX

Memory trick: GROUP BY sorts customers into buckets, COUNT tallies each bucket.

A mechanical or logical malfunction of a hard disk drive, often indicated by unusual noises, data corruption, or inability to boot.

• HDDs contain spinning platters and moving read/write heads.
• Grinding, clicking, or whirring noises are common signs of impending or active mechanical failure.
• Can lead to data loss and operating system boot issues.

Memory trick: Noisy drives mean data strives.

A database table is organized into fields (columns) and records (rows). Each record represents one complete entry, and each field represents one attribute of that entry.

• Field = column = single attribute (e.g., Email)
• Record = row = one complete entity's data
• Table = collection of related records

Memory trick: Rows are Records, Columns are Categories (fields)

A trial-and-error method used to obtain information such as user passwords or encryption keys by systematically trying all possible combinations.

• Involves guessing credentials.
• Generates many failed login attempts.
• Can be time-consuming but effective against weak passwords.

Memory trick: Many failed keys mean a 'brute' is trying to force their way in.

Online storage services that provide robust security features, including data encryption in transit and at rest, access controls, and often compliance certifications, suitable for sharing sensitive or large files.

• Encrypts data during upload/download (in transit) and while stored (at rest).
• Allows controlled sharing with specific users or groups.
• Scalable for large files and long-term retention.

Memory trick: Sending big, secret files needs a strong, digital vault.

Standardized port numbers (0-1023) assigned to common network services by the Internet Assigned Numbers Authority (IANA).

• Facilitate communication between clients and servers.
• Help identify the application protocol being used.
• Examples: HTTP (80), HTTPS (443), FTP (20, 21), SSH (22).

Memory trick: 22 is SSH, secure and free.

A small form-factor solid-state drive that uses the NVMe protocol over the PCIe bus for very high-speed data transfer.

• Much faster than SATA SSDs due to direct PCIe connection
• Common in thin laptops and modern desktops
• M.2 slots can support either SATA or NVMe protocols, so compatibility must be checked

Memory trick: NVMe = 'No Vast Middleman here' — data goes straight to PCIe.

The latest and most secure encryption protocol for wireless networks, providing enhanced security features over its predecessors.

• Uses 128-bit or 192-bit cryptographic algorithms.
• Provides stronger protection against brute-force attacks (SAE).
• Offers individualized data encryption in public Wi-Fi (Enhanced Open).

Memory trick: WEP, WPA, WPA2, WPA3: Stronger with each iteration.

A collection of pre-compiled code, resources, and tools that provide common functionalities required by applications during their execution.

• Applications rely on them to perform common tasks.
• Examples: Visual C++ Redistributable, .NET Framework, Java Runtime Environment (JRE).
• Ensures consistency and reusability of code.
• Must be installed for dependent applications to run.

Memory trick: Runtime libraries are the building blocks apps need to run and thrive.

A special marker in a database used to indicate that a field's data is missing, unknown, or not applicable.

• NULL is different from zero or an empty string, both of which are actual values.
• Comparisons with NULL require special operators like IS NULL rather than equals.
• Primary key columns typically cannot contain NULL values.

Memory trick: NULL is an empty mailbox, not a letter that says 'nothing.'

A memory management technique where a portion of a storage device (like a hard drive) is used as an extension of physical RAM. When RAM is full, less frequently used data is moved to virtual memory (swapped out) to free up RAM.

• Extends usable memory beyond physical RAM limits.
• Slower than physical RAM.
• Excessive use (thrashing) leads to significant performance degradation.

Memory trick: RAM's low, disk goes flow, that's where the slowness grows.

A backup method that copies all selected data in its entirety every time it is performed.

• Simplest to restore from since only one backup set is needed.
• Requires the most storage space and time to complete.
• Often used as the baseline before incremental or differential backups.

Memory trick: Full backup packs everything every single time, like repacking your entire suitcase.

A Set is an unordered collection of unique elements. It is commonly used when membership testing, removing duplicates, and mathematical set operations (union, intersection, difference) are desired.

• Stores only unique elements
• Elements are unordered
• Supports fast membership testing

Memory trick: Unique items, think 'Set' them apart!

A USB standard capable of up to 10 Gbps data transfer, typically implemented via USB-C connectors.

• USB 2.0 = 480 Mbps
• USB 3.2 Gen 1 = 5 Gbps
• USB 3.2 Gen 2 = 10 Gbps
• Often uses USB-C connector shape

Memory trick: Higher the Gen number, faster the data train.

A data structure consisting of a collection of elements (values or variables), each identified by at least one array index or key. Arrays store multiple items of the same or different data types.

• Stores multiple items in a single structure.
• Elements are typically accessed via an index (e.g., 0, 1, 2).
• Useful for lists, collections, and sequences of data.

Memory trick: An 'array' of items is like an 'array' of boxes in a row.

The primary component of a computer that executes instructions and performs arithmetic/logical operations.

• Installed in a dedicated socket on the motherboard
• Speed measured in GHz (clock speed)
• Often paired with a cooling solution due to heat generation

Memory trick: CPU is the 'brain' that thinks for the whole machine.

A network cable that transmits data using light pulses through glass or plastic strands, offering high bandwidth, long distance capabilities, and immunity to electromagnetic interference.

• Immune to EMI and RFI.
• Supports much longer distances than copper cables.
• Provides significantly higher bandwidth.
• More expensive and delicate to install than copper.

Memory trick: Fiber flies, copper crawls, light laughs at EMI walls.

A macOS utility that displays information about processes running on the system, including CPU, memory, energy, disk, and network usage.

• Analogous to Windows Task Manager.
• Helps identify resource-intensive applications.
• Allows termination of unresponsive processes.
• Provides real-time system performance data.

Memory trick: Activity Monitor shows the Mac's busy activities and helps find the culprits.

The principle that ensures data and systems are accurate, complete, and protected from unauthorized modification or destruction.

• Prevents unauthorized changes to data.
• Ensures data consistency and trustworthiness.
• Achieved through hashing, access controls, backups, and patching.

Memory trick: CIA: Confidentiality is private, Integrity is true, Availability is always there.

Keeping a copy of backup data in a physically separate location or in the cloud to protect against site-wide disasters like fire, flood, or theft.

• Protects data even if the primary site is destroyed
• Often implemented via cloud storage or a remote data center
• A key component of the 3-2-1 backup rule

Memory trick: Don't keep all your eggs in one building — send a copy to the cloud.

A model of computer data storage in which digital data is stored in logical pools, on physical storage servers in data centers, managed by a hosting provider.

• Frees up local device storage.
• Provides accessibility from multiple devices and locations.
• Offers scalability and often data redundancy.

Memory trick: To clear disk space without losing files, think outside the local box.

A router function that translates private internal IP addresses into a single public IP address for internet communication.

• Commonly performed by home and small office routers
• Allows many private-network devices to share one public IP
• Helps conserve limited public IPv4 addresses

Memory trick: NAT = 'Neighborhood Address Translator' — many houses, one street sign.

A control flow statement that allows code to be executed repeatedly based on a given Boolean condition. The loop continues as long as the condition evaluates to true.

• Repeats code block as long as a condition is true.
• Number of iterations can be unknown beforehand.
• Condition is checked before each iteration.

Memory trick: While you 'wait' for a condition, the loop 'runs'.

An object (or struct) is a composite data type that bundles data (attributes or properties) and/or methods (functions) into a single unit. It represents a real-world entity or concept within a program.

• Encapsulates related data
• Can include functions (methods)
• Provides a blueprint (class) for creating instances

Memory trick: To group data into one, make an Object, it's done!

A hierarchical naming system that translates human-readable domain names into IP addresses.

• Acts like the internet's phone book
• Uses DNS servers to resolve names
• Port 53 for DNS queries
• Works with caching to speed resolution

Memory trick: DNS is the internet's phonebook, translating names to numbers.

A specialized operating system designed for thin client devices, focusing on minimal local resources, network-centric operation, and efficient remote access to applications and virtual desktops.

• Small footprint and low resource consumption.
• Enhanced security due to reduced attack surface and no local data storage.
• Centralized management and deployment.

Memory trick: Choose the OS brain that fits the computer's body and task.

A relationship where multiple records in one table can relate to multiple records in another table, resolved using a junction (associative) table.

• Cannot be modeled with a simple foreign key on one side
• Requires a junction table with foreign keys to both parent tables
• The junction table's combined foreign keys often form a composite primary key

Memory trick: Many-to-many needs a middleman table to link both sides.

A feature in programming languages that allows a function to accept an unspecified or arbitrary number of arguments. These arguments are typically collected into a data structure like a tuple or array within the function.

• Allows flexible function signatures
• Useful for functions like 'sum' or 'print'
• Syntax varies by language (e.g., *args, ...rest)

Memory trick: Unknown number of args? Use a Variable list!

Wi-Fi Protected Access 3, the latest security standard for wireless networks, offering enhanced encryption and authentication protocols.

• Successor to WPA2
• Improved security for public Wi-Fi (Opportunistic Wireless Encryption)
• Enhanced protection against brute-force attacks

Memory trick: Wireless security evolves, WPA3 leads the way.

Relational databases use structured tables with fixed schemas and SQL; non-relational (NoSQL) databases use flexible formats like documents, key-value pairs, or graphs.

• Relational = tables, rows, columns, fixed schema
• NoSQL = flexible schema, good for unstructured/varied data
• Examples: MySQL (relational), MongoDB (NoSQL document)

Memory trick: Relational = Rigid rows; NoSQL = No-fixed Shape

An informal high-level description of the operating principle of a computer program or other algorithm. It uses natural language and common programming constructs to outline logic, without strict syntax rules.

• High-level, informal description.
• Uses natural language and programming constructs.
• Focuses on logic, not syntax.

Memory trick: Pseudocode: 'Pseudo' means 'almost', so it's 'almost code'.

A base-16 number system that uses 16 distinct symbols: 0-9 and A-F, which represent decimal values 10-15.

• Often used in computing to represent binary data concisely.
• One hexadecimal digit represents four binary digits (a nibble).
• Prefixes like 0x or suffixes like h are used to denote hexadecimal numbers.

Memory trick: Binary two, Octal eight, Decimal ten, Hex sixteen, don't be late!

A self-contained block of code designed to perform a specific task. Functions can take inputs (arguments/parameters) and may return a value. They promote code reusability and modularity.

• Reusable block of code.
• Performs a specific task.
• Can take input and return output.

Memory trick: Functions are 'fun' because you can 'call' them again and again.

A command-line utility in Linux that provides a dynamic real-time view of a running system, including process activity, CPU usage, and memory consumption.

• Displays processes ranked by CPU usage by default.
• Shows total CPU and memory statistics.
• Interactive; allows sorting and killing processes.
• Essential for troubleshooting system performance bottlenecks.

Memory trick: 'top' shows you the 'top' hungry processes.

A cloud deployment model that combines private and public cloud resources, allowing data and applications to be shared between them.

• Combines private (dedicated) and public (shared) clouds
• Allows sensitive workloads to stay private
• Provides scalability of public cloud when needed

Memory trick: Hybrid cloud is a 'mix tape' blending private security with public scale.

The newer Internet Protocol version using 128-bit addresses, vastly increasing available unique addresses compared to IPv4's 32-bit scheme.

• 128-bit address length (vs IPv4's 32-bit)
• Written in hexadecimal, separated by colons
• Provides approximately 3.4x10^38 addresses

Memory trick: IPv6 = 'six' times bigger jump, from 32-bit to 128-bit addresses.

Reserved IP address blocks not routed on the public internet, used for internal networks.

• 10.0.0.0/8
• 172.16.0.0/12 (172.16.0.0-172.31.255.255)
• 192.168.0.0/16
• Require NAT to reach the internet

Memory trick: Think '10-172-192' as the private club membership numbers.

Instructions that dictate which network traffic is allowed or denied based on criteria such as source/destination IP, port number, and protocol.

• Define network security policies.
• Can be inbound (traffic entering) or outbound (traffic leaving).
• Specific rules are prioritized and processed sequentially.
• Principle of least privilege applies: only allow what is necessary.

Memory trick: Firewall rules are like a bouncer at a club: only specific, approved guests get in.

The process of securing a system by reducing its attack surface, eliminating unnecessary functionalities, and applying security best practices.

• Reduces vulnerabilities
• Involves disabling unused services/ports
• Includes changing default credentials and updating firmware

Memory trick: Best practices make systems strong and secure.

Branching, or conditional statements, are control structures that allow a program to execute different blocks of code based on whether specific conditions are true or false. Common examples include if-else statements and switch-case statements.

• Alters program flow based on conditions
• Uses keywords like 'if', 'else if', 'else', 'switch', 'case'
• Essential for decision-making in programs

Memory trick: Conditions met? Branch off and go!

A foreign key is a column in one table that references the primary key of another table, creating a relationship between the tables.

• Links two tables together
• Value matches a primary key elsewhere
• Enables relational integrity between tables

Memory trick: Foreign Key = a Foreign visitor pointing back home (to the primary key)

The process of organizing database tables to minimize data redundancy and prevent update anomalies, typically by splitting data into related tables.

• Repeated customer or product data across many rows is a sign a table needs normalization.
• Related data is separated into its own table and linked via foreign keys.
• Reduces the risk of inconsistent data when a value changes in only some rows.

Memory trick: Normalization is decluttering a messy junk drawer into labeled organized bins.

Data refers to raw, unorganized facts, figures, or symbols, while information is data that has been processed, organized, and structured to provide meaning and context.

• Data is raw, information is refined.
• Data lacks inherent meaning, information has meaning.
• Information is derived from data.

Memory trick: Data is raw, Info is true, processed for me and you.

Small software modules that customize or enhance the functionality of a web browser, but can also be malicious.

• Extend browser capabilities.
• Can access browser data and modify web content.
• Malicious extensions can lead to hijacking, data theft, and performance issues.

Memory trick: Extensions extend, but can also entangle your browser's intentions.

A relationship type where one record in a table can relate to multiple records in another table, but each of those records relates back to only one record in the first table.

• Most common relationship type in relational databases
• Implemented by placing a foreign key in the 'many' side table
• Example: one customer can place many orders

Memory trick: One teacher, many classes — the foreign key lives on the many side.

A mapping within an operating system that links a specific file extension (e.g., .docx) to the application designed to open or handle that file type.

• Defines which program launches when a file is double-clicked.
• Can be changed by the user or by installing/uninstalling software.
• Incorrect associations can prevent files from opening or open them in the wrong program.

Memory trick: When a file won't open, think about its assigned opener.