In the context of spaceflight, a satellite is an artificial object, intentionally placed into orbit. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as Earth's Moon. On 4 October 1957 the Soviet Union launched the world's first artificial satellite, Sputnik 1. Since about 8,100 satellites from more than 40 countries have been launched. According to a 2018 estimate, some 4,900 remain in orbit, of those about 1,900. 500 operational satellites are in low-Earth orbit, 50 are in medium-Earth orbit, the rest are in geostationary orbit. A few large satellites have been assembled in orbit. Over a dozen space probes have been placed into orbit around other bodies and become artificial satellites to the Moon, Venus, Jupiter, Saturn, a few asteroids, a comet and the Sun. Satellites are used for many purposes. Among several other applications, they can be used to make star maps and maps of planetary surfaces, take pictures of planets they are launched into.
Common types include military and civilian Earth observation satellites, communications satellites, navigation satellites, weather satellites, space telescopes. Space stations and human spacecraft in orbit are satellites. Satellite orbits vary depending on the purpose of the satellite, are classified in a number of ways. Well-known classes include low Earth orbit, polar orbit, geostationary orbit. A launch vehicle is a rocket, it lifts off from a launch pad on land. Some are launched at sea aboard a plane. Satellites are semi-independent computer-controlled systems. Satellite subsystems attend many tasks, such as power generation, thermal control, attitude control and orbit control. "Newton's cannonball", presented as a "thought experiment" in A Treatise of the System of the World, by Isaac Newton was the first published mathematical study of the possibility of an artificial satellite. The first fictional depiction of a satellite being launched into orbit was a short story by Edward Everett Hale, The Brick Moon.
The idea surfaced again in Jules Verne's The Begum's Fortune. In 1903, Konstantin Tsiolkovsky published Exploring Space Using Jet Propulsion Devices, the first academic treatise on the use of rocketry to launch spacecraft, he calculated the orbital speed required for a minimal orbit, that a multi-stage rocket fuelled by liquid propellants could achieve this. In 1928, Herman Potočnik published The Problem of Space Travel -- The Rocket Motor, he described the use of orbiting spacecraft for observation of the ground and described how the special conditions of space could be useful for scientific experiments. In a 1945 Wireless World article, the English science fiction writer Arthur C. Clarke described in detail the possible use of communications satellites for mass communications, he suggested. The US military studied the idea of what was referred to as the "earth satellite vehicle" when Secretary of Defense James Forrestal made a public announcement on 29 December 1948, that his office was coordinating that project between the various services.
The first artificial satellite was Sputnik 1, launched by the Soviet Union on 4 October 1957, initiating the Soviet Sputnik program, with Sergei Korolev as chief designer. This in turn triggered the Space Race between the United States. Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio-signal distribution in the ionosphere; the unanticipated announcement of Sputnik 1's success precipitated the Sputnik crisis in the United States and ignited the so-called Space Race within the Cold War. Sputnik 2 was launched on 3 November 1957 and carried the first living passenger into orbit, a dog named Laika. In May, 1946, Project RAND had released the Preliminary Design of an Experimental World-Circling Spaceship, which stated, "A satellite vehicle with appropriate instrumentation can be expected to be one of the most potent scientific tools of the Twentieth Century." The United States had been considering launching orbital satellites since 1945 under the Bureau of Aeronautics of the United States Navy.
The United States Air Force's Project RAND released the report, but considered the satellite to be a tool for science and propaganda, rather than a potential military weapon. In 1954, the Secretary of Defense stated, "I know of no American satellite program." In February 1954 Project RAND released "Scientific Uses for a Satellite Vehicle," written by R. R. Carhart; this expanded on potential scientific uses for satellite vehicles and was followed in June 1955 with "The Scientific Use of an Artificial Satellite," by H. K. Kallmann and W. W. Kellogg. In the context of activities planned for the International Geophysical Year, the White House announced on 29 July 1955 that the U. S. intended to launch satellites by the spring of 1958. This became known as Project Vanguard. On 31 July, the Soviets announced that they intended to launch a satellite by the fall of 1957. Following pressure by the American Rocket Society, the National Science Foundation, the International Geophysical Year, military interest picked up and in early 1955 the Army and Navy were worki
Massively multiplayer online role-playing game
Massively multiplayer online role-playing games are a combination of role-playing video games and massively multiplayer online games in which a large number of players interact with one another within a virtual world. As in all RPGs, the player assumes the role of a character and takes control over many of that character's actions. MMORPGs are distinguished from single-player or small multi-player online RPGs by the number of players able to interact together, by the game's persistent world, which continues to exist and evolve while the player is offline and away from the game. MMORPGs are played throughout the world. Worldwide revenues for MMORPGs exceeded half a billion dollars in 2005, Western revenues exceeded a billion dollars in 2006. In 2008, the spending on subscription MMORPGs by consumers in North America and Europe grew to $1.4 billion. World of Warcraft, a popular MMORPG, has over 10 million subscribers as of November 2014. World of Warcraft's total revenue was $1.04 billion US dollars in 2014.
Star Wars: The Old Republic, released in 2011, became the world's'Fastest-Growing MMOG Ever' after gaining more than 1 million subscribers within the first three days of its launch. Although modern MMORPGs sometimes differ from their predecessors, many of them share the same basic characteristics; these include several common features: persistent game environment, some form of level progression, social interaction within the game, in-game culture, system architecture, membership in a group, character customization. The majority of popular MMORPGs are based on traditional fantasy themes occurring in an in-game universe comparable to that of Dungeons & Dragons; some employ hybrid themes that either merge or replace fantasy elements with those of science fiction and sorcery, or crime fiction. Still, others draw thematic material from American comic books, the occult, other genres; these elements are developed using similar tasks and scenarios involving quests and loot. In nearly all MMORPGs, the development of the player's character is the primary goal.
Nearly all MMORPGs feature a character progression system, in which players earn experience points for their actions and use those points to reach character "levels", which makes them better at whatever they do. Traditionally, combat with monsters and completing quests for non-player characters, either alone or in groups, are the primary ways to earn experience points; the accumulation of wealth is a way to progress in many MMORPGs. This is traditionally best accomplished via combat; the cycle produced by these conditions, combat leading to new items allowing for more combat with no change in gameplay, is sometimes pejoratively referred to as the level treadmill, or "grinding". The role-playing game Progress Quest was created as a parody of this trend. Eve Online trains skills in real time rather than using experience points as a measure of progression. In some MMORPGs, there is no limit to a player's level, allowing the grinding experience to continue indefinitely. MMORPGs that use this model glorify top ranked players by displaying their avatars on the game's website or posting their stats on a high score screen.
Another common practice is to enforce a maximum reachable level for all players referred to as a level cap. Once reached, the definition of a player's progression changes. Instead of being awarded with experience for completing quests and dungeons, the player's motivation to continue playing will be replaced with collecting money and equipment; the widened range of equipment available at the maximum level will have increased aesthetic value to distinguish high ranking players in game between lower ranked players. Colloquially known as endgame gear, this set of empowered weapons and armor adds a competitive edge to both scripted boss encounters as well as player vs player combat. Player motivation to outperform others is fueled by acquiring such items and is a significant determining factor in their success or failure in combat-related situations. MMORPGs always have tools to facilitate communication between players. Many MMORPGs offer support for in-game guilds or clans, though these will form whether the game supports them or not.
In addition, most MMOGs require some degree of teamwork in parts of the game. These tasks require players to take on roles in the group, such as protecting other players from damage, "healing" damage done to other players or damaging enemies. MMORPGs have Game Moderators or Game Masters, who may be paid employees or unpaid volunteers who attempt to supervise the world; some GMs may have additional access to features and information related to the game that are not available to other players and roles. Relationships formed in MMORPGs can be just as intense as relationships formed between friends or partners met outside the game, involve elements of collaboration and trust between players. Most MMORPGs provide different types of classes. Among those classes, a small portion of players choose to roleplay their characters, there are rules that provide functionality and content to those who do. Community resources such as forums and guides exist in support of this play style. For example, if a player wants to play a priest role in his MMORPG world, he might buy a cope from a shop and learn priestly skills, proceeding to speak and interact with others as their character would.
This may not include pursuing other goals such as wealth or experience. Guilds or similar groups with a focus on roleplaying may develop extended in-depth n
A computing platform or digital platform is the environment in which a piece of software is executed. It may be the hardware or the operating system a web browser and associated application programming interfaces, or other underlying software, as long as the program code is executed with it. Computing platforms have different abstraction levels, including a computer architecture, an OS, or runtime libraries. A computing platform is the stage. A platform can be seen both as a constraint on the software development process, in that different platforms provide different functionality and restrictions. For example, an OS may be a platform that abstracts the underlying differences in hardware and provides a generic command for saving files or accessing the network. Platforms may include: Hardware alone, in the case of small embedded systems. Embedded systems can access hardware directly, without an OS. A browser in the case of web-based software; the browser itself runs on a hardware+OS platform, but this is not relevant to software running within the browser.
An application, such as a spreadsheet or word processor, which hosts software written in an application-specific scripting language, such as an Excel macro. This can be extended to writing fully-fledged applications with the Microsoft Office suite as a platform. Software frameworks. Cloud computing and Platform as a Service. Extending the idea of a software framework, these allow application developers to build software out of components that are hosted not by the developer, but by the provider, with internet communication linking them together; the social networking sites Twitter and Facebook are considered development platforms. A virtual machine such as the Java virtual machine or. NET CLR. Applications are compiled into a format similar to machine code, known as bytecode, executed by the VM. A virtualized version of a complete system, including virtualized hardware, OS, storage; these allow, for instance, a typical Windows program to run on. Some architectures have multiple layers, with each layer acting as a platform to the one above it.
In general, a component only has to be adapted to the layer beneath it. For instance, a Java program has to be written to use the Java virtual machine and associated libraries as a platform but does not have to be adapted to run for the Windows, Linux or Macintosh OS platforms. However, the JVM, the layer beneath the application, does have to be built separately for each OS. AmigaOS, AmigaOS 4 FreeBSD, NetBSD, OpenBSD IBM i Linux Microsoft Windows OpenVMS Classic Mac OS macOS OS/2 Solaris Tru64 UNIX VM QNX z/OS Android Bada BlackBerry OS Firefox OS iOS Embedded Linux Palm OS Symbian Tizen WebOS LuneOS Windows Mobile Windows Phone Binary Runtime Environment for Wireless Cocoa Cocoa Touch Common Language Infrastructure Mono. NET Framework Silverlight Flash AIR GNU Java platform Java ME Java SE Java EE JavaFX JavaFX Mobile LiveCode Microsoft XNA Mozilla Prism, XUL and XULRunner Open Web Platform Oracle Database Qt SAP NetWeaver Shockwave Smartface Universal Windows Platform Windows Runtime Vexi Ordered from more common types to less common types: Commodity computing platforms Wintel, that is, Intel x86 or compatible personal computer hardware with Windows operating system Macintosh, custom Apple Inc. hardware and Classic Mac OS and macOS operating systems 68k-based PowerPC-based, now migrated to x86 ARM architecture based mobile devices iPhone smartphones and iPad tablet computers devices running iOS from Apple Gumstix or Raspberry Pi full function miniature computers with Linux Newton devices running the Newton OS from Apple x86 with Unix-like systems such as Linux or BSD variants CP/M computers based on the S-100 bus, maybe the earliest microcomputer platform Video game consoles, any variety 3DO Interactive Multiplayer, licensed to manufacturers Apple Pippin, a multimedia player platform for video game console development RISC processor based machines running Unix variants SPARC architecture computers running Solaris or illumos operating systems DEC Alpha cluster running OpenVMS or Tru64 UNIX Midrange computers with their custom operating systems, such as IBM OS/400 Mainframe computers with their custom operating systems, such as IBM z/OS Supercomputer architectures Cross-platform Platform virtualization Third platform Ryan Sarver: What is a platform
A starship, starcraft or interstellar spacecraft is a theoretical spacecraft designed for traveling between planetary systems, as opposed to an aerospace-vehicle designed for orbital spaceflight or interplanetary travel. The term is found in science fiction, because such craft is not known to have been constructed. Reference to a "star-ship" appears as early as 1882 in Oahspe: A New Bible. Whilst the Voyager and Pioneer probes have travelled into local interstellar space, the purpose of these uncrewed craft was interplanetary and they are not predicted to reach another star system Several preliminary designs for starships have been undertaken through exploratory engineering, using feasibility studies with modern technology or technology thought to be available in the near future. In April 2016, scientists announced Breakthrough Starshot, a Breakthrough Initiatives program, to develop a proof-of-concept fleet of small centimeter-sized light sail spacecraft, named StarChip, capable of making the journey to Alpha Centauri, the nearest extrasolar star system, at speeds of 20% and 15% of the speed of light, taking between 20 and 30 years to reach the star system and about 4 years to notify Earth of a successful arrival.
On November 8, 2018, Elon Musk announced that SpaceX was renaming the Big Falcon Rocket, a reusable launch vehicle and spacecraft system, to Starship. Though the spacecraft will not possess any reasonable interstellar capability, Musk defended the name by claiming that "later versions will." To travel between stars in a reasonable time using rocket-like technology requires high effective exhaust velocity jet, enormous energy to power this, such as might be provided by fusion power or antimatter. There are few scientific studies that investigate the issues in building a starship; some examples of this include: Project Orion manned interplanetary spacecraft Project Daedalus, unmanned interstellar probe Project Longshot, unmanned interstellar probe Project Icarus, unmanned interstellar probe Hundred-Year Starship, manned interstellar craft See interstellar probes, interstellar travelThe Bussard ramjet is an idea to use nuclear fusion of interstellar gas to provide propulsion. Examined in an October 1973 issue of Analog, the Enzmann Starship proposed using a 12,000 ton ball of frozen deuterium to power thermonuclear powered pulse propulsion units.
Twice as long as the Empire State Building and assembled in-orbit, the proposed spacecraft would be part of a larger project preceded by interstellar probes and telescopic observation of target star systems. The NASA Breakthrough Propulsion Physics Program, was a professional scientific study examining advanced spacecraft propulsion systems. A common literary device is to posit a faster-than-light propulsion system or travel through hyperspace, although some starships may be outfitted for centuries-long journeys of slower-than-light travel. Other designs posit a way to boost the ship to near-lightspeed, allowing "quick" travel to nearer stars; this results in a general categorization of the kinds of starships: Sleeper, which put their passengers into stasis during a long trip. This includes Cryonics-based systems. Generation, where the destination will be reached by descendants of the original passengers. Relativistic, taking advantage of time dilation at close-to-light-speeds, so long trips will seem much shorter.
Faster-than-light, which can move between places quickly. Certain common elements are found in most fiction. Fiction that discusses slower-than-light starships is rare, since the time scales are so long. Instead of describing the interaction with the outside world, those fictions tend to focus on setting the whole story within the world of the starship during its long travels. Sometimes the starship is a world, in reality. Travel at velocities greater than the speed of light is impossible according to the known laws of physics, although apparent FTL is not excluded by general relativity; the Alcubierre drive provides a theoretical way of achieving FTL, although it requires negative mass, which has not yet been discovered. Harold G. White at NASA has designed the White–Juday warp-field interferometer to detect a microscopic instance of a warping of space-time according to the Alcubierre drive; the following is a listing of some of the most known vessels in various science fiction franchises. The most prominent cultural use and one of the earliest common uses of the term starship was in Star Trek: The Original Series.
This list is not exhaustive. Andromeda Ascendant Battlestar Galactica Heart of Gold High Charity Hyperion Jupiter 2 Long Shot Moya NSEA Protector SDF-1 Macross SSV Normandy UNSC Infinity USG Ishimura USS Sulaco Yamato White Star Star Trek starships USS Defiant USS Enterprise USS Voyager Stargate starships Star Wars starships Millennium Falcon Star Destroyers Starship Dimensions (to-scale size comparison
The Universe is all of space and time and their contents, including planets, stars and all other forms of matter and energy. While the spatial size of the entire Universe is unknown, it is possible to measure the size of the observable universe, estimated to be 93 billion light years in diameter. In various multiverse hypotheses, a universe is one of many causally disconnected constituent parts of a larger multiverse, which itself comprises all of space and time and its contents; the earliest scientific models of the Universe were developed by ancient Greek and Indian philosophers and were geocentric, placing Earth at the center of the Universe. Over the centuries, more precise astronomical observations led Nicolaus Copernicus to develop the heliocentric model with the Sun at the center of the Solar System. In developing the law of universal gravitation, Isaac Newton built upon Copernicus' work as well as observations by Tycho Brahe and Johannes Kepler's laws of planetary motion. Further observational improvements led to the realization that the Sun is one of hundreds of billions of stars in the Milky Way, one of at least hundreds of billions of galaxies in the Universe.
Many of the stars in our galaxy have planets. At the largest scale galaxies are distributed uniformly and the same in all directions, meaning that the Universe has neither an edge nor a center. At smaller scales, galaxies are distributed in clusters and superclusters which form immense filaments and voids in space, creating a vast foam-like structure. Discoveries in the early 20th century have suggested that the Universe had a beginning and that space has been expanding since and is still expanding at an increasing rate; the Big Bang theory is the prevailing cosmological description of the development of the Universe. Under this theory and time emerged together 13.799±0.021 billion years ago and the energy and matter present have become less dense as the Universe expanded. After an initial accelerated expansion called the inflationary epoch at around 10−32 seconds, the separation of the four known fundamental forces, the Universe cooled and continued to expand, allowing the first subatomic particles and simple atoms to form.
Dark matter gathered forming a foam-like structure of filaments and voids under the influence of gravity. Giant clouds of hydrogen and helium were drawn to the places where dark matter was most dense, forming the first galaxies and everything else seen today, it is possible to see objects that are now further away than 13.799 billion light-years because space itself has expanded, it is still expanding today. This means that objects which are now up to 46.5 billion light-years away can still be seen in their distant past, because in the past when their light was emitted, they were much closer to the Earth. From studying the movement of galaxies, it has been discovered that the universe contains much more matter than is accounted for by visible objects; this unseen matter is known as dark matter. The ΛCDM model is the most accepted model of our universe, it suggests that about 69.2%±1.2% of the mass and energy in the universe is a cosmological constant, responsible for the current expansion of space, about 25.8%±1.1% is dark matter.
Ordinary matter is therefore only 4.9% of the physical universe. Stars and visible gas clouds only form about 6% of ordinary matter, or about 0.3% of the entire universe. There are many competing hypotheses about the ultimate fate of the universe and about what, if anything, preceded the Big Bang, while other physicists and philosophers refuse to speculate, doubting that information about prior states will be accessible; some physicists have suggested various multiverse hypotheses, in which our universe might be one among many universes that exist. The physical Universe is defined as all of their contents; such contents comprise all of energy in its various forms, including electromagnetic radiation and matter, therefore planets, stars and the contents of intergalactic space. The Universe includes the physical laws that influence energy and matter, such as conservation laws, classical mechanics, relativity; the Universe is defined as "the totality of existence", or everything that exists, everything that has existed, everything that will exist.
In fact, some philosophers and scientists support the inclusion of ideas and abstract concepts – such as mathematics and logic – in the definition of the Universe. The word universe may refer to concepts such as the cosmos, the world, nature; the word universe derives from the Old French word univers, which in turn derives from the Latin word universum. The Latin word was used by Cicero and Latin authors in many of the same senses as the modern English word is used. A term for "universe" among the ancient Greek philosophers from Pythagoras onwards was τὸ πᾶν, tò pân, defined as all matter and all space, τὸ ὅλον, tò hólon, which did not include the void. Another synonym was ho kósmos. Synonyms are found in Latin authors and survive in modern languages, e.g. the German words Das All and Natur for Universe. The same synonyms are found in English, such as everything, the cosmos, the world (as in the many-worlds interpr
Extraterrestrial life called alien life, is life that occurs outside of Earth and that did not originate from Earth. These hypothetical life forms may range from simple prokaryotes to beings with civilizations far more advanced than humanity; the Drake equation speculates about the existence of intelligent life elsewhere in the universe. The science of extraterrestrial life in all its forms is known as exobiology. Since the mid-20th century, there has been an ongoing search for signs of extraterrestrial life; this encompasses a search for current and historic extraterrestrial life, a narrower search for extraterrestrial intelligent life. Depending on the category of search, methods range from the analysis of telescope and specimen data to radios used to detect and send communication signals; the concept of extraterrestrial life, extraterrestrial intelligence, has had a major cultural impact, chiefly in works of science fiction. Over the years, science fiction communicated scientific ideas, imagined a wide range of possibilities, influenced public interest in and perspectives of extraterrestrial life.
One shared space is the debate over the wisdom of attempting communication with extraterrestrial intelligence. Some encourage aggressive methods to try for contact with intelligent extraterrestrial life. Others—citing the tendency of technologically advanced human societies to enslave or wipe out less advanced societies—argue that it may be dangerous to call attention to Earth. Alien life, such as microorganisms, has been hypothesized to exist in the Solar System and throughout the universe; this hypothesis relies on consistent physical laws of the observable universe. According to this argument, made by scientists such as Carl Sagan and Stephen Hawking, as well as well-regarded thinkers such as Winston Churchill, it would be improbable for life not to exist somewhere other than Earth; this argument is embodied in the Copernican principle, which states that Earth does not occupy a unique position in the Universe, the mediocrity principle, which states that there is nothing special about life on Earth.
The chemistry of life may have begun shortly after the Big Bang, 13.8 billion years ago, during a habitable epoch when the universe was only 10–17 million years old. Life may have emerged independently at many places throughout the universe. Alternatively, life may have formed less then spread—by meteoroids, for example—between habitable planets in a process called panspermia. In any case, complex organic molecules may have formed in the protoplanetary disk of dust grains surrounding the Sun before the formation of Earth. According to these studies, this process may occur outside Earth on several planets and moons of the Solar System and on planets of other stars. Since the 1950s, scientists have proposed that "habitable zones" around stars are the most places to find life. Numerous discoveries in such zones since 2007 have generated numerical estimates of Earth-like planets —in terms of composition—of many billions; as of 2013, only a few planets have been discovered in these zones. Nonetheless, on 4 November 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs in the Milky Way, 11 billion of which may be orbiting Sun-like stars.
The nearest such planet may be 12 light-years away, according to the scientists. Astrobiologists have considered a "follow the energy" view of potential habitats. A study published in 2017 suggests that due to how complexity evolved in species on Earth, the level of predictability for alien evolution elsewhere would make them look similar to life on our planet. One of the study authors, Sam Levin, notes "Like humans, we predict that they are made-up of a hierarchy of entities, which all cooperate to produce an alien. At each level of the organism there will be mechanisms in place to eliminate conflict, maintain cooperation, keep the organism functioning. We can offer some examples of what these mechanisms will be." There is research in assessing the capacity of life for developing intelligence. It has been suggested that this capacity arises with the number of potential niches a planet contains, that the complexity of life itself is reflected in the information density of planetary environments, which in turn can be computed from its niches.
Biologist David Zeigler has argued that, based on evolutionary convergence from many different ancestral groups on Earth, a worm form is a life form on other life-bearing planets. Life on Earth requires water as a solvent in place. Sufficient quantities of carbon and other elements, along with water, might enable the formation of living organisms on terrestrial planets with a chemical make-up and temperature range similar to that of Earth. More life based on ammonia has been suggested, though this solvent appears less suitable than water, it is conceivable that there are forms of life whose solvent is a liquid hydrocarbon, such as methane, ethane or propane. About 29 chemical elements play an active positive role in living organisms on Earth. About 95% of living matter is built upon only six elements: carbon, nitrogen, oxygen and sulfur; these six elements form the basic building blocks of all life on Earth, whereas most of the remaining elements are found only in trace amounts. The unique characteristics of carbon make it unlikely that it could be replaced on another planet, to generate the biochemistry necessary for life.
The carbon atom has the unique ability to make four strong chemical
Microsoft Windows is a group of several graphical operating system families, all of which are developed and sold by Microsoft. Each family caters to a certain sector of the computing industry. Active Windows families include Windows Embedded. Defunct Windows families include Windows Mobile and Windows Phone. Microsoft introduced an operating environment named Windows on November 20, 1985, as a graphical operating system shell for MS-DOS in response to the growing interest in graphical user interfaces. Microsoft Windows came to dominate the world's personal computer market with over 90% market share, overtaking Mac OS, introduced in 1984. Apple came to see Windows as an unfair encroachment on their innovation in GUI development as implemented on products such as the Lisa and Macintosh. On PCs, Windows is still the most popular operating system. However, in 2014, Microsoft admitted losing the majority of the overall operating system market to Android, because of the massive growth in sales of Android smartphones.
In 2014, the number of Windows devices sold was less than 25 %. This comparison however may not be relevant, as the two operating systems traditionally target different platforms. Still, numbers for server use of Windows show one third market share, similar to that for end user use; as of October 2018, the most recent version of Windows for PCs, tablets and embedded devices is Windows 10. The most recent versions for server computers is Windows Server 2019. A specialized version of Windows runs on the Xbox One video game console. Microsoft, the developer of Windows, has registered several trademarks, each of which denote a family of Windows operating systems that target a specific sector of the computing industry; as of 2014, the following Windows families are being developed: Windows NT: Started as a family of operating systems with Windows NT 3.1, an operating system for server computers and workstations. It now consists of three operating system subfamilies that are released at the same time and share the same kernel: Windows: The operating system for mainstream personal computers and smartphones.
The latest version is Windows 10. The main competitor of this family is macOS by Apple for personal computers and Android for mobile devices. Windows Server: The operating system for server computers; the latest version is Windows Server 2019. Unlike its client sibling, it has adopted a strong naming scheme; the main competitor of this family is Linux. Windows PE: A lightweight version of its Windows sibling, meant to operate as a live operating system, used for installing Windows on bare-metal computers, recovery or troubleshooting purposes; the latest version is Windows PE 10. Windows IoT: Initially, Microsoft developed Windows CE as a general-purpose operating system for every device, too resource-limited to be called a full-fledged computer. However, Windows CE was renamed Windows Embedded Compact and was folded under Windows Compact trademark which consists of Windows Embedded Industry, Windows Embedded Professional, Windows Embedded Standard, Windows Embedded Handheld and Windows Embedded Automotive.
The following Windows families are no longer being developed: Windows 9x: An operating system that targeted consumers market. Discontinued because of suboptimal performance. Microsoft now caters to the consumer market with Windows NT. Windows Mobile: The predecessor to Windows Phone, it was a mobile phone operating system; the first version was called Pocket PC 2000. The last version is Windows Mobile 6.5. Windows Phone: An operating system sold only to manufacturers of smartphones; the first version was Windows Phone 7, followed by Windows Phone 8, the last version Windows Phone 8.1. It was succeeded by Windows 10 Mobile; the term Windows collectively describes any or all of several generations of Microsoft operating system products. These products are categorized as follows: The history of Windows dates back to 1981, when Microsoft started work on a program called "Interface Manager", it was announced in November 1983 under the name "Windows", but Windows 1.0 was not released until November 1985.
Windows 1.0 was to achieved little popularity. Windows 1.0 is not a complete operating system. The shell of Windows 1.0 is a program known as the MS-DOS Executive. Components included Calculator, Cardfile, Clipboard viewer, Control Panel, Paint, Reversi and Write. Windows 1.0 does not allow overlapping windows. Instead all windows are tiled. Only modal dialog boxes may appear over other windows. Microsoft sold as included Windows Development libraries with the C development environment, which included numerous windows samples. Windows 2.0 was released in December 1987, was more popular than its predecessor. It features several improvements to the user memory management. Windows 2.03 changed the OS from tiled windows to overlapping windows. The result of this change led to Apple Computer filing a suit against Microsoft alleging infringement on Apple's copyrights. Windows 2.0