Official usage of Romanian language in Vojvodina, Serbia
Mount Athos - view from NW
Distribution of first-language native Romanian speakers by country—Voivodina is an autonomous province of northern Serbia bordering Romania, while Altele means "Other"
A map of Mount Athos
Flag of the Greek Orthodox Church used by the monastic community
Romanian as secondary or foreign language in Central and Eastern Europe
A 3D model of Athos
Diamonētērion ("access permit") from 1978
Romanian language in the Romance language family
Imaginary view of the Alexander monument, proposed by Dinocrates. Engraving by Johann Bernhard Fischer von Erlach, 1725
A map of Mount Athos with the monasteries indicated
Romanian's core lexicon (2,581 words); Marius Sala, VRLR (1988)
The peninsula as seen from the summit of Mount Athos (40.15778°N, 24.32667°W)
A view of Nea Skiti
Neacșu's letter is the oldest surviving document written in Romanian.
A Byzantine watch tower, protecting the dock (αρσανάς, arsanás) of Xeropotamou monastery
Sign at entrance to Mount Athos
A sample of Romanian written in the Romanian Cyrillic alphabet, which was still in use in the early 19th century
Emperor Nicephorus Phocas
A close shot of some keys with Romanian characters on the keyboard of a laptop
Athanasios the Athonite
Holy Mount Athos: The Holy Mount Athos: Sheltering the Oldest Orthodox Literary Treasures (1926), by Alphonse Mucha, The Slav Epic
View of the area around Vatopedi monastery

The monastic community of Mount Athos is an Eastern Orthodox community of monks living on the Mount Athos peninsula in Northern Greece.

- Monastic community of Mount Athos

It is governed as an autonomous polity within the Hellenic Republic, namely the monastic community of Mount Athos under the direct jurisdiction of the Ecumenical Patriarch of Constantinople.

- Mount Athos

Today, the group consists of the Daco-Romance subgroup, which comprises the Romanian language (Daco-Romanian), Aromanian language and two other related minor languages, Megleno-Romanian, and Istro-Romanian.

- Eastern Romance languages

Romanian is a part of the Eastern Romance sub-branch of Romance languages, a linguistic group that evolved from several dialects of Vulgar Latin which separated from the Western Romance languages in the course of the period from the 5th to the 8th centuries.

- Romanian language

She also wrote a book called Un mois chez les Hommes (A Month With the Guys) about infiltrating the all-male monastic community of Mount Athos.

- Maryse Choisy
Venn diagram showing the uppercase glyphs shared by the Greek, Latin, and Cyrillic alphabets
"Socrates" at the Louvre
An Euler diagram illustrating that the set of "animals with four legs" is a subset of "animals", but the set of "minerals" is disjoint (has no members in common) with "animals"
Sets A (creatures with two legs) and B (creatures that fly)
An Euler diagram showing the relationships between different Solar System objects
Stained-glass window with Venn diagram in Gonville and Caius College, Cambridge
A page from Hamilton's Lectures on Logic. The symbolism A, E, I, and O refers to the categorical statements that can occur in a syllogism. The small text to the left erroneously states: "The first employment of circular diagrams in logic improperly ascribed to Euler. To be found in Christian Weise", a book actually written by Johann Christian Lange.
Venn diagram as a truth table
On the right is page 74 from Couturat 1914 wherein he labels the 8 regions of the Venn diagram. The modern name for these "regions" is minterms. These are shown on the left with the variables x, y and z per Venn's drawing. The symbolism is as follows: logical AND ( & ) is represented by arithmetic multiplication, and the logical NOT ( ~ ) is represented by " ' " after the variable, e.g. the region x'y'z is read as "NOT x AND NOT y AND z" i.e. ~x & ~y & z.
Euler diagram
Both the Veitch diagram and Karnaugh map show all the minterms, but the Veitch is not particularly useful for reduction of formulas. Observe the strong resemblance between the Venn and Karnaugh diagrams; the colors and the variables x, y, and z are per Venn's example.
Venn diagram
Composite of two pages 115–116 from Venn 1881 showing his example of how to convert a syllogism of three parts into his type of diagram. Venn calls the circles "Eulerian circles" (cf Sandifer 2003, Venn 1881:114 etc) in the "Eulerian scheme" (Venn 1881:100) of "old-fashioned Eulerian diagrams" (Venn 1881:113).
Venn's construction for four sets
Examples of small Venn diagrams (on left) with shaded regions representing empty sets, showing how they can be easily transformed into equivalent Euler diagrams (right)
Venn's construction for five sets
Before it can be presented in a Venn diagram or Karnaugh Map, the Euler diagram's syllogism "No Y is Z, All X is Y" must first be reworded into the more formal language of the propositional calculus: " 'It is not the case that: Y AND Z' AND 'If an X then a Y' ". Once the propositions are reduced to symbols and a propositional formula ( ~(y & z) & (x → y) ), one can construct the formula's truth table; from this table the Venn and/or the Karnaugh map are readily produced. By use of the adjacency of "1"s in the Karnaugh map (indicated by the grey ovals around terms 0 and 1 and around terms 2 and 6) one can "reduce" the example's Boolean equation i.e. (x'y'z' + x'y'z) + (x'yz' + xyz') to just two terms: x'y' + yz'. But the means for deducing the notion that "No X is Z", and just how the reduction relates to this deduction, is not forthcoming from this example.
Venn's construction for six sets
Euler diagram
Venn's four-set diagram using ellipses
Venn diagram
Non-example: This Euler diagram is {{em|not}} a Venn diagram for four sets as it has only 13 regions (excluding the outside); there is no region where only the yellow and blue, or only the red and green circles meet.
A Venn diagram shows all possible intersections.
Five-set Venn diagram using congruent ellipses in a five-fold rotationally symmetrical arrangement devised by Branko Grünbaum. Labels have been simplified for greater readability; for example, A denotes {{nowrap|A ∩ B{{sup|c}} ∩ C{{sup|c}} ∩ D{{sup|c}} ∩ E{{sup|c}}}}, while BCE denotes {{nowrap|A{{sup|c}} ∩ B ∩ C ∩ D{{sup|c}} ∩ E}}.
Euler diagram visualizing a real situation, the relationships between various supranational European organizations. (clickable version)
Six-set Venn diagram made of only triangles (interactive version)
Humorous diagram comparing Euler and Venn diagrams.
Three sets
Euler diagram of types of triangles, using the definition that isosceles triangles have at least (rather than exactly) 2 equal sides.
Four sets
Euler diagram of terminology of the British Isles.
Five sets
The 22 (of 256) essentially different Venn diagrams with 3 circles (top) and their corresponding Euler diagrams (bottom) Some of the Euler diagrams are not typical, and some are even equivalent to Venn diagrams. Areas are shaded to indicate that they contain no elements.
Six sets

In logic, a categorical proposition, or categorical statement, is a proposition that asserts or denies that all or some of the members of one category (the subject term) are included in another (the predicate term).

- Categorical proposition

A syllogism (, syllogismos, 'conclusion, inference') is a kind of logical argument that applies deductive reasoning to arrive at a conclusion based on two propositions that are asserted or assumed to be true.

- Syllogism

They are similar to another set diagramming technique, Venn diagrams.

- Euler diagram

Aristotelian logic identifies a categorical proposition as a sentence which affirms or denies a predicate of a subject, optionally with the help of a copula.

- Proposition

They are thus a special case of Euler diagrams, which do not necessarily show all relations.

- Venn diagram
Venn diagram showing the uppercase glyphs shared by the Greek, Latin, and Cyrillic alphabets
Original cover. Black or red text reading "Pink Floyd The Wall" was stickered on top of the original physical releases.
Waters in Barcelona during The Wall Live, 5 April 2011
Pink Floyd in January 1968, from the only known photoshoot including all five members.
Clockwise from bottom: David Gilmour, Nick Mason, Syd Barrett, Roger Waters and Richard Wright.
A poster advertising the February 1981 concerts at the Westfalenhallen in Dortmund, West Germany
Japanese cover
The album's concept was born out of an altercation with audience members at Olympic Stadium (pictured in 2006).
Waters performing with Pink Floyd at Leeds University in 1970
The psychedelic artwork for A Saucerful of Secrets was the first of many Pink Floyd covers designed by Hipgnosis
Head of the 'wife' puppet; displayed at the Pink Floyd: Their Mortal Remains exhibition.
Co-producer Bob Ezrin (pictured in 2011) helped Waters refine the album's plot.
A live performance of The Dark Side of the Moon at Earls Court Exhibition Centre, shortly after its release in 1973: (l–r) David Gilmour, Nick Mason, Dick Parry, Roger Waters
Pink Floyd in 1971, following Barrett's departure. From left to right: Waters, Mason, Gilmour, Wright.
Mannequin dressed in one of Waters' costumes from the tour; displayed at the Pink Floyd: Their Mortal Remains exhibition
The death of Pink's father during the Battle of Anzio (pictured) forms the backdrop of the story.
Waters performing The Wall – Live in Berlin, Germany, on 21 July 1990
Waters performing with Pink Floyd at Leeds University in 1970
Waters' relationship with Richard Wright (pictured in 2006) collapsed during production, leading to Wright's firing.
The Wall – Live in Berlin, 21 July 1990
The iconic artwork for The Dark Side of the Moon was designed by Hipgnosis and George Hardie.
Waters (in spotlight), dressed in military attire, performing at The Wall – Live in Berlin, 1990
Waters (far right) performing with Pink Floyd at Live 8, 2 July 2005
Pink Floyd performing on their early 1973 US tour, shortly before the release of The Dark Side of the Moon
Waters playing "In the Flesh" on his Dark Side of the Moon Tour at Viking Stadion, Stavanger, 26 June 2006
Battersea Power Station is featured in the cover image for Animals
Waters in Barcelona during The Wall Live in 2011
The Astoria recording studio
Waters performed a series of concerts in Mexico City in October 2016
Pink Floyd in 1989 on the Momentary Lapse of Reason tour
Waters performing "Comfortably Numb" during The Wall Live in Kansas City, 30 October 2010
The album artwork for The Division Bell, designed by Storm Thorgerson, was intended to represent the absence of Barrett and Waters from the band.
Waters performing in Gdańsk in August 2018 during the Us + Them Tour, criticising the Polish government's treatment of the courts and media.
Waters (right) rejoined his former bandmates at Live 8 in Hyde Park, London on 2 July 2005
Andriy Khlyvnyuk of Boombox, whose vocals are featured in "Hey, Hey, Rise Up!"
A live performance of The Dark Side of the Moon at Earls Court, shortly after its release in 1973: (l–r) Gilmour, Mason, Dick Parry, Waters
Pink Floyd's The Wall exhibit at the Rock and Roll Hall of Fame

The Wall is the eleventh studio album by the English progressive rock band Pink Floyd, released on 30 November 1979 by Harvest/EMI and Columbia/CBS Records.

- The Wall

The Wall Tour was a concert tour by the English progressive rock band Pink Floyd throughout 1980–1981 in support of their concept album The Wall.

- The Wall Tour (1980–1981)

"Comfortably Numb" is a song on English rock band Pink Floyd's eleventh album, The Wall (1979).

- Comfortably Numb

In 1965, he co-founded the progressive rock band Pink Floyd.

- Roger Waters

Pink Floyd were founded in 1965 by Syd Barrett (guitar, lead vocals), Nick Mason (drums), Roger Waters (bass guitar, vocals), and Richard Wright (keyboards, vocals).

- Pink Floyd
Original cover. Black or red text reading "Pink Floyd The Wall" was stickered on top of the original physical releases.
The Baraha-mihir or Khana-mihir mound at Berachampa. It was first excavated in 1956–57 revealing a continuous sequence of cultural remains from 11th century BC pre-Mouryan period to 12th century AD Pala period.
Naihati railway station
St Bartholomew's Cathedral, Barrackpore
Dutch Kuthi in Baranagar
Omega and Infinity Benchmark, office buildings in Salt Lake, Kolkata
Jubilee Bridge
Barrackpore Chiria More is the junction of Barrackpore Trunk Road and Surendranath Banerjee Road
Satellite view of city Baranagar
The Bengal Intelligent Park in Sector V.
A dramatic moment from Totakahini.
Tala Bridge, Barrackpore Trunk Road ( BT Road) is a four-laned road in Kolkata, India. It connects Shyambazar 5-point Crossing with Barrackpore Chiria More.
Baranagar Road railway station
The Cognizant Technology Solutions office in Sector V.
Bankim Chandra Chatterjee
Kolkata new proposed Metro Line 5 (Baranagar - Barrackpore)
Ferry ghat at Kuthi Ghat in Baranagar
Narula Institute of Technology
Kendriya Vidyalaya Barrackpore Army HQ
Indian Statistical Institute
Baranagore Ramakrishna Mission Ashrama High School
B.N. Bose Subdivisional Hospital, B.T. Road
Pond Heron in Baranagar
Dakshineswar Kali Temple
Disha Eye Hospitals, Ghosh Para Road
Stork-billed Kingfisher in Baranagar
Durga idol at a pandel in Baranagar
White-throated kingfisher in Baranagar
Cityside view of the new Integrated Terminal of Netaji Subhash Chandra Bose International Airport
Kolkata Suburban EMU Train
Kolkata Metro's largest station Noapara metro station at Noapara, Baranagar

Naihati is a city and a municipality of North 24 Parganas district in the Indian state of West Bengal.

- Naihati

Barrackpore (also known as Barrackpur) is a city and a municipality of urban Kolkata of North 24 Parganas district in the Indian state of West Bengal.

- Barrackpore

Garshyamnagar is a census town in Barrackpore I CD Block in Barrackpore subdivision in North 24 Parganas district in the state of West Bengal, India.

- Garshyamnagar

Baranagar or Baranagore is a city and a municipality of North 24 Parganas district in the Indian state of West Bengal.

- Baranagar

In 1817, Falta and Baranagar and in 1820, some portions of Nadia's Balanda and Anwarpur were encompassed to it.

- North 24 Parganas district
The Baraha-mihir or Khana-mihir mound at Berachampa. It was first excavated in 1956–57 revealing a continuous sequence of cultural remains from 11th century BC pre-Mouryan period to 12th century AD Pala period.
The triskelion appearing on the Isle of Man flag has rotational symmetry because it appears the same when rotated by one third of a full turn about its center. Because its appearance is identical in three distinct orientations, its rotational symmetry is three-fold.
Eiffel Tower
The Egyptian pyramids of the Giza Necropolis, as seen from the air. Built circa 2600 BC.
The structure of a DNA molecule is essential to its function.
The Arcade du Cinquantenaire in Brussels, Belgium
Prasat Thom temple at Koh Ker, Cambodia
A traditional Sami food storage structure
Golden Gate Bridge
Pyramid of the Moon, Teotihuacan. Built between AD 100 and 450.
Gothic quadripartite cross-ribbed vaults of the Saint-Séverin church in Paris
Kapellbrücke (Chapel Bridge), a covered bridge in Lucerne, Switzerland
Pyramid of Khafre, Egypt, circa 2600 BC.
The spiral arrangement of small bright yellow florets that make up the flower head of a sunflower is an example of the highly ordered structure that characterizes all organisms.
The Olmsted ramada over the Big House of Casa Grande National Monument in Arizona
Nubian Pyramids at Meroe with pylon-like entrances.
A skeletal formula for dopamine
Silos in Acatlán, Hidalgo, Mexico
Pyramid of Hellinikon
A motif from the Preludes by Chopin, Op. 28 no.6, bars 1–3
Transmission tower near Le Cluzeau, Saint-Romain, France
Pyramid of Cestius in Rome, Italy
In a singly linked list, each element has a data value and a pointer to the next element.
The Triumphal Arch of Orange, France
A diagram showing the various components of Eastern North American platform mounds
Dulles Airport control tower
Ancient Korean tomb in Ji'an, Northeastern China
Borobudur, Central Java, Indonesia.
Dotō, Stupa of Ōno-dera Temple, Sakai, Osaka Prefecture,Japan.
Louvre Pyramid (Paris, France)
Luxor Hotel in Las Vegas, Nevada
The central part of the "Tama-Re" village, as seen from the air
Pyramid Arena in Memphis, Tennessee
Sunway Pyramid in Subang Jaya is the mall that has an Egyptian-inspired Pyramid with a lion designed Sphinx.
Walter Pyramid in Long Beach, California
Oscar Niemeyer's design for a museum in Caracas
Transamerica Pyramid in San Francisco, California
The granite gopuram (tower) of Brihadeeswarar Temple, 1010 CE.
The pyramidal structure above the sanctum at Brihadisvara Temple.
Pyramid-structure inside Airavatesvara Temple.
Ranganathaswamy Temple gopurams at Srirangam dedicated to Ranganatha, a reclining form of the Hindu deity Maha Vishnu.
Chogha Zanbil is an ancient Elamite complex in the Khuzestan province of Iran.
Nubian pyramids at Archaeological Sites of the Island of Meroe
Shaohao Tomb, Qufu, China
El Castillo at Chichen Itza
Candi Sukuh in Java, Indonesia
Pyramid Shaped Hindu Temple
thumb|Pyramids of Güímar, Tenerife, Spain
Monks Mound, Cahokia
Stockport Pyramid in Stockport, United Kingdom
Karlsruhe Pyramid, Germany
The Pyramid Arena in Memphis, Tennessee
Hanoi Museum in Vietnam features an overall design of an inverted Pyramid.
Metairie Cemetery, New Orleans
The Summum Pyramid in Salt Lake City
Zafer Plaza shopping center in Bursa, Turkey
"Pyramide" ("Pharao-Haus") in Munich, Germany, architect Karl Helmut Bayer, 1974. Apartment building called also "Terrassenhochhaus" inspired by Le Corbusier's principles of modernism.
Slovak Radio Building, Bratislava, Slovakia.
"Pyramid" culture-entertainment complex in Kazan, Russia.
Pyramidal road church in Baden-Baden, Germany.
Ferrohaus, Zürich, Switzerland, architect Justus Dahinden, 1970. Pyramid for offices and apartments, later hospital, brutalist architecture, corten steel, registered as monument historique in 2021.<ref>https://www.baublatt.ch/baubranche/ferrohaus-pyramide-am-see-in-zuerich-wird-unter-schutz-gestellt-31764 Ferrohaus: «Pyramide am See» in Zürich wird unter Schutz gestellt] af baublatt.ch vom 6. Oktober 2021</ref>

A pyramid (from πυραμίς pyramís) is a structure whose outer surfaces are triangular and converge to a single step at the top, making the shape roughly a pyramid in the geometric sense.

- Pyramid

The term is used by architects, structural engineers, and mechanical engineers to distinctly identify built structures that are not buildings.

- Nonbuilding structure

Rotations are direct isometries, i.e., isometries preserving orientation.

- Rotational symmetry

The results of construction are divided into buildings and non-building structures, and make up the infrastructure of a human society.

- Structure

Of these, n can be attributed to available translational symmetry, and the remaining n(n − 1)/2 to rotational symmetry.

- Euclidean group
The triskelion appearing on the Isle of Man flag has rotational symmetry because it appears the same when rotated by one third of a full turn about its center. Because its appearance is identical in three distinct orientations, its rotational symmetry is three-fold.
Argument terminology used in logic
Aristotle, 384–322 BCE.
A depiction from the 15th century of the square of opposition, which expresses the fundamental dualities of syllogistic.

Logic programming is a programming paradigm which is largely based on formal logic.

- Logic programming

Prolog is a logic programming language associated with artificial intelligence and computational linguistics.

- Prolog

A non-monotonic logic is a formal logic whose conclusion relation is not monotonic.

- Non-monotonic logic

F-logic (frame logic) is a knowledge representation and ontology language.

- F-logic

This characteristic is closely related to non-monotonicity and defeasibility: it may be necessary to retract an earlier conclusion upon receiving new information or in the light of new inferences drawn.

- Logic
Argument terminology used in logic
Altair 8K BASIC on paper tape. In 1976, Microsoft co-founder Bill Gates expressed frustration with most computer hobbyists who were using his company's software without having paid for it.
Microsoft CEO Steve Ballmer
Tom Hanrahan, Director of Microsoft's Open Source Technology Center, speaking at Solutions Linux 2010 in Paris
Microsoft CEO Satya Nadella in 2014
Miguel de Icaza, founding member of the Mono, and Xamarin projects and member of the board of directors of the .NET Foundation
The ten organizations with the most open-source contributors on GitHub in 2016
Nat Friedman, former CEO of Microsoft's GitHub subsidiary, the largest host of source code in the world
Michelle Noorali, Sr. Software Engineer at Microsoft and core maintainer on open source projects in the Kubernetes ecosystem including Helm speaking at LinuxCon 2018 in China. Noorali serves on the Kubernetes Steering Committee.
Microsoft Azure booth at LinuxCon 2018 in Beijing, China
Atom text and source code editor with an open project on Windows 10
ChronoZoom
DiskSpd
MonoDevelop IDE for Linux, macOS, and Windows
PowerShell for Linux on Ubuntu
Windows Terminal
Vowpal Wabbit
Windows Package Manager
XML Notepad XML editor

Microsoft Power Fx is a free and open source low-code, general-purpose programming language for expressing logic across the Microsoft Power Platform.

- Microsoft Power Fx

Microsoft developed the Power Fx low-code programming language for expressing logic across the Power Platform.

- Microsoft Power Platform

It is part of the Microsoft Power Platform line of products together with products such as Power Apps and Power BI.

- Microsoft Power Automate

Power Automate, formerly Microsoft Flow (until 2019 ), a toolkit similar to IFTTT for implementing business workflow products.

- Microsoft Dynamics

Power Fx – Low-code, general-purpose programming language for expressing logic across the Microsoft Power Platform

- Microsoft and open source
A Howler sent to Ron Weasley
Voldemort (centre) with Bellatrix Lestrange (left), Lucius Malfoy (right) and several masked Death Eaters (back) in Harry Potter and the Order of the Phoenix
Cover art of the original UK edition
Gringotts Bank film set at ''The Making of Harry Potter
Dumbledore is using his deluminator in the film ''Harry Potter and the Philosopher's Stone
Rowling completed the final chapters of Deathly Hallows in Room 552 of the Balmoral Hotel.
The sign of the Deathly Hallows represents all three objects symbolically: the Wand, the Stone, and the Cloak.
J. K. Rowling has said that the main theme of the series is Harry dealing with death.
A replica of the Elder Wand used in the film
The Philosopher's Stone as pictured in Michael Maier's 1617 alchemical work Atalanta Fugiens, similar to the presentation of the Deathly Hallows and Resurrection Stone.
Invisibility cloak
The Russian translation of the seventh book—"Harry Potter and the Gift of Death"—went on sale at the bookstore Moskva in Moscow on 13 October 2007
After first appearing in Harry Potter and the Prisoner of Azkaban the Marauder's Map was redesigned for each subsequent film
350px
Remembrall at Warner Bros. Studio Tour London – The Making of Harry Potter
The Weasleys’ clock
Chess pieces
Tom Riddle's diary, with the basilisk fang that destroyed its horcrux
Marvolo Gaunt's ring with the Resurrection Stone
Helga Hufflepuff's cup
Salazar Slytherin's locket
Rowena Ravenclaw's diadem
Goblet of Fire
Gryffindor's Sword
Philosopher's stone
The Sorting Hat as seen on the queue for the theme park attraction, Harry Potter and the Forbidden Journey.
Mirror at the Wizarding World of Harry Potter, Universal Studios Hollywood
Moody’s Magical Trunk
Pensieve stone basin
One of the Ford Anglia 105E cars that appears in the films
Broomsticks displayed at the Warner Bros. Studio Tour London: The Making of Harry Potter
Floo Powder as seen in Chris Columbus' film adaptation of Harry Potter and the Chamber of Secrets.
The Knight Bus, seen in the Harry Potter and the Prisoner of Azkaban film, at Warner Bros. Studios, Leavesden.
Sirius Black‘s motorbike
Time-Turner
Cauldrons
Range of wands

The following is a list of magical objects used in the fictional universe of Harry Potter in the original book series, as well as in the adapted film series.

- Magical objects in Harry Potter

For members of the Order of the Phoenix, Dumbledore's Army, Hogwarts staff, Ministry of Magic, or for Death Eaters, see the respective articles.

- List of supporting Harry Potter characters

The depiction of the Wizarding World is centred on magic, which not only imbues objects such as wands, but is portrayed as an inborn ability.

- Fictional universe of Harry Potter

As an orphan, Harry was placed in the care of his Muggle (non-magical) relatives Petunia Dursley and Vernon Dursley, with their son Dudley Dursley.

- Harry Potter and the Deathly Hallows

The Ministry rounded many of them up and imprisoned them in the Wizarding prison Azkaban, but some eluded justice by claiming they were bewitched by the Imperius Curse (it is implied that Lucius Malfoy did so) or by turning in other Death Eaters, as Igor Karkaroff did; Harry witnesses Karkaroff's testimony against former Death Eaters in Albus Dumbledore's Pensieve during the course of the series.

- Death Eater
A Howler sent to Ron Weasley
The free-software-licensing spectrum and some examples of programs under those licenses
A screenshot of Manjaro running the Cinnamon desktop environment, Firefox accessing Wikipedia which uses MediaWiki, LibreOffice Writer, Vim, GNOME Calculator, VLC and Nemo file manager, all of which are open-source software.
License compatibility between common FOSS software licenses according to David A. Wheeler (2007): the vector arrows denote a one directional compatibility, therefore better compatibility on the left side ("permissive licenses") than on the right side ("copyleft licenses")
The logo of the Open Source Initiative
Linus Torvalds, principal author of the Linux kernel
5.25-inch floppy disks holding a very early version of Linux
Ubuntu, a popular Linux distribution
Nexus 5X running Android
In-flight entertainment system booting up displaying the Linux logo
Simplified history of Unix-like operating systems. Linux shares similar architecture and concepts (as part of the POSIX standard) but does not share non-free source code with the original Unix or MINIX.
Linux is ubiquitously found on various types of hardware.
The name "Linux" is also used for a laundry detergent made by Swiss company Rösch.

It is the opposite of open-source or free software.

- Proprietary software

Unlike copyleft software licenses, the MIT License also permits reuse within proprietary software, provided that all copies of the software or its substantial portions include a copy of the terms of the MIT License and also a copyright notice.

- MIT License

Starting in the mid-1990s and until the mid-2000s, the open-source movement pushed and focused the free-software idea forward in the wider public and business perception.

- Free-software license

In 1984, AT&T divested itself of its regional operating companies, and was released from its obligation not to enter the computer business; freed of that obligation, Bell Labs began selling Unix as a proprietary product, where users were not legally allowed to modify Unix.

- Linux

Examples of free software license / open-source licenses include Apache License, BSD license, GNU General Public License, GNU Lesser General Public License, MIT License, Eclipse Public License and Mozilla Public License.

- Open-source software
The free-software-licensing spectrum and some examples of programs under those licenses
Three DS8800 and one DS8870 servers

IBM storage media platform with hybrid flash and hard disk storage for IBM mainframes and other enterprise grade computing environments.

- IBM DS8000 series

Global Mirror is based on IBM Copy Services functions: Global Copy and FlashCopy.

- IBM Global Mirror

Channel Gateway (CGX) is mainframe virtual tape controller software and hardware (together, an "MVT controller") that provides mainframe access to disk-based open systems storage by acting as tape control units and presenting the storage as "virtual" tape drives (emulating IBM 3490/3590) via FICON or ESCON channels.

- Luminex Software

FlashCopy consistency groups are used in a single-site scenario in order to create a time-consistent copy of data that can then be backed-up and sent off site, or in a multi-site Global Mirror for ESS implementation to force time consistency at the remote site.

- FlashCopy

Mainframe-attached storage, such as IBM's System Storage DS8000, often supports both protocols.

- FICON