text:
Roguelike

Roguelike (or rogue-like) is a style of role-playing game traditionally characterized by a dungeon crawl through procedurally generated levels, turn-based gameplay, grid-based movement, and permanent death of the player character. Most roguelikes are based on a high fantasy narrative, reflecting their influence from tabletop role-playing games such as Dungeons & Dragons.

Though Beneath Apple Manor predates it, the 1980 game Rogue, which is an ASCII based game that runs in terminal or terminal emulator, is considered the forerunner and the namesake of the genre, with derivative games mirroring Rogues character- or sprite-based graphics. These games were popularized among college students and computer programmers of the 1980s and 1990s, leading to hundreds of variants. Some of the better-known variants include Hack, NetHack, Ancient Domains of Mystery, Moria, Angband, Tales of Maj'Eyal, and Dungeon Crawl Stone Soup. The Japanese series of Mystery Dungeon games by Chunsoft, inspired by Rogue, also fall within the concept of roguelike games.

The exact definition of a roguelike game remains a point of debate in the video game community. A "Berlin Interpretation" drafted in 2008 defined a number of high- and low-value factors that distinguished the "pure" roguelike games Rogue, NetHack and Angband from edge cases like Diablo. Since then, with more powerful home computers and gaming systems and the rapid growth of indie video game development, several new "roguelikes" have appeared, with some but not all of these high-value factors, nominally the use of procedural generation and permadeath, while often incorporating other gameplay genres, thematic elements, and graphical styles; common examples of these include Spelunky, FTL: Faster Than Light, The Binding of Isaac, Slay the Spire, and Hades. To distinguish these from traditional roguelikes, such games may be referred to as "rogue-lite" or "roguelike-like".

Origin
The term "roguelike" came from Usenet newsgroups around 1993, as this was the principal channel the players of roguelike games of that period were using to discuss these games, as well as what the developers used to announce new releases and even distribute the game's source code in some cases. With several individual groups for each game, it was suggested that with rising popularity of Rogue, Hack, Moria, and Angband, all of which shared common elements, that the groups be consolidated under an umbrella term to facilitate cross-game discussion. Debate among users of these groups ensued to try to find an encapsulating term that described the common elements, starting with, but after three weeks of discussion,  , based on Rogue being the oldest of these types of games, was picked as "the least of all available evils". By the time it was suggested that a group be created to discuss the development of these kind of games in 1998, the "roguelike" term was already established within the community. This usage parallels that of "Doom clone", a term used in 1990s that later evolved into more generic "first-person shooter".

Gameplay and design
Drawing from the concepts of tabletop role-playing games such as Dungeons & Dragons, nearly all roguelikes give the player control of a character, which they may customize by selecting a class, race, and gender, and adjusting attributes points and skills. At the start of the game, the character is placed at the top-most level of a dungeon, with basic equipment such as a simple weapon, armor, torches, and food. Following along the role-playing concept of a dungeon crawl, the player moves the character through the dungeon, collecting treasure which can include new weapons, armours, magical devices, potions, scrolls, food, and money, while having to fight monsters that roam the dungeon. Most combat is performed simply by attempting to move the character into the same space as the monster. The game then calculates the damage that the character and monster deal. Other types of attacks, such as firing an arrow or performing an offensive magic spell, can often be performed as well.

Defeating monsters earns the character experience points, and after earning enough points, the character will gain an experience level, improving their hit points, magic capability, and other attributes. Monsters may drop treasure to be looted. The character dies if they lose all their hit points. As most roguelikes feature the concept of permadeath, this represents the end of the game, and the player will need to restart the game with a newly made character. Roguelikes are nearly always turn-based, with the game only reacting when the player makes an action with the character. This allows players to evaluate a difficult situation, such as being cornered by several monsters, at their own pace and determine the best strategy.

The player generally has to explore the dungeon to reveal its contents, similar to a fog of war. Many roguelikes include visibility elements, such as a torch to provide illumination to see monsters in nearby squares, or line of sight to limit which monsters are visible from the player's position. Dungeons tend to be connected by stairs; lower dungeon levels generally are more difficult than higher ones, so that an underdeveloped character will have difficulty progressing too fast. Dungeon levels and the population of monsters and treasure within them are generated randomly using procedural generation, so no game is the same on subsequent playthroughs. Most roguelikes have an ultimate goal of either claiming an item located at the deepest level of the dungeon, or defeating a specific monster that lives on that level. Typical roguelikes assess the player's performance at the end of the game through a score based on the amount of treasure, money, experience earned, and how fast the player finished the game, if they managed to do so. The score is displayed in a ranked scoreboard to compare the player's performance on successive runs.

Key features
What gameplay elements explicitly define a "roguelike" game remains a point of debate within the video game community. There is broad agreement that roguelike games incorporate gameplay elements popularized by the text-based game Rogue (1980), which bore out many variations due to its success; As of 2015, several hundred games claiming to be roguelikes were available through the Steam game catalog, and the user-run wiki RogueBasin tracks hundreds of roguelikes and their development.

Some players and developers sought a more narrow definition for "roguelike" as variations on Rogue introduced new concepts or eschewed other principles that they felt moved the games away from the flavor of what Rogue was. At the International Roguelike Development Conference 2008 held in Berlin, Germany, players and developers established a definition for roguelikes known as the "Berlin Interpretation". The Berlin Interpretation set out a set of high-value and low-value factors, basing these lists on five canon roguelike games: ADOM, Angband, Linley's Dungeon Crawl, NetHack, and Rogue. The Interpretation was designed to determine "how roguelike a game is", noting that missing a factor does not eliminate a game from being a roguelike, nor does possessing the features make a game roguelike. John Harris of Game Set Watch exemplified this by using these criteria to numerically score some seemingly roguelike games; Linley's Dungeon Crawl and NetHack scored highest, earning 57.5 points of 60 available based on the Interpretation, while Toe Jam & Earl and Diablo, games commonly compared to roguelikes, earned only about half of the points.

The Berlin Interpretation defined nine high-value factors:
 * The game uses random dungeon generation to increase replayability. Games may include pre-determined levels such as a town level common to the Moria family where the player can buy and sell equipment, but these are considered to reduce the randomness set by the Berlin Interpretation. This "random generation" is nearly always based on some procedural generation approach rather than true randomness. Procedural generation uses a set of rules defined by the game developers to seed the generation of the dungeon generally to assure that each level of the dungeon can be completed by the player without special equipment, and also can generate more aesthetically pleasing levels. In addition, the appearances of magical items may vary from run to run. For example, a "bubbly" potion might heal wounds one game, then poison the player character in the next.
 * The game uses permadeath. Once a character dies, the player must begin a new game, known as a "run", which will regenerate the game's levels anew due to procedural generation. A "save game" feature will only provide suspension of gameplay and not a limitlessly recoverable state; the stored session is deleted upon resumption or character death. Players can circumvent this by backing up stored game data ("save scumming"), an act that is usually considered cheating; the developers of Rogue introduced the permadeath feature after introducing a save function, finding that players were repeatedly loading saved games to achieve the best results. According to Rogue's Michael Toy, they saw their approach to permadeath not as a means to make the game painful or difficult but to put weight on every decision the player made as to create a more immersive experience.
 * The game is turn-based, giving the player as much time as needed to make a decision. Gameplay is usually step-based, where player actions are performed serially and take a variable measure of in-game time to complete. Game processes (e.g., monster movement and interaction, progressive effects such as poisoning or starvation) advance based on the passage of time dictated by these actions.
 * The game is grid-based. Gameplay takes place on a uniform grid of tiles. This is usually presented in an ASCII representation of the dungeon.
 * The game is non-modal, in that every action should be available to the player regardless of where they are in the game. The Interpretation notes that shops like in Angband do break this non-modality.
 * The game has a degree of complexity due to the number of different game systems in place that allow the player to complete certain goals in multiple ways, creating emergent gameplay. For example, to get through a locked door, the player may attempt to pick the lock, kick it down, burn down the door, or even tunnel around it, depending on their current situation and inventory. A common phrase associated with NetHack is "The Dev Team Thinks of Everything" in that the developers seem to have anticipated every possible combination of actions that a player may attempt to try in their gameplay strategy, such as using gloves to protect one's character while wielding the corpse of a cockatrice as a weapon to petrify enemies by its touch.
 * The player must use resource management to survive. Items that help sustain the player, such as food and healing items, are in limited supply, and the player must figure out how to use these most advantageously to survive in the dungeon. USGamer further considers "stamina decay" as another feature related to resource management. The player's character constantly needs to find food to avoid starvation, which prevents the player from exploiting health regeneration by simply either passing turns for a long period of time or fighting very weak monsters at low level dungeons. Rich Carlson, one of the creators of an early roguelike-like Strange Adventures in Infinite Space, called this aspect a sort of "clock", imposing some type of deadline or limitation on how much the player can explore and creating tension in the game.
 * The game is focused on hack and slash-based gameplay, where the goal is to kill many monsters, and where other peaceful options do not exist.
 * The game requires the player to explore the world, and discover the purpose of unidentified items. In games featuring random generation, this must be done again every playthrough, as both the map and the appearances of items change.

Low-value factors from the Berlin Interpretation are:
 * The game is based on controlling only a single character throughout one playthrough.
 * Monsters have behavior that is similar to the player-character, such as the ability to pick up items and use them, or cast spells.
 * The game aimed to provide a tactical challenge that may require players to play through several times to learn the appropriate tactics for survival.
 * The game involves exploring dungeons which are made up of rooms and interconnecting corridors. Some games may have open areas or natural features, such as rivers, though these are considered against the Berlin Interpretation.
 * The game presents the status of the player and the game through numbers on the game's screen/interface.

Though this is not addressed by the Berlin Interpretation, roguelikes are generally single-player games. On multi-user systems, leaderboards are often shared between players. Some roguelikes allow traces of former player characters to appear in later game sessions in the form of ghosts or grave markings. Some games such as NetHack even have the player's former characters reappear as enemies within the dungeon. Multi-player turn-based derivatives such as TomeNET, MAngband, and Crossfire do exist and are playable online.

Early roguelikes
Early roguelikes were developed to be played on text-based user interfaces, commonly UNIX-based computer mainframes and terminals used at colleges and universities before transitioning to personal computers. Games used a mix of ASCII or ANSI characters to visually represent elements of the dungeon levels, creatures, and items on the level as in ASCII art. These games typically included one or two text lines presenting the player's current status at the bottom of the screen, and text-based menu screens to manage inventory, statistics, and other details.

The player's character was nearly always represented by the  character across text-based roguelikes, which had been chosen by the developers of Rogue to stand for "where you're at". Other common examples would include  for monetary treasure and   for a dragon. Later games would take advantage of colour-based text graphics to increase the variation of creature types, such as a red  for a red dragon that would shoot fire, while a green   could indicate a green dragon that would shoot acid. Players would use the keyboard, using one keypress to enter a command. Sociologist Mark R. Johnson described these commonality of symbols and glyphs as semiotic codes that gave an "aesthetic construction of nostalgia" by "depicting textual symbols as aesthetic forms in their own right" and consistency across multiple roguelikes.

With modern computer systems, users developed alternate means of displaying the game, such as graphical tilesets and Isometric-based graphical front ends, as well as interfaces that took advantage of keyboard and mouse UI controls, but otherwise still kept to the core tile-based gameplay.

As computers offered more advanced user interfaces, such as windows and point-and-click menus, many traditional roguelikes were modified to include support for having multiple windows. This was useful to not only show the character-based dungeon, but details on the character's inventory, the monster they were in battle with, and other status messages, in separate windows. Having access to multiple windows also allowed having menus to complete more complex commands. More recent examples of roguelikes that have stayed with ASCII art-based displays include Cogmind (2017) and Cataclysm: Dark Days Ahead (2013).

Rogue-lites and procedural death labyrinths
With computers and video game consoles capable of more advanced graphics and gameplay, numerous games have emerged that are loosely based on the classic roguelike design but diverge in one or more features. Many of these games use the concepts of procedurally generated maps and permadeath, while moving away from tile-based movement and turn-based gameplay, often using another gameplay genre such as action games or platformers. Other titles deriving from roguelike games are based on the observation that the traditional roguelikes are difficult with a steep learning curve, and a player may never complete these games over numerous play sessions, making these titles difficult to sell to a broader audience. These new games would include elements to reduce the difficulty as to draw in a larger audience.

Many games with some of the Berlin Interpretation elements call themselves "roguelike", but bear little resemblance to the original Rogue, causing confusion and dilution of the term. Some players of the Berlin Interpretation roguelikes disliked the dilution of the term, believing that in the 1990s and 2000s, the term "roguelikes" served well to distinguish games that forwent aesthetics to focus on depth of gameplay from games more comparable to interactive movies, particularly games that incorporated real-time gameplay elements which tended to reduce the game's complexity. As such, the term "rogue-lite" or "roguelike-like" has been used by some to distinguish these games that possess some, but not all, of the Berlin Interpretation features from those that exactly meet the Berlin roguelike definition. The phrase "procedural death labyrinth" has also been applied to such games, as they retain the notion of permadeath and random level generation but lack the other high-value factors normally associated with roguelike games.

Rogue-lites favor short gameplay runs with victory conditions, in contrast to some traditional roguelikes that can be played indefinitely. The shortness of a single gameplay run in rogue-lites can motivate players to continually replay the game in the hope of reaching completion, making replayability a high-value factor in these types of games. Game journalist Joshua Bycer observed that several games considered as rogue-lites feature fixed events, even if the means to reach that may be through procedural generation, whereas a roguelike game typically lacks this level of predictability. For example, several rogue-lites require the player to travel a fixed number of biomes, each which culminates in a boss fight, such as Rogue Legacy. Associated with their short length, many rogue-lites feature a metagame, whereby achieving certain goals will unlock persistent features such as the ability to select a new character at the start of the game or the addition of new items and monsters in the procedural generation of the game's levels. Alternatively, each run through rogue-lite may be to collect resources which one then advances their character within the metagame, and a player may simply forgo a complete run once they have collected sufficient materials for that advancement.

Several rogue-lites feature daily challenges, in which a preset random seed is used to generate the game's levels in a deterministic fashion so that each player will have the same encounters; players attempt to complete the game through those levels or otherwise get the highest score through online leaderboards. Rogue-lites may also allow the player to enter the random seed directly as to be able to rechallenge the same set of levels or share a difficult set of levels with other players.

US Gamer further identified games they consider edge cases of being roguelikes or rogue-lites, as they are inspired by Rogue, and "that stray a bit further from the genre but still manage to scratch the same itch as a great roguelike". These include games such as the Diablo series, ToeJam & Earl, and Dwarf Fortress, the latter which retains the classic ASCII art-approach to gameplay as traditional roguelikes. Ars Technica writer Richard C. Moss alternatively suggested that the term "roguelike" is less necessarily about any specific genre definition but instead the idea that "games can be deep, inventive, challenging, and endlessly compelling experiences through their rules and their systems alone".

Subgenres within roguelikes
In considering the popularity of roguelikes that deviate from the Berlin Interpretation, the rogue-lites, some subgenres have emerged.

Action roguelikes are typically based on combining gameplay of action games within roguelikes instead of the turn-based gameplay. Spelunky is an example of combining a platform game with the roguelike formula, while The Binding of Isaac and Enter the Gungeon are effective roguelike shooter games. Within action roguelikes have also emerged a minimalistic shooter roguelike, with Vampire Survivors as a leading example; in such games, the player generally fights through wave after wave of enemies, their character often fully firing or using all possible attacks without player intervention, with the ability to expand their character through a random selection of power-ups as they defeat more enemies.

Another type of roguelike subgenre is the roguelike deck-builder, where combat is resolved by using cards or an equivalent object. These games are inspired by physical living card games, where the player builds their deck over the course of the game, forcing them to plan strategy on the fly. While the 2014 game Dream Quest is considered the first example of such a video game, the popularity of the genre was cemented with Slay the Spire in 2017.

Early history (1975–1980)
The creation of roguelike games came from hobbyist programmers and computer hackers, attempting to create games for the nascent computer field in the early 1980s, particularly influenced by the 1975 text adventure game Colossal Cave Adventure (often simply titled Adventure, or advent on filesystems without long filenames), and from the high fantasy setting of the tabletop game Dungeons & Dragons. Some elements of the roguelike genre were present in dungeon crawlers written for the PLATO system. This includes pedit5 (1975) believed to be the first dungeon crawl game, and featured random monster encounters, though only used a single fixed dungeon level. pedit5 inspired similar PLATO-based dungeon crawlers dnd (1975), orthanc (1978), Moria (1978), and avatar (1979). It is unclear if these PLATO games inspired the roguelike genre as there is no evidence that the early roguelike creators had access to these games. The core roguelike games were developed independently of each other, many of the developers not learning about their respective projects until several years after the genre took off.

Roguelike games were initially developed for computing environments with limited memory, including shared mainframe systems and early home computers; this limitation prevented developers from retaining all but a few dungeon levels in memory while the game was running, leading to procedural generation to avoid the memory storage issue. Procedural generation led to high replayability, as no two games were alike.

Concurrent variants
Though the term "roguelike" derives from the 1980 game Rogue, the first known game with the core roguelike gameplay elements was Beneath Apple Manor (1978), written by Don Worth for the Apple II; Beneath Apple Manor is also recognized as the first commercial roguelike game. The game, inspired by Worth's enjoyment of Dungeons & Dragons roleplaying, included procedural generation using a modification of the random maze generator from the game Dragon Maze, role-playing elements for the characters, tile-based movement and turn-based combat. Though Beneath Apple Manor predated Rogue, it was not as popular as Rogue: Rogue had advantage of being distributed over ARPANET which many college students had easy access to, while Beneath Apple Manor was packaged and sold by hand by Worth either at local stores or through mail fulfillment.

Another early roguelike whose development pre-dated Rogue was Sword of Fargoal (1982), developed by Jeff McCord starting in 1979. The game was based on GammaQuest, an earlier title McCord had created on the Commodore PET which he shared locally with friends while a student at Henry Clay High School in Kentucky; the game itself was based on a Dungeons & Dragons campaign he had run himself in the prior years. Before graduating and attending the University of Tennessee in 1981, he had started work on GammaQuest II, which required the player to navigate through randomly generated dungeon levels, acquire a sword, and make it back to the surface with that sword through more randomly generated levels. The more advanced computers available at the school, such as the VIC-20, enabled him to expand out the game further from the highly limited memory on the PET. On seeing the prospects of selling computer software, he eventually got a publication deal with Epyx, where they helped him to refine the marketing of the game, renaming it Sword of Fargoal, and giving him access to the more powerful Commodore 64, enabling him to use graphics and sound as part of the game. The game was considered a success, and when it was ported to the PC in 1983, it out-shone Rogues PC release the same year due to Sword of Fargoals superior graphics and sound.

Rogue
Rogue was written by Glenn Wichman and Michael Toy in 1980 while students at the University of California, Santa Cruz. The game was inspired by Toy's prior experience in playing the 1971 Star Trek game and programming clones of it for various other computer systems. It was also inspired by interactive fiction Adventure. While looking for a way to randomize the experience of Adventure, they came across Ken Arnold's curses library that enabled them to better manipulate characters on the terminal screen, prompting Toy and Wichman to create a graphical-like randomized adventure game. They created the story of the game by having the player seek out the "Amulet of Yendor", "Yendor" being "Rodney" spelled backwards, the name of the wizard they envisioned had created the dungeon. Rogue was originally executed on a VAX-11/780 computer; its limited memory forced them to use a simple text-based interface for the game. Toy eventually dropped out of school but got a job at the computing labs at University of California, Berkeley, where he met with Arnold. Arnold helped to optimize the curses code and implement more features into the game.

Rogue proved popular with college students and computer researchers at the time, including Ken Thompson; Dennis Ritchie had joked at the time that Rogue was "the biggest waste of CPU cycles in history". Its popularity led to the game's inclusion on BSD UNIX v4.2 in 1984, though at that time, without its source code. Toy and Arnold had anticipated selling Rogue commercially and were hesitant about releasing it; Toy would go on to meet Jon Lane at Olivetti, and together they would go on to create the company A.I. Design to port the games for various home systems along with publishing support by Epyx, later bringing Wichman back to help.

Following evolution (1980–1995)
The hierarchy of the major Roguelike games that are known to descend from Rogue. Solid lines represent games developed from the parent's source code, while dotted lines represent games that were inspired by the parent game. The popularity of Rogue led developers to create their own versions of the game, though their efforts were originally limited by the lack of access to Rogue's source, which was not released until BSD v4.3 in 1986. These developers resorted to building games from scratch similar to Rogue but with features that they wanted to see. These versions would be distributed with source code, and along with the original Rogue source, other developers were able to create software forks of the games, adding in new monsters, items, and gameplay features, creating several dozen variants. This process was aided by switching code to languages with better data typing, including object-oriented and scripting languages, and cleaning up and modularizing the code so that contributors can better follow where changes can be made.

While there are some direct variants of Rogue, such as Brogue, most variants of Rogue could be classified into two branches based on two key games, Moria and Hack, that were developed in the spirit of Rogue.

Moria-based
Moria (1983) was developed by Robert Alan Koeneke while a student at University of Oklahoma, inspired by both Adventure and Rogue. Having access to a VAX-11/780, but without the source to Rogue due to computer administrator restrictions, he began trying to recreate Rogue but specifically flavored with the complex cave maze of the same name in J.R.R. Tolkien's Middle Earth stories. Following Tolkien's fiction, the player's goal was to descend to the depths of Moria to defeat the Balrog, akin to a boss battle. As with Rogue, levels were not persistent: when the player left the level and then tried to return, a new level would be procedurally generated. Among other improvements to Rogue, Koeneke included a persistent town at the highest level where players could buy and sell equipment, and the use of data structures within the Pascal language allowed him to create a more diverse bestiary within the game. He got help from several playtesters as well as another student, Jimmey Wayne Todd, who helped to program a deeper character generation system. UMoria (short for UNIX Moria) is a close variation on Moria by Jim E. Wilson, making the game more portable to a larger variety of computers while fixing various bugs.

Angband (1990) was developed by Alex Cutler and Andy Astrand while attending the University of Warwick. Having played UMoria, they wanted to expand the game even further. Working from UMoria's code, they increased the number of levels and monsters, flavored the game based on Angband, the massive fortress controlled by Morgoth from Tolkien's fiction, and incorporated more of the deadlier creatures described within the Middle Earth mythology. They kept the Balrog as a difficult creature that must be overcome at a mid-game level, while Morgoth became the final boss the player must defeat to win the game. Following Cutler and Astrand's graduation, Sean March and Geoff Hill took over the development to see the game through to a public release outside of the university, adding in elements such as giving the player a sense of the rewards and dangers of a level when they entered it the first time.

Once Angband was released to the public via USENET, there were efforts to have code maintainers (the "devteam") to fix bugs, clean up the code and implement suggestions into the code. Due to numerous shifts in those maintaining the code (due to other obligations), and the number of potential user suggestions to include, Angband would become highly forked, leading to a number of Angband variants; at least sixty known variants exist with about a half dozen still under active development. One significant fork was ZAngband (1994) (short for Zelazny Angband), which expanded on Angband and altered the theme towards Roger Zelazny's The Chronicles of Amber. The ZAngband codebase would be used to create Troubles of Middle Earth (ToME) in 2002, which later swapped out the Tolkien and Zelazny fiction setting for a new original one to become Tales of Maj'Eyal (2009). The vanilla Angband remains in development today by the devteam.

Hack-based
Hack (1982) was developed by Jay Fenlason with help from Kenny Woodland, Mike Thome, and Jonathan Payne, students at Lincoln-Sudbury Regional High School at the time, while participating in the school's computer lab overseen by Brian Harvey. Harvey had been able to acquire a PDP-11/70 minicomputer for the school and instituted a course curriculum that allowed students to do whatever they wanted on the computers, including playing games, as long as they had completed assignments by the end of each semester. Fenlason, Woodland, Thome, and Payne met through these courses and became a close group of friends and competent programmers. Harvey had invited the group to the computer labs at UC Berkeley where they had the opportunity to use the mainframe systems there, and were introduced to Rogue, inspiring them to create their own version as their class project. Fenlason had created a list of features they wanted to improve upon in Rogue such as having a level's layout saved once the player moved off that level. They approached Toy and Arnold at a local USENIX conference for the source code to Rogue, but were refused, forcing them to develop the routines from scratch. The resulting program, Hack, stayed true to the original Dungeons and Dragons influences, and derived its name from being both a "hack and slash" game as well as a programming hack to recreate Rogue without having access to its source code. Fenlason was not able to include all the desired features, and his involvement in Hack's development concluded after the students had left the school. Fenlason had provided the source code to Hack to the USENIX conferences to be distributed on their digital tapes, from which it was later discovered and built upon through USENET newsgroups, porting it to various systems. Like Angband, the maintainership of the Hack code passed through several hands, and some variants were created by different forks.

Hack would eventually be dropped in favor of NetHack (1987). When Mike Stephenson, an analyst at a computer hardware manufacturer, took maintainership of Hack's code, he improved it, taking suggestions from Izchak Miller, a philosophy professor at University of Pennsylvania, and Janet Walz, another computer hacker. Calling themselves the DevTeam, they began to make major modifications to Hack's code. They named their new version NetHack, in part due to their collaboration over the game being done through USENET. NetHack's major deviations from Hack were the introduction of a wider variety of monsters, borrowing from other mythologies and lores, including anachronistic and contemporary cultural elements (such as a tourist class with a flash-bulb camera inspired by Terry Pratchett's Discworld series) in the high fantasy setting, and the use of pre-defined levels with some procedural elements that the player would encounter deeper in the dungeons. Further iterations of the game included branching pathways through the dungeon and optional character-based quests that could grant the player an extremely useful item to complete the game. Though the DevTeam released the code publicly, they carefully maintained who could contribute to the code base to avoid excessive forking of the vanilla game, and remain relatively quiet about suggested improvements to each release, working in relatively secrecy from its player base.

Ancient Domains of Mystery (1994), or ADOM for short, derived from concepts presented in NetHack. ADOM was originally developed by Thomas Biskup while a student at Technical University of Dortmund. After playing through Rogue and Hack, he came to NetHack and was inspired by the game but dismayed at the complexity and elements he found unnecessary or distracting. Biskup created ADOM from scratch with the aim of creating a more story-driven game than NetHack that kept the depth of gameplay with a focused theme and setting. The resulting game featured several different dungeons, many generated procedurally, connected through an overworld map of the fictional realm of Ancardia, and would have the player complete various quests in those dungeons to progress the game. A major feature was the influence of Chaos forces through unsealed portals, which the player would have to close. While in areas affected by Chaos, the player's character would become tainted, causing mutations that could be either detrimental or beneficial. ADOM, like NetHack and Angband, would gain a devteam to maintain the code and implement updates and patches to avoid excessive forking.

Other variants
Not all early roguelikes were readily classified as Hack or Moria descendants. Larn (1986), developed by Noah Morgan, borrowed concepts from both Hack (in that there are persistent and fixed levels) and Moria (in the availability of a shop level and general difficulty increasing with dungeon level), but while these two games have spiraled in size to take multiple play sessions to complete, Larn was aimed to be completed in a single session. Larn also uses a fixed-time feature, in that the player had only so many turns to complete a goal, though there were ways to jump back in time as to extend play. Omega, developed by Laurence Brothers in the late 1980s, is credited with introducing an overworld concept to the roguelike genre, prior to the feature's appearance in ADOM. Omega was often remembered for its odd inventory approach in which the player would have to pick up an object, considering it being held, and then moving that object to a bag or an equipment slot. Linley's Dungeon Crawl (1995) was created by Linley Henzell and featured a skill-based character progression system, in which experience points could be used to improve specific skills, such as weapon proficiency or trap detection. One fork of this would form the basis for Dungeon Crawl Stone Soup (2006). SSI's Dungeon Hack (1993) offered randomized dungeons and permadeath within AD&D 2nd Edition rules.

Mystery Dungeon games (1993–onward)
Through 1993, roguelikes primarily existed in computer space, and no home console variants had yet existed. Two of the earliest-known attempts were Sega's Fatal Labyrinth (1990) and Dragon Crystal (1990), but which lacked the depth of a typical computer-based roguelike. Neither proved to be successful games. There was also the 1991 Japanese exclusive Game Boy game Cave Noire from Konami, that centred on four distinct roguelike questlines divided into ten difficulty levels.

Chunsoft had gained success by developing the Dragon Quest series, a series which established fundamental aspects of the computer role-playing game genre, popular for Western computer audiences, into a more streamlined approach better suited for Japanese players that preferred consoles. With roguelikes starting to gain popularity, Chunsoft's developers believed they could do a similar treatment for that genre to make it better suited for Japanese audiences. Chunsoft's Koichi Nakamura stated their intent was to take Rogue and make it "more understandable, more easy-to-play version" of the title that could be played on consoles. This led to the creation of the Mystery Dungeon, with the first title being Torneko no Daibōken: Fushigi no Dungeon (トルネコの大冒険 不思議のダンジョン) (1993) based on the Dragon Quest series. Several changes to the roguelike formula had to be made for this conversion: they had developed ways to reduce the difficulty of the roguelike by using progressively more difficult dungeons that were randomly generated, and made permadeath an option by selection of difficulty level. An added benefit for Torneko no Daibōken was that it used the established Dragon Quest 4 setting and the character Torneko, helping to make the game familiar to its planned audience and giving a story for the player to follow. While Torneko no Daibōken did not sell as well as typical Dragon Quest games, it was successful enough for Chunsoft to develop a second title based on a wholly original character and setting, Mystery Dungeon: Shiren the Wanderer, released in 1995. Chunsoft found that they were more creative with how they developed the game without the need to respect an existing property. Since then, Chunsoft has developed over 25 games in the Mystery Dungeon series for various platforms, In addition to their Shiren titles, many of the other Chunsoft Mystery Dungeon games span various franchises, including Chocobo series based on Final Fantasy, Pokémon Mystery Dungeon based on Pokémon, and a crossover with Atlus' Etrian Odyssey in Etrian Mystery Dungeon. Several titles in the Mystery Dungeon series were popular, and would become a staple of the Japanese video game market.

A primary difference between the Mystery Dungeon games and Western roguelikes following the Berlin Interpretation is the lack of permadeath – in Mystery Dungeon games, player-characters may die or become too injured, resetting their progress to the start of the dungeon, but the games typically provide means to store and recover equipment and other items from the previous run. The Mystery Dungeon games were not as successful in Western markets when published there, as the target players – younger players who likely had not experienced games like Rogue – found the lack of a traditional role-playing game save system odd.

Other Japanese role-playing games would incorporate random dungeon generation as part of their design, mimicking part of the nature of roguelikes, and were considered roguelike titles when published in Western markets. Such titles include Azure Dreams, Dark Cloud, Shining Soul, and Baroque. The massively multiplayer online role playing game Final Fantasy XIV added a randomly-generated Deep Dungeon that was inspired by the procedural generation of roguelikes.

Continued development in Western markets (2002–onward)
Though new classical roguelike variants would continue to be developed within the Western market, the genre languished as more advanced personal computers capable of improved graphics capabilities and games that utilized these features became popular. However, some of these new graphical games drew influence for roguelike concepts, notably action role-playing games like Blizzard Entertainment's Diablo (1996). Diablo's creator, David Brevik, acknowledged that games like Rogue, NetHack, Telengard and other roguelikes influenced the design of Diablo, including the nature of randomly generated dungeons and loot.

Existing roguelikes continue to be developed: a sequel to ADOM successfully received crowd funding in 2012, while NetHack's first major release in ten years in 2015 is set to help the DevTeam expand the game further. New roguelikes that adhere to core Berlin Interpretation rules are still being created, including Dungeon Crawl Stone Soup (2006), Dungeons of Dredmor (2011), and Dragon Fin Soup (2015). A subclass of "coffeebreak roguelikes" that could be completed in a short period of time have developed, often derived from entries in the Seven Day Roguelike Challenge; examples include such as DoomRL (2013) and Desktop Dungeons (2013) Some games would also take advantage of the ease of developing in the tile-based ASCII interfaces common to roguelikes. For example, the highly popular Dwarf Fortress (2006) uses the roguelike interface atop a construction and management simulation, and would serve as a major inspiration for Minecraft, while SanctuaryRPG (2014) is a more traditional turn-based role playing game featuring a scripted story that uses an ASCII interface and roguelike gameplay elements. UnReal World (1992), the game that is considered to be the forerunner of the survival game genre, and which frequently uses procedural generation to create the worlds that players must survive in, was developed by Sami Maaranen and was influenced by roguelikes, with its initial interface being similar to that of NetHack.

Growth of the rogue-lite (2005–onward)
The roguelike genre saw a resurgence in Western markets after 2000 through independent developers who created a new subgenre designated "rogue-lite", though the games are also sometimes called "roguelike-likes". Indie developers began to incorporate roguelike elements into genres not normally associated with roguelikes, creating games that would form the basis of this new subgenre. Two of the earliest cited examples of rogue-lites are Strange Adventures in Infinite Space (2002) and its sequel Weird Worlds: Return to Infinite Space (2005) by Digital Eel, both space exploration games that included randomly generated planets and encounters, and permadeath. Digital Eel based their work on the space exploration game Starflight along with roguelikes like NetHack but wanted to provide a shorter experience that would be easier to replay, akin to tabletop beer and pretzels games like Deathmaze and The Sorcerer's Cave that has elements in common with roguelikes.

Spelunky (2008), released shortly after the formation of the Berlin Interpretation, is considered to be a major contribution to the growth of indie-developed rogue-lites. Spelunky was developed by Derek Yu, who wanted to take the deep gameplay that is offered by roguelikes and combine it with the ease and pick-up-and-play of a platformer. The result was a platform game incorporating the notion of permadeath in which the player takes an explorer character through randomly-generated caves. The intent was to create "deep" gameplay in which the game could be replayed over and over again, with the randomly generated situations driving the need for the player to develop novel, emergent strategies on the fly. Developer Jason Rohrer stated that Spelunky "totally revamped my thinking about single-player videogame design". Edmund McMillen, the developer of The Binding of Isaac (2011), and Kenny and Teddy Lee, the co-developers of Rogue Legacy (2012), credit Yu's approach with Spelunky as showing how to distill down the nature of a traditional roguelike to apply it to other gaming genres which they had done for their rogue-lites. Justin Ma and Matthew Davis, the co-developers of FTL: Faster Than Light (2012), credited both Weird Worlds: Return to Infinite Space and Spelunky as part of their influence for FTL. All of these games earned critical praise, and their success has led to a more modern resurgence in rogue-lites since their release.

The newfound success in rogue-lites is considered part of a larger trend in those that play both board and computer games, looking for "rich play experiences", as described by 100 Rogues developer Keith Burgun, that more popular titles may not always offer. David Bamguart of Gaslamp Games stated that there is a thrill of the risk inherent in rogue-lites with random generation and permadeath, helping the player become more invested in the fate of their player character: "The deadly precariousness inherent to the unknown environments of roguelikes gives that investment a great deal of meaning." Additionally, many of these newer rogue-lites strive to address the apparent high difficulty and ruthlessness that traditional roguelikes were known for, and newer players will be able to find more help through user-generated game guides and walkthroughs made possible through wide Internet accessibility. Fabien Fischer offers that players have taken to independently developed rogue-lites as they have tired from "superficial gameplay, whitewashing spectacle, the content craze, and Skinner Box design" in titles produced by AAA developers and publishers.

McMillen of The Binding of Isaac said that including roguelike elements into other game mechanics can be difficult due to the complex interfaces roguelikes tend to have, but eventually "it becomes an increasingly beautiful, deep, and everlasting design that allows you to generate a seemingly dynamic experience for players, so that each time they play your game they're getting a totally new adventure". Procedural-generated world lets developers create many hours worth of game content without spending resources on designing detailed worlds.

Examples of successful games that have integrated roguelike components into other genres include:

 * Dead Cells, a roguelike incorporated with Metroidvania-style of platform games
 * Slay the Spire, bringing roguelike progression to a deck building game
 * Crypt of the Necrodancer which uses a rhythm game-style approach in a roguelike dungeon
 * Enter the Gungeon which establishes roguelike progression in a shoot 'em up
 * Vampire Survivors, a minimalistic roguelike shoot 'em up.

Hades, a roguelike action role-playing game, was built to strongly incorporate elements of non-linear narrative into the game, giving the reason for the player to continually delve into replaying the game, and helped to draw in players to the roguelike genre that otherwise had been put off by its high difficulty level before.

Community
The roguelike genre has developed with the expansion of both classical roguelikes and rogue-lite titles, a dedicated fan community has come about to not only discuss games within it but to craft their own tales of near-death adventures or amusing stories in roguelikes. Within this community, there is strong interest in developing roguelikes. The 7 Day Roguelike challenge (7DRL) was born out of a USENET newsgroup in 2005 for roguelike developers, informally challenging them to create the core of a novel roguelike within 7 days to be submitted for judging and play by the public. The competition has continued annually each year, since growing from 5–6 entries in 2005 to over 130 in 2014. In the spirit of the 2008 International Roguelike Conference, the "Roguelike Celebration" was held for the first time in September 2016 in San Francisco where several past and present roguelike developers gathered to discuss the history and future direction of the genre. It has since been organized again in 2017, 2018 and 2019 in San Francisco, and as virtual events in 2020, 2021 and 2022.

title: Roguelike


text:
Disruptive innovation

In business theory, disruptive innovation is innovation that creates a new market and value network or enters at the bottom of an existing market and eventually displaces established market-leading firms, products, and alliances. The term, "disruptive innovation" was popularized by the American academic Clayton Christensen and his collaborators beginning in 1995, but the concept had been previously described in Richard N. Foster's book "Innovation: The Attacker's Advantage" and in the paper Strategic Responses to Technological Threats.

Not all innovations are disruptive, even if they are revolutionary. For example, the first automobiles in the late 19th century were not a disruptive innovation, because early automobiles were expensive luxury items that did not disrupt the market for horse-drawn vehicles. The market for transportation essentially remained intact until the debut of the lower-priced Ford Model T in 1908. The mass-produced automobile was a disruptive innovation, because it changed the transportation market, whereas the first thirty years of automobiles did not.

Disruptive innovations tend to be produced by outsiders and entrepreneurs in startups, rather than existing market-leading companies. The business environment of market leaders does not allow them to pursue disruptive innovations when they first arise, because they are not profitable enough at first and because their development can take scarce resources away from sustaining innovations (which are needed to compete against current competition). Small teams are more likely to create disruptive innovations than large teams. A disruptive process can take longer to develop than by the conventional approach and the risk associated to it is higher than the other more incremental, architectural or evolutionary forms of innovations, but once it is deployed in the market, it achieves a much faster penetration and higher degree of impact on the established markets.

Beyond business and economics disruptive innovations can also be considered to disrupt complex systems, including economic and business-related aspects. Through identifying and analyzing systems for possible points of intervention, one can then design changes focused on disruptive interventions.

Usage history
 Christensen's Types of Innovation
 * Sustaining
 * An innovation that does not significantly affect existing markets. It may be either:

 * Evolutionary
 * An innovation that improves a product in an existing market in ways that customers are expecting (e.g., fuel injection for gasoline engines, which displaced carburetors.)

 * Revolutionary (discontinuous but sustaining)
 * An innovation that is unexpected, but nevertheless does not affect existing markets (e.g., the first automobiles in the late 19th century, which were expensive luxury items, and as such very few were sold)

 * Disruptive
 * An innovation that creates a new market or enters at the bottom of an existing market by providing a different set of values, which ultimately (and unexpectedly) overtakes incumbents (e.g., the lower-priced, affordable Ford Model T, which displaced horse-drawn carriages)

The term disruptive technologies was coined by Clayton M. Christensen and introduced in his 1995 article Disruptive Technologies: Catching the Wave, which he cowrote with Joseph Bower. The article is aimed at both management executives who make the funding or purchasing decisions in companies, as well as the research community, which is largely responsible for introducing the disruptive vector to the consumer market. He describes the term further in his book The Innovator's Dilemma. Innovator's Dilemma explored the case of the disk drive industry (the disk drive and memory industry, with its rapid technological evolution, is to the study of technology what fruit flies are to the study of genetics, as Christensen was told in the 1990s) and the excavating and Earth-moving industry (where hydraulic actuation slowly, yet eventually, displaced cable-actuated machinery). In his sequel with Michael E. Raynor, The Innovator's Solution, Christensen replaced the term disruptive technology with disruptive innovation because he recognized that most technologies are not intrinsically disruptive or sustaining in character; rather, it is the business model that identifies the crucial idea that potentiates profound market success and subsequently serves as the disruptive vector. Comprehending Christensen's business model, which takes the disruptive vector from the idea borne from the mind of the innovator to a marketable product, is central to understanding how novel technology facilitates the rapid destruction of established technologies and markets by the disruptor. Christensen and Mark W. Johnson, who cofounded the management consulting firm Innosight, described the dynamics of "business model innovation" in the 2008 Harvard Business Review article "Reinventing Your Business Model". The concept of disruptive technology continues a long tradition of identifying radical technological change in the study of innovation by economists, and its implementation and execution   by its management at a corporate or policy level.

According to Christensen, "the term 'disruptive innovation' is misleading when it is used to refer to the derivative, or 'instantaneous value', of the market behavior of the product or service, rather than the integral, or 'sum over histories', of the product's market behavior."

In the late 1990s, the automotive sector began to embrace a perspective of "constructive disruptive technology" by working with the consultant David E. O'Ryan, whereby the use of current off-the-shelf technology was integrated with newer innovation to create what he called "an unfair advantage". The process or technology change as a whole had to be "constructive" in improving the current method of manufacturing, yet disruptively impact the whole of the business case model, resulting in a significant reduction of waste, energy, materials, labor, or legacy costs to the user.

In keeping with the insight that a persuasive advertising campaign can be just as effective as technological sophistication at bringing a successful product to market, Christensen's theory explains why many disruptive innovations are not advanced or useful technologies, rather combinations of existing off-the-shelf components, applied shrewdly to a fledgling value network.

Online news site TechRepublic proposes an end using the term, and similar related terms, suggesting that, as of 2014, it is overused jargon.

Definition

 * Disruption is a process, not a product or service, that occurs from the nascent to the mainstream
 * Originates in low-end (less demanding customers) or new market (where none existed) footholds
 * New firms don't catch on with mainstream customers until quality catches up with their standards
 * Success is not a requirement and some business can be disruptive but fail
 * New firm's business model differs significantly from incumbent

Christensen continues to develop and refine the theory and has accepted that not all examples of disruptive innovation perfectly fit into his theory. For example, he conceded that originating in the low end of the market is not always a cause of disruptive innovation, but rather it fosters competitive business models, using Uber as an example. In an interview with Forbes magazine he stated:"'Uber helped me realize that it isn’t that being at the bottom of the market is the causal mechanism, but that it’s correlated with a business model that is unattractive to its competitor'."

Entrepreneur Chris Dixon cited the theory for the idea that "the next big thing always starts out being dismissed as a 'toy'."

Theory
The current theoretical understanding of disruptive innovation is different from what might be expected by default, an idea that Clayton M. Christensen called the "technology mudslide hypothesis". This is the simplistic idea that an established firm fails because it doesn't "keep up technologically" with other firms. In this hypothesis, firms are like climbers scrambling upward on crumbling footing, where it takes constant upward-climbing effort just to stay still, and any break from the effort (such as complacency born of profitability) causes a rapid downhill slide. Christensen and colleagues have shown that this simplistic hypothesis is wrong; it doesn't model reality. What they have shown is that good firms are usually aware of the innovations, but their business environment does not allow them to pursue them when they first arise, because they are not profitable enough at first and because their development can take scarce resources away from that of sustaining innovations (which are needed to compete against current competition). In Christensen's terms, a firm's existing value networks place insufficient value on the disruptive innovation to allow its pursuit by that firm. Meanwhile, start-up firms inhabit different value networks, at least until the day that their disruptive innovation is able to invade the older value network. At that time, the established firm in that network can at best only fend off the market share attack with a me-too entry, for which survival (not thriving) is the only reward.

In the technology mudslide hypothesis, Christensen differentiated disruptive innovation from sustaining innovation. He explained that the latter's goal is to improve existing product performance. On the other hand, he defines a disruptive innovation as a product or service designed for a new set of customers. "Generally, disruptive innovations were technologically straightforward, consisting of off-the-shelf components put together in a product architecture that was often simpler than prior approaches. They offered less of what customers in established markets wanted and so could rarely be initially employed there. They offered a different package of attributes valued only in emerging markets remote from, and unimportant to, the mainstream."

Christensen also noted that products considered as disruptive innovations tend to skip stages in the traditional product design and development process to quickly gain market traction and competitive advantage. He argued that disruptive innovations can hurt successful, well-managed companies that are responsive to their customers and have excellent research and development. These companies tend to ignore the markets most susceptible to disruptive innovations, because the markets have very tight profit margins and are too small to provide a good growth rate to an established (sizable) firm. Thus, disruptive technology provides an example of an instance when the common business-world advice to "focus on the customer" (or "stay close to the customer", or "listen to the customer") can be strategically counterproductive.

While Christensen argued that disruptive innovations can hurt successful, well-managed companies, O'Ryan countered that "constructive" integration of existing, new, and forward-thinking innovation could improve the economic benefits of these same well-managed companies, once decision-making management understood the systemic benefits as a whole.

Christensen distinguishes between "low-end disruption", which targets customers who do not need the full performance valued by customers at the high end of the market, and "new-market disruption", which targets customers who have needs that were previously unserved by existing incumbents.

Low-end disruption
"Low-end disruption" occurs when the rate at which products improve exceeds the rate at which customers can adopt the new performance. Therefore, at some point the performance of the product overshoots the needs of certain customer segments. At this point, a disruptive technology may enter the market and provide a product that has lower performance than the incumbent but that exceeds the requirements of certain segments, thereby gaining a foothold in the market.

In low-end disruption, the disruptor is focused initially on serving the least profitable customer, who is happy with a good enough product. This type of customer is not willing to pay premium for enhancements in product functionality. Once the disruptor has gained a foothold in this customer segment, it seeks to improve its profit margin. To get higher profit margins, the disruptor needs to enter the segment where the customer is willing to pay a little more for higher quality. To ensure this quality in its product, the disruptor needs to innovate. The incumbent will not do much to retain its share in a not-so-profitable segment, and will move up-market and focus on its more attractive customers. After a number of such encounters, the incumbent is squeezed into smaller markets than it was previously serving. And then, finally, the disruptive technology meets the demands of the most profitable segment and drives the established company out of the market.

New market disruption
"New market disruption" occurs when a product fits a new or emerging market segment that is not being served by existing incumbents in the industry. Some scholars note that the creation of a new market is a defining feature of disruptive innovation, particularly in the way it tend to improve products or services differently in comparison to normal market drivers. It initially caters to a niche market and proceeds on defining the industry over time once it is able to penetrate the market or induce consumers to defect from the existing market into the new market it created.

Critics
The extrapolation of the theory to all aspects of life has been challenged, as has the methodology of relying on selected case studies as the principal form of evidence. Jill Lepore points out that some companies identified by the theory as victims of disruption a decade or more ago, rather than being defunct, remain dominant in their industries today (including Seagate Technology, U.S. Steel, and Bucyrus). Lepore questions whether the theory has been oversold and misapplied, as if it were able to explain everything in every sphere of life, including not just business but education and public institutions. W.Chan Kim and Renée Mauborgne, the authors of Blue Ocean Strategy, also published a book in 2023, Beyond Disruption, criticizing disruptive innovation for the social costs it tends to incur.

Disruptive technology
In 2009, Milan Zeleny described high technology as disruptive technology and raised the question of what is being disrupted. The answer, according to Zeleny, is the support network of high technology. For example, introducing electric cars disrupts the support network for gasoline cars (network of gas and service stations). Such disruption is fully expected and therefore effectively resisted by support net owners. In the long run, high (disruptive) technology bypasses, upgrades, or replaces the outdated support network.

Questioning the concept of a disruptive technology, Haxell (2012) questions how such technologies get named and framed, pointing out that this is a positioned and retrospective act.

Technology, being a form of social relationship, always evolves. No technology remains fixed. Technology starts, develops, persists, mutates, stagnates, and declines, just like living organisms. The evolutionary life cycle occurs in the use and development of any technology. A new high-technology core emerges and challenges existing technology support nets (TSNs), which are thus forced to coevolve with it. New versions of the core are designed and fitted into an increasingly appropriate TSN, with smaller and smaller high-technology effects. High technology becomes regular technology, with more efficient versions fitting the same support net. Finally, even the efficiency gains diminish, emphasis shifts to product tertiary attributes (appearance, style), and technology becomes TSN-preserving appropriate technology. This technological equilibrium state becomes established and fixated, resisting being interrupted by a technological mutation; then new high technology appears and the cycle is repeated.

Regarding this evolving process of technology, Christensen said: "The technological changes that damage established companies are usually not radically new or difficult from a technological point of view. They do, however, have two important characteristics: First, they typically present a different package of performance attributes—ones that, at least at the outset, are not valued by existing customers. Second, the performance attributes that existing customers do value improve at such a rapid rate that the new technology can later invade those established markets."

The World Bank's 2019 World Development Report on The Changing Nature of Work examines how technology shapes the relative demand for certain skills in labor markets and expands the reach of firms - robotics and digital technologies, for example, enable firms to automate, replacing labor with machines to become more efficient, and innovate, expanding the number of tasks and products. Joseph Bower explained the process of how disruptive technology, through its requisite support net, dramatically transforms a certain industry. "When the technology that has the potential for revolutionizing an industry emerges, established companies typically see it as unattractive: it’s not something their mainstream customers want, and its projected profit margins aren’t sufficient to cover big-company cost structure. As a result, the new technology tends to get ignored in favor of what’s currently popular with the best customers. But then another company steps in to bring the innovation to a new market. Once the disruptive technology becomes established there, smaller-scale innovation rapidly raise the technology’s performance on attributes that mainstream customers’ value."

For example, the automobile was high technology with respect to the horse carriage. It evolved into technology and finally into appropriate technology with a stable, unchanging TSN. The main high-technology advance in the offing is some form of electric car—whether the energy source is the sun, hydrogen, water, air pressure, or traditional charging outlet. Electric cars preceded the gasoline automobile by many decades and are now returning to replace the traditional gasoline automobile. The printing press was a development that changed the way that information was stored, transmitted, and replicated. This allowed empowered authors but it also promoted censorship and information overload in writing technology.

Milan Zeleny described the above phenomenon. He also wrote that: "Implementing high technology is often resisted. This resistance is well understood on the part of active participants in the requisite TSN. The electric car will be resisted by gas-station operators in the same way automated teller machines (ATMs) were resisted by bank tellers and automobiles by horsewhip makers. Technology does not qualitatively restructure the TSN and therefore will not be resisted and never has been resisted. Middle management resists business process reengineering because BPR represents a direct assault on the support net (coordinative hierarchy) they thrive on. Teamwork and multi-functionality is resisted by those whose TSN provides the comfort of narrow specialization and command-driven work."

Social media could be considered a disruptive innovation within sports. More specifically, the way that news in sports circulates nowadays versus the pre-internet era where sports news was mainly on TV, radio and newspapers. Social media has created a new market for sports that was not around before in the sense that players and fans have instant access to information related to sports.

High-technology effects
High technology is a technology core that changes the very architecture (structure and organization) of the components of the technology support net. High technology therefore transforms the qualitative nature of the TSN's tasks and their relations, as well as their requisite physical, energy, and information flows. It also affects the skills required, the roles played, and the styles of management and coordination—the organizational culture itself.

This kind of technology core is different from regular technology core, which preserves the qualitative nature of flows and the structure of the support and only allows users to perform the same tasks in the same way, but faster, more reliably, in larger quantities, or more efficiently. It is also different from appropriate technology core, which preserves the TSN itself with the purpose of technology implementation and allows users to do the same thing in the same way at comparable levels of efficiency, instead of improving the efficiency of performance.

On differences between high and low technologies, Milan Zeleny wrote: "The effects of high technology always breaks the direct comparability by changing the system itself, therefore requiring new measures and new assessments of its productivity. High technology cannot be compared and evaluated with the existing technology purely on the basis of cost, net present value or return on investment. Only within an unchanging and relatively stable TSN would such direct financial comparability be meaningful. For example, you can directly compare a manual typewriter with an electric typewriter, but not a typewriter with a word processor. Therein lies the management challenge of high technology."

Not all modern technologies are high technologies, only those used and functioning as such, and embedded in their requisite TSNs. They have to empower the individual because only through the individual can they empower knowledge. Not all information technologies have integrative effects. Some information systems are still designed to improve the traditional hierarchy of command and thus preserve and entrench the existing TSN. The administrative model of management, for instance, further aggravates the division of task and labor, further specializes knowledge, separates management from workers, and concentrates information and knowledge in centers.

As knowledge surpasses capital, labor, and raw materials as the dominant economic resource, technologies are also starting to reflect this shift. Technologies are rapidly shifting from centralized hierarchies to distributed networks. Nowadays knowledge does not reside in a super-mind, super-book, or super-database, but in a complex relational pattern of networks brought forth to coordinate human action.

Proactive approach
A proactive approach to addressing the challenge posed by disruptive innovations has been debated by scholars. Petzold criticized the lack of acknowledgment of underlying process of the change to study the disruptive innovation over time from a process view and complexify the concept to support the understanding of its unfolding and advance its manageability. Keeping in view the multidimensional nature of disruptive innovation a measurement framework has been developed by Guo to enable a systemic assessment of disruptive potential of innovations, providing insights for the decisions in product/service launch and resource allocation. Middle managers play an important role in long term sustainability of any firm and thus have been studied to have a proactive role in exploitation of the disruptive innovation process.

Examples
In the practical world, the popularization of personal computers illustrates how knowledge contributes to the ongoing technology innovation. The original centralized concept (one computer, many persons) is a knowledge-defying idea of the prehistory of computing, and its inadequacies and failures have become clearly apparent. The era of personal computing brought powerful computers "on every desk" (one person, one computer). This short transitional period was necessary for getting used to the new computing environment, but was inadequate from the vantage point of producing knowledge. Adequate knowledge creation and management come mainly from networking and distributed computing (one person, many computers). Each person's computer must form an access point to the entire computing landscape or ecology through the Internet of other computers, databases, and mainframes, as well as production, distribution, and retailing facilities, and the like. For the first time, technology empowers individuals rather than external hierarchies. It transfers influence and power where it optimally belongs: at the loci of the useful knowledge. Even though hierarchies and bureaucracies do not innovate, free and empowered individuals do; knowledge, innovation, spontaneity, and self-reliance are becoming increasingly valued and promoted.

Uber is not an example of disruption because it did not originate in a low-end or new market footholds. One of the conditions for the business to be considered disruptive according to Clayton M. Christensen is that the business should originate on a) low-end or b) new-market footholds. Instead, Uber was launched in San Francisco, a large urban city with an established taxi service and did not target low-end customers or created a new market (from the consumer perspective). In contrast, UberSELECT, an option that provides luxurious cars such as limousine at a discounted price, is an example of disruption innovation because it originates from low-end customers segment - customers who would not have entered the traditional luxurious market.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Disruptive innovation


text:
212

Year 212 (CCXII) was a leap year starting on Wednesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Asper and Camilius (or, less frequently, year 965 Ab urbe condita). The denomination 212 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Roman Empire

 * The edict of Emperor Caracalla (Constitutio Antoniniana) extends Roman citizenship to all free inhabitants of the Roman Empire, with the exception of a limited group that may include Egyptians. The Jewish people are among those who receive citizenship. All free women in the Empire are given the same rights as Roman women.
 * Roman jurist Papinian, one of the famous jurists who flourished during the reign of the late emperor Septimius Severus, refuses to write a legal defence for the murder of Caracalla's brother, Publius Septimius Geta. He is beheaded in Rome, in Caracalla's presence.
 * Caracalla quiets the objections of the Roman army to Geta's murder, by huge donations.
 * Construction begins on the Baths of Caracalla in Rome.
 * Edessa in Mesopotamia becomes a Roman province.

Deaths

 * Annia Cornificia Faustina Minor, daughter of Marcus Aurelius (b. 160)
 * Gao You, Chinese scholar, historian, politician and writer (b 168).
 * Ma Teng (or Shoucheng), Chinese general and warlord
 * Papinian, Roman jurist and praetorian prefect (b. 142)
 * Serenus Sammonicus, Roman poet and physician
 * Xun Yu, Chinese politician and adviser (b. 163)
 * Zhang Hong, Chinese official and politician (b. 153)

title: 212


text:
Augur

An augur was a priest and official in the classical Roman world. His main role was the practice of augury, the interpretation of the will of the gods by studying events he observed within a predetermined sacred space (templum). The templum corresponded to the heavenly space above. The augur's decisions were based on what he personally saw or heard from within the templum; they included thunder, lightning and any accidental signs such as falling objects, but in particular, birdsigns; whether the birds he saw flew in groups or alone, what noises they made as they flew, the direction of flight, what kind of birds they were, how many there were, or how they fed. This practice was known as "taking the auspices". As circumstance did not always favour the convenient appearance of wild birds or weather phenomena, domesticated chickens kept for the purpose were sometimes released into the templum, where their behaviour, particularly how they fed, could be studied by the augur.

The augural ceremony and function of the augur was central to any major undertaking in Roman society – public or private – including matters of war, commerce, and religion. Augurs sought the divine will regarding any proposed course of action which might affect Rome's pax, fortuna, and salus (peace, good fortune, and well-being).

Etymology
Although ancient authors believed that the term "augur" contained the words avis and gerō – Latin for "directing the birds", historical-linguistic evidence points instead to the root augeō: "to increase, to prosper".

History and public role
Political, military and civil actions were sanctioned by augury and by haruspices.

Historically, augury was performed by priests of the college of augurs on behalf of senior magistrates. The practice itself likely comes from the neighboring region of Etruria, where augurs were highly respected as officials. Magistrates were empowered to conduct augury as required for the performance of their official duties. Magistracies included senior military and civil ranks, which were therefore religious offices in their own right, and magistrates were directly responsible for the pax, fortuna, and salus of Rome and everything that was Roman.

The presiding magistrate at an augural rite held the "right of augury" (ius augurii). The right of nuntiatio – announcing the appearance of auspicia oblativa (unexpected sign) – was reserved for the officiating augur, which would require the interruption of the proceedings then underway.

Kingdom of Rome
The Roman historian Livy stressed the importance of the augurs: "Who does not know that this city was founded only after taking the auspices, that everything in war and in peace, at home and abroad, was done only after taking the auspices?"

In the Regal period, which ended 509 BC, tradition holds that there were three augurs at a time; they numbered nine by the third century BC; Sulla increased their number to fifteen. By the Principate, their numbers swelled even further to an estimated 25 members.

Roman Republic
During the Republic, priesthoods were prized as greatly as the consulship, the censorship, and the triumph. Membership gave the lifelong right to participate prominently in processions at ludi and in public banquets; augurs proudly displayed the symbol of the office, the lituus.

Roman augurs were part of a college (Latin collegium) of priests who shared the duties and responsibilities of the position. At the foundation of the Republic in 510 BC, the patricians held sole claim to this office; by 300 BC, the office was open to plebeian occupation as well. Senior members of the collegium put forth nominations for any vacancies, and members voted on whom to co-opt.

According to Cicero, the auctoritas of ius augurum included the right to adjourn and overturn the process of law: Consular election could be – and was – rendered invalid by inaugural error. For Cicero, this made the augur the most powerful authority in the Republic. Cicero himself was co-opted into the college only late in his career.

In the later Republic, augury was supervised by the college of pontifices, a priestly-magistral office whose powers were increasingly woven into the cursus honorum. The office of pontifex maximus eventually became a de facto consular prerogative.

Roman Empire
The effectiveness of augury could only be judged retrospectively; the divinely ordained condition of peace (pax deorum) was an outcome of successful augury. Those whose actions had led to divine wrath (ira deorum) could not have possessed a true right of augury (ius augurum). Of all the protagonists in the Civil War, only Octavian could have possessed it, because he alone had restored the pax deorum to the Roman people. Lucan, writing during the Principate, described the recent Civil War as "unnatural" – a mirror to supernatural disturbances in the greater cosmos. His imagery is apt to the traditional principles of augury and its broader interpretation by Stoic apologists of the Imperial cult. In the Stoic cosmology the pax deorum is the expression of natural order in human affairs.

When his colleague Lepidus died, Augustus assumed his office as pontifex maximus, took priestly control over the State oracles (including the Sibylline books), and used his powers as censor to suppress the circulation of "unapproved" oracles.

Despite their lack of political influence under the Empire, the augurate, as with its fellow quattuor amplissima collegia, continued to confer prestige on its members.

Augurs, auguria, and auspices
In ancient Rome the auguria (augural rites) were considered to be in equilibrium with the sacra ("sacred things" or "rites") and were not the only way by which the gods made their will known.

The augures publici (public augurs) concerned themselves only with matters related to the state. The role of the augur was that of consulting and interpreting the will of gods about some course of action such as accession of kings to the throne, of magistrates and major sacerdotes to their functions (inauguration) and all public enterprises. It sufficed to say that the augur or magistrate had heard a clap of thunder to suspend the convocation of the comitia.

Since auguria publica and inaugurations of magistrates are strictly connected to political life this brought about the deterioration and abuses that condemned augury to progressive and irreversible debasement, stripping it of all religious value.

Ancient tradition
According to Varro, before his time augures had distinguished five kinds of territory: ager Romanus, ager Gabinus, ager peregrinus, ager hosticus, ager incertus. These distinctions clearly point to the times of the prehistory of Latium and testify the archaic quality of the art of augury.

The jus augurale (augural law) was rigorously secret, therefore very little about the technical aspects of ceremonies and rituals has been recorded. We have only the names of some auguria:
 * The augurium salutis took place once a year, before the magistrates and the people, in which the gods were asked whether it was auspicious to ask to for the welfare of the Romans,
 * The augurium canarium required the sacrifice of red dogs and took place after wheat grains had formed and before they were shelled.
 * The vernisera auguria – we know only the name that implies a ritual related to the harvest.

The terms augurium and auspicium are used indifferently by ancient authors. Modern scholars have debated the issue at length but have failed to find a distinctive definition that may hold for all the known cases. By such considerations Dumezil thinks that the two terms refer in fact to two aspects of the same religious act: In Varro's words "Agere augurium, aves specit", "to conduct the augurium, he observed the birds".
 * auspicium would design the technical process of the operation, i.e. aves spicere, looking at the birds;
 * augurium would be the resulting interpretation i.e. the determination, acknowledgement of the presence of the *auges, the action favoured by the god(s), the intention and the final product of the whole operation.

Categories
The auspicia were divided into two categories: requested by man (impetrativa) and offered spontaneously by the gods (oblativa). Both impetrativa and oblativa auspices could be further divided into five subclasses:
 * ex caelo (thunder, lightning)
 * ex avibus (birds)
 * ex tripudiis (attitude to food, and feeding manner of Mars' sacred chickens)
 * ex quadrupedibus (dog, horse, wolf, and fox)
 * ex diris (ominous events).

Only some species of birds (aves augurales) could yield valid signs whose meaning would vary according to the species. Among them were ravens, woodpeckers, owls, ossifragae, and eagles.

Signs from birds were divided into alites, from the flight, and oscines, from the voice: The alites included region of the sky, height and type of flight, behaviour of the bird and place where it would come to rest. The oscines included the pitch and direction of the sound.

Ritual
Magistrates endowed by the law with the right of spectio (observation of auspices) would establish the requested auspicium (observation platform) before taking the auspicia impetrativa ("requested" or "sought" auspices; see above). The templum, or sacred space within which the operation would take place had to be established and delimited (it should be square and have only one entrance) and purified (effari, liberare).

The enunciation of the requested auspicia that began the observation portion of the ceremony was called legum dictio. Observation conditions were rigorous and required absolute silence for validity of the operation. Technically the sky was divided into four sections or regions: dextera, sinistra, antica, and postica (right, left, anterior and posterior).

The prototype of the ritual of inauguration of people is described in Livy's description of the inauguration of king Numa Pompilius:"The augur asks Jupiter: 'Si fas est' (i.e. if it is divine justice to do this) '... send me a certain signum (sign)' then the augur listed the auspicia he wanted to see. When they appeared Numa was declared king."

Precedence
Since the observation was complex, conflict among signs was common. A hierarchy among signs was devised: e.g. a sign from the eagle would prevail on that from the woodpecker and the ossifragae (parra).

During the last centuries of the republic the auspices ex caelo and ex tripudiis supplanted other types, as the other forms could be easily used in a fraudulent way, i.e. bent to suit the desire of the asking person. Cicero condemned the fraudulent use and denounced the decline in the level of knowledge of the doctrine by the augurs of his time, but in fact the abuse developed from the evasion of negative signs, described in the next subsection.

Evasion
The interpretation of signs was vast and complex, and magistrates devised protective tricks to avoid being paralysed by negative signs. Against the negative auspicia oblativa the admitted procedures included:
 * actively avoiding seeing them
 * repudiare – refuse them through an interpretative sleight of hand
 * non observare – by assuming one had not paid attention to them
 * declaring something that in fact had not appeared
 * tempestas – choosing the time of the observation at one's will
 * renuntiatio – making a distinction between observation and formulation
 * vitia – resorting to acknowledging the presence of mistakes
 * repeating the whole procedure.

Attus Navius
Contrary to other divinatory practices present in Rome (e.g. haruspicina, consultation of the libri Sibyllini) Roman augury appears to be autochthonous and pre-historical, originally Latin or Italic, and attested in the Iguvine Tables (avif aseria) and among other Latin tribes.

The very story or legend of the foundation of Rome is based on augury. the ascertaining of the will of gods through observation of the sky and of birds. Romulus and Remus indeed acted as augurs and Romulus was considered a great augur throughout the course of his life.

The character that best represented and portrayed the art however was Attus Navius. His story is related by Cicero: He was born into a very poor family. One day he lost one of his pigs. He then promised the gods that if he found it, he would offer them the biggest grapes growing in his vineyard. After recovering his pig he stood right at the middle of his grape yard facing South. He divided the sky into four sections and observed birds: when they appeared he walked in that direction and found an extraordinary large grape that he offered to the gods.

His story was immediately famous and he became the augur of the king (see above the episode with king Tarquinius narrated by Livy). Henceforth he was considered the patron of the augurs.

title: Augur