- Bit vs. byte
- A bit is a single binary digit (0 or 1); a byte is 8 bits. A byte can represent 256 values and typically stores one character.
- Binary number system
- Base-2: uses only 0 and 1. All digital data is ultimately stored and processed as binary.
- Hexadecimal
- Base-16: digits 0-9 then A-F. A compact way to write binary — each hex digit equals 4 bits. Used for MAC addresses, colors, and memory addresses.
- Decimal number system
- Base-10: the everyday system using digits 0-9. Humans read it; computers convert to binary internally.
- Convert binary 1010 to decimal
- 10. Place values 8+0+2+0 = 10 (8×1 + 4×0 + 2×1 + 1×0).
- Kilobyte (KB)
- About 1,000 bytes (1,024 in binary). Units rise by ~1,000×: KB → MB → GB → TB → PB.
- Order data units smallest to largest
- Bit → Byte → KB → MB → GB → TB → PB. Each step is roughly 1,000× larger.
- Bits per second (bps)
- A measure of data transfer rate (network/throughput). Note: networking is measured in bits (Mbps), storage in bytes (MB).
- Hertz (Hz)
- Cycles per second — measures clock speed/frequency. CPU speed is in gigahertz (GHz = billions of cycles per second).
- Notational value vs. units of measure
- Notation = how numbers are written (binary, decimal, hex). Units = what a quantity measures (bytes, Hz, bps, pixels).
- Input vs. output (I/O)
- Input sends data into a computer (keyboard, mouse, mic, scanner). Output sends data out (monitor, speakers, printer).
- Processing (in the IT system)
- The CPU manipulating input data to produce useful output; the core of the input → processing → output → storage model.
- Value of data and information
- Data is raw facts; information is processed, meaningful data. Organizations protect it because it drives decisions and has business value.
- Intellectual property (IP)
- Creations of the mind protected by law: trademarks, copyrights, and patents.
- Trademark vs. copyright vs. patent
- Trademark protects brands/logos; copyright protects creative works (text, music, code); patent protects inventions/processes.
- Digital products
- Goods delivered electronically rather than physically — software, e-books, streaming media, online services.
- Data-driven business decisions
- Using captured, correlated, and meaningful data to guide choices, rather than guesswork.
- Boolean values
- True or false — the basis of computer logic and decision-making in programming.
- AND, OR, NOT (logic)
- Boolean operators. AND: both true. OR: either true. NOT: reverses the value. They drive conditions and searches.
- ASCII
- American Standard Code for Information Interchange — a character-encoding standard mapping letters/symbols to numbers (e.g., A = 65).
- Unicode
- A universal character-encoding standard that represents text from virtually all writing systems, far beyond ASCII's 128 characters.
- Data point
- A single piece of information (one value). Many data points together form a data set used for analysis.
- Latency
- The delay before data transfer begins or completes — lower latency means a more responsive system or network.
- Throughput / bandwidth
- Bandwidth is the maximum data rate a link can carry; throughput is the actual rate achieved. Measured in bits per second.
- Pixel
- The smallest controllable element of a digital image or display. Resolution is the count of pixels (e.g., 1920 × 1080).
- Why convert binary to decimal/hex?
- Computers work in binary, but humans read decimal and hex. Conversions help interpret addresses, colors, and low-level data.
- Megabyte (MB) vs. megabit (Mb)
- MB (capital B) = bytes, used for file size. Mb (lowercase b) = bits, used for network speed. 1 byte = 8 bits.
- Compression
- Reducing file size by encoding data more efficiently. Lossless preserves all data; lossy discards some (e.g., JPEG, MP3).
- Convert decimal 12 to binary
- 1100. 8 + 4 = 12, so the 8 and 4 place values are 1, the 2 and 1 are 0.
- Convert hex A to decimal
- 10. In hexadecimal, A=10, B=11, C=12, D=13, E=14, F=15.
- Information system (the four parts)
- Input → Processing → Output → Storage. The model behind how all computers handle data.
- Structured vs. unstructured data
- Structured data fits a defined model (rows/columns in a database). Unstructured data has no fixed format (emails, images, video).
- CPU (central processing unit)
- The 'brain' of a computer — executes instructions and performs calculations. Speed is measured in GHz; modern CPUs have multiple cores.
- RAM (random access memory)
- Fast, volatile working memory that holds running programs and data. It is cleared when the computer loses power.
- Volatile vs. non-volatile storage
- Volatile (RAM) loses data when powered off. Non-volatile (SSD, HDD, flash, ROM) keeps data without power.
- HDD vs. SSD
- HDD uses spinning magnetic platters — cheap, high capacity, slower. SSD uses flash memory — faster, more durable, no moving parts.
- Motherboard
- The main circuit board connecting and powering all components — CPU, RAM, storage, and expansion cards.
- GPU (graphics processing unit)
- A processor specialized for rendering images and parallel tasks. Can be integrated or a dedicated graphics card.
- Power supply unit (PSU)
- Converts wall AC power to the DC voltages a computer's internal components need.
- NIC (network interface card)
- Hardware that connects a device to a network (wired Ethernet or wireless). Each has a unique MAC address.
- Peripheral device
- Any external device connected to a computer — keyboard, mouse, monitor, printer, webcam, external drive.
- USB
- Universal Serial Bus — the most common port for connecting peripherals; also provides power. USB-C is the reversible modern connector.
- HDMI vs. DisplayPort
- Both carry digital video and audio to displays. HDMI is common on TVs/consumer gear; DisplayPort is common on PCs/monitors.
- Ethernet (RJ45)
- The standard wired networking connector and cable. Provides a reliable, fast connection to a LAN.
- Wired vs. wireless connection
- Wired (Ethernet) is faster, more reliable, and more secure. Wireless (Wi-Fi) is convenient and mobile but subject to interference.
- IP address
- A unique logical address identifying a device on a network. IPv4 is four numbers (192.168.1.10); IPv6 is longer hexadecimal.
- IPv4 vs. IPv6
- IPv4 is 32-bit (about 4.3 billion addresses, running out). IPv6 is 128-bit (vastly more), written in hexadecimal.
- MAC address
- A unique 48-bit hardware address burned into a network adapter, written in hexadecimal. Used for local (Layer 2) delivery.
- Router
- A device that connects different networks and forwards traffic between them — for example, your home network to the internet.
- Switch
- A device that connects multiple wired devices on the same local network, forwarding traffic by MAC address.
- Modem
- Modulates/demodulates signals to connect your network to your internet service provider (ISP) over cable, DSL, or fiber.
- Access point (AP)
- A device that broadcasts a Wi-Fi signal, letting wireless devices join a wired network.
- DHCP
- Dynamic Host Configuration Protocol — automatically assigns IP addresses and network settings to devices, avoiding manual setup.
- DNS
- Domain Name System — translates human-readable names (example.com) into IP addresses computers use to connect.
- LAN vs. WAN
- LAN (local area network) covers a small area like a home/office. WAN (wide area network) spans large distances — the internet is the largest WAN.
- Wi-Fi (802.11)
- The IEEE family of wireless LAN standards. Newer generations (Wi-Fi 5, 6, 6E) are faster and use 2.4, 5, and 6 GHz bands.
- SSID
- Service Set Identifier — the broadcast name of a Wi-Fi network that you select when connecting.
- Bluetooth
- A short-range wireless standard for connecting peripherals like headphones, keyboards, mice, and speakers.
- Firmware
- Low-level software stored on a hardware device that controls its basic functions (e.g., BIOS/UEFI, router firmware).
- BIOS / UEFI
- The firmware that starts a computer, initializes hardware, and loads the operating system. UEFI is the modern replacement for BIOS.
- Driver (device driver)
- Software that lets the operating system communicate with and control a hardware device.
- Virtualization
- Running multiple virtual machines on one physical host. A hypervisor creates and manages the VMs, each with its own OS.
- Hypervisor
- Software (also called a virtual machine monitor) that creates and runs virtual machines, sharing one host's hardware among them.
- Cloud computing
- Delivering computing resources (servers, storage, apps) over the internet, on demand, usually pay-as-you-go.
- IaaS, PaaS, SaaS
- Cloud service models. IaaS = raw infrastructure (VMs). PaaS = a platform to build/deploy apps. SaaS = ready-to-use software (e.g., Gmail).
- Cloud benefit: elasticity
- The ability to scale resources up or down on demand, paying only for what you use.
- Internet of Things (IoT)
- Everyday devices (thermostats, cameras, sensors, appliances) connected to the internet to collect and exchange data.
- Storage capacity vs. speed
- Choose storage by capacity (how much it holds) and speed (how fast it reads/writes). SSDs trade some capacity-per-dollar for speed.
- Optical drive
- Reads/writes CDs, DVDs, or Blu-ray discs using a laser. Increasingly rare on modern systems.
- Network attached storage (NAS)
- A storage device connected to a network so multiple users/devices can access shared files.
- Localhost / loopback (127.0.0.1)
- A reserved IP address a device uses to refer to itself, for testing the local network stack.
- VPN
- Virtual Private Network — an encrypted tunnel that securely connects a device to a private network over the public internet.
- Cellular (mobile data)
- Wireless internet via a cellular network (4G LTE, 5G), used by phones, tablets, and mobile hotspots.
- Port (physical)
- A physical connection point on a device (USB, HDMI, Ethernet, audio jack) for attaching cables and peripherals.
- Expansion card
- An add-in board (graphics, sound, network) installed in a motherboard slot to add capability.
- Operating system (OS)
- Software that manages hardware, runs applications, and provides a user interface. Examples: Windows, macOS, Linux, Android, iOS.
- Functions of an OS
- Manages the CPU, memory, storage, devices, and processes; provides a file system; and offers a user interface for running apps.
- GUI vs. CLI
- GUI (graphical user interface) uses windows, icons, and a mouse. CLI (command-line interface) uses typed text commands.
- Application software
- Programs that do user tasks — word processors, browsers, spreadsheets, games — as opposed to system software like the OS.
- System software
- Software that runs and supports the computer itself: the operating system, drivers, and utilities.
- Productivity software
- Apps for everyday work: word processing, spreadsheets, presentations, email, and note-taking.
- Word processing software
- An application for creating and editing text documents (e.g., Microsoft Word, Google Docs).
- Spreadsheet software
- An application for organizing data in rows/columns, performing calculations with formulas, and making charts (e.g., Excel).
- Presentation software
- An application for building slide decks (e.g., PowerPoint, Google Slides).
- Web browser
- Software that retrieves and displays web pages (e.g., Chrome, Edge, Firefox, Safari).
- Browser cache
- Locally stored copies of web content that speed up page loads. Clearing it can fix display or login issues.
- Browser cookies
- Small files a site stores in your browser to remember settings, logins, and tracking info between visits.
- Pop-up blocker
- A browser feature that prevents unwanted pop-up windows, often used to block ads or malicious prompts.
- Private/incognito browsing
- A browser mode that doesn't save history, cookies, or form data locally after the session ends.
- Plugins/extensions
- Add-ons that extend a browser's functionality. Install only from trusted sources, as they can pose security risks.
- Local vs. cloud-hosted application
- Local apps install and run on your device. Cloud-hosted (web) apps run on remote servers and are accessed via a browser.
- Software license
- The legal agreement defining how you may use software. Types: single-use, group/volume, concurrent, subscription, and open-source.
- Open-source vs. proprietary software
- Open-source publishes its code and is often free to use/modify. Proprietary keeps code closed and is licensed by a vendor.
- Subscription vs. one-time license
- Subscription = recurring fee for ongoing access/updates (SaaS). One-time (perpetual) = pay once to own that version.
- EULA
- End-User License Agreement — the contract you accept that governs how you may legally use a piece of software.
- Patch / update
- Software changes that fix bugs, close security holes, or add features. Keeping software patched is a core security practice.
- File extension
- The suffix after a filename's dot (.docx, .jpg, .exe) that indicates the file type and which app opens it.
- Common document formats
- .txt (plain text), .rtf (rich text), .docx (Word), .pdf (portable/fixed layout), .odt (OpenDocument).
- Common image formats
- .jpg (photos, lossy), .png (graphics, lossless, transparency), .gif (simple animation), .bmp, .tiff.
- Common audio/video formats
- Audio: .mp3, .wav, .flac, .aac. Video: .mp4, .mov, .avi, .mkv.
- Compressed/archive formats
- .zip, .rar, .7z, .tar, .gz — bundle and shrink files for storage or transfer.
- File management
- Organizing data into folders/directories with clear names, and using copy, move, rename, and delete to maintain it.
- Folder/directory structure
- A hierarchy of folders that organizes files. A path (e.g., C:\Users\Docs\file.txt) describes a file's location.
- Read-only vs. read-write
- Read-only files can be viewed but not changed; read-write files can be edited. File permissions control this access.
- Single-platform vs. cross-platform software
- Single-platform runs on one OS only; cross-platform runs on several (e.g., a browser available on Windows, macOS, and Linux).
- Installing vs. uninstalling software
- Installing adds a program and its files/registry entries. Uninstalling should use the proper tool to remove all of them cleanly.
- Process (running program)
- An instance of a program currently executing. Task Manager/Activity Monitor shows running processes and resource use.
- Collaboration software
- Tools that let teams work together remotely — chat, video conferencing, shared docs, and project boards.
- Programming language
- A formal language used to write instructions a computer can execute. Examples: Python, Java, C, JavaScript.
- Compiled vs. interpreted language
- Compiled languages (C, C++) translate to machine code before running — fast. Interpreted languages (Python, JavaScript) run line-by-line via an interpreter — flexible.
- Markup language
- Uses tags to define structure/format, not logic. HTML structures web pages; XML stores/transports data.
- Query language
- A language for retrieving and manipulating data, such as SQL for relational databases.
- Scripting language
- An interpreted language used to automate tasks and glue systems together (e.g., Python, Bash, PowerShell, JavaScript).
- Variable
- A named container that stores a value which can change while a program runs (e.g., score = 10).
- Constant
- A named value that does not change during program execution (e.g., PI = 3.14159).
- Data types (programming)
- Categories of values: integer (whole number), float (decimal), char (single character), string (text), boolean (true/false).
- Integer vs. float
- An integer is a whole number (5, -12). A float has a decimal point (3.14). Choosing the right type avoids errors.
- String
- A sequence of characters (text), usually enclosed in quotes, such as "Hello, world".
- Array / list
- A container that holds multiple values in order, accessed by index (position). Useful for collections of related data.
- Function (procedure)
- A named, reusable block of code that performs a task and can accept inputs (parameters) and return a result.
- Branching (if/else)
- A control structure that runs different code based on a condition — the program's decision-making.
- Looping (iteration)
- Repeating a block of code while a condition holds (while) or a set number of times (for). Avoids duplicating code.
- Pseudocode
- A plain-language outline of program logic, written before code to plan the steps without worrying about syntax.
- Flowchart
- A diagram of a program's logic using shapes for steps (rectangles), decisions (diamonds), and start/end (ovals).
- Sequence (in logic)
- Instructions executed in order, one after another — the most basic program flow.
- Operator (programming)
- A symbol that performs an action: arithmetic (+ - × ÷), comparison (>, <, ==), or logical (AND, OR, NOT).
- Comparison operators
- Test relationships between values: == (equal), != (not equal), > (greater), < (less), >= , <= . Return true or false.
- Logical operators
- Combine boolean conditions: AND (both true), OR (either true), NOT (reverse). Used in branching and loops.
- Identifier
- The name a programmer gives to a variable, function, or constant. Should be clear and descriptive.
- Object (programming)
- A self-contained unit bundling related data (properties) and actions (methods), the basis of object-oriented programming.
- Property vs. method
- A property is data stored on an object (a car's color). A method is an action it can perform (a car's drive()).
- Attribute
- A characteristic or data value associated with an object or element (similar to a property).
- Container (in code)
- A structure that holds multiple values — arrays, lists, vectors — letting you group related data together.
- Comment (code)
- A note in source code, ignored by the computer, that explains what the code does for human readers.
- Syntax
- The grammar rules of a programming language. A syntax error means the code breaks those rules and won't run.
- Logic error vs. syntax error
- A syntax error breaks the language rules (won't run). A logic error runs but produces the wrong result.
- Debugging
- Finding and fixing errors (bugs) in code so the program behaves correctly.
- Why use functions and loops?
- They reduce repetition, make code reusable and readable, and limit mistakes — write logic once, use it many times.
- Database
- An organized, structured collection of data stored so it can be easily accessed, managed, and updated.
- DBMS
- Database Management System — software that creates, manages, and queries databases (e.g., MySQL, PostgreSQL, Microsoft SQL Server, Oracle).
- Why use a database instead of a flat file?
- Databases scale, prevent duplicate data, enforce relationships and rules, allow multiple concurrent users, and support fast queries.
- Relational database
- Stores data in tables (rows and columns) and links tables by shared keys. Queried with SQL.
- Table (database)
- A structure of rows and columns that stores data about one type of entity (e.g., a Customers table).
- Record (row)
- A single entry in a table — one complete set of related fields (e.g., one customer's details).
- Field (column)
- A single attribute in a table (e.g., LastName). Every record has a value for each field.
- Primary key
- A field (or set of fields) that uniquely identifies each record in a table. No duplicates and no nulls allowed.
- Foreign key
- A field in one table that references the primary key of another table, creating a relationship between them.
- Schema (database)
- The blueprint defining a database's structure: its tables, fields, data types, and relationships.
- SQL
- Structured Query Language — the standard language to create, read, update, and delete data in relational databases.
- SELECT statement
- The SQL command used to retrieve (query) data from one or more tables.
- INSERT / UPDATE / DELETE
- SQL data-manipulation commands: INSERT adds rows, UPDATE changes existing rows, DELETE removes rows.
- CREATE / ALTER / DROP
- SQL data-definition commands: CREATE makes a table/database, ALTER modifies its structure, DROP deletes it.
- Query
- A request to a database to retrieve or change data, usually written in SQL.
- Relational vs. non-relational (NoSQL)
- Relational uses structured tables and SQL. Non-relational (NoSQL) uses flexible formats (documents, key-value, graph) for unstructured/large data.
- Flat file database
- Data stored in a single table or file (like a spreadsheet) with no relationships. Simple but doesn't scale or prevent duplication.
- Document database
- A NoSQL type that stores data as documents (often JSON), good for flexible, semi-structured data (e.g., MongoDB).
- Key-value store
- A NoSQL type that stores data as simple key → value pairs; very fast for lookups (e.g., Redis).
- Data persistence
- Storing data so it survives after a program closes or the device powers off — the role of databases and files.
- Import vs. export (data)
- Importing brings external data into a system. Exporting sends data out, often as CSV, XML, or JSON.
- CSV
- Comma-Separated Values — a plain-text format storing tabular data, widely used to move data between systems.
- Backup vs. archive
- A backup is a recent copy for recovery if data is lost. An archive is long-term storage of data no longer actively used.
- Database backup
- A saved copy of a database used to restore it after corruption, failure, or accidental deletion.
- Concurrent access
- Multiple users reading/writing the same database at once. The DBMS manages this to keep data consistent.
- Data integrity
- The accuracy, consistency, and reliability of data. Constraints, keys, and validation rules protect it.
- Structured query vs. report
- A query retrieves specific data; a report formats and presents that data for people to read and analyze.
- Data warehouse (concept)
- A large central store of integrated data from many sources, optimized for analysis and reporting rather than daily transactions.
- CIA triad
- The three goals of information security: Confidentiality (keep data private), Integrity (keep data accurate), Availability (keep data accessible).
- Confidentiality
- Ensuring only authorized people can access data — achieved with encryption, access controls, and authentication.
- Integrity (security)
- Ensuring data is accurate and unaltered. Hashing and checksums detect unauthorized changes.
- Availability
- Ensuring systems and data are accessible when needed — supported by backups, redundancy, and uptime planning.
- Authentication
- Verifying who a user is — proving identity with something you know, have, or are.
- Authorization
- Determining what an authenticated user is allowed to do or access (their permissions).
- Accounting (AAA)
- Logging and tracking what users do, for auditing and accountability. Part of Authentication, Authorization, Accounting.
- Multi-factor authentication (MFA)
- Requiring two or more proofs of identity from different categories (e.g., password + phone code), making accounts far harder to breach.
- Authentication factors
- Something you know (password/PIN), something you have (token/phone), something you are (fingerprint/face).
- Strong password practices
- Long, unique, complex passwords; never reused; stored in a password manager; changed if a breach is suspected.
- Password manager
- An app that generates, stores, and fills strong unique passwords in an encrypted vault, so you only remember one master password.
- Encryption
- Scrambling data so only someone with the key can read it. Protects data at rest (stored) and in transit (moving).
- Encryption at rest vs. in transit
- At rest protects stored data (disk/database encryption). In transit protects data moving over a network (HTTPS/TLS, VPN).
- HTTPS / TLS
- The secure version of HTTP — encrypts web traffic with TLS so data between browser and site can't be read or altered.
- Hashing
- A one-way function that turns data into a fixed-length value (a hash). Used to store passwords and verify integrity; can't be reversed.
- Malware
- Malicious software designed to harm or exploit systems — viruses, worms, trojans, ransomware, spyware, and adware.
- Virus vs. worm
- A virus attaches to a file and needs a user to run it. A worm self-replicates and spreads across networks on its own.
- Ransomware
- Malware that encrypts your files and demands payment to restore them. Reliable backups are the best defense.
- Trojan
- Malware disguised as legitimate software. Once run, it gives an attacker access or installs other malware.
- Spyware
- Malware that secretly gathers information about a user — keystrokes, browsing, credentials — without consent.
- Phishing
- A social-engineering attack using fake emails/messages to trick you into revealing credentials or clicking malicious links.
- Social engineering
- Manipulating people (not systems) into giving up information or access — phishing, pretexting, tailgating, baiting.
- Spam
- Unsolicited bulk messages, often advertising or carrying phishing/malware. Filters and caution reduce the risk.
- Firewall
- Hardware or software that filters network traffic by rules, blocking unauthorized connections to protect a device or network.
- Antivirus / anti-malware
- Software that detects, blocks, and removes malicious programs. Keep it updated to catch new threats.
- Software updates and patching
- Applying vendor fixes promptly closes known security holes attackers exploit — one of the most effective defenses.
- Principle of least privilege
- Give users and programs only the minimum access they need to do their job, limiting damage if an account is compromised.
- User account types
- Standard users have limited rights; administrators can change the system. Use a standard account for daily work to reduce risk.
- Permissions (access control)
- Settings that define who can read, write, or execute a file or resource. The basis of authorization.
- Physical security
- Protecting hardware and access to it — locks, badges, cameras, locked server rooms, and screen privacy.
- Backup (3-2-1 rule)
- Keep 3 copies of data, on 2 different media, with 1 copy offsite. Protects against loss, failure, and ransomware.
- Privacy vs. security
- Security protects data from unauthorized access. Privacy concerns how personal data is collected, used, and shared.
- PII
- Personally Identifiable Information — data that can identify an individual (name, SSN, address). Must be protected carefully.
- Secure Wi-Fi (WPA2/WPA3)
- Use WPA3 (or WPA2 at minimum) with a strong passphrase. Avoid open networks and the obsolete, insecure WEP.
- Public Wi-Fi risk
- Open networks let attackers intercept traffic. Use a VPN and HTTPS sites, and avoid sensitive logins on public Wi-Fi.
- Brute-force attack
- Trying many passwords until one works. Long passwords, lockouts, and MFA defend against it.
- On-path (man-in-the-middle) attack
- An attacker secretly relays/alters traffic between two parties. Encryption (HTTPS, VPN) makes intercepted data useless.
- Software-as-a-service security shared responsibility
- In the cloud, the provider secures the infrastructure; you secure your data, accounts, and access settings.
- Device hardening
- Reducing a device's attack surface: remove unused software, disable unneeded services, patch, and enforce strong settings.
- Behavioral security: verify requests
- Confirm unexpected requests for money or credentials through a separate channel — a key defense against phishing/BEC.
- Troubleshooting methodology (concept)
- A repeatable process: identify the problem, research/establish a theory, test it, fix or escalate, verify, and document.
- Clock speed
- How many cycles per second a CPU executes, measured in GHz. Higher generally means faster, but cores and architecture matter too.
- Core (CPU)
- An independent processing unit within a CPU. Multi-core CPUs run several tasks truly in parallel.
- Cache (CPU)
- Very fast memory close to the CPU that stores frequently used data to speed up processing.
- Data correlation
- Finding relationships between data points to turn raw data into useful information for decisions.
- Why protect data?
- Data has business, legal, and personal value; loss or exposure causes financial harm, legal liability, and lost trust.
- Analog vs. digital
- Analog signals are continuous; digital signals are discrete (0s and 1s). Computers are digital.
- Megahertz vs. gigahertz
- 1 GHz = 1,000 MHz. Both measure frequency/clock speed; modern CPUs are rated in GHz.
- Tablet
- A mobile touchscreen computer larger than a phone, used for browsing, media, and light productivity.
- Workstation vs. server
- A workstation is a powerful PC for one user/task. A server provides shared resources/services to many clients over a network.
- Thin client
- A lightweight computer that relies on a server for most processing and storage.
- Embedded system
- A computer built into a larger device to perform a dedicated function (e.g., a car's controller, a smart appliance).
- Internal vs. external storage
- Internal drives sit inside the device; external drives connect via USB or network for portability or extra capacity.
- Cloud storage
- Storing files on remote servers accessed over the internet (e.g., Google Drive, OneDrive, Dropbox), with anywhere access.
- Wireless interference
- Signals from other devices, walls, or networks that degrade Wi-Fi. Causes include distance, microwaves, and channel overlap.
- Hotspot
- A device (often a phone) that shares its cellular internet connection with other devices over Wi-Fi.
- ISP
- Internet Service Provider — the company that provides your internet connection (cable, fiber, DSL, cellular, satellite).
- Default gateway
- The router address a device sends traffic to when the destination is outside its local network.
- Subnet mask (concept)
- A value that tells a device which part of an IP address is the network and which part identifies the host.
- Static vs. dynamic IP
- A static IP is manually fixed and stays the same. A dynamic IP is assigned automatically by DHCP and can change.
- Wired connection types
- Ethernet (RJ45) for networking; USB, HDMI, DisplayPort, Thunderbolt, and audio for peripherals/displays.
- Setting up a small wireless network
- Connect modem → router, set a unique SSID, enable WPA3/WPA2 with a strong passphrase, change default admin credentials, and update firmware.
- Display resolution
- The number of pixels on screen (e.g., 1920 × 1080 = Full HD). Higher resolution shows more detail.
- RAM vs. storage (common confusion)
- RAM is temporary working memory for active tasks. Storage (SSD/HDD) keeps files permanently. More RAM ≠ more storage.
- Mobile operating system
- An OS designed for phones/tablets — Android and iOS are the two dominant examples.
- Workstation operating system
- A desktop/laptop OS such as Windows, macOS, or a Linux distribution.
- Server operating system
- An OS optimized to provide network services to many clients (e.g., Windows Server, Linux server distributions).
- File system
- How an OS organizes and stores files on a drive (e.g., NTFS, FAT32, exFAT, APFS, ext4).
- Default application
- The program the OS automatically uses to open a given file type (e.g., a default browser or PDF reader).
- Task Manager / Activity Monitor
- A utility that shows running processes and CPU, memory, and disk usage, and lets you end unresponsive programs.
- Software compatibility
- Whether software runs on a given OS, version, and hardware. Check system requirements before installing.
- 32-bit vs. 64-bit software
- 64-bit software/OS can use far more RAM and is standard today. 32-bit is legacy and limited to ~4 GB of RAM.
- Web application
- Software that runs in a browser via the internet, requiring no local install (e.g., Google Docs, webmail).
- Utility software
- Tools that maintain a system — antivirus, backup, disk cleanup, compression, and diagnostics.
- Saving vs. saving as
- Save updates the current file. Save As creates a new copy, letting you change name, location, or format.
- Free vs. freemium vs. paid
- Free has no cost; freemium is free with paid upgrades; paid requires purchase or subscription.
- Browser security settings
- Manage pop-ups, cookies, saved passwords, HTTPS warnings, and extensions to browse safely.
- Algorithm
- A step-by-step set of instructions to solve a problem or complete a task — the logic behind a program.
- Source code
- Human-readable instructions a programmer writes, later compiled or interpreted into something the computer runs.
- IDE
- Integrated Development Environment — software that combines a code editor, compiler/interpreter, and debugger (e.g., VS Code, Eclipse).
- Assembly / machine language
- Low-level languages close to hardware. Machine code is binary the CPU runs directly; assembly is its human-readable form.
- High-level language
- A programmer-friendly language (Python, Java) abstracted away from hardware details, easier to read and write.
- HTML
- HyperText Markup Language — uses tags to structure the content of web pages (headings, links, images).
- Parameter / argument
- A value passed into a function so it can work on different inputs. The function uses it inside its logic.
- Return value
- The result a function sends back to the code that called it.
- Vector (in code)
- A dynamic, ordered collection of values that can grow or shrink — a flexible kind of list/array.
- Concatenation
- Joining strings together end to end (e.g., "Hello, " + "world" = "Hello, world").
- Nested loop
- A loop inside another loop, used to work through grids, tables, or combinations of data.
- Branching example (if/else)
- if score >= 650 then print "Pass" else print "Fail" — the program chooses a path based on a condition.
- Input validation
- Checking that user-entered data is correct and safe before using it — prevents errors and security flaws.
- Field data type
- The kind of value a database column holds — text, integer, decimal, date/time, or boolean.
- Constraint (database)
- A rule that enforces data validity — NOT NULL, UNIQUE, primary key, and foreign key constraints.
- Index (database)
- A structure that speeds up searches on a column, like a book's index — at the cost of extra storage and slower writes.
- One-to-many relationship
- One record in a table relates to many records in another (e.g., one customer has many orders).
- Many-to-many relationship
- Records on both sides relate to many on the other (e.g., students and courses), usually via a join table.
- JOIN (SQL)
- A query operation that combines rows from two or more tables based on a related column (often keys).
- WHERE clause
- A SQL filter that limits a query to rows meeting a condition (e.g., WHERE state = 'CA').
- ORDER BY
- A SQL clause that sorts query results by one or more columns, ascending or descending.
- Null value
- A field with no value (unknown or missing). Not the same as zero or an empty string.
- Data definition vs. data manipulation
- DDL defines structure (CREATE, ALTER, DROP). DML changes data (SELECT, INSERT, UPDATE, DELETE).
- Spreadsheet vs. database
- Spreadsheets suit small, simple data and calculations. Databases scale, enforce rules, link tables, and serve many users.
- JSON
- JavaScript Object Notation — a lightweight, human-readable text format for storing and exchanging structured data.
- XML
- Extensible Markup Language — a tag-based format for storing and transporting structured data between systems.
- Tailgating
- A physical social-engineering attack where someone follows an authorized person through a secure door without credentials.
- Shoulder surfing
- Stealing information (passwords, PINs) by watching someone enter it. Privacy screens and awareness defend against it.
- Dumpster diving
- Searching discarded materials for sensitive information. Shredding documents prevents it.
- Patch management (concept)
- A routine of testing and applying software updates promptly to close vulnerabilities across all systems.
- Single sign-on (SSO)
- Authenticating once to access multiple related applications, reducing password fatigue while centralizing security.
- Biometric authentication
- Using a physical trait (fingerprint, face, iris) to verify identity — a 'something you are' factor.
- Account lockout
- Temporarily disabling an account after too many failed logins, to slow brute-force attacks.
- Data loss vs. data breach
- Data loss means data becomes unavailable (deleted, corrupted). A breach means data is accessed/stolen by unauthorized parties.
- Secure deletion / wiping
- Permanently erasing data so it can't be recovered, important before disposing of or reselling a device.
- VPN (security view)
- Encrypts your internet traffic and hides it from local snoopers — essential on public/untrusted networks.
- Adware
- Software that displays unwanted ads; some tracks behavior. Often bundled with free downloads — install carefully.
- Zero-day
- A vulnerability unknown to the vendor with no patch yet available, making it especially dangerous.
- Disaster recovery
- A plan to restore IT systems and data after a major outage, attack, or disaster — backups are its foundation.