# Computers glossary - part 4 ## 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 ## Q QLED - quantum light-emitting diode, the next evolution of LED screens that uses quantum dots Quantization - a digital signal processing that maps an analog signal into a less dynamic digital one Quantum dots - small dots only a few nanometers long that are overlaid on a screen on top of pixels QPU - quantum processing unit, a CPU that uses qubits instead of bits QR code - Quick Response code, a barcode with two dimensions of information involved Qubit - a quantum computing bit, can be in a superstate of 0/1 as well as 0 or 1 Query - a computer requesting information and possibly doing something with it, often used in databases and networks Queue - a specific type of stack data structure where information is placed onto one end of the sequence and removed from the other QoS - Quality of Service, a router/switch feature that prioritizes some protocols, IP addresses, or MAC addresses more than others, is either a tedious experience requiring networking knowledge to set up or is well-automated ## R Race condition - a bad situation where the various speeds of data traveling (usually via electricity) changes the information in a later clock cycle, a hardware issue but can be used as an exploit Racers - pirates who access FTP sites to download and redistribute a *lot* of media Radar - radio detection and ranging, determining a location and distance using radio signals Rage-quit - leaving software, usually a game, out of frustration RAID - redundant array of independent disks, a specialized array of disks that hold data, can be RAM - random access memory, a set of memory outside the CPU that's quickly accessible but disappears after power-off, often designed as a detachable and upgradeable circuit board that plugs into the motherboard RAM slots - memory slots on the circuit board, the RAM must match its form factor Range header - a header that only requests a specified range Ransomware - malware designed to scare the user into paying an extortionate fee Raster - using a grid matrix of dots to represent a screen (with pixels) or a printer RAT - remote access tool, software, or a feature that controls a computer over a network, often used by hackers Rate-limit - aka throttling, slowing the bandwidth speed of a network or data transfer Ray casting - aka ray tracing, following the pathway of a straight line in a 3D environment, often used to cut down on graphics rendering or create shadow effects RCE - remote code execution, a type of attack where code is remotely executed RDMS - relational database management system, a database system that uses SQL to create a relational database Readahead - a feature of a file system designed to read ahead in a memory block Read-only memory - media that's meant to only be read from, includes EEPROM and most CDs Rear ports - ports on the back of a device that allows you to plug other stuff into it Recommender system - an algorithm designed to recommend user data to other users Recursion - code that references itself (see: recursion), very useful for extremely tedious tasks Red Team - the attacking Pentester who tests the resilience of a cybersecurity implementation, in contrast with Blue Team Redundant - a broad computing concept meaning there's a backup system in place for the currently working one Refactor - to redesign existing code, often code from someone the programmer never met or a public repository Reference - aka "ref", a mapped location elsewhere that can be anything including a network/memory location, a variable, or function Register - a DFF attached to a multiplexer, the implementation of storing memory in a computer Regular expression - aka regex, the sequence of characters used in computer code to sort through text for specific conditions, syntax varies by programming language Relational database - a database that links its data together with a primary key, uses SQL to interact with it, contrast to NoSQL Relative motion - the distance between two points irrespective of where they're at, how a mouse and touchpad send information, opposite of absolute motion Rem - aka root em, a measurement of pixels based on the standard font size (em), typically defaults to 16 pixels Remote - broad concept for something that's not nearby, contrast to local Removable media - long-term storage that's designed for removing while the computer is still on, such as CDs or flash drives Render - produce an end-user graphics element Repeater - a device that simply magnifies and duplicates a signal, useful to send a long-distance signal such as Wi-Fi in a large house or a poor cell connection Repository - a place where computer code is stored and maintained Resource/asset - jargon that can apply contextually to memory (disk space or RAM), processing (CPUs or GPUs), network speed, computer code, database entries, and sometimes peripherals Resource record - a DNS record that indicates where something is Responsive web design - using media queries to manage the UX for various screen sizes a browser may use Reverse-engineer - to re-engineer something by observing what that thing does Right to repair - an individual's rights to fix the things they own, should be implicit but many FAANG companies try to subvert it, works directly against planned obsolescence Rip - copy physical media into a digital format, typically associated with piracy RISC - reduced instruction set computer, a computer architecture designed to simplify individual instructions, meaning more code and less processing per command, contrast to CISC RISC-V - pronounced "risk-five", an open-source implementation of the RISC standard RMF - risk management framework, a system created by NIST to implement risk management organizational programs Roll back - to restore a previous known-good version of software Roll out - when software is released to the public ROM - read-only memory, often doesn't depend on electricity, but you can't write anything to it Rootkit - malware that affects core operating system files Rotoscoping - a tedious animation technique of drawing over an existing thing, frame by frame Router - effectively, a switch that works with IP addresses instead of MAC addresses Routing table - a record of IP addresses that a router records for reference RPC - remote procedure call, a protocol for managing another computer's service Runtime - the period of time when a computer is running a program Runtime error - a situation where a computer does exactly what it's told, but won't finish a task because it's waiting on a condition that can never be met (e.g., add 1 to 5 over and over, stop when it reaches 4)