CompTIA Tech+ (FC0-U71) flashcards

A data protection strategy recommending 3 total copies of data, on 2 different media types, with 1 copy stored offsite.

• Protects against hardware failure, theft, and site-wide disasters.
• Different media types might include local disk, tape, and cloud storage.
• The offsite copy ensures recovery even if the primary location is destroyed.

Memory trick: 3 copies, 2 media, 1 far away, keeps your data safe from any bad day.

Recursion is a method of solving a problem where the solution depends on solutions to smaller instances of the same problem. A recursive function calls itself until it reaches a base case, which is a simple, non-recursive solution.

• Function calls itself
• Requires a base case to terminate
• Elegant for naturally recursive problems (e.g., factorials, tree traversals)

Memory trick: Self-similar problem? Recursion's the solution!

In flowcharts, a diamond shape (菱形) represents a point where a decision needs to be made. It typically has one entry point and two or more exit points, labeled with the possible outcomes (e.g., Yes/No, True/False).

• Diamond shape.
• Represents a decision or conditional check.
• Has multiple exit paths (e.g., Yes/No).

Memory trick: Decisions are 'diamonds' – precious choices.

A SQL statement used to modify existing data in one or more rows of a table.

• Basic syntax: UPDATE table SET column = value WHERE condition.
• Omitting WHERE updates every row in the table.
• Different from INSERT, which adds new rows instead of changing existing ones.

Memory trick: UPDATE is like erasing and rewriting one line in a ledger, not the whole book.

Records generated by a firewall that document all network traffic attempts (allowed or denied), including source/destination IP addresses, ports, protocols, and data sizes.

• Crucial for network security monitoring.
• Shows attempted and successful connections.
• Essential for detecting data exfiltration and unauthorized access.

Memory trick: Logs: F.O.A.A. - Firewall for traffic, OS for system, Auth for logins, App for software.

A composite key is a primary key made up of two or more columns that, together, uniquely identify each record in a table.

• Used when no single column is unique alone
• Combines two or more columns for uniqueness
• Common in many-to-many relationship tables (like OrderItems)

Memory trick: Composite Key = 'Combine' pieces to unlock uniqueness

A data destruction method that uses a powerful electromagnetic field to neutralize the magnetic data patterns on storage media, rendering all data unrecoverable.

• Used for magnetic media like hard disk drives (HDDs) and magnetic tapes.
• Irreversibly destroys data.
• Makes the media unusable afterward.

Memory trick: Wipe, crush, or zap for data's end.

A security principle that requires that a user or process be given only the minimum level of access or permissions needed to perform their job function or task.

• Minimizes potential damage from errors or attacks
• Reduces the attack surface
• Fundamental to secure system design

Memory trick: Principles guide security, keeping everything tight.

A subnet mask defines how many bits are used for the network vs. host portion of an IP address, determining the number of usable addresses.

• 255.255.255.240 = /28, leaving 4 host bits
• Usable hosts = 2^(host bits) - 2
• Subtract 2 for the network address and broadcast address

Memory trick: Always subtract 2 — one for the network sign, one for the broadcast bullhorn.

A primary key is a column (or set of columns) in a table that uniquely identifies each record and cannot contain duplicate or null values.

• Must be unique for every row
• Cannot be null
• Often an ID number or auto-generated code

Memory trick: Primary Key = Personal ID, one-of-a-kind

A key cloud computing characteristic allowing resources to be automatically scaled up or down to match changing demand.

• Enables handling of traffic spikes without manual intervention
• One of the essential characteristics of cloud computing (NIST definition)
• Works closely with on-demand self-service and resource pooling

Memory trick: Elasticity = a rubber band that stretches and snaps back with demand.

Software designed to run on multiple operating system platforms (e.g., Windows, macOS, Linux) without requiring significant modifications to its core code.

• Often achieved using frameworks (e.g., Electron, React Native) or universal languages (e.g., Java, Python).
• Databases provide a platform-independent way to manage persistent data.
• Reduces development time and maintenance costs across different OS environments.

Memory trick: Building apps for data needs a sturdy, flexible foundation.

A column or set of columns constrained so that all values are distinct, but which is not the table's primary key.

• A table can have multiple unique keys but only one primary key.
• Unique keys can allow one NULL value depending on the database system.
• Commonly used for natural identifiers like email or SKU.

Memory trick: Primary is the boss key, Unique is a backup boss key.

A physical component within a smartphone responsible for transmitting and receiving signals over the cellular network for calls, text messages, and mobile data.

• Essential for cellular network connectivity.
• Damage can lead to 'no service', 'intermittent signal', or slow mobile data.
• Often integrated into the phone's frame or back cover.

Memory trick: Cellular antenna: your phone's voice to the world.

An operating system designed primarily for web-based applications and cloud services, typically featuring minimal local storage and enhanced security.

• Optimized for internet connectivity and web apps.
• Often has strong security features and automatic updates.
• Minimal local storage, relies heavily on cloud storage.

Memory trick: Cloud-first, web-centric, simple management? ChromeOS is your champion.

A binary operation that compares corresponding bits of two numbers. If either bit is 1, the resulting bit is 1. Otherwise, it is 0.

• Used to set specific bits to 1 without affecting other bits.
• Syntax often `A | B` in programming languages.
• Common in low-level programming, flag manipulation, and device control.

Memory trick: AND, OR, XOR: Logic's Core!

A hypervisor that runs directly on the host hardware to control the hardware and manage guest operating systems. Also known as a bare-metal hypervisor.

• Installs directly on physical server hardware.
• Offers high performance and security for VMs.
• Commonly used in data centers and server environments.

Memory trick: Type 1: Bare-metal beast, for dedicated server virtualization.

A type of non-relational database that stores data as simple key-value pairs, optimized for extremely fast lookups by a unique key.

• Each key maps to one value or data block
• Examples include Redis and Amazon DynamoDB
• Ideal for caching, session storage, and shopping carts

Memory trick: Key-value is a locker 🗝️ — one key opens one box, instantly.

A non-relational database that stores data as flexible, often JSON-like documents, allowing each record to have a different structure.

• Does not require a fixed schema like relational tables.
• Common examples include MongoDB and CouchDB.
• Well suited for rapidly changing or inconsistent data structures.

Memory trick: Document databases are like folders where each file can hold different papers.

The recommended procedures for installing device drivers to ensure proper hardware functionality and system stability.

• Always use drivers specifically designed for the operating system version.
• Obtain drivers from the manufacturer's official website.
• Contact manufacturer support if suitable drivers are unavailable.

Memory trick: When drivers are missing, manufacturer support is your guiding light.

An OOP principle that focuses on showing only essential information to the outside world and hiding complex implementation details. It provides a simplified view of an object or system through interfaces.

• Hides complexity, shows essentials.
• Achieved through interfaces and abstract classes.
• Focuses on 'what' an object does, not 'how'.

Memory trick: APIE: Abstraction, Polymorphism, Inheritance, Encapsulation.

Software that aims to gather information about a person or organization without their knowledge and can send this information to another entity. Adware is a common form of spyware focused on displaying unwanted advertisements.

• Monitors browsing behavior and collects personal data.
• Often causes pop-up ads, browser redirects, and changes to browser settings.
• Can be difficult to detect with standard antivirus due to its 'legal' but intrusive nature.

Memory trick: Each malware has its own nasty way of showing up.

The process of adding one or more drives to an existing RAID 5 array to increase its storage capacity while maintaining its data striping with parity fault tolerance.

• RAID 5 requires a minimum of 3 drives initially.
• Can be expanded by adding single drives to an existing array.
• Maintains single-drive fault tolerance during and after expansion.
• Expansion process can be lengthy and impact performance.

Memory trick: RAID 5: Add one, and your data's still spun.

A macOS security feature that helps protect the system from malicious applications by checking the origin of downloaded apps before allowing them to run.

• Blocks apps from unidentified developers or non-App Store sources.
• Requires apps to be signed by an Apple Developer ID.
• Can be temporarily bypassed for specific apps via a right-click 'Open' option.
• Configurable in 'Security & Privacy' settings.

Memory trick: Gatekeeper guards the gate, FileVault locks the crate.

The distinction between using powers of 2 (binary, e.g., 1KB = 1024 bytes) and powers of 10 (decimal, e.g., 1KB = 1000 bytes) for data storage units.

• Computing typically uses binary prefixes (KiB, MiB, GiB, TiB) but often labels them with decimal prefixes (KB, MB, GB, TB).
• 1 KB = 1024 bytes (binary standard, KiB).
• 1 TB = 1024 GB (binary standard, TiB).
• Storage manufacturers often use decimal prefixes (1KB = 1000 bytes) which leads to perceived discrepancies.

Memory trick: Binary's 1024, Decimal's 1000, know the difference, or your data's numb'd.

A full-disk encryption feature included with Microsoft Windows Pro and Enterprise editions that protects data by encrypting entire volumes.

• Encrypts entire hard drives or removable drives.
• Requires a Trusted Platform Module (TPM) for enhanced security.
• Protects data even if the device is stolen.

Memory trick: BitLocker secures the whole bit, not just a bit of the files.

A satellite-based navigation system that provides precise geographic location and timing information to compatible devices.

• Relies on signals from multiple orbiting satellites
• Works without cellular or Wi-Fi connectivity
• Common in smartphones, cars, and wearables for navigation

Memory trick: GPS = 'satellites Guide your Position on Screen.'

A flat file stores all data in a single table-like structure, often causing repeated data, while a relational database splits data into separate related tables to reduce redundancy and improve integrity.

• Flat files (like CSV) have no built-in relationships between data
• Relational databases link tables via keys to avoid duplication
• Normalization is the process of restructuring data to reduce redundancy

Memory trick: One giant spreadsheet repeats itself; a relational database splits and links.

A data type used to store whole numbers (positive, negative, or zero) without any fractional or decimal components.

• Represents whole numbers.
• Commonly used for counts, ages, IDs.
• Does not store decimal values.

Memory trick: Integers are for 'int'act whole numbers.

A SQL operator used in a WHERE clause to search for a specified pattern in a text column, often combined with wildcard characters.

• % represents zero or more characters
• _ represents exactly one character
• Used with WHERE to filter partial text matches

Memory trick: LIKE plus percent sign is like a search net catching anything after the S.

WPA2-PSK (Wi-Fi Protected Access 2 - Pre-Shared Key) uses a passphrase that is converted into a 256-bit encryption key for securing wireless networks.

• Uses AES encryption for strong security.
• Requires a pre-shared passphrase on both the access point and client devices.
• The passphrase is used to derive a 256-bit (64 hex character) encryption key.

Memory trick: WEP is Weak, WPA2 is Strong, Enterprise is Complex!

Type coercion (implicit) or casting (explicit) is the process of converting a value from one data type to another. It's crucial for ensuring data integrity and preventing unexpected behavior when operations or assignments involve different data types.

• Converts data from one type to another
• Can be implicit (coercion) or explicit (casting)
• Important for type-safe operations

Memory trick: Whole numbers needed? Integer cast, problem ceded!

Converting between units of computer memory (e.g., MB to GB) using powers of 2 (1024) instead of powers of 10 (1000).

• 1 KB = 1024 Bytes
• 1 MB = 1024 KB
• 1 GB = 1024 MB
• Used for RAM, CPU cache, and often storage capacity.

Memory trick: Memory: Always Multiply/Divide by 1024!

The process by which a web browser verifies the authenticity and validity of a website's digital certificate, crucial for establishing secure (HTTPS) connections.

• Relies on correct system date and time.
• Verifies certificate expiration dates.
• Failure leads to 'Secure Connection Failed' or similar errors.
• Ensures communication with the legitimate server.

Memory trick: Time's ticking! An incorrect clock makes secure sites think their certificates are rotten.

Virtualization software installed on top of an existing operating system, allowing a user to run guest VMs within that OS.

• Examples include VMware Workstation and Oracle VirtualBox
• Relies on the host OS for hardware access
• Easier to set up on personal computers than Type 1 hypervisors

Memory trick: Type 2 = 'Two layers deep' — OS first, hypervisor on top.

2.4 GHz offers longer range but slower speeds and more interference; 5 GHz offers faster speeds with shorter range and less interference.

• 2.4 GHz: longer range, more interference
• 5 GHz: faster speeds, shorter range
• Dual-band routers support both
• 6 GHz added in Wi-Fi 6E for even faster speeds

Memory trick: 2.4 GHz travels far like a marathon runner; 5 GHz sprints fast but tires quickly.

SSDs use flash memory with no moving parts for faster speeds; HDDs use spinning magnetic platters offering more capacity per dollar.

• SSD: faster, no moving parts, more expensive per GB
• HDD: cheaper per GB, higher capacities, slower
• SSDs more shock-resistant
• HDDs use read/write heads over platters

Memory trick: SSD = Speedy Silent Drive; HDD = Heavy Disk Drive.

A programming language that is typically interpreted rather than compiled, often used for automating tasks, manipulating data, and extending the functionality of applications. Examples include Python, JavaScript, and PowerShell.

• Often interpreted, not compiled.
• Good for automation, data manipulation, string processing.
• Known for rapid development and ease of use.

Memory trick: Scripting: 'Scripts' for 'quick' tasks and 'strings'.

The weakening of a Wi-Fi signal as it passes through physical obstructions (walls, metal, water), which is more pronounced at higher frequencies (shorter wavelengths).

• Higher frequencies (5 GHz, 6 GHz) have shorter wavelengths.
• Shorter wavelengths are more easily absorbed or reflected by objects.
• 2.4 GHz (longer wavelength) penetrates objects better but has more interference from other devices.
• Industrial environments with metal structures severely impact higher frequency bands.

Memory trick: Higher the Hertz, shorter the reach, more obstructed, the less it can preach.

Different versions of the High-Definition Multimedia Interface standard offer varying bandwidths, supporting different resolutions, refresh rates, and features.

• HDMI 1.4: Max 4K@30Hz, Ethernet, Audio Return Channel.
• HDMI 2.0: Max 4K@60Hz, HDR, increased bandwidth.
• HDMI 2.1: Max 8K@60Hz/4K@120Hz, dynamic HDR, Variable Refresh Rate (VRR).

Memory trick: Cables and Connectors: Check Your Specs!

A database rule that ensures foreign key values always match an existing primary key value in the related table, preventing orphaned or invalid references.

• Enforced through foreign key constraints
• Prevents inserting child records with non-existent parent keys
• Also prevents deleting a parent record still referenced by child rows

Memory trick: No orphan orders — every CustomerID needs a matching parent.

A memory management technique that allows a computer to compensate for physical memory shortages by temporarily transferring data from RAM to disk storage.

• Uses a paging file or swap space on the hard drive.
• Significantly slower than accessing physical RAM.
• Excessive paging (thrashing) leads to severe system slowdowns.

Memory trick: RAM, CPU, Disk: The Trio of Speed!

A type of programming language where the source code is translated directly into machine code (or an intermediate bytecode) by a compiler before the program is executed. The resulting executable file can then be run independently.

• Requires a compilation step before execution.
• Results in faster execution speeds because code is pre-translated.
• Errors are largely detected during compilation (compile-time errors).
• Executables are typically platform-specific (e.g., Windows .exe, Linux ELF).

Memory trick: Compiled: 'Compile' it once, then 'run' it fast.

A Microsoft file system optimized for flash memory such as USB flash drives and SD cards. It addresses the limitations of FAT32 in terms of file size and partition size.

• Supports very large files (up to 16 EB).
• Cross-platform compatibility (Windows, macOS, Linux).
• Does not support journaling.

Memory trick: ExFAT: Extended For All Terabytes (and beyond).

An object (or struct in languages like C/C++) is a composite data type that groups together related data items, potentially of different types, under a single name, representing a single entity.

• Allows combining multiple data types into one logical unit.
• Provides a way to model real-world entities.
• In OOP, objects also include methods (behaviors).

Memory trick: An Object/Struct is like a personalized folder for all an item's details.

In object-oriented programming, a class is a blueprint or a template for creating objects. It defines the common properties (attributes) and behaviors (methods) that all objects of that type will possess.

• Acts as a template from which objects are created.
• Encapsulates data (properties) and methods (behaviors).
• Does not consume memory until an object (instance) is created from it.

Memory trick: A Class is like a cookie cutter, making many identical cookies (objects).

A firewall rule that specifies which incoming network traffic is permitted to reach a protected system or application.

• Controls traffic originating from outside the protected system.
• Often defined by protocol, port number, and source IP address.
• Essential for allowing legitimate external access to services.

Memory trick: Inbound is for visitors coming in, Outbound is for you going out.

A specialized operating system designed to perform a dedicated function within a larger mechanical or electronic system, often with limited hardware resources.

• Optimized for specific tasks and hardware.
• Typically lightweight and highly reliable.
• Found in IoT devices, POS systems, industrial controllers.

Memory trick: Embedded: Exactly for My Box's Every Duty.

A command-line utility in Windows operating systems used to register and unregister DLLs (Dynamic Link Libraries) and ActiveX controls in the Windows Registry.

• Used for troubleshooting application component issues.
• Syntax: regsvr32 [options] <dllname.dll>
• Requires administrative privileges to run.

Memory trick: REGSVR32: Register Server 32-bit.

A hypervisor that runs as an application on a conventional operating system (the host OS).

• Examples include VirtualBox, VMware Workstation, Parallels Desktop.
• Easier to set up for personal or testing use.
• Performance can be slightly lower than Type 1 due to host OS overhead.

Memory trick: Type 2 hypervisors are Hosted on an OS.

A virtualization method that packages an application with its dependencies into an isolated unit called a container, sharing the host OS kernel.

• Provides lightweight, isolated environments.
• Shares the host OS kernel, unlike VMs.
• Facilitates consistent deployment across environments.

Memory trick: Containers are like tiny apartments, VMs are whole houses.

A security feature in Windows operating systems that helps prevent unauthorized changes to the computer by prompting users for administrative approval before allowing actions that require elevated privileges.

• Requires user consent for system-level changes.
• Runs applications with standard user privileges by default.
• Helps mitigate malware and accidental configuration errors.

Memory trick: UAC: User Asks Control.

A method to open a specific application from an 'unidentified developer' on macOS without disabling the Gatekeeper security feature system-wide.

• Right-click (or Control-click) the application icon.
• Select 'Open' from the contextual menu.
• Confirms intent to run the application, creating an exception.

Memory trick: Gatekeeper guards the gate; 'Open' with a right-click lets one through.

Type casting, also known as explicit type conversion, is the manual process of converting a value from one data type to another data type in a programming language.

• Performed explicitly by the programmer using specific syntax.
• Used when implicit conversion (coercion) is not desired or not possible.
• Can sometimes lead to data loss or errors if not handled carefully.

Memory trick: Casting is like manually reshaping clay, coercion is like it melting naturally.

A control flow statement that allows code to be executed repeatedly. It is typically used when the number of iterations is known or can be determined before the loop starts.

• Consists of an initialization, a condition, and an increment/decrement.
• Often used for iterating over arrays, lists, or a specific range of numbers.
• More structured than a while loop for fixed iterations.

Memory trick: For a known count, 'For' is the best route.

A high-level programming language is characterized by a strong abstraction from the computer's hardware, using a syntax closer to human language, and is designed for ease of use and portability.

• Human-readable syntax (e.g., Python, Java, JavaScript).
• Abstracts away hardware details (e.g., memory management).
• Often used for general-purpose programming, web development, and applications.

Memory trick: Language levels are like layers of talking to a computer.

Configuration options within a web browser that specify an intermediary server (proxy) to handle all internet requests on behalf of the user, often for security, content filtering, or anonymity.

• Routes web traffic through a specified server.
• Used for content filtering, security, and caching.
• Can be configured manually or via a PAC (Proxy Auto-Configuration) file.

Memory trick: Proxy: Pass Requests Over to Your Gateway.

A set of runtime library files required by applications developed using Microsoft Visual C++, enabling them to run on systems without Visual Studio installed.

• Provides common DLLs (e.g., MSVCR.dll, MSVCP.dll).
• Many applications depend on specific versions.
• Must be installed separately if not bundled with the application.

Memory trick: MSVCR means Visual C++, DirectX is for graphics, OS is big, Shortcut is small.

The automatic or implicit conversion of values from one data type to another by a programming language during an operation. This can sometimes lead to unexpected results if not understood.

• Happens automatically, without explicit instruction from the programmer.
• Common in dynamically typed languages like JavaScript or Python.
• Can lead to errors like '1' + 2 resulting in '12' instead of 3.
• Explicit conversion (casting) is generally preferred for clarity and control.

Memory trick: Coercion is when types 'co-operate' on their own, sometimes badly.

A feature in many programming languages that allows a function to accept an arbitrary number of arguments. These arguments are typically collected into a single array, list, or tuple within the function's scope.

• Enables functions to be more flexible and reusable for varying input sizes.
• Syntax varies by language (e.g., `*args` in Python, `...` in JavaScript/Java).
• Arguments are usually accessed as a collection inside the function.
• Simplifies function design by avoiding overloading for argument count variations.

Memory trick: Varargs: 'Var'iable arguments, 'arg's that just keep coming.