CompTIA Tech+ (FC0-U71) flashcards

A technology that creates an encrypted tunnel over a public network, allowing secure remote access to a private network's resources.

• Encrypts data in transit to protect against interception
• Makes remote devices appear as if locally connected to the network
• Commonly used by remote employees and for accessing geo-restricted content

Memory trick: VPN = 'Very Private Network' tunnel through the public internet.

A String is a sequence of characters, such as letters, numbers, symbols, and spaces, enclosed in quotes. It is used to represent text.

• Used for textual data
• Can contain letters, numbers, symbols
• Immutable in many languages

Memory trick: Text options? String is the strong choice!

An infinite loop is a control flow statement that iterates indefinitely because the loop's termination condition is never met. It is intentionally used for processes that are meant to run continuously, such as server applications or simulations.

• Runs without a natural end condition
• Requires explicit break or external termination
• Common in simulations or daemon processes

Memory trick: Continuous cycle? Infinite Loop, no finale!

Variable naming conventions are a set of rules or guidelines for choosing identifiers for variables, functions, and other entities in code. Good conventions improve code readability, maintainability, and consistency.

• Names should be descriptive and meaningful
• Avoid single-letter or cryptic names
• Follow language-specific conventions (e.g., camelCase, snake_case)
• Avoid using reserved keywords

Memory trick: Clear names make code easy to tame!

A systematic approach to diagnosing and resolving problems in a logical and efficient manner.

• Follows a structured sequence of steps.
• Aims to identify root causes, not just symptoms.
• Ensures consistent and effective problem resolution.

Memory trick: Don't Guess, Get Solutions Systematically!

A data type defines what kind of value a database column can hold, such as numbers, text, dates, or true/false values.

• Integer stores whole numbers only
• Decimal/Numeric stores fractional values with precision
• Choosing the wrong type can break calculations or waste storage

Memory trick: Decimal = dollars and cents need dots.

Twisted-pair cable standards (Cat3, Cat5, Cat5e, Cat6) that define maximum speed and distance for wired networking.

• Cat5e supports up to 1 Gbps
• Cat6 supports up to 10 Gbps at shorter distances (~55m)
• Higher category numbers generally mean better shielding and less interference

Memory trick: Bigger cable number = bigger bandwidth.

A saved point-in-time image of a virtual machine's state, allowing quick rollback after changes like updates or configuration errors.

• Captures disk, memory, and settings state
• Enables fast rollback if issues occur
• Common before risky updates or testing

Memory trick: A snapshot is a photo of the VM you can step back into.

The IP address of a router that a device uses to send traffic to destinations outside its local subnet.

• Required for inter-subnet/internet communication
• Local traffic works without it
• Usually the router's LAN IP address

Memory trick: Default gateway is the 'exit door' from your local subnet to the world.

Methods used by IT administrators to control and restrict web browser usage and settings to comply with organizational security and compatibility requirements.

• Often involves Group Policy Objects (GPOs) or MDM solutions.
• Can enforce default browsers, proxy settings, and URL-to-browser mapping.
• Aims to enhance security and maintain application compatibility.
• Prevents user circumvention of critical browser settings.

Memory trick: GPOs and MDM are the only true 'bosses' of browser behavior in an enterprise.

A configuration error where two connected Ethernet devices are set to different duplex modes (e.g., one is full-duplex, the other is half-duplex), leading to severe network performance issues and high collision rates.

• Full-duplex allows simultaneous send/receive; half-duplex allows one at a time.
• Mismatches cause collisions and retransmissions.
• Results in significantly reduced throughput and intermittent connectivity.
• Auto-negotiation usually prevents this, but manual misconfiguration can cause it.

Memory trick: Duplex mismatch: A traffic jam of communication.

A control flow statement that allows a program to execute different blocks of code based on whether a specified condition evaluates to true or false. It enables conditional execution paths.

• Allows conditional execution.
• Typically uses IF, ELSE IF, ELSE.
• Program flow diverges based on a condition.

Memory trick: Branching: Choose a 'branch' based on a condition.

A network protocol that automatically assigns IP addresses and other communication parameters to devices connected to a network.

• Simplifies network administration by eliminating manual IP configuration.
• Prevents IP address conflicts.
• Provides IP address, subnet mask, default gateway, and DNS server information.

Memory trick: DHCP Doles out Handy Configurations Promptly.

A communication interface and protocol specifically designed for SSDs to take full advantage of the high speeds offered by PCIe.

• Uses PCIe lanes for direct CPU access.
• Offers significantly higher throughput and lower latency than SATA.
• Ideal for high-performance computing, gaming, and enterprise applications.

Memory trick: NVMe is the fastest lane for your data train.

A database object that creates a fast-access structure on one or more columns to speed up search and retrieval operations.

• Works like a book index for quick lookups
• Speeds up reads but can slow down writes/inserts
• Commonly created on columns frequently used in WHERE or ORDER BY clauses

Memory trick: An index is a book's table of contents — jump straight to the page.

Unsolicited bulk electronic messages, usually commercial in nature, sent indiscriminately to a large number of recipients.

• Often advertising products or services.
• Can contain suspicious links or attachments.
• Primary characteristic is being unsolicited.

Memory trick: Spam is like a can of unwanted emails.

A software or hardware solution used to monitor and restrict access to certain websites or categories of web content based on predefined rules.

• Blocks access to malicious or inappropriate sites
• Can enforce acceptable use policies
• Often integrated into firewalls or proxy servers

Memory trick: Network tools protect, each with a specific task.

The principle of preventing unauthorized disclosure of information, ensuring that data is accessible only to those authorized to see it.

• Often achieved through encryption and access controls.
• Protects against eavesdropping and data breaches.
• One of the three core principles of information security (Confidentiality, Integrity, Availability).

Memory trick: Confidentiality for secrets, Integrity for truth, Availability for access.

A non-volatile storage device that stores persistent data on solid-state flash memory, offering faster performance and greater durability than traditional hard disk drives.

• No moving parts, leading to higher durability and silent operation.
• Significantly faster read/write speeds and lower latency than HDDs.
• Generally more expensive per gigabyte than HDDs.

Memory trick: Speed and Storage: Choose Your Device Wisely!

A programming construct that repeatedly executes a block of code until a specified condition is met or for a fixed number of iterations.

• Automates repetitive tasks.
• Common types include 'for' loops and 'while' loops.
• Essential for processing collections of data.

Memory trick: Repeat tasks with loops, like a record on repeat.

A differential backup captures all changes made since the last full backup, growing larger each day until the next full backup resets the cycle.

• Backs up changes since the last FULL backup
• Restoration needs only the full backup plus the latest differential
• Grows larger over time between full backups

Memory trick: Differential = keeps 'Adding the Difference' since the full backup

A type of malware that modifies a web browser's settings without the user's permission, typically changing the homepage, default search engine, or redirecting to unwanted sites.

• Alters browser settings (homepage, search engine).
• Often difficult to remove via standard browser options.
• Can redirect users to malicious or advertising websites.

Memory trick: Hijacked browser means unwanted searches and persistent redirects.

A unique 48-bit hardware identifier burned into a network interface card by its manufacturer, used for local network communication.

• Typically written as six pairs of hexadecimal digits (e.g., 00:1A:2B:3C:4D:5E)
• Operates at Layer 2 (Data Link) of the OSI model
• Unlike IP addresses, it generally does not change

Memory trick: MAC = 'Manufacturer's Address Card' burned in forever.

A security principle, commonly applied in firewalls and access control lists, stating that if a specific action (e.g., network traffic, access to a resource) is not explicitly permitted, it is automatically denied.

• Default security posture is to deny.
• Only explicitly allowed actions are permitted.
• Enhances security by reducing attack surface.

Memory trick: Implicit Deny: If it's not on the 'allow' list, it's denied.

Elevated permissions within an operating system that allow a user to make system-wide changes, install software, and manage other user accounts.

• Required for many installation and configuration tasks.
• Accessed by right-clicking an executable and selecting 'Run as administrator'.
• Prompts for a password if the current user is not an administrator.

Memory trick: When an install fails, check who's in charge.

A command-line utility in Windows that scans for and restores corrupted, damaged, or missing protected system files with their correct versions.

• Used to repair Windows system files.
• Scans for integrity violations.
• Replaces incorrect versions with correct Microsoft versions.

Memory trick: SFC scans for bad files, 'cause system files are a sacred trust.

A security method that encrypts all data on a hard drive, including the operating system, preventing unauthorized access if the device is lost or stolen.

• Encrypts every sector of the disk.
• Protects data at rest.
• Requires a password or key at boot-up.

Memory trick: From Full Disk to File, each level protects less.

A method of Windows activation that links the license to a user's Microsoft account or the unique hardware signature of a device, eliminating the need for a product key.

• Introduced with Windows 10 as 'Digital Entitlement'.
• Activates automatically when reinstalling Windows on the same hardware.
• Can be linked to a Microsoft account for easier re-activation after major hardware changes.

Memory trick: Remember the different keys and how they lock in Windows.

A social engineering technique that uses deceptive electronic communications (e.g., email) to trick individuals into revealing sensitive information or performing actions.

• Often impersonates trusted entities (banks, companies).
• Aims to steal credentials, financial data, or install malware.
• Relies on urgency, fear, or curiosity to manipulate victims.

Memory trick: Social engineers trick you with human nature.

An application program that is stored on a remote server and delivered over the internet through a web browser.

• Requires only a web browser to access.
• Updates are managed centrally on the server.
• Reduces local storage and installation requirements.
• Can be accessed from any device with internet connectivity.

Memory trick: Native lives local, Web lives online, PWA bridges the design.

Microsoft's native virtualization platform (Type 1 hypervisor) integrated into Windows Server and Windows Pro/Enterprise editions, enabling the creation and management of virtual machines.

• Allows multiple operating systems to run concurrently on a single physical server.
• Provides hardware-level virtualization.
• Key component for server consolidation and testing environments.
• Managed through Hyper-V Manager.

Memory trick: Hyper-V virtualizes, AD authorizes, IIS web-serves, RDS remote-accesses.

A control flow construct that allows a program to execute different blocks of code based on whether a specified condition evaluates to true or false.

• Executes code conditionally.
• Uses IF, ELSE IF, and ELSE keywords.
• Only one block of code is executed per branching structure.

Memory trick: If this, then that; else, the other.

The process of periodically restoring data from backup files to verify that the backup is complete, uncorrupted, and usable for actual disaster recovery.

• Untested backups may be corrupted or incomplete without anyone knowing
• Should be performed on a regular schedule, not just after creation
• Confirms both data integrity and the recovery procedure work as expected

Memory trick: A backup you never tested is just a guess — restore it to prove it works.

Volatile memory (RAM) requires power to retain data; non-volatile memory (ROM, SSD, HDD) retains data without power.

• RAM = temporary working memory
• ROM = stores firmware/BIOS
• SSD/HDD = permanent storage
• Power loss clears RAM contents

Memory trick: RAM is like a whiteboard—erased when the lights go out.

A RAID level that duplicates data identically across two drives for redundancy, so data survives a single drive failure.

• Requires exactly two drives (or pairs)
• Usable capacity equals one drive's size
• No performance boost for writes, but redundant

Memory trick: RAID 1 = a mirror image, one drive reflecting the other exactly.

Software that automatically displays or downloads unwanted advertisements, often bundled with legitimate software, leading to pop-ups and performance issues.

• Displays unsolicited advertisements.
• Can be bundled with free software.
• Often causes system slowdowns and pop-up windows.

Memory trick: Slow computer, annoying ads, new icons: Adware's calling card.

A virtualization setting that guarantees a minimum amount of CPU, memory, or storage resources to a specific virtual machine, ensuring consistent performance regardless of host load.

• Allocates resources exclusively to a VM.
• Prevents resource contention with other VMs.
• Essential for performance-critical applications.
• Reduces the flexibility of resource overcommitment.

Memory trick: Reservation ensures VIP performance, no resource starvation.

A security control that tracks a user's previously used passwords and prevents them from reusing any of them within a specified number of cycles.

• Prevents users from cycling through a few common passwords.
• Increases password entropy over time.
• Makes brute-force and dictionary attacks less effective against old passwords.

Memory trick: Strong passwords need length, complexity, and memory.

A hypervisor that runs as an application on a host operating system, providing virtualization services to guest operating systems.

• Also known as 'hosted hypervisor'.
• Relies on the host OS for hardware access.
• Examples include VirtualBox, VMware Workstation, VMware Fusion.
• Easier to set up for personal use or testing.

Memory trick: Type 1 is bare, Type 2 is a software layer there.

A SQL command used to remove one or more rows from a table based on a specified condition.

• Syntax: DELETE FROM table WHERE condition;
• Omitting WHERE deletes all rows in the table
• Does not remove the table structure itself

Memory trick: DELETE digs out rows, DROP demolishes the whole table.

A SQL statement used to add one or more new rows of data into a table.

• Basic syntax is INSERT INTO table (columns) VALUES (values).
• Column list and value list must match in order and count.
• Different from UPDATE, which changes existing data.

Memory trick: INSERT is like adding a new card to a card catalog drawer.

CIDR notation (e.g., /26) indicates the number of network bits; remaining bits determine host addresses, minus 2 for network and broadcast.

• Formula: 2^(32-CIDR)-2 = usable hosts
• /24 = 254 usable hosts
• /26 = 62 usable hosts
• /30 = 2 usable hosts (point-to-point links)

Memory trick: Take host bits, power of 2, then subtract 2 party crashers (network & broadcast).

Records of user activity, including logins, resource access, and actions performed within a system or application, along with timestamps.

• Crucial for auditing and forensic investigations.
• Help identify unauthorized access or actions.
• Part of an effective accountability framework.

Memory trick: Logs reveal who did what, when.

A secure version of HTTP that uses SSL/TLS to encrypt communication between a web browser and a website, protecting sensitive data.

• Uses encryption (SSL/TLS) for data in transit.
• Ensures data integrity and confidentiality.
• Identifies the website's authenticity.
• Standard for secure web browsing and transactions.

Memory trick: HTTPS protects your secrets, keeping web data safe and sound.

The process of allowing a macOS application from an 'unidentified developer' to run, typically by using a contextual menu option.

• Gatekeeper is a security feature that verifies app sources.
• Right-clicking and choosing 'Open' allows a one-time override.
• Completely disabling Gatekeeper is not recommended for security.

Memory trick: Gatekeeper's 'Open' gate allows trusted apps to enter.

A RAID level that provides data striping with two independent parity blocks distributed across all drives, allowing the array to continue operating even after the failure of any two drives.

• Requires a minimum of 4 drives.
• Offers very high data redundancy (tolerates two drive failures).
• Has higher write overhead than RAID 5 due to double parity calculations.
• Used for critical applications where maximum uptime and data integrity are paramount.

Memory trick: RAID 6: Two shields strong, data lives on.

A small, coin-cell battery on the motherboard that powers the complementary metal-oxide-semiconductor (CMOS) chip, which stores BIOS/UEFI settings and keeps the real-time clock running when the computer is off.

• Maintains system date, time, and BIOS/UEFI configurations.
• Failure leads to loss of time and default settings upon reboot.
• Typically a CR2032 coin cell.

Memory trick: CMOS battery's dead, time's in dread, settings reset in your head.

SELECT is the SQL command used to query and retrieve data from a database table; the asterisk (*) wildcard retrieves all columns.

• Basic syntax: SELECT columns FROM table;
• * wildcard means all columns
• Statements typically end with a semicolon

Memory trick: SELECT * FROM = 'Select Everything From' the table

A short-range wireless technology used to directly connect peripherals like keyboards, mice, and headsets to devices.

• Range typically under 30 feet
• No router/internet required
• Common for pairing accessories

Memory trick: Bluetooth 'buddies up' close devices without needing the internet.

A Boolean operator that returns true only if all of its operands are true. If any operand is false, the result is false.

• Requires all conditions to be true.
• Used to combine multiple conditions.
• Commonly represented as '&&' or 'AND'.

Memory trick: AND means 'both' must be true.

A protocol that automatically assigns IP addresses and network configuration to devices when they join a network.

• Eliminates manual IP configuration
• Assigns IP, subnet mask, gateway, DNS
• Uses a lease/renewal process

Memory trick: DHCP 'Delivers Home Configuration Promptly' to new devices.

The process of changing a base-10 number to its equivalent base-16 representation, using digits 0-9 and letters A-F.

• Hexadecimal uses 16 unique symbols (0-9, A-F).
• Each hexadecimal digit represents four binary bits.
• Often used in computing for memory addresses, color codes, and network masks.

Memory trick: De-Hex Your Net Masks!

A short-range wireless technology (a few centimeters) used for contactless payments, tap-to-pair, and data exchange.

• Range: typically under 4 cm
• Used in mobile payment systems (Apple Pay, Google Pay)
• No manual pairing required
• Derived from RFID technology

Memory trick: NFC = 'Near Fingers Contact'—just tap and go.

A security system that requires two or more distinct forms of authentication to verify a user's identity for a login or other transaction.

• Combines different 'factors': knowledge, possession, inherence.
• Greatly enhances security beyond just a password.
• Commonly uses a password plus a code from a device.

Memory trick: MFA: More Factors, More Secure Access.

Type 1 hypervisors run directly on hardware (bare-metal); Type 2 hypervisors run on top of a host operating system.

• Type 1: e.g., VMware ESXi, Microsoft Hyper-V
• Type 2: e.g., VMware Workstation, VirtualBox
• Type 1 offers better performance for servers
• Type 2 easier for desktop testing/dev use

Memory trick: Type 1 sits on 'bare metal' like a king on a throne; Type 2 needs a host OS 'chair' first.

A stealthy type of malware designed to hide the existence of certain processes or programs from normal detection methods and enable persistent privileged access to a computer.

• Modifies core OS components (e.g., boot sector, kernel).
• Aims for persistent, hidden access.
• Difficult to detect and remove.

Memory trick: Malware: Viruses attack, Rootkits hide, Ransomware locks.

A RAID level that uses block-level striping with distributed parity, providing both fault tolerance against a single drive failure and good read/write performance.

• Requires a minimum of 3 drives.
• One drive's capacity is used for parity, resulting in (N-1) * drive_size usable capacity.
• Offers a balance of performance, fault tolerance, and storage efficiency.

Memory trick: Zero for speed, One for mirror, Five for parity, Ten for both, no fear.

A hypervisor that runs directly on the host computer's hardware, controlling the hardware and managing guest operating systems directly, offering high performance and direct resource access.

• Also known as bare-metal hypervisor.
• Examples include VMware ESXi, Microsoft Hyper-V, Citrix XenServer.
• Provides better performance and security compared to Type 2 hypervisors due to less overhead.

Memory trick: Hypervisors layer virtual worlds on real hardware.

A SQL clause used to sort the result set of a query by one or more columns, ascending or descending.

• Default sort order is ascending (ASC) unless DESC is specified.
• Can sort by multiple columns, listed in priority order.
• Placed at the end of a SELECT statement, after WHERE if present.

Memory trick: ORDER BY lines up rows like students in alphabetical roll call.

A deep-packet inspection firewall that moves beyond port/protocol inspection and blocking to add application-level inspection, intrusion prevention, and advanced threat intelligence.

• Combines traditional firewall with advanced features.
• Performs deep packet inspection (DPI).
• Can inspect and control application-layer traffic, including encrypted traffic (with SSL decryption).

Memory trick: NGFW: Next-Gen is for Nasty stuff in encrypted traffic.