# Computers glossary part 4 ## M MAC - media access control, a subset of the [Data Link layer](https://gainedin.site/networks/) that deals with labeling various nodes, moves to logical link control (LLC) MAC address - media access control address, a unique identifier for network-enabled computer parts, uses hexadecimal and often uses colons for ease of reading (e.g., 0f:4c:3b:a5:a3:d1) Machine code - binary information that computers work with, often directly translates from assembly code from a high-level language Machine learning - an algorithm designed to track a flow of repetitive trained information, then repeat back permutations of that information Magic pixels - the edge pixels of a screen, named because of their relatively easy UX compared to the rest of the screen Magnet link - a hash for a BitTorrent client to open and interpret, contains information about that torrent and its contents Mainframe - an enterprise-grade computer that often has many terminals/endpoints Malvertising - ads that direct to malicious software that are designed to look like legitimate software Malware - malicious software, designed by a hacker to destroy or steal Man-in-the-Middle (MitM) attack - a hack that involves appearing legitimate while standing in the middle of a transaction, the mobile version is Man-in-the-Mobile Managed services - a technology contract with a routine fee to keep technology running, contrast with break-fix Map - to make a link between something and something else, such as mapping a game controller button to a keyboard key Markdown - a lightweight markup language, useful for maintaining formatting elements (e.g., headings, hyperlinks) when storing things as plaintext Marker-based AR - augmented reality that displays content on top of an image Markerless AR - augmented reality that simply needs an empty space Master - aka main (now that [Leftism](politics-leftism.md) has gotten offended at it), a dominant drive or record that has a higher importance than others, contrast to slave Matrix - a grid of data MBR - master boot record, a relatively small record placed at the beginning of a hard drive that indicates what's on that drive and what memory register to start accessing it MDF - main distribution frame, the location for most of a data center's network activity, may connect to an IDF Media - information expressed via a medium, typically refers to audio, video, and image files Media query - a set of CSS styles that activate when a property of a media is activated (e.g., min/max width/height on a screen/printer) Megatransfer - 10^6, or 1,000,000, cycles per second, measured specifically for data transfer, also known as MB/s Memory - stored information, can be short-term (like RAM) and deleted on power-off, or long-term (like HDD) and stored between power cycles Memory hierarchy - the engineering reality that you can't have lots of memory that's also fast, so there's a constant speed/amount tradeoff that visually looks like a pyramid (e.g., 5 kb @ 10,000 writes/sec vs. 5,000 kb @ 1,000 writes/sec) Memory leak - memory in that was heap allocated, but the program wasn't instructed to release it when it was finished, creates stack overflows and other weird issues Memristor - memory resistor, a relatively new component made of electric switches that hold their memory even without electrical charge Merkle tree - aka hash tree, a data structure that converts each element into a hash, then makes hashes off multiple hashes, until there's eventually 1 hash for all of it. Merge - a necessary and complicated procedure of combining code bases together, a core feature of Git Metadata - quick-access information placed in the header of a file meant to make managing the files easier without the computer having to dig through them each time Metrics - measurements Microcomputer - aka mini, an old term for a silicon-based computer, rather than older vacuum tube computers Microcontroller - affordable, cheap computers with a very limited capacity and are designed to do a relatively small set of computing tasks, often to serve a more robust computer elsewhere Microkernel - an operating system kernel architecture that has a minimalist system management that takes up less memory, contrast with monolithic kernel Middleware - software designed to be in the middle of other things MIDI - musical instrument digital interface, a standard that sends musical instrument input to time-mapped data MIDI voice - sounds mapped to MIDI inputs, which permits a musical instrument to play as an entirely different instrument at the user's preference Mining - creating a new block in a blockchain, often is *very* resource-intensive, especially with cryptocurrency MMU - memory management unit, a specialized component that connects virtual and physical memory locations, uses the translation lookaside buffer MNO - mobile network operator, the organization that manages a cell tower, compare to MVNO Modal window - a pop-out context window in design that temporarily locks out interaction with other elements Mode - a state that allows for more varieties or iterations of inputs or outputs Modem - modulator/demodulator, translates information for sending via a network, then translates back for the computer to use, usually built right into the motherboard Modular - components of something are interchangeable Module - aka subsystem, an independent piece of a larger thing Modulo operator - A math calculation represented by % that effectively returns the remainder of a division operation, not to be confused with a modulus (the entire *range* of numbers that fit in that operation's set) Monolithic kernel - an operating system kernel architecture that encompasses almost all aspects of system management at the expense of taking more memory and everything running as superuser, contrast with microkernel Monospaced font - a font that uses the same width for each character, popular in older computers and with ASCII art Motherboard - a specific printed circuit board designed to have at least a CPU, input, memory, and output Motion blur - a camera artifact caused by the aperture being open too long or an object moving too fast, a convenient way to cut down on graphics load Mount - to connect a partition to a computer for accessing, can be a hard drive or external media Mount file - a file used as a placeholder for a temporary file system, such as a virtual machine Mouse/Trackball/Touchpad - a peripheral that sends x/y coordinates into the computer using relative motion, represented by a cursor on the screen Move - either copying computer code and deleting the original, or re-linking an association in memory (such as in a hierarchical file system) MTU - maximum transmission unit, the limit of how large a frame can get, can be subverted by jumbo frames MU-MIMO - multiple-user multiple-input multiple-output, a transceiver configuration that allows the most bandwidth on a network compared to SU-MIMO or SISO MVNO - mobile variable network operator, organizations that rent out the extra bandwidth from MNOs' cell towers Multi-licensing - issuing multiple types of software license for the same software product Multimap - a data structure where the key is designed to grab more than one value Multiplexer - a logic gate where one set of inputs is a selector to determine which of the inputs will go out Multiset - a data structure that's a set, but can store multiple values of the same thing ## N N-key rollover - the maximum number of keys that can be reliably pressed on a mechanical keyboard before noticing ghosting/blocking, requires diodes so higher n-key rollover will cost more Name server - a computer in a DNS that stores a record of domains corresponding with IP addresses Namespace - a system that separates things into groups to allow the same names across multiple areas, very useful for programming Nanosheet - a panel of *tiny* transistors, also known as nanoribbon, nanowire or gate-all-around device, depending on who you ask NAS - network-attached storage, a computer designed to do nothing but keep information available on a network NAT - network address translation, converting IPs into other IPs, necessary for IPv4 when they started running out of IPs but not necessary for IPv6 Netcode - computer code that executes across a network, often refers to internet-based games Nested function - a function inside a function, extremely useful but can get complicated to follow the code (especially if there's a recursion) Network - computers connected where they can send and receive data Network edge - the closest network connection to the endpoint Network interface card - aka NIC, a device that's designed to connect to a network, can be a peripheral or built straight into a motherboard Network sniffing - using software to capture packets, can be used for hacking or for diagnostics/learning Neural network - a mechanism of machine learning that consists of a network of individual rule-defining components NFT - non-fungible token, a unique cryptographic token for something, refers to blockchain Node - very broad word for a place on a network that has connections to other things Noise floor - the minimum amount of white noise that exists throughout a recording Non-diegetic - not naturally part of the established environment, such as lighting or sound Nonce - unimportant code that's used to validate a cryptographic hash Non-validated input - an exploit that involves entering data information in a way that the computer mistakes it for code Non-volatile/Long-term storage - memory that persists in between power cycles (i.e., non-volatile), often is a hard drive or removable media, opposite of volatile storage NOP - an opcode for no operation, which basically tells the computer to wait for a cycle NOP slide - an exploit that slides data into NOP opcodes Normalize - make a database have less memory, but with a longer read time, opposite of denormalize, an alternately mean reducing data into a canonical form NoSQL - any database that isn't strictly a relational database Null - a completely blank value in memory, it's *not* a "zero" value ## O OCR - optical character recognition, software that detects [language](language.md) on scanned media OEM - original equipment manufacturer, the organization that creates the original components of a computer, can often be several organizations removed from the group that actually sells the whole computer OLED - organic light-emitting diode, the next technological evolution of the plasma screen, not at all associated to LED screens despite the name OMR - optical mark recognition, informally called scantron, a method of computer input that involves reading marks on a paper Onboarding - the UX from first initializing software that stores configuration information and starts differently the second time onward On-prem - on-premises, having a computer that you can physically touch One-to-one correspondence - one instruction creates one machine code instruction, the major limitation of low-level languages Opacity - how opaque, or invisible, an element or color is Opcodes - operation codes, control bits of an ALU that determine which logic to run on the inputs Open-core - software that is open source, but has a proprietary implementation or front-end that isn't Open-source - computer code that's free to view and therefore modify, allows for easier debugging at the risk of losing potential profit off it, often contrasts to proprietary software or closed-source Operating system - the large system that runs the basic things in a computer, is most often Windows, Mac, or Linux in most general-purpose computers Oscillator - something that goes back-and-forth to track time, a major component of a clock OSINT - open-source intelligence, any potentially useful information or information-gathering tool OSPF - open shortest path first, a link-state routing protocol Out-of-band - outside a natural hardware environment, often remotely, contrast to in-band Output - any information the computer sends out, which could be anything from a screen to other computers Overclocking - cranking up the speed of the computer beyond the manufacturer specifications, which may make better benchmarks but might melt your processor, opposite of underclocking Overflow - the leftmost carry gets dropped in adding, a huge difference between computer math and algebra (e.g., 1000 plus 1001 makes 0001 instead of 10001) Overhead - a general concept usually referring to maintenance cost, space, electrical use, or processing power Over-provisioning - giving more resources than necessary, can be a good idea or a bad idea depending on whether you want redundancy or efficiency, opposite of under-provisioning ## P P/E cycle - a unit of measurement to determine how fast memory can read and write P2P - peer-to-peer, protocols where each node on a network is *both* the client *and* the host Package - premade, downloadable file(s) designed to install onto a computer, typically used for distributing code and programs Packet - a specifically sized string of data sent over a network, designed to reassemble into a file on the other end of a network transfer Parallax scrolling - a form of background scrolling that uses various scrolling rates to simulate an illusion that recreates the parallax effect in reality Parallel processing - using two or more CPUs to run program instructions Parallel programming - software programmed to run on two or more CPUs at once Parameter - something that modifies the scope of a variable or command Parametric curves - curves with parameters Parity - using a bit at the end of a string of binary elements to round out the result to an even or odd number (e.g., 0010100 becomes 0110100**1**, with the last number making that string of numbers even), very useful for error-checking, can also refer to redundancy in a RAID array Particle system - a modeling system to create a randomized, predictable pre-rendered range of events to simulate a real-life chaotic thing (such as a fire) Particle effect - a visual effect made by a particle system Passphrase - an alternative to a password that uses a human-readable sentence Password - a typed phrase that authenticates a system Password cracking - hacking that involves figuring out a password, nowhere near as common as before because of [encryption](encryption.md), but people still leave Post-It notes lying around Patch - a quick software update that fixes bugs or makes software safer from hacking Path - short for pathway, the relative location necessary to access a resource Payload - code designed to take advantage of an exploit Paywall - a software barrier that prevents the user going further without making a purchase PCM - pulse-code modulation, a method of encoding the sound waves of an object relative to a fixed point (i.e., the pulse becomes a code), in contrast with PDM PDM - pulse-density modulation, a method of encoding the sound waves of an object relative to other sounds before and after it, in contrast with PCM PDU (networking) - protocol data unit, a standard of measurement defined by which [networking layer](https://gainedin.site/networks/) the protocol operates on PDU (supercomputers) - power distribution unit, a big power management device that can fit on a server rack that's effectively a huge power strip with regulators to make sure all the connected cables are getting equal voltage Pentest - penetration tester, a specific form of hacking that involves finding vulnerabilities in a computer system Peripheral - something that plugs into the base computer equipment, like a computer screen or headphones, can also contextually be something built-in Permissions - aka access rights or privileges, rules that specify what a computer/user can do when using a computer Permissive license - a license that allows for-profit distribution of software, in contrast with copyleft Persistent - where a software is always running a service on a computer Persona - an artificial reproduction of a likely user, usually for UX/visual design PGA - pin grid array, where the pins for the chip are on the chip, meaning the chip would need replacing if the pins are bent Phi phenomenon - an illusion of movement we get from seeing many similar images back-to-back, with the bare minimum of at least 24 frames required Phishing - sending fake information that looks real (often in an email), spear phishing is targeting a specific person Physical memory - the physical amount of memory in a computer, in contrast with logical memory Ping - a network tool that simply checks if a computer can be reached Pipelining - the convention where operating system processes work like a factory assembly line and focus on the purpose they're designed for, allows processes to take any input the user wants and send it to any output they want Piracy - copying data that's in violation of [intellectual property law](legal-ip.md), not to be confused with violent acts and theft in a remote location Pixel - short for picture element, one colored dot on a screen, sets up as an array to communicate information on the computer Placeholder - information in a text field that simply prompts the user to enter it (e.g., "John Doe" for the Name field) Plaintext - unsophisticated Unicode/ASCII text file, often used for log files and a quick-and-dirty way for veteran programmers to store code/notes, in contrast with ciphertext Planned obsolescence - a manufacturer's tendency to make parts of a device that break down at an approximately predictable time in the future to encourage more consumer spending, thwarted by the right to repair Plasma screen - a type of screen where each pixel is ionized mercury gas that illuminates when triggered by electricity Platform - a modular software that allows users/developers to add or remove features Plugin - optional software features or components, similar to plugging in hardware into an expansion slot Pointer - the location a call is referring to in memory, sometimes can stack into dual-pointed variables Pointer record - a DNS' pointer to an IP address from a web domain Policy - human-made security permissions Polling rate - a [statistical](math-stat.md) term referring to how often mice update their information to the computer Polygon - a complex 3-dimensional graphically rendered shape, is composed of triangles at its simplest but can have curved elements to create a vast variety of intersections Pop - read and remove information from the top of a stack Port - very context-sensitive, can apply to places you can physically plug something in or a network endpoint, not to be confused with slots Port scanner - software that checks for open ports Potting - filling a high-voltage electronic assembly with a solid or gelatinous compound to enhance resistance to shock, moisture, vibration, or corrosion Power draw - the amount of electricity that a computer is using Power supply - A device that converts AC power from the power grid into continuous wattage DC power for the computer to use for its [logic](computers-alu.md) Power user - a savvy computer user, often tends to test the limits of the hardware during normal operation Pretexting - A social engineering exploit that uses subtle appeals to reliable sources to gain a person's trust, often exploits fear Primary key - a unique and unchanging identifier in a relational database, is called a foreign key when it shows up in a separate table as the same ID Primitives - base components that can get built or incorporated into more elaborate ones Print - originally referred to the printer before screens were invented, but now applies to all human-readable output Print spooler - a queue in memory that sends output to a printer Printed circuit board - aka PCB, a plate-like board of integrated circuits (preassembled circuits) that things can plug into, which also often has various functioning parts in it, the most common example is a motherboard Printer - a peripheral that writes characters and images into flat sheets of paper Procedural generation - using an algorithm to make something, rather than manually making it by hand Process - a set of instructions that runs on an operating system (typically through the CPU), can sometimes be on multiple threads, can sometimes run indefinitely or repeatedly Product-market fit - a [marketing](marketing.md) term for whether a technology already has people who want it Production server - an enterprise server that is presently available to customers Profile page - a social media system that involves a user editing information without others' input Program/application/software/app - A set of instructions inside a computer, tends to perform as a tool for someone else who's not the programmer Program counter - a counter that helps with performing the tasks in a computer program by incrementing 1 normally each cycle when left alone or overwriting that number with whatever you want Programming - technically inputting information into a program, but informally means altering or building a computer program Proof of stake - a cryptographic concept where a computer is trusted about new information proportionally to the amount of existing information it already has, critical in blockchain Proof of work - a cryptographic concept where adding a nonce to the same data inside the hash will keep the hash the same, critical in blockchain Propagation - the state of DNS records changing to an updated record Proportional font - a font that uses character spacing relative to the size of the text Proprietary - owned by a company, often compared to open-source or public domain Protection rings - also called privilege rings or hierarchical protection domains, general classifications to protect computer information, often used in cybersecurity Port - a faithful blow-for-blow recreation of software on a different software system, usually with emulation on the back-end to reproduce the original environment Priority queue - a specific type of queue that includes a priority for each value to reference for placing into the queue Programmer - someone who creates applications/programs Protocol - a unified [standard](standards-computers.md) for how computers process data Prototype - a new thing that hasn't been fully tested or ready for manufacturing/production, the physical/design side of "beta version" Proxy server - a computer that uses its IP as a proxy for another computer, thereby hiding the IP address of the source computer from immediate detection PS/2 - from IBM's "Personal System 2", a largely obsolete pin-based plug for sending keyboard and mouse information Public domain - something that anyone can use without any [intellectual property](legal-ip.md) enforcement Pull request - a commit made to another maintainer's code, which submits it to a review process before it's included into the code base PUP - potentially unwanted program, a program that installs alongside a legitimate program someone downloaded Push - add information to a stack Pushdown automation - information that has been ordered into a stack, can be pushed onto or popped