# Computers glossary part 2

## C

CA - aka certificate authority, an organization that issues digital certificates to authenticate a computer's permissions

Cache - information stored to make it easier to use later, a solution to the memory hierarchy

CAD - computer-aided design, a very broad class of software that helps design things such as 3D models and visual elements on a website

Call - an instruction that points to something stored in memory previously, a type of reference that's a bit like an arrow

Callback - a function in code that feeds backward in time into another function, effectively making the other function hung until it returns a value

Callback hell - many callbacks that slow down code and make it difficult to understand

Canonical - a standardized input format that's the "right" way for the computer to understand, often specific in [technical documentation](language-writing-documentation.md)

Capacitor - two surfaces close to each other separated by an insulator, a means of holding a charge for future use (such as memory)

Captive portal - a proxy server that blocks access to the rest of a network until a user does something, often involves consenting to [Terms of Service](people-contracts.md)

Carry - the product of a half-adder, the leftmost number of adding, like the carry of normal algebra but used *way* more often in binary

CD - Compact Disc, stores binary information in a removable media disc by reflecting laser light, typically read-only, modern iterations are DVDs (digital video discs) and Blu-ray (which uses blue-wavelength lasers instead of red-wavelength to store more information)

CDN - content delivery network, a network configuration where nearby computers save cached copies of mainframe data to make accessing it faster across long distances

Cel shading - a graphics technique of stripping down a color palette into clearly defined colors, which gives a timeless cartoon-like feel to the elements

Cell - a predefined zone where a cell tower operates, as a cell phone moves around the cell tower hands off the connection to an adjacent cell

Cell phone - a phone that sends and receives signals with a cell tower

Cell tower - a communications tower that relays information to other towers in adjacent cells or to landlines

Cellular network - a network of cell towers that a cell phone uses

Centralized ledger - where one computer has priority on the record of changes it's making, in contrast to distributed ledger

Certificate - relatively long-term credentials among computers that last weeks, months, or sometimes indefinitely

CGI - common gateway interface, a set of standards that allow a server to run a program remotely

Chain of custody - aka provenance, a sequence of historical events, typically refers to blockchain

Changelog - aka release notes, documentation for technical people to read that summarizes changes that happen between versions

Channel - designated streams of independent information, can refer to radio frequencies or sound, signals from neighboring channels may bleed over

Character - a data type of one piece of text information, represented by a number (typically as Unicode or ASCII)

Checksum - a method of verifying a large block of data with a small block, often by adding up the 1s together to create a "check sum" that another computer can verify on the other side

Chipset - the baked-in circuitry built into a CPU or printed circuit board

Chromatic aberration - aka spherochromatism, a camera artifact where the lens refracts light differently from its focus, which makes the light change hue depending on where it was focused

CIDR - classless inter-domain routing, a system to demarcate classes of IPv4 addresses

Cipher - a key that encrypts or decrypts

Ciphertext - encoded computer information, often looks like gibberish in a text file, in contrast to plaintext

Circuit board - a prefabricated silicon board designed as a framework for electrical circuits

CISC - complex instruction set computer, a computer architecture designed to use complex instructions, meaning less code and more processing per command, in contrast to RISC

Class - short for classification, refers to a portion of the whole, can be synonymous with folders or types depending on its use

Clause - (mostly) optional elements to add to a function, applies especially to SQL

Cleaning - a data term for making a consistent dataset (e.g., converting "John Smith, Marksmith, Diane Johnson" into "John Smith, Mark Smith, Diane Johnson")

CLI - command-line interface, aka terminal or command prompt or console, a simple interface that only takes text input and almost always only outputs text

Client - the application in a host-client network relationship which is requesting data, can sometimes *be* the host (especially with a VM) so it's not always with 2 computers

Clipboard - a memory buffer for holding temporary computer information, part of most GUI OS's

Clock - the way a computer keeps track of time, using a CMOS powered by a rechargeable battery and based on each back-and-forth of an oscillator, typically measured in Hz

Clock cycle - one measure of discrete time, measured using a clock on the BIOS

Clone - software term for "copying", usually large-scale

Closed-source - the source code of a software program is inaccessible to the public, in contrast to open source

Cloud - remotely accessible computers, often meant for enterprise use

Cluster - a small computer that runs on a clusterboard as part of a distributed system

Clusterboard - a motherboard for a cluster

CMOS - complementary metal-oxide semiconductor, typically used for computer clocks and BIOS settings

CNC - computer numerical control, the system that gives precise numerical instructions to a computer for a physical implementation

Code as law - a legal concept that computer code is legally binding, regardless of the intent of the programmer

Code base - the non-plugin, non-feature-added primitive of software code, contrasts to the database

Code page - a reference table that creates a symbolic association between text characters and numbers for computers to work with, often tends to be ASCII or Unicode nowadays

Code point - a designated spot where computer code is located

Codec - short for compressor/decompressor, a proprietary media standard, often refers to audio or video

Cold storage - holding computer information in a relatively unsynced drive, opposite of hot storage

Collision - data that confuses the computer because it was sent at the same time

Collision detection - a system designed to detect a collision

Colocation - aka colo, a server that can use its computes and storage for multiple users

Color space - an arbitrarily established barrier for a range of represented color, is typically bounded but can be unbounded

Color temperature - a tweak to the domain of color represented by a screen, with the colors representing as either cool (blue-leaning) or warm (red-leaning)

Combinational logic - where a computer performs logic calculations instantly, rather than sequential logic

Combinatorials - aka combinatorics, a branch of math that deals exclusively with the broad concept of counting things, constantly involved with computers because that's all that they technically do

Command - input that a computer receives and does something with

Comment - documentation within code but can also be unused code by "commenting out", about as important as computer code itself for future programmers who may need to modify it

Commit - to send an update to computer code, typically referring to Git

Common case - a typical situation, usually referring to the input elements that a typical user would use, opposite of edge case, important to understand for debugging purposes

Compiler - computer code that converts high-level programming language into assembly or machine code all at once (often before runtime), in contrast to interpreter

Complement - a math idea that implies that there's a wholeness of something, and then the complement of something is the other part of it (e.g., if A+B=C, the complement of A is B)

Composite - combine together

Compute - enterprise-grade computer term for CPU

Computer - a machine that performs [logic](logic.md) and [math](math.md) based on what people command it to do

Concatenate - combine multiple strings together (e.g., ABC and DEF becomes ABCDEF)

Conditional jump - aka branching, an instruction in code that will tell the computer to jump only if a specific condition is met, absolutely critical to permit computers to work correctly, in contrast to unconditional jump

Configuration - settings on a computer, starts with a default setting but can often be changed to something else

Configuration/settings - broad term for various defined instructions in a computer, reverts to default settings with new software/hardware

Connectionless communication - aka CL-mode, the status of a packet transfer where the only routing information comes from inside the packet

Connection-oriented communication - the status of a packet transfer where the computers have to first establish a connection

Constant - a math concept of something that's fixed, usually refers to very specific numbers in math but can also be letters in programming, opposite of variable

Container - aka endpoint, an instance or box inside a virtual machine hypervisor

Content negotiation - mechanisms in the HTTP protocol that make it possible to serve different version of a resource from the same URI (e.g., different languages)

Continuing education - learning without specific certifications or projects in mind, a necessity for knowledge workers

Continuous integration - regularly merging work from multiple software developers

Continuous time - the regular flow of time without breaking it up into segments, rather than discrete time

Continuous wattage - evenly fed power through a power supply

Convention - something everyone has been doing, often becomes a standard but doesn't have to be

Cookie - a file that a host saves on a client computer, typically for web browsing purposes

Copy - duplicating computer code, rather than moving

Copyleft - the legal requirement to keep created works completely free, such as code, in contrast with copyright or permissive license

Copyright - the legal right to profit from written works, such as code, in contrast to copyleft

Core - one processor on a CPU's chipset, can be dual-core, quad-core, or more

CPU - central processing unit, the component that performs most of the computer's [logic](logic.md) and [math](math.md), can have one core or multiple, often has L1/L2/L3/etc. cache memory in the chip, an implementation of an ISA

CPU socket - the place on the motherboard for inserting a CPU, arranged as LGA or PGA

Crack - breaking or removing DRM on media or software

Crash - broad computer term for failing, often refers to OS failure but can also refer to a network

Critical path - the core gameplay experience of a game

CRC - cyclic redundancy check, a mathematical means of checking [Boolean math](logic.md), often part of an FCS

Credential - something that a computer uses to authenticate a user/computer, is often a password but can be various things

Critical consensus - where all the blocks in a blockchain are synchronized

CRM - customer relationship management, software designed to manage a company's [marketing](marketing.md) needs

Cross-platform - software that runs on multiple platforms

Crosstalk - conflicting signals, an annoying byproduct of Wi-Fi and UTP

CRT - cathode ray tube, a type of screen that involves shooting 3 beams of light at a fluorescent screen and routing the lights to get the desired intensities

Cryptocurrency - aka crypto, blockchains that are used as a currency or commodity

Crypto wallet - software meant to make managing cryptocurrency more sane

CSE - custom search engine, a custom-made search engine configured to search specific things, such as a particular set of websites

CSS - cascading style sheet, a language that visually styles information, usually pairs with HTML and often activates with JavaScript

CSS reset - changing the default CSS style to conform to a designer's preferred style

Cursor - An indicator to show where the user input is pointing to on a screen, tends to angle rightward because [expectations](imagination.md) are difficult to break

## D

Dark mode - a color scheme that emphasizes darker colors, typically useful for users in darker rooms but is strictly a matter of preference

Dark pattern - UX/UI tricks to motivate users to perform differently than they otherwise would have decided

Dark web - the parts of the internet that aren't indexed by search engines, typically implies illegal activity

Data - information, plural of datum, can classify into various data types

Data center - a large set of enterprise-grade computers, often run by companies that sell storage or compute power

Data structure - a collected form of data

Data type - the form of the data which can include integers, boolean, floats, doubles, strings, characters, and more

Database - a collection of data structures that assemble into a clearly defined order

Datagram - data telegram, a network packet that cuts down on extra data transmission by not requesting a reply from the receiving computer

DAW - digital audio workstation, a software system specialized for working with audio

DC power - direct current electricity, where the electrons are traveling in a domino-effect cascade from one point to another

DDoS attack - distributed denial-of-service attack, blasting a target computer with an ocean of network requests at once from many computers, typically uses a botnet, aka DoS attack.

De-encapsulate - prepare data that's coming in, opposite of encapsulate

Deallocation - putting something set aside back in with the collective whole, opposite of allocation

Debrid - a hosting arrangement that torrents from multiple seeders, then provides a direct download link for the user

Debugging - getting rid of bugs in the computer code

Decrypt - to decode data with a key, opposite of encode

Dedicated - a broad term to refer to a computer resource completely allocated for a specific purpose

Dedicated plan - a pricing plan that directs specific hardware for customers who need it, opposite of shared plan

Default - aka out-of-the-box, the normal configuration without any extra input, sometimes called "vanilla" or "stock"

Definition - a value in code, can be things like an integer or a function

Demosaicing - Converting color information into pixels by filling in the gaps between a camera's color sensors

Demultiplexer - a logic gate where one set of inputs is a selector to determine which output the input will travel to

Denary - 0 through 9, the base-10 system we learn from grade school, has to be converted to binary for computers to work with it

Denormalize - make a database have a shorter read time, but have more redundant records, opposite of normalize

Dependency - computer code that's necessary to run something else

Deploy - install software or hardware

Deprecated - technology that's no longer being maintained

Depth of field - the nearest and farthest range that a lens can clearly focus at one time

Determinism - a philosophy that things are pre-planned, and a standard for making computer programs (especially games) behave predictably

Device controller - a specific-function chip designed to manage the specific tasks pertaining to various peripherals

Device driver - instructions to the computer on how to run a peripheral, while most operating systems have built-in generic drivers the vendor's drivers will often work better or have more features

DFF - data flip-flop, a stopping point in between logic units, where the electron data migrates to and stays in between clock cycles

DHT - distributed hash table, a distributed system where the lookup, in the form of a hash table, is distributed as well

Dialogue tree - a flowchart of written dialogue to capture the various responses in a game to various player decisions

Diary testing - gathering anecdotal information about an interface from the users as they experience it

Dictionary - aka "associative array" or "map" or "symbol table", an array that uses a key/value pair to cross-reference a value to a specific key

Dictionary attack - password cracking by running through all possible words, doesn't work if there are numbers in it

Digital certificate - an authorization by a certificate authority that indicates a computer automatically has permissions for a fixed window of time into the future

Digital signal - a logically divided signal that represents a black-and-white measurement, the opposite of an analog signal

Digitizer - something that converts an analog signal into a digital one, often refers to a touch screen

Diode - an electrical component where electricity only travels in one direction, critical for many circuit boards

Discrete time - breaking time apart into clearly defined blocks, instead of continuous time

Disk partition - a region of a drive, generally separated to keep different file systems separate, the record of the partitions on each drive is stored in the MBR (master boot record) at the beginning of the drive or has an entire convention arranged across the drive with GPT (GUID partition table)

Disk partition table - a mapped database of primary partitions on a drive, located inside the MBR

Distance-vector routing protocol - a protocol that counts the length of time between points and picks the route with the shortest distance, contrast to link-state routing protocol

Distributed ledger - a distributed system for the record of changes, contrast to centralized ledger

Distributed system - several computers sharing resources together, typically meaning it's for one purpose, rather than a network which can have various purposes

Distro - short for distribution, refers to a software version, but most often refers to varieties of Linux

Dithering - randomizing the quantization of a signal to avoid patterns arising and disrupting anything

Divide and conquer algorithm - a sorting algorithm that breaks up the entire dataset into chunks, then organizes each chunk, then organizes the entire set using the organized chunks

DNS - domain name service, a web server that keeps a constantly updated cross-reference between domains and IP addresses, operates as a directory to the internet

DNS zone - a portion of DNS that specifies a specific part of the DNS

Dock - a GUI element that hides away until activated by a smaller element

DoH - DNS over HTTPS, ensures that the computer looks up all its DNS through a secure network port

Domain - aka web domain, a name (e.g., something.com) in a system maintained by ICANN that makes internet access easier than entering IP addresses

Doppler shift - a known scientific phenomenon where wavelengths compress or expand relative to a perceiver when they're traveling at a different speed than the sender, necessary for satellite information

Double - a data type that holds decimal places up to 64 bits (1.844674407×10¹⁹ combinations)

Downsampling - lowering the sampling quality, usually for memory or network reasons

Downtime - the time that a computer is continuously off, in contrast with uptime

Drive-by download - also called simply "drive-bys", malware that installs through a dodgy website

DRM - digital rights management, software, or code meant to enforce [intellectual property rights](legal-ip.md)

Driver - a set of instructions for a CPU to operate a peripheral

Drop shadow - a graded color element that implies a lightweight shadow beneath an element.

Dropped packet - a packet that somehow failed to get to its destination correctly

DTH - direct-to-home, another term for satellite television

Dual-pointed variables - where a variable is pointing to another variable

Duplex - data transmission that's two-way, can be half duplex (one way at a time) or full duplex (both ways at the same time), in contrast with simplex

Duplex print - printing onto both sides of a piece of paper

DVI - digital video interface, a relatively newer pin-based plug for sending video information

## E

Easter egg - an unimportant small detail or element that's an entertaining reference from the developer about something else (e.g, a Star Trek reference in a side room in a game)

ECC - error correcting code, computer code meant to verify that the information was stored/retrieved correctly, typically includes a checksum

Edge case - an extreme situation, usually referring to abnormal circumstances, opposite of common case

EEPROM - electronically erasable programmable read-only memory, can hold relatively smaller amounts of non-volatile data than a hard drive or RAM, similar but not the same as flash memory (NOR gates instead of NAND and meant to be mostly read)

EFSS - enterprise file sharing and sync, large-scale cloud synchronization

Electricity - the energy caused by many electrons flowing between atoms, the means of almost anything with computers

Electrostatic interference - interference of electrical signals from other electrical signals

Element - a piece of something designed, often refers to visually designed things, can also refer to a mathematical value

Embedded systems - small computers designed to be affordable and small

Empty state - a database entry that has no information in it

Emulator - software designed to reproduce the conditions of a different hardware to make *other* software run correctly (e.g., make Linux run on Windows)

Encapsulate - prepare data to go out, opposite of de-encapsulate

Encrypt - to encode data using a key, the opposite of decrypt

End user - the non-technical person using the product

End-of-life - end support for an outdated software version, often because the developers are focusing on a newer version of the same software

End-user license agreement - the software [contract](people-contracts.md) given to the users who consume the software

Endpoint/Terminus - the place where something is supposed to go, usually used in networking and enterprise computing

Engineer - to design something technical, often for a specific purpose

Enterprise server - large-scale computer meant for massive operations

Entropy - a physics term referring to randomness, but refers to [uncertain](understanding-certainty.md) aspects of a computer's input, especially regarding machine learning

Enumerated type - a data type consisting of set values that operate as constants (e.g., SHIRT may have hat, coat, pants, and glove)

Environment - a configuration, often used to imply a specific technology (e.g., cloud environment)

Error - whenever a computer doesn't fulfill the predefined purpose of the programmer or user

Ethernet - LAN protocol designed in the mid-1970s, the only surviving LAN protocol

EUV - extreme ultraviolet lithography, a silicon chip-making technique of spraying tin with a 25-kilowatt UV laser to turn it into a gas, then blasting it a second time through a series of mirrors onto a silicon wafer

Exchange point - routing mainframe data for an end user

Execution - when computers run code as a set of instructions

Exit point - a clearly designed UX element that clarifies the user can safely leave

Expansion slots - places on the motherboard for adding stuff like graphics cards and sound cards, typically uses PCI (peripheral component interconnect)

Exploit/Vulnerability - a portion of computer code/interface that a hacker can use to gain access that would otherwise be impossible

External media - removable memory, such as a USB stick or CD