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Semi-automatic rifle

A semi-automatic rifle is an autoloading rifle that fires a single cartridge with each pull of the trigger and uses part of the fired cartridge's energy to eject the case and load another cartridge into the chamber. In contrast, a bolt-action rifle requires the user to cycle the bolt manually before they can fire a second time, and a fully automatic rifle fires continuously until the trigger is released.

History
In 1883, Hiram Maxim patented in Britain a recoil-operated conversion of a Winchester rifle. In 1884 another recoil-operated semi-automatic rifle was patented by the American Horace Updegraff. Another one of the first designs of a recoil-operated semi-automatic rifle is attributed to Ferdinand Mannlicher, who unveiled the design in 1885 based on work begun in 1883. Other non-gas operated semi-automatic models were the Model 85 and Mannlicher Models 91, 93 and 95 rifles. The designs were deeply flawed and never made past the conceptual/prototype stage due to issues inherent to the black powder used in their cartridges (based around the Austrian 11×58mmR M/77), such as insufficient velocity and excessive fouling. Automatic firearms would only become feasible after smokeless powder became widespread. Mannlicher's designs were, nonetheless, the forerunner of automatic rifles and served as a base for a number of future weapons, such as Browning machine guns (M1917, M1919 and M2). Furthermore, from the early 1890s up until his death in 1904, Mannlicher produced smokeless powder versions of its guns.

Blowback semi-automatic
In 1903 and 1905, the Winchester Repeating Arms Company introduced the first low-power blowback (non-gas operated) semi-automatic rimfire and centerfire rifles. The Winchester Model 1903 and Winchester Model 1905 operated on the principle of blowback to function semi-automatically. Designed by T.C. Johnson, the Model 1903 achieved commercial success and continued to be manufactured until 1932, when the Winchester Model 63 replaced it.

By the early 20th century, several manufacturers had introduced semi-automatic .22 rifles, including Winchester, Remington, Fabrique Nationale, and Savage Arms, all using the direct blowback system of operation. Winchester introduced a .351 Winchester Self-Loading semi-automatic rifle, the Model 1907, as an upgrade to the Model 1905, utilizing a blowback system of operation, offering more power than its .22 counterpart. Both the Model 1905 and Model 1907 saw limited military and police use.

Early semi-automatic rifles
In 1883, two Danes, Madsen and Rasmussen started work on recoil operated self loading designs and in 1887 a working rifle had been developed and was later named as the M1888 Forsøgsrekylgevær and was tested by the Danish military however was rejected for military use. After failing trials a new design was developed labeled as the M1896 Flaadens Rekylgevær. It was tested by the Danish military and found to be reliable enough and 60 were procured for the Danish navy making it one of the first military adopted semi auto rifles.

In the final years of the 19th century and early 20th century experiments and patents with Gas-operated reloading were developed from Hiram Maxim and Richard Paulson as well a gas operated conversion system from an American inventor called Henry Pitcher. Designs also developed such as the Cei-Rigotti in 1900.

In 1906, Remington Arms introduced the "Remington Auto-loading Repeating Rifle". Remington advertised this rifle, renamed the "Model 8" in 1911, as a sporting rifle. It was sold in Europe by FN Herstal as the "FN Browning 1900". This is a locked-breech, long recoil action designed by John Browning. The rifle was offered in .25, .30, .32, and .35 caliber models, and gained popularity among civilians as well as some law enforcement officials who appreciated the combination of a semi-automatic action and relatively powerful rifle cartridges. In 1936 the Model 81 superseded the Model 8, and was offered in .300 Savage as well as the original Remington calibers.

In 1908, General Manuel Mondragón patented the Mondragón rifle, designated the M1908. The rifle was used by Mexican forces in the Mexican Revolution, making Mexico the first nation to use a semi-automatic rifle in battle, in 1911.

Shortly after the Mondragón rifle was produced, France had its own semi-automatic rifle, the Fusil Automatique Modele 1917. This is a locked breech, gas-operated action which is similar in its mechanical principles to the subsequent American M1 Garand. The M1917 was fielded during the latter stages of World War I, where it did not receive a favorable reception among troops. However, its shortened and improved version, the Model 1918, gave complete satisfaction during the Moroccan Rif War from 1920 to 1926. Still, the bolt-action Lebel Model 1886 rifle remained the standard French infantry rifle until replaced in 1936 by the MAS-36, also a bolt action, despite the various semi-automatic rifles designed between 1918 and 1935.

Other nations experimented with self-loading rifles during the interwar period, including the United Kingdom, which had intended to replace the bolt-action Lee–Enfield with a self-loading rifle, but this plan had to be discarded when the Second World War became imminent, shifting its emphasis to speeding up re-armament with existing weapons.

Gas-operated rifles

In 1936, the American M1 Garand rifle was historically significant as it became the first gas-operated semi-automatic rifle to be adopted by a country as their standard issued service rifle. The gas-operated M1 Garand was developed by Canadian-born John Garand for the U.S. government at the Springfield Armory in Springfield, Massachusetts. After years of research and testing, the first production model of the M1 Garand was unveiled in 1937 and the first production model was cleared on July 21 of the same year. During World War II, the M1 Garand gave American infantrymen an advantage over their opponents, most of whom were issued slower firing bolt-action rifles. General George S. Patton described the M1 Garand as "the greatest battle implement ever devised."

The Soviet AVS-36, SVT-38, and SVT-40, as well as the German Gewehr 43, were semi-automatic gas-operated rifles issued during World War II in relatively small numbers. In practice, they did not replace the bolt-action rifle as a standard infantry weapon of their respective nations - Germany produced 402,000 Gewehr 43 rifles, and over 14,000,000 of the Kar98k.

Another gas-operated semi-automatic rifle developed toward the end of World War II was the SKS. Designed by Sergei Gavrilovich Simonov in 1945, it came equipped with a bayonet and could be loaded with ten rounds, using a stripper clip. It was the first widely issued rifle to use the 7.62×39mm cartridge, and the SKS, along with its Chinese copy, the Type 56, is one of the most popular semi-automatic rifles. By the end of World War II, however, semi-automatic rifles had been largely superseded in military usage by their fully automatic counterparts - weapons such as the AK-47, FN FAL and M16 limited the viability of widespread deployment of semi-automatic rifles. Gradually, military doctrine placed less emphasis on individual marksmanship, as a large volume of fire was deemed more important - during World War II, American ground forces fired approximately 25,000 rounds for each enemy killed. In the Korean War, this was raised to 50,000, and in the Vietnam War it was 200,000. The first fully automatic rifle to see widespread usage was the German StG 44, which was well liked by troops, as the 30-round, selective fire rifle gave them much more flexibility than their service rifle, the bolt action Karabiner 98k. Ultimately, automatic rifles would become standard in military usage, as their firepower was superior to that of a semi-automatic rifle, but both semi-automatics and even bolt actions are still used worldwide in military service in specific roles, such as designated marksman rifles where the greater accuracy compared to automatics is valued. Furthermore, to accommodate for this greater firepower, battle rifles were mostly replaced by assault rifles, whose lighter bullets allowed more to be carried at once, but where semi-automatic rifles continue to be used, they are usually in higher calibers, such as the .50 BMG Barrett M82.

Operation
Semi-automatic weapons use gas, blow-forward, blowback or recoil energy to eject the spent cartridge after the round has moved down the barrel, chambering a new cartridge from its magazine, and resetting the action. This enables another round to be fired once the trigger is depressed again.

Semi-automatic rifles can be efficiently fed by an en-bloc clip, external magazine, or stripper clip.

The self-loading design was a successor to earlier rifles that required manual cycling of the weapon after each shot, such as the bolt-action rifle or repeating rifles. The ability to automatically load the next round results in an increase in the rounds per minute the operator can fire.

Advantages
The primary advantage of self-loading rifles is the possibility of increasing the number of effective shots fired within any given time period by avoiding the necessity for changing the aiming position of the rifle to manually chamber new cartridges. The actual number of hits per unit of time depends upon the magazine capacity and the availability of detachable magazines, but semi-automatic rifles can typically more than double the number of hits from comparable manually-loaded rifles at close range and increase the number of hits by about 50 percent at longer distances which require more precise aiming. Firing for prolonged periods may increase this advantage as the manual-loading process can cause fatigue. The additional weight of springs and fittings using a portion of the cartridge energy to reload self-loading rifles have the additional advantage of reducing recoil.

Disadvantages
The self-loading mechanism tuned for cartridges of specified dimensions and power may fail to reload dirty or bent cartridges that will otherwise fire satisfactorily. The self-loading mechanism may fail to extract empty low-power cartridge cases useful for training, and high-power cartridges useful at longer ranges may damage the self-loading mechanism. Some self-loading rifles require externally lubricated cartridges vulnerable to dirt adhesion. Any reliability problems causing failure of the self-loading mechanism to function as designed may eliminate the advantage of increased hits per unit of time, and may actually reduce the comparative rate of fire below what is possible with manually-loaded rifles if the self-loading rifle is not designed for convenient manual-loading. The United Kingdom regarded the reliable rate of fire from manually-loaded rifles to be nearly as high as self-loading rifles as recently as World War II.

Semi-automatic rifles are uniquely susceptible to slamfire malfunctions caused by abrupt cartridge acceleration during self-loading. Slamfire discharges are unlikely to hit the target, and may cause collateral damage.

The time required for changing or reloading magazines can weaken the effectiveness of a rifle, as it imposes an effective duration limit on the continuous rate of fire of any rifle. High-capacity magazines increase the weight of the rifle, and typically reduce feeding reliability due to the varying spring tension from a full to a nearly empty magazine. Detachable magazines in general are usually less durable than internal magazines.

The complexity of a self-loading mechanism makes self-loading rifles more expensive to manufacture and heavier than manually-loaded rifles. The semi-automatic M1 Garand weighs about 410 grams (0.9 lb) more (seven percent heavier) than the manually-loaded M1903 Springfield it replaced. American development of a self-loading infantry rifle began with the .276 Pedersen cartridge in recognition of the difficulties of producing reliable self-loading mechanisms for more powerful cartridges. Although the M1 Garand was ultimately adapted to fire the .30-06 Springfield cartridge at the insistence of General Douglas MacArthur, most subsequent self-loading rifles for infantry use have been chambered for less powerful cartridges to reduce weight making rifles easier to carry.

Select examples
• Mondragón rifle

• Mauser M1916

• M1917 RSC

• M1922 Bang rifle

• General Liu rifle

• M1 Garand

• Type 4 rifle

• SKS

• Dragunov Rifle

• Gewehr 43

• SVT-40

• Ag m/42

• Hakim rifle

• Rasheed Carbine

• AR-10

• AR-15

• L1A1 Rifle

• Heckler & Koch PSG1

• Heckler & Koch SL8

• Heckler & Koch SL7

• Heckler & Koch SL6

• Farquhar-Hill Rifle

• Kbsp wz. 1938M

• M1 Carbine

• Springfield Armory M1A

• Ruger Mini-14

• M1941 Johnson rifle

• Gewehr 41

• vz. 52 rifle

• MAS-49 rifle

• FN Model 1949

• Ruger 10/22

• Marlin Model 60

• Remington Model 7400

• Remington Model 8

• Winchester Model 1907

• Walther WA2000

• ZH-29

• Smith & Wesson M&P15-22

Sport shooting
Target shooting has a long history, pre-dating the firearm, as the first example of it would be archery, and as weapons that demanded user accuracy developed, so did their usage in competitions. Today, semi-automatic rifles are one of the more popular firearms in sport shooting. There are various types of sport shooting, ranging from rapid fire shooting, target shooting, which is predominantly accuracy based, and distance shooting. Shooting clubs in America became increasingly commonplace in the 1830s, and have since grown in popularity. Semi-automatic rifles are commonly used in sport shooting events because of their accuracy, versatility, and their light weight- which has invited more people, specifically women and children, to compete as well.

Hunting
Semi-automatic rifles have grown in status among hunters. Many hunters are adopting semi-automatic rifles, particularly AR-15 style rifles to take advantage of their compact design and modularity, effectively making it easier to traverse rugged terrain while tracking a target. And providing a large variety of customization ranging from scopes and muzzle devices, to different calibers. Semi-automatic fire greatly assists in maintaining one's sight picture, which is especially important when follow-up shots are required. Due to their demand, the manufacturers of semi-automatic firearms have greatly increased the effective firing distance of their products, compared to the first semi-automatics sold on the civilian market.

Self defense
Semi-automatic rifles are sometimes used for self-defense. Most semi-automatic rifles are rather lightweight and simple to operate, without compromising accuracy. Semi-automatic rifles are able to quickly dispatch multiple targets in a home invasion. Most semi-automatic rifles also have sights which can be adjusted for range, providing versatility.

title: Semi-automatic rifle


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Talk:Jean Baptiste Bernadotte

I think we may have a plagiarized page here. The "last updated" date, being well before Wikipedia, worries me. Does anyone have access to Encarta? Vicki Rosenzweig

Actually, this just needs to be deleted -- it's another of Helga's double entries. There is now a Charles XIV of Sweden page. JHK

 * Actually, I don't think it was HJ. I put Mr. Bernadotte on the Requested Articles page four or five months ago with the thought that I'd do it myself if no-one else took my bait. But someone did a few days later -- I forget who, but someone coherent. -- user:Paul Drye
 * I think you're right, Paul -- it was one of those "HJ didn't look for an existing article" things. JHK

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

title: Talk:Jean Baptiste Bernadotte


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Racquetball

Racquetball is a racquet sport and a team sport played with a hollow rubber ball on an indoor or outdoor court. Joseph Sobek invented the modern sport of racquetball in 1950, adding a stringed racquet to paddleball in order to increase velocity and control. Unlike most racquet sports, such as tennis and badminton, there is no net to hit the ball over, and, unlike squash, no tin (out of bounds area at the bottom of front wall) to hit the ball above. Also, the court's walls, floor, and ceiling are legal playing surfaces, with the exception of court-specific designated hinders being out-of-bounds. Racquetball is played between various players on a team who try to bounce the ball with the racquet onto the ground so it hits the wall, so that an opposing team’s player cannot bounce it back to the wall.

The sport is very similar to 40×20 American handball, which is played in many countries. It is also very similar to the British sport Squash 57, which was called racketball before 2016 (see below for a comparison).

History
Joe Sobek is credited with inventing the sport of racquetball in the Greenwich, Connecticut, YMCA, though not with naming it. A professional tennis and American handball player, Sobek sought a fast-paced sport that was easy to learn and play. He designed the first strung paddle, devised a set of rules, based on those of squash, handball, and paddleball, and named his game paddle rackets.

In February 1952, Sobek founded the National Paddle Rackets Association (NPRA), codified the rules, and had the rules printed as a booklet. The new sport was rapidly adopted and became popular through Sobek's continual promotion of it; he was aided by the existence of some 40,000 handball courts in the country's YMCAs and Jewish Community Centers, wherein racquetball could be played.

In 1969, aided by Robert W. Kendler, the president-founder of the U.S. Handball Association (USHA), the International Racquetball Association (IRA) was founded using the name coined by Bob McInerney, a professional tennis player. That same year, the IRA assumed the national championship from the NPRA. In 1973, after a dispute with the IRA board of directors, Kendler formed a competing organization called the National Racquetball Club (NRC), which eventually became the dominant professional tour in the 1970s. For a period of time in the 1970s, the NRC and the IRA both offered competing "Amateur" and "Professional" tournaments, but by the late 1970s the NRC was focused on the professional game while the IRA became focused on the amateur side, and became recognized by the United States Olympic Committee as the official National Governing Body (NGB) of the sport.

The IRA was a founding member of the International Racquetball Federation (IRF). Eventually, the IRA became the American Amateur Racquetball Association (AARA); in late 1995, it renamed itself as the United States Racquetball Association (USRA). In 2003, the USRA again renamed itself to USA Racquetball (USAR), to mirror other Olympic sports associations, even though Racquetball is not an Olympic sport.

Kendler used his publication ACE to promote both handball and racquetball. Starting in the 1970s, and aided by the fitness boom of that decade, the sport's popularity increased to an estimated 3.1 million players by 1974. Consequent to increased demand, racquetball clubs and courts were founded and built, and sporting goods manufacturers began producing racquetball-specific equipment. This growth continued until the early 1980s, and declining in the decade's latter part when racquet clubs converted to physical fitness clubs, in service to a wider clientele, adding aerobics exercise classes and physical fitness and bodybuilding machines. Since then, the number of players has remained steady, an estimated 5.6 million.

The NRC and Kendler ruled over professional racquetball throughout its early stages of growth, but upon his death in 1982 the organization declared bankruptcy and the professional men's tours fell into disarray. Several professional governing bodies ruled the Men's pro tour throughout the 1980s, and the Women broke away and self-organized their own professional tour in the same time period. Eventually, after the tour collapsed in the fall of 1988, a new men's tour called the International Racquetball Tour (IRT) was created by Oregon State President and popular tournament promotor Hank Marcus, which remains the primary men's professional sanctioning body to this day. The women's pro tour has gone by several names in the interim, but is currently known as the Ladies Professional Racquetball tour (LPRT) and has marketing partnerships with the USAR, IRT, and other sanctioning bodies to this day.

United Kingdom
In 1976, Ian D.W. Wright created the sport of racketball based on U.S. racquetball. British racketball is played in a 32 ft long by 21 ft wide squash court –8 ft shorter and 1 ft wider than the U.S. racquetball court–, using a smaller, less dynamic ball than the American racquetball. In racketball, the ceiling is out-of-bounds. The racketball is served after a bounce on the floor then struck into play with the racket. Scoring is like squash with point-a-rally scoring of up to 11 points. The British Racketball Association was formed on 13 February 1984, and confirmed by the English Sports Council as the sport's governing body on 30 October 1984. The first National Racketball Championship was held in London on 1 December 1984. The sport is now played in countries where squash is played, Australia, Bermuda, France, Germany, Malaysia, the Netherlands, New Zealand, South Africa, Argentina, Ireland and Sweden. Currently, racketball also is played in parts of North America.

In 1988, the British Racketball Association merged with the Squash Rackets Association. England Squash & Racketball is now recognised by Sport England as the English national governing body for the sports of squash and racketball. There is now an established UK Racketball Tournament Series consisting of 8 events around the UK, which forms the basis of the national rankings along with the National Racketball championships held annually at The Edgbaston Priory Club.

In 2016, World Squash Federation announced an international 're-branding' of racketball as Squash 57, the 57 referring to the diameter of the ball, in order to emphasise both its membership of the 'squash rackets' family, and its distinctiveness from the U.S. racquetball

Governing bodies
The International Racquetball Federation (IRF) governs the World Racquetball Championships, which were first held in 1981 in conjunction with the first World Games. The second World Championships were played in 1984, and since then have been held biennially in August. Players from the United States have won the most World Championship titles.

The IRF also runs the World Junior Racquetball Championships that occur annually in either late October, or early to mid November, as well as the annual World Senior Racquetball Championships for players who are 35 years of age or older.

The sport has a high appeal in the Americas, and because of this racquetball has been included in the Pan American Games in 1995, 1999, 2003, 2011, 2015 and Lima 2019. And will be part of the games again in Santiago 2023. Racquetball has also been included in the World Games on five occasions: 1981, 1989, 1993, 2009 and 2013, and is on the program for 2022. There men's and women's professional racquetball organizations. The International Racquetball Tour (IRT) is the men's professional organization, and the Ladies Professional Racquetball Tour (LPRT) is the women's professional organization. Both began in the 1980s.

Equipment
This court and equipment are required for playing racquetball:

 * A racquetball court; fully enclosed indoor or outdoor with a front wall. The standard racquetball court is rectangular: 40 feet long, 20 feet wide, and 20 feet high with red lines defining the service and serve reception areas. There are variations on the standard court with some courts having sidewalls that don't extend the full length of the court and some courts don't have any sidewalls.

The "service box" is formed by the short line (a solid red line running the court's width parallel to the front and back walls at a distance of 20 feet) and the service line (which runs parallel to the short line and is 15 feet from the front wall). Within the service box there are two sets of lines perpendicular to the short and service lines.

One set of lines is 18 inches from, and parallel to, the side walls. Along with the short line, service line, and side wall these lines define the doubles box, where the non-serving doubles partner stands during the serve; 36 inches from the side wall is another set of lines which, along with the short line and the service line, define an area that the server must not enter if he wishes to hit a drive serve between himself and the nearest side wall. The receiving line is a parallel dashed line 5 feet behind the short line.

Other equipment needed:

 * A racquetball; a dynamic (bouncy) rubber ball of 2.25 in. (57 mm) diameter
 * A racquetball racquet; no longer than 22 inches
 * Racquetball eyeguards (mandatory during competitions; some recreational players play without eyeguards but this is not recommended, as being hit in the eye by the ball can cause serious injury and/or permanent vision damage).

Racquetball differs from other racquet sports as most competitive players wear a glove on their racquet hand for the purpose of getting a better grip on the racquet (similar to golfers using a glove when driving), but gloves are optional equipment. Also, players usually wear a comfortable short sleeved shirt and shorts, as well as racquetball court shoes designed for enabling quick lateral as well as forward and backward movement.

Ball colors
Racquetballs are manufactured in a variety of colors such as blue, green, purple, black, red, and pink, and some are for specific purposes (e.g., outdoor play and indoor play), but the differences are unlikely to matter for recreational play. Beginners are recommended to use a blue ball by Penn, Ektelon, or Wilson. The blue ball is the most commonly used and it is the most neutral ball for average speed and accuracy of contact. Green balls are similar to blue balls. In the United States the main choices of ball are blue and green for tournament play. In some cases the International Pro Racquetball Tour (IRT) will use a purple Penn HD ball as the official ball. A black ball is often used in tournaments for senior players because the ball is designed to be slower moving and allows for longer rallies. The red ball is the fastest in production, and they are known as Red Ektelon Fireballs. This ball is heavier and allows for a quicker pace.

Balls do break occasionally, and will lose their bounce over time even without breaking. To keep balls around for a long time it is best to keep them in a room temperature setting and keep them out of extreme cold or heat because this will cause the balls to become less effective and lose their bounce.

Rules
Play begins with the serve. The serving player must bounce the ball on the floor once and hit it directly to the front wall, making the ball hit the floor beyond the short line; otherwise the serve counts as a fault. The ball may touch one side wall, but not two, prior to hitting the floor; hitting both side walls after the front wall (but before the floor) is a "three wall serve," and a fault. Also, serving the ball into the front wall so that it rebounds to the back wall without hitting the floor first is a long serve, and a fault.

Other fault serves include a ceiling serve, in which the ball touches the ceiling after the front wall, and serving before the receiving player is ready. Also, the server must wait until the ball passes the short line before stepping out of the service box, otherwise it is a fault serve.

If the server hits the ball directly to any surface other than the front wall the server immediately loses serve regardless of whether it was first or second serve.

After the ball bounces behind the short line, or passes the receiving line, the ball is in play and the opposing player(s) may play it.

Usually, the server is allowed two opportunities (called first serve and second serve) to put the ball into play (two serve rule), although elite level competitions often allow the server only one opportunity (one serve rule).

After a successful serve, players alternate hitting the ball against the front wall. The player returning the hit may allow the ball to bounce once on the floor or hit the ball on the fly. However, once the player returning the shot has hit the ball, it must strike the front wall before striking the floor. Unlike during the serve, a ball in play may touch as many walls, including the ceiling, as necessary so long as it reaches the front wall without striking the floor.

Scoring
If the server wins the rally, then the server scores one point and continues to serve. If the opposing player wins the rally, then no point is scored, but that player then takes over serving.

Several different scoring methods have been or are used in the sport.

– Under USA Racquetball Amateur scoring rules, matches are best of three games with the first two games to 15 points and a third game to 11 points, if necessary. USA Racquetball rules do not require players to win by two, so a match score line could read 15–14, 14–15, 11–10.

– Racquetball Canada matches are also the best of three format two games to 15, tiebreaker to 11, but require a winning margin of at least two points.

– From 1981 to 2017, the IRT's scoring was best-of-five games to 11 points, requiring a two-point margin for victory. However, in December 2017 the tour announced they were modifying their scoring methods to be in line with USAR and IRF standards at the time, and converted to the standard two games to 15, tiebreaker to 11 format.

– International competitions run by the International Racquetball Federation (IRF) also followed the two-games to 15, tiebreaker to 11 format from 1981 (inception) until 2022, when they announced that international competitions were going to move to Rally Scoring. IRF competitions will now be played best 3 of 5 games to 15, win by one except in the last game, with rally scoring. However, the IRF immediately modified its rally scoring limits and announced that the 2022 World games and World Juniors would be 3 out of 5 games to 11, win by two. The IRF cited several factors for this change: length of matches, confusing scoring system to casual fans, and the need for faster matches to accommodate more matches. IRF's pivot to rally scoring had an immediate reaction in the NGBs, as most IRF qualifying events in USAR, Racquetball Canada, and other NGBs are now played under the IRF's rally scoring rules.

Hinders
Due to the nature of the game, players often occupy the space their opponent(s) want(s) to occupy. This may result in a player blocking his opponent's ability to play the ball. Such occurrences are termed either hinders or penalty hinders. A hinder is a replay of the current rally (the server resumes play at the first serve), while a penalty hinder results in the player who caused the avoidable obstruction to lose the rally. A type of hinder is a screen in which the player is unable to see the ball prior to it passing the opponent.

The difference between a hinder and a penalty hinder (or formerly an avoidable hinder) is that in the latter case a player has missed out on a clear opportunity to make a rally-winning shot due to the obstruction by the player's opponent, while in the former case the opportunity missed would not clearly have led to a winning shot. This difference is almost always a judgment call by the referee (if available).

There is also a "court" hinder in which some part of the playing field caused the ball to bounce untrue. Often this is the door frame or (recessed) handle or a flaw in the floor or walls. In this case, the rally is a re-serve.

Game variations
Racquetball games can be played with two, three or four players, with doubles or singles matches being most common. Two player games are called singles or "one-up" (one vs. one for the entire game), while four player games are doubles with two pairs playing against each other (two vs. two for the entire game). Tournament competitions have divisions for singles or doubles or both.

Three-player games are most commonly called "Cut-throat" and sometimes "Ironman" (two-on-one for the entire game) where each player takes turns serving to the other two, who play as a team against the serving player. Another three-player game is "California", "In-and-Out", or "King of the Court" where play is 1 vs. 1 with the third player remaining in the back court out of play while the other two play a rally; the rally winner then serves to the player who was sitting out, and the rally loser stays out of play. Another three-player variation is "Sevens" in which one player plays against two players as a team, with the game being played to seven points; if the two player team gets to seven first, the game is over, but if the solo player gets to seven first then the game continues to 14; if the solo player again reaches 14 first, then the game continues to 21, where the game ends regardless of whether the solo player or the two player team reach 21 first.

Service
Serve style varies drastically from player to player. Generally, they are divided into two types: offensive and defensive. Most players use an offensive serve for the first serve, and a defensive serve if they need to hit a second serve. Of the offensive serves, the most common is the drive. The intention with this serve is for the ball to travel low and fast towards either back corner, and to bounce twice before striking either side wall or the back wall. If the opponent is adjusting to the drive serve, the server will throw in any variety of jam serves.

A jam serve is an offensive serve which attempts to catch the opponent off balance by making use of difficult angles and unfrequented play space. The most common jam serve is the Z-serve, which strikes the front wall close to a side wall. The ball bounces quickly off the side wall, then strikes the floor and then the opposite side wall about 30–35 feet back. Depending upon the spin the server gives the Z-serve, the resulting carom may prove unpredictable and difficult to return. Side spin may cause the ball to bounce parallel to the back wall.

A pinch serve is similar to a drive serve; however, the ball strikes a side wall very low and close to the serving box. With the appropriate spin, the ball has little bounce, and is difficult to return. It is possible that a successful serve would strike the sidewall before the short line, and land on the floor after the short line.

If the player faults on the first serve, they will usually hit a defensive serve. Defensive serves do not usually garner aces, but they are designed to generate a weak return by the opponent, thereby setting up the server to win the point. Most defensive serves are any variety of lob serves. A plain lob serve is a ball hit with a long, high arch into either back corner. The goal is to hit the ball so that it lands as close as possible to the back wall, giving the opponent very little room to hit a solid return. A junk lob takes a shallower arch, and lands close to the side wall somewhere between the dotted line and the back wall. This lob is intended to deceive the opponent into thinking he has an easy kill. However, since the ball is in the deep zone, it will more likely set up the server for an offensive shot.

Offensive shots
Straight-in shots are usually meant to hit the front wall as low as possible. If the ball contacts the front wall so low as to bounce twice before it reaches the service line it is called a "kill" shot. Straight-in shots are normally attempted with the idea of hitting toward the area of the court the opponent cannot cover.

Straight-in shots hit where the opponent cannot return them are called down-the-line and cross court passing shots. Often kill shots are returned very close to the back wall as the ball is moving towards the front wall.

Pinches and splats are shots that strike the side wall before the front wall. This often makes the ball bounce twice quickly to end the rally. Pinches normally strike the side wall towards the front part of the court, often within a few inches from the front wall.

The "splat" shot is an elongated pinch that strikes the side wall towards the back part of the court. It often makes a distinctive splatting sound. The advantage to a splat shot, beyond an unpredictable angle, is that it creates a longer distance to travel forward for the opponent who is held between a tension of going forward and staying back because of velocity of passing shots.

Pinches are classified as frontside or reverse. A right-handed player shooting a forehand shot to the right front corner is shooting a frontside pinch. A right-handed player shooting to the left front corner is a reverse pinch. A right-handed player shoots a backhand frontside pinch to the left corner and a reverse double pinch to the right corner. Everything for a left-handed player would be the opposite.

The dink is another very effective offensive shot designed to end the point. It is a shot very low to the front wall hit very softly so as to bounce twice before the opponent can get to it. Dinks are most effective when the opponent is positioned deep in the court.

Another important shot type is the "Z" shot. This shot is effective at confusing and tiring out an opponent. To hit a "Z" shot one hits the side wall hard and up high causing the ball to hit the front then the other side wall then back to the original side wall. If done correctly, the path of the ball will be Z-shaped. This shot can have confusing bounces which can frustrate opponents. If done correctly, a "Z" shot will apply spin to the ball on the final bounce as well, causing it to rebound perpendicular to the second wall and fall parallel to the back wall, the closer the better. This makes the "Z" shot very difficult to return.

Defensive shots
Defensive shots are defined as shots which are not returned low to the front wall.

The ceiling ball shot is the primary defensive shot. This is a shot that strikes the ceiling at or near the front wall. The ball will bounce once in the forecourt and should then travel in a high arc to arrive as close to, and as vertical to, the back wall as possible. Often this is aimed at the corner which would require a backhand return by the opponent. This makes it difficult for the opponent to return the ball as he cannot make a full arc of the racquet. However, if the ball comes down too long or too short of the back wall, this can allow the opponent a kill shot.

Another defensive shot is the high Z. Used when the defensive player is near the front wall, the high Z is hit ten feet high or higher into the front wall near a corner. The ball then bounces from the side wall all the way to the opposite side wall, usually traveling over the top of the opponent, hitting the opposite side wall with spin. The spin will cause the ball to leave the opposite wall almost perpendicular to it. This may confuse inexperienced opponents but importantly, if very close to and parallel to the rear wall, makes for a difficult return shot.

The "around the world" or "3 wall" defensive shot is hit like a pinch shot but high on the wall toward the ceiling. It travels around the court in a high trajectory and is an alternative to hitting a ceiling ball.

Two other defensive shots are used but are less effective. If the defensive player is in the backcourt but unable to position himself for a non-defensive shot, he may need to hit the ball off of the back wall. The ball often returns without much force and is easily returned. The round-the-world shot is hit high into the side wall first so the ball then hits the front wall and then the other side wall, effectively circling the court. It can be easily cut off and is rarely used anymore.

Strategy
The primary strategy of racquetball is to command the center of the court just at or behind the dashed receiving line. This allows the player to move as quickly as possible to all areas of the court and limit open court areas which are difficult to defend. After a shot, players should return quickly to center court. The antithesis of this is to be against a wall which severely limits the player's movement and allows the opponent an open court.

Important tactics include keeping an eye on the opponent by glancing sideways to anticipate their return shot, learning the typical return shots of the opponent, and attempting to not be predictable with return shots.

Other more obvious strategies are to keep the returned ball as low on the front wall as possible, keeping the ball moving fast (limiting reaction time) and to keep your opponent moving away from center court by the use of lobs, cross court shots, and dinks.

Major competitions and players
Racquetball World Championships

Organized competitive racquetball began in the 1970s. The best male players of that era were Charlie Brumfield and Marty Hogan, as well as Bud Muehleisen, Dan Southern, Jerry Hilecher, Steve Keeley, Davey Bledsoe, Steve Serot, and Steve Strandemo. Hogan continued to be a dominant player into the 1980s, and was rivaled on the scene by Brett Harnett, Dave Peck, and Mike Yellen.

In the 1990s, Ruben Gonzalez, Cliff Swain and Sudsy Monchik dominated pro tournaments, and other great players like Andy Roberts, John Ellis, and Drew Kachtik were often left out of the winner's circle. In the 2000s, Kane Waselenchuk, Jack Huczek, Jason Mannino, Ben Croft, and Rocky Carson have all excelled, but Waselenchuk has been dominant the last two seasons losing only once since September 2008.

The first great woman player was Peggy Steding in the 1970s. She was succeeded by Shannon Wright, who was then rivaled by Heather McKay, a great Australian squash player who made the transition to racquetball when living in Canada. McKay then developed a great rivalry with Lynn Adams, and after McKay moved back to Australia, Adams dominated women's racquetball for the better part of the 1980s.

The 1990s belonged to Michelle Gould (née Gilman) whose drive serve was a huge weapon against her opponents. In the late 1990s and into the 2000s, Jackie Paraiso and then Cheryl Gudinas were the dominant players. Then in the mid-2000s, Christie Van Hees and Rhonda Rajsich were the dominant players, but Paola Longoria finished #1 at the end of the 2008–2009 and 2009–2010 seasons.

The professional tours have been dominated by two players since the 2010 time frame. On the Men's side, Kane Waselenchuk has won 14 year-end #1 titles since 2004, which Paola Longoria has now won 13 year end pro titles dating to 2009, including the last 11 straight.

US Open
Held annually in October, the US Open is the most prestigious professional racquetball event. First held in 1996, the US Open was in Memphis, Tennessee until 2010, when it moved to Minneapolis, Minnesota. In men's play, Kane Waselenchuk (Canada) has won the most US Open titles with thirteen ahead of Sudsy Monchik (US) with four, while Jason Mannino (US) and Cliff Swain (US) have both won the title twice, and Rocky Carson (US) once.

In women's play, Paola Longoria (Mexico) has the most US Open titles with five, Rhonda Rajsich (US) has four, one more than Christie Van Hees (Canada) with three. Michelle Gould (US), Cheryl Gudinas (US), and Jackie Paraiso (US) have each won two US Open titles. Kerri Wachtel (US) won the title once.

Other championships
Racquetball is included in the Pan American Games, World Games and Central American and Caribbean Games. Also, the regional associations of the International Racquetball Federation organize their own continental championships: Asian Championships, European Championships and Pan American Championships.

Comparison to racketball
Racquetball is very similar to the British sport of 'racketball', which was patterned on racquetball in 1976. The main differences are that the British ball is smaller, denser, and less bouncy; the British sport's court is a squash court, which is substantially shorter and somewhat wider; and the ceiling in the British game is out of bounds.

A racquetball court measures 20 feet wide, 20 feet high and 40 feet long, while a squash court is slightly smaller in height and length than a racquetball court, measuring 21 feet wide, 15 feet high and 32 feet long.

title: Racquetball


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William Thurston

William Paul Thurston (October 30, 1946 – August 21, 2012) was an American mathematician. He was a pioneer in the field of low-dimensional topology and was awarded the Fields Medal in 1982 for his contributions to the study of 3-manifolds.

Thurston was a professor of mathematics at Princeton University, University of California, Davis, and Cornell University. He was also a director of the Mathematical Sciences Research Institute.

Early life and education
William Thurston was born in Washington, D.C., to Margaret Thurston (Martt), a seamstress, and Paul Thurston, an aeronautical engineer. William Thurston suffered from congenital strabismus as a child, causing issues with depth perception. His mother worked with him as a toddler to reconstruct three-dimensional images from two-dimensional ones.

He received his bachelor's degree from New College in 1967 as part of its inaugural class. For his undergraduate thesis, he developed an intuitionist foundation for topology. Following this, he received a doctorate in mathematics from the University of California, Berkeley under Morris Hirsch, with his thesis Foliations of Three-Manifolds which are Circle Bundles in 1972.

Career
After completing his Ph.D., Thurston spent a year at the Institute for Advanced Study, then another year at the Massachusetts Institute of Technology as an assistant professor.

In 1974, Thurston was appointed a full professor at Princeton University. He returned to Berkeley in 1991 to be a professor (1991-1996) and was also director of the Mathematical Sciences Research Institute (MSRI) from 1992 to 1997. He was on the faculty at UC Davis from 1996 until 2003, when he moved to Cornell University.

Thurston was an early adopter of computing in pure mathematics research. He inspired Jeffrey Weeks to develop the SnapPea computing program.

During Thurston's directorship at MSRI, the institute introduced several innovative educational programs that have since become standard for research institutes.

His Ph.D. students include Danny Calegari, Richard Canary, David Gabai, William Goldman, Benson Farb, Richard Kenyon, Steven Kerckhoff, Yair Minsky, Igor Rivin, Oded Schramm, Richard Schwartz, William Floyd, and Jeffrey Weeks.

Foliations
His early work, in the early 1970s, was mainly in foliation theory. His more significant results include:
 * The proof that every Haefliger structure on a manifold can be integrated to a foliation (this implies, in particular, that every manifold with zero Euler characteristic admits a foliation of codimension one).
 * The construction of a continuous family of smooth, codimension-one foliations on the three-sphere whose Godbillon–Vey invariant (after Claude Godbillon and Jacques Vey) takes every real value.
 * With John N. Mather, he gave a proof that the cohomology of the group of homeomorphisms of a manifold is the same whether the group is considered with its discrete topology or its compact-open topology.

In fact, Thurston resolved so many outstanding problems in foliation theory in such a short period of time that it led to an exodus from the field, where advisors counselled students against going into foliation theory, because Thurston was "cleaning out the subject" (see "On Proof and Progress in Mathematics", especially section 6 ).

The geometrization conjecture
His later work, starting around the mid-1970s, revealed that hyperbolic geometry played a far more important role in the general theory of 3-manifolds than was previously realised. Prior to Thurston, there were only a handful of known examples of hyperbolic 3-manifolds of finite volume, such as the Seifert–Weber space. The independent and distinct approaches of Robert Riley and Troels Jørgensen in the mid-to-late 1970s showed that such examples were less atypical than previously believed; in particular their work showed that the figure-eight knot complement was hyperbolic. This was the first example of a hyperbolic knot.

Inspired by their work, Thurston took a different, more explicit means of exhibiting the hyperbolic structure of the figure-eight knot complement. He showed that the figure-eight knot complement could be decomposed as the union of two regular ideal hyperbolic tetrahedra whose hyperbolic structures matched up correctly and gave the hyperbolic structure on the figure-eight knot complement. By utilizing Haken's normal surface techniques, he classified the incompressible surfaces in the knot complement. Together with his analysis of deformations of hyperbolic structures, he concluded that all but 10 Dehn surgeries on the figure-eight knot resulted in irreducible, non-Haken non-Seifert-fibered 3-manifolds. These were the first such examples; previously it had been believed that except for certain Seifert fiber spaces, all irreducible 3-manifolds were Haken. These examples were actually hyperbolic and motivated his next theorem.

Thurston proved that in fact most Dehn fillings on a cusped hyperbolic 3-manifold resulted in hyperbolic 3-manifolds. This is his celebrated hyperbolic Dehn surgery theorem.

To complete the picture, Thurston proved a hyperbolization theorem for Haken manifolds. A particularly important corollary is that many knots and links are in fact hyperbolic. Together with his hyperbolic Dehn surgery theorem, this showed that closed hyperbolic 3-manifolds existed in great abundance.

The hyperbolization theorem for Haken manifolds has been called Thurston's Monster Theorem, due to the length and difficulty of the proof. Complete proofs were not written up until almost 20 years later. The proof involves a number of deep and original insights which have linked many apparently disparate fields to 3-manifolds.

Thurston was next led to formulate his geometrization conjecture. This gave a conjectural picture of 3-manifolds which indicated that all 3-manifolds admitted a certain kind of geometric decomposition involving eight geometries, now called Thurston model geometries. Hyperbolic geometry is the most prevalent geometry in this picture and also the most complicated. The conjecture was proved by Grigori Perelman in 2002–2003.

Density conjecture
Thurston and Dennis Sullivan generalized Lipman Bers' density conjecture from singly degenerate Kleinian surface groups to all finitely generated Kleinian groups in the late 1970s and early 1980s. The conjecture states that every finitely generated Kleinian group is an algebraic limit of geometrically finite Kleinian groups, and was independently proven by Ohshika and Namazi–Souto in 2011 and 2012 respectively.

Orbifold theorem
In his work on hyperbolic Dehn surgery, Thurston realized that orbifold structures naturally arose. Such structures had been studied prior to Thurston, but his work, particularly the next theorem, would bring them to prominence. In 1981, he announced the orbifold theorem, an extension of his geometrization theorem to the setting of 3-orbifolds. Two teams of mathematicians around 2000 finally finished their efforts to write down a complete proof, based mostly on Thurston's lectures given in the early 1980s in Princeton. His original proof relied partly on Richard S. Hamilton's work on the Ricci flow.

Awards and honors
In 1976, Thurston and James Harris Simons shared the Oswald Veblen Prize in Geometry.

Thurston received the Fields Medal in 1982 for "revolutioniz[ing] [the] study of topology in 2 and 3 dimensions, showing interplay between analysis, topology, and geometry" and "contribut[ing] [the] idea that a very large class of closed 3-manifolds carry a hyperbolic structure."

In 2005, Thurston won the first American Mathematical Society Book Prize, for Three-dimensional Geometry and Topology. The prize "recognizes an outstanding research book that makes a seminal contribution to the research literature". He was awarded the 2012 Leroy P. Steele Prize by the American Mathematical Society for seminal contribution to research. The citation described his work as having "revolutionized 3-manifold theory".

Personal life
Thurston and his first wife, Rachel Findley, had three children: Dylan, Nathaniel, and Emily. Dylan was a MOSP participant (1988–90) and is a mathematician at Indiana University Bloomington. Thurston had two children with his second wife, Julian Muriel Thurston: Hannah Jade and Liam.

Thurston died on August 21, 2012, in Rochester, New York, of a sinus mucosal melanoma that was diagnosed in 2011.

Selected publications

 * William Thurston, The geometry and topology of three-manifolds, Princeton lecture notes (1978–1981).
 * William Thurston, Three-dimensional geometry and topology. Vol. 1. Edited by Silvio Levy. Princeton Mathematical Series, 35. Princeton University Press, Princeton, New Jersey, 1997. x+311 pp. ISBN 0-691-08304-5
 * William Thurston, Hyperbolic structures on 3-manifolds. I. Deformation of acylindrical manifolds. Ann. of Math. (2) 124 (1986), no. 2, 203–246.
 * William Thurston, Three-dimensional manifolds, Kleinian groups and hyperbolic geometry, Bull. Amer. Math. Soc. (N.S.) 6 (1982), 357–381.
 * William Thurston, On the geometry and dynamics of diffeomorphisms of surfaces. Bull. Amer. Math. Soc. (N.S.) 19 (1988), no. 2, 417–431
 * Epstein, David B. A.; Cannon, James W.; Holt, Derek F.; Levy, Silvio V. F.; Paterson, Michael S.; Thurston, William P. Word Processing in Groups. Jones and Bartlett Publishers, Boston, Massachusetts, 1992. xii+330 pp. ISBN 0-86720-244-0
 * Eliashberg, Yakov M.; Thurston, William P. Confoliations. University Lecture Series, 13. American Mathematical Society, Providence, Rhode Island and Providence Plantations, 1998. x+66 pp. ISBN 0-8218-0776-5
 * William Thurston, On proof and progress in mathematics. Bull. Amer. Math. Soc. (N.S.) 30 (1994) 161–177
 * William P. Thurston, "Mathematical education". Notices of the AMS 37:7 (September 1990) pp 844–850

title: William Thurston


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Leisure Suit Larry

Leisure Suit Larry is an adult-themed sex comedy video game series created by Al Lowe. Drawing inspiration from Softporn Adventure, the Leisure Suit Larry series centers on Larry Laffer—a middle-aged man known for his balding head, penchant for double entendre, and iconic leisure suits. The stories typically focus on his unsuccessful attempts to seduce young women, portraying him as an unsuccessful pickup artist. A common link between the games are Larry's explorations of luxurious and cosmopolitan hotels, ships, beaches, resorts, and casinos.

The series became notable for its blend of humor, parody, and sexual fantasy, a departure from the norm in Sierra's otherwise family-friendly catalog. Under Lowe’s creative direction, the franchise launched its first six games between 1987 and 1996, becoming a cult classic. Following a hiatus, the series was revived with new installments overseen by a variety of development teams without Lowe's involvement. As of 2011, the series has sold 10 million copies. Sierra co-founder Ken Williams describes Leisure Suit Larry as the company's best-known franchise.

Original series
Al Lowe, a designer and programmer on titles like Donald Duck's Playground and King's Quest III, sought to innovate by creating a game that blended humor with interactive storytelling. Inspired by the humor in movies and TV, Lowe aimed to prove that games could be funny too. Lowe leveraged the technological advancements established by Adventure Game Interpreter, the engine that behind Sierra's successful series, King's Quest and Space Quest, to venture into an untapped commercial niche.

The series originated with Softporn Adventure, a 1981 text adventure game by Chuck Benton, published by Sierra. This game's plot set the stage for the first the first "Larry" installment. Al Lowe, reflecting on the game's dated feel, likened it to a '70s leisure suit, a comment that not only influenced the franchise's direction but also inspired the creation of its main character, Larry Laffer. Laffer's persona was partly based on individuals Lowe encountered while performing as a musician in 1970s bars, where he observed their often-unsuccessful attempts to pick-up women.

Lowe maintained the original's structure but rewrote the narrative to include a comedic voice that pokes fun at Larry, significantly altering Softporn's tone. This approach retained just one original line, emphasizing Lowe's significant reimagining of the game’s narrative voice. Although Chuck Benton, Softporn’s creator, is credited in Larry, he did not contribute to its development.

The Leisure Suit Larry series distinguished itself from other adult-themed games with its focus on comedy over explicit content. Marketed by Sierra as a light-hearted adult adventure, Larry aimed for laughs rather than pure titillation, setting it apart in a landscape populated by titles like Strip Poker, Sex Vixens from Space, Leather Goddesses of Phobos, MacPlaymate and Cobra Mission. At most, the raunchier moments were usually hidden as Easter eggs.

Leisure Suit Larry gained notoriety not just for its adult-themed content but also as a symbol of the rampant issue of software piracy. The scale of piracy was such that, according to Sierra, sales of hint books for the game at one point surpassed the sales of the game itself. Moreover, pirated versions of Leisure Suit Larry carried an unexpected threat: computer viruses. Banks in Switzerland, Germany, and England experienced significant data losses after employees, in ill-advised attempts to play pirated versions on work computers, introduced these viruses into their systems.

Recognized as one of 1988's best-selling games by the Software Publishers Association, sales of Leisure Suit Larry in the Land of the Lounge Lizards surpassed 250,000 copies in its first year. And the first three installments each sold more than their predecessors their initial 90 days of release. However, by the time Leisure Suit Larry 5: Passionate Patti Does a Little Undercover Work was released, sales began to plateau. Leisure Suit Larry: Love for Sail!, despite critical acclaim and a booming home PC market, only sold around 280,000 copies—a figure below expectations for a mid-90s flagship game, and insufficient to recoup the millions spent on development and manufacturing.

Following its acquisition by CUC International in 1996, Lowe's relationship with Sierra underwent significant changes. The adult content of the series became a source of contention within the conglomerate, especially within the conservative business culture of its educational software division, Davidson & Associates. Furthermore, Ken Williams, who had been a fervent supporter of designers with a strong vision for their games, left the company that same year. This departure left Lowe without a key advocate.

In 1998, while Leisure Suit Larry 8: Lust in Space was getting underway, Sierra decided to halt production. Subsequent Larry games were released without Lowe's involvement. Lowe, who was on contract rather than a salaried position at Sierra, did not design any more Leisure Suit Larry games.

Spin-offs and sequels
Leisure Suit Larry: Magna Cum Laude, a spin-off from the original series, introduced Larry Lovage, Leisure Suit Larry's college-aged nephew, as the new protagonist, along with changes in gameplay. It was the first to feature full 3D graphics and to be released on consoles. Developed by High Voltage Software and published by Sierra in 2004, the game received mixed reviews.

In 2008, Sierra Entertainment announced plans to release Leisure Suit Larry: Box Office Bust. It was developed by Team17, and the publishing rights were offered to Codemasters, who published the game in 2009. Box Office Bust was panned by critics, including Al Lowe himself, who thanked the publisher for keeping him away from developing the game.

Assemble Entertainment released two Leisure Suit Larry games, rejuvenating the series with contemporary settings while retaining its humor. Leisure Suit Larry: Wet Dreams Don't Dry (2018) places Larry in the modern dating world, while its sequel, Leisure Suit Larry: Wet Dreams Dry Twice (2020), continues his quest for love.

Remakes and remasters
In 1991, Sierra leveraged advancements in technology to support 256-color graphics for the Leisure Suit Larry VGA remake. Bill Davis, an Emmy-winning artist and graphic designer, served as the creative director for the Leisure Suit Larry I remake. His choice of a Cubist style challenged conventional video game aesthetics while echoing the series' humor and cartoon-like nature of Larry's universe. The creative process included converting hand-painted backgrounds into digital formats, ensuring they complemented the game’s established aesthetic and the recognizable character design of Larry, previously defined by the series' box art.

In 2013, Leisure Suit Larry: Reloaded, a crowdfunded Kickstarter project and the second remake of the original game, was released in collaboration with series creator Al Lowe. While it received mixed to average reviews, critics noted its nostalgic charm but also pointed out that its features and design felt outdated. Lowe discussed the possibility of remaking Leisure Suit Larry 2 or creating a new sequel, Leisure Suit Larry 8. However, both projects were ultimately canceled.

Voice acting
The CD-ROM version of Leisure Suit Larry 6: Shape Up or Slip Out!, which doubled the resolution of the original floppy version, is the first Larry game with voice acting. The character of Larry Laffer was voiced by Jan Rabson. Larry Lovage, the protagonist of Magna Cum Laude and Box Office Bust, was voiced by Tim Dadabo.

Leisure Suit Larry 4: The Missing Floppies
Leisure Suit Larry 4: The Missing Floppies is the name for a never-made fourth installment, often regarded as an in-joke. The name, used by official sources and fans, refers to rumors that the reason for the cancellation of the game was the losing of the game's original production floppy disks, after which the developers refused to remake the game from scratch. Other sources claim that it was nothing but an internal office prank. The franchise's installments were numbered as if this installment had been published; the actual fourth installment was Leisure Suit Larry 5: Passionate Patti Does a Little Undercover Work.

Al Lowe gave two official reasons for the cancellation of Leisure Suit Larry 4. The first was that Sierra had begun work on a multiplayer installment for The Sierra Network, but the project failed mostly due to technical reasons. The second was that the ending of Larry 3 was definitive and somehow metafictional, since it showed Larry and Patti coming to the Sierra studios to make games based on their adventures, as well as living happily in a mountain cabin in Coarsegold. This completed a relatively cohesive trilogy, and was a dead-end for a new story arc. In 2012, Lowe discussed what happened to the fourth installment in a video made for a Kickstarter project, in which he said that the idea for skipping Larry 4 came as a flippant comment in the office, and became a "real marketing coup" when selling Larry 5 because buyers would immediately ask what happened to the fourth. It became "one of software's big jokes".

According to production notes given by Lowe, the following events must be assumed to have happened between Larry 3 and Larry 5 to connect the two games: Larry and Patti plan to marry; Patti leaves him at a Yosemite church to pursue her career, but Larry is gone when she returns; The villain of Larry 5, Julius Biggs, somehow steals the game disks and Larry suffers amnesia. The absence of the floppy disks was introduced as a plot element in the sequel to explain how Larry, as a computer generated character, came to suffer from amnesia. Larry 4 appears in several of the other games in the series, including being played in Leisure Suit Larry: Magna Cum Laude. Leisure Suit Larry: Love For Sale Mobile takes place during the Larry 4 development years, and a subplot for the best ending requires finding the lost disks. A folder named LSL4 could be found on the CD of Leisure Suit Larry Collection in which Al Lowe left a note in a readme file referencing the game and concluding "who says sequels have to be done sequentially?".

MAD Magazine proposed what Leisure Suit Larry 4 might have looked like in a 1990 issue spoofing video games. Their idea was "the after effect of Larry's screwing around with the time coming for Larry having to pay the piper." They proposed the idea of Larry in a maze game similar to Berzerk, where he must steer clear of out-of-wedlock pregnancies he has caused, as well as private investigators, case workers and angry fathers wielding shotguns, making it extremely difficult for Larry to continue his infamous carefree attitude towards casual sex. On April 1, 2009, the abandonware site Abandonia released an alleged "leaked copy" for download. This turned out in fact to be an elaborate April Fools' Day prank: the screenshots were fakes, the review was fictional, and the "game" archive actually contained 55 identical copies of scanned front casing of Leisure Suit Larry: Box Office Bust.

The game is a part of the plot of Space Quest 4: Roger Wilco and the Time Rippers, another Sierra title. In the game, LSL4 is labeled as the cause of a supercomputer virus that crippled Roger's home planet Xenon.

The fourth part is also considered as the remake of the first game, since it is included in the compilations together with the regular games and was released between the third and fifth part.

Leisure Suit Larry 8
Leisure Suit Larry 8, tentatively subtitled Lust in Space (as well as Explores Uranus in some references), was in full development in 1998 until funding was cut. Shortly afterwards, Sierra's adventure games department was disbanded, and Al Lowe left Sierra on February 22, 1999. Like the canned Space Quest sequel, Larry 8 was to feature 3D computer graphics, but no more than a few test renders now survive. The game Leisure Suit Larry: Explores Uranus, as well as its teaser, was referenced in Leisure Suit Larry: Love for Sail! triggered with an Easter egg, as well as a teaser after completing the game. In 2013, Al Lowe pointed out that this title is still being considered, with support from series co-writer Josh Mandel. Lowe stated that even though he would like to complete the Reloaded series first, Leisure Suit Larry 8 is "absolutely" still in the works.

Leisure Suit Larry: Pocket Party
Leisure Suit Larry: Pocket Party was a canceled game meant to be released in the second half of 2005 for the N-Gage. The publishers were Vivendi and Nokia, while the developer was TKO-Software. In the game, players would explore a 3D college campus, while solving puzzles and engaging in risque activities. As they search for the ultimate good time, gamers bump into Rosie Palmer, the head cheerleader at Larry's college. Attempting to win over Rosie's heart, Larry is thoroughly embarrassed by her jock boyfriend Chuck Rockwell, but humiliation has never stopped Larry before and he is determined to do anything to be with Rosie. In addition to singleplayer game play, players could also wirelessly battle an opponent in four different turn-based mini-games. Concept art and design document of the game are in hands of Jody Hicks, one of the game's developers. An alpha prototype was spotted at the ObscureGamers forum in February 2021.

Leisure Suit Larry: Cocoa Butter
In late 2005, Target department stores (through online vendor Amazon.com) began accepting pre-orders for a sequel to Leisure Suit Larry: Magna Cum Laude titled Leisure Suit Larry: Cocoa Butter. This new game was being developed for the PC, PS2, Xbox and PSP systems, but has since been canceled.

Collections
Several Larry collections have been compiled:

Other software and products

 * The Official Book of Leisure Suit Larry (1990) (written by Al Lowe and Ralph Roberts, containing background information and hint guides). The book was revised and edited so that there was a second (1991), a third (1993), and a fourth (1997) edition, and Special Edition (released with Larry Collection).
 * The Authorized Uncensored Leisure Suit Larry Bedside Companion (1990) (written by Peter Spear), containing the stories of the first three Leisure Suit Larry games, as well as detailed walkthroughs, point lists and maps. The book, like other Sierra books by Peter Spear such as The King's Quest Companion, was revised and edited so that there was a second edition (1991) covering Larry 5.

Reception and legacy
The Leisure Suit Larry series became one of Sierra's most popular during the adventure genre's peak. It was ranked as the 85th top game of all time by Next Generation in 1996, praised for its blend of campy humor and bad puns. The total sales of the first five Leisure Suit Larry games surpassed 2 million copies by 1996, as of Love for Sail's release. By 1996, following the release of Love for Sail!, the first five games had collectively sold over 2 million copies. By 2011, the series had reached a milestone of 10 million copies sold.

The New York Times described Leisure Suit Larry as a "profoundly lonely" representation of American masculinity.

title: Leisure Suit Larry


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Ext2

ext2, or second extended file system, is a file system for the Linux kernel. It was initially designed by French software developer Rémy Card as a replacement for the extended file system (ext). Having been designed according to the same principles as the Berkeley Fast File System from BSD, it was the first commercial-grade filesystem for Linux.

The canonical implementation of ext2 is the "ext2fs" filesystem driver in the Linux kernel. Other implementations (of varying quality and completeness) exist in GNU Hurd, MINIX 3, some BSD kernels,   in MiNT, Haiku and as third-party Microsoft Windows and macOS (via FUSE) drivers. This driver was deprecated in Linux version 6.9 in favor of the ext4 driver, as the ext4 driver works with ext2 filesystems.

ext2 was the default filesystem in several Linux distributions, including Debian and Red Hat Linux, until supplanted by ext3, which is almost completely compatible with ext2 and is a journaling file system. ext2 is still the filesystem of choice for flash-based storage media (such as SD cards and USB flash drives) because its lack of a journal increases performance and minimizes the number of writes, and flash devices can endure a limited number of write cycles. Since 2009, the Linux kernel supports a journal-less mode of ext4 which provides benefits not found with ext2, such as larger file and volume sizes.

History
The early development of the Linux kernel was made as a cross-development under the MINIX operating system. The MINIX file system was used as Linux's first file system. The Minix file system was mostly free of bugs, but used 16-bit offsets internally and thus had a maximum size limit of only 64 megabytes, and there was also a filename length limit of 14 characters. Because of these limitations, work began on a replacement native file system for Linux.

To ease the addition of new file systems and provide a generic file API, VFS, a virtual file system layer, was added to the Linux kernel. The extended file system (ext), was released in April 1992 as the first file system using the VFS API and was included in Linux version 0.96c. The ext file system solved the two major problems in the Minix file system (maximum partition size and filename length limitation to 14 characters), and allowed 2 gigabytes of data and filenames of up to 255 characters. But it still had problems: there was no support of separate timestamps for file access, inode modification, and data modification.

As a solution for these problems, two new filesystems were developed in January 1993 for Linux kernel 0.99: xiafs and the second extended file system (ext2), which was an overhaul of the extended file system incorporating many ideas from the Berkeley Fast File System. ext2 was also designed with extensibility in mind, with space left in many of its on-disk data structures for use by future versions.

Since then, ext2 has been a testbed for many of the new extensions to the VFS API. Features such as the withdrawn POSIX draft ACL proposal and the withdrawn extended attribute proposal were generally implemented first on ext2 because it was relatively simple to extend and its internals were well understood.

On Linux kernels prior to 2.6.17, restrictions in the block driver mean that ext2 filesystems have a maximum file size of 2 TiB.

ext2 is still recommended over journaling file systems on bootable USB flash drives and other solid-state drives. ext2 performs fewer writes than ext3 because there is no journaling. As the major aging factor of a flash chip is the number of erase cycles, and as erase cycles happen frequently on writes, decreasing writes increases the life span of the solid-state device. Another good practice for filesystems on flash devices is the use of the noatime mount option, for the same reason.

Beginning with Linux kernel 6.9, the ext2fs driver was deprecated and is no longer enabled in the default configuration. The central reason was that it did not support dates past 2038. Users are recommended to upgrade to ext4.

ext2 data structures
The space in ext2 is split up into blocks. These blocks are grouped into block groups, analogous to cylinder groups in the Unix File System. There are typically thousands of blocks on a large file system. Data for any given file is typically contained within a single block group where possible. This is done to minimize the number of disk seeks when reading large amounts of contiguous data.

Each block group contains a copy of the superblock and block group descriptor table, and all block groups contain a block bitmap, an inode bitmap, an inode table, and finally the actual data blocks.

The superblock contains important information that is crucial to the booting of the operating system. Thus backup copies are made in multiple block groups in the file system. However, typically only the first copy of it, which is found at the first block of the file system, is used in the booting.

The group descriptor stores the location of the block bitmap, inode bitmap, and the start of the inode table for every block group. These, in turn, are stored in a group descriptor table.

Inodes
Every file or directory is represented by an inode. The term "inode" comes from "index node" (over time, it became i-node and then inode). The inode includes data about the size, permission, ownership, and location on disk of the file or directory.

Example of ext2 inode structure:

Quote from the Linux kernel documentation for ext2: "There are pointers to the first 12 blocks which contain the file's data in the inode. There is a pointer to an indirect block (which contains pointers to the next set of blocks), a pointer to a doubly indirect block and a pointer to a trebly indirect block."

Thus, there is a structure in ext2 that has 15 pointers. Pointers 1 to 12 point to direct blocks, pointer 13 points to an indirect block, pointer 14 points to a doubly indirect block, and pointer 15 points to a triply indirect block.

Directories
Each directory is a list of directory entries. Each directory entry associates one file name with one inode number, and consists of the inode number, the length of the file name, and the actual text of the file name. To find a file, the directory is searched front-to-back for the associated filename. For reasonable directory sizes, this is fine. But for very large directories this is inefficient, and ext3 offers a second way of storing directories (HTree) that is more efficient than just a list of filenames.

The root directory is always stored in inode number two, so that the file system code can find it at mount time. Subdirectories are implemented by storing the name of the subdirectory in the name field, and the inode number of the subdirectory in the inode field. Hard links are implemented by storing the same inode number with more than one file name. Accessing the file by either name results in the same inode number, and therefore the same data.

The special directories "." (current directory) and ".." (parent directory) are implemented by storing the names "." and ".." in the directory, and the inode number of the current and parent directories in the inode field. The only special treatment these two entries receive is that they are automatically created when any new directory is made, and they cannot be deleted.

Allocating data
When a new file or directory is created, ext2 must decide where to store the data. If the disk is mostly empty, then data can be stored almost anywhere. However, clustering the data with related data will minimize seek times and maximize performance.

ext2 attempts to allocate each new directory in the group containing its parent directory, on the theory that accesses to parent and children directories are likely to be closely related. ext2 also attempts to place files in the same group as their directory entries, because directory accesses often lead to file accesses. However, if the group is full, then the new file or new directory is placed in some other non-full group.

The data blocks needed to store directories and files can be found by looking in the data allocation bitmap. Any needed space in the inode table can be found by looking in the inode allocation bitmap.

File-system limits
The reason for some limits of ext2 are the file format of the data and the operating system's kernel. Mostly these factors will be determined once when the file system is built. They depend on the block size and the ratio of the number of blocks and inodes.

In Linux the block size is limited by the architecture page size.

There are also some userspace programs that cannot handle files larger than 2 GiB.

If b is the block size, the maximal file size is limited to min( ((b/4)3 + (b/4)2 + b/4 + 12) × b, (232 − 1) × 512 ) due to the i_block structure (an array of direct/indirect EXT2_N_BLOCKS) and i_blocks (32-bit integer value) representing the number of 1024 byte (1 kilobyte) "blocks" in the file.

The maximal number of sublevel-directories is 31998, due to the link-count limit. Directory indexing is not available in ext2, so there are performance issues for directories with a large number of files (>10,000). The theoretical limit on the number of files in a directory is 1.3 × 1020, although this is not relevant for practical situations.

Note: In Linux 2.4 and earlier, block devices were limited to 2 TiB, limiting the maximal size of a partition, regardless of block size.

Compression extension
e2compr is a modification to the ext2 driver in the Linux kernel to support compression and decompression of files by the file system, without any support by user applications. e2compr is a small patch against ext2.

e2compr compresses only regular files; the administrative data (superblock, inodes, directory files, etc.) are not compressed (mainly for safety reasons). Access to compressed blocks is provided for read and write operations. The compression algorithm and cluster size is specified on a per-file basis. Directories can also be marked for compression, in which case every newly created file in the directory will be automatically compressed with the same cluster size and the same algorithm that was specified for the directory.

e2compr is not a new file system. It is only a patch to ext2 made to support the EXT2_COMPR_FL flag. It does not require user to make a new partition, and will continue to read or write existing ext2 file systems. One can consider it as simply a way for the read and write routines to access files that could have been created by a simple utility similar to gzip or compress. Compressed and uncompressed files coexist nicely on ext2 partitions.

The latest e2compr-branch is available for current releases of Linux 2.4, 2.6, and 3.0. The latest patch for Linux 3.0 was released in August 2011 and provides multicore and High memory support. There are also branches for Linux 2.0 and 2.2.

Under other operating systems
Access to ext2 partitions under Microsoft Windows is possible through an Installable File System, such as ext2ifs or ext2Fsd. Filesystem in Userspace can be used on macOS.

title: Ext2


text:
Ext3

ext3, or third extended filesystem, is a journaled file system that is commonly used by the Linux kernel. It used to be the default file system for many popular Linux distributions. Stephen Tweedie first revealed that he was working on extending ext2 in Journaling the Linux ext2fs Filesystem in a 1998 paper, and later in a February 1999 kernel mailing list posting. The filesystem was merged with the mainline Linux kernel in November 2001 from 2.4.15 onward. Its main advantage over ext2 is journaling, which improves reliability and eliminates the need to check the file system after an unclean shutdown. Its successor is ext4.

Advantages
The performance (speed) of ext3 is less attractive than competing Linux filesystems, such as ext4, JFS, ReiserFS, and XFS, but ext3 has a significant advantage in that it allows in-place upgrades from ext2 without having to back up and restore data. Benchmarks suggest that ext3 also uses less CPU power than ReiserFS and XFS. It is also considered safer than the other Linux file systems, due to its relative simplicity and wider testing base.

ext3 adds the following features to ext2:
 * A journal
 * Online file system growth
 * HTree indexing for larger directories

Without these features, any ext3 file system is also a valid ext2 file system. This situation has allowed well-tested and mature file system maintenance utilities for maintaining and repairing ext2 file systems to also be used with ext3 without major changes. The ext2 and ext3 file systems share the same standard set of utilities, e2fsprogs, which includes an fsck tool. The close relationship also makes conversion between the two file systems (both forward to ext3 and backward to ext2) straightforward.

ext3 lacks "modern" filesystem features, such as dynamic inode allocation and extents. This situation might sometimes be a disadvantage, but for recoverability, it is a significant advantage. The file system metadata is all in fixed, well-known locations, and data structures have some redundancy. In significant data corruption, ext2 or ext3 may be recoverable, while a tree-based file system may not.

Size limits
The maximum number of blocks for ext3 is 232. The size of a block can vary, affecting the maximum number of files and the maximum size of the file system:

. However,  may destroy data, depending on the feature bits turned on in the filesystem; it does not know how to handle many of the newer ext3 features.

There are userspace defragmentation tools, like Shake and defrag. Shake works by allocating space for the whole file as one operation, which will generally cause the allocator to find contiguous disk space. If there are files which are used at the same time, Shake will try to write them next to one another. Defrag works by copying each file over itself. However, this strategy works only if the file system has enough free space. A true defragmentation tool does not exist for ext3.

However, as the Linux System Administrator Guide states, "Modern Linux filesystem(s) keep fragmentation at a minimum by keeping all blocks in a file close together, even if they can't be stored in consecutive sectors. Some filesystems, like ext3, effectively allocate the free block that is nearest to other blocks in a file. Therefore it is not necessary to worry about fragmentation in a Linux system."

While ext3 is resistant to file fragmentation, ext3 can get fragmented over time or for specific usage patterns, like slowly writing large files. Consequently, ext4 (the successor to ext3) has an online filesystem defragmentation utility e4defrag and currently supports extents (contiguous file regions).

Undelete
ext3 does not support the recovery of deleted files. The ext3 driver actively deletes files by wiping file inodes for crash safety reasons.

There are still several techniques and some free and proprietary software for recovery of deleted or lost files using file system journal analysis; however, they do not guarantee any specific file recovery.

Compression
e3compr is an unofficial patch for ext3 that does transparent compression. It is a direct port of e2compr and still needs further development. It compiles and boots well with upstream kernels, but journaling is not implemented yet.

Lack of snapshots support
Unlike a number of modern file systems, ext3 does not have native support for snapshots, the ability to quickly capture the state of the filesystem at arbitrary times. Instead, it relies on less-space-efficient, volume-level snapshots provided by the Linux LVM. The Next3 file system is a modified version of ext3 which offers snapshots support, yet retains compatibility with the ext3 on-disk format.

No checksumming in journal
ext3 does not do checksumming when writing to the journal. On a storage device with extra cache, if barrier=1 is not enabled as a mount option (in /etc/fstab), and if the hardware is doing out-of-order write caching, one runs the risk of severe filesystem corruption during a crash. This is because storage devices with write caches report to the system that the data has been completely written, even if it was written to the (volatile) cache.

If hard disk writes are done out-of-order (due to modern hard disks caching writes in order to amortize write speeds), it is likely that one will write a commit block of a transaction before the other relevant blocks are written. If a power failure or unrecoverable crash should occur before the other blocks get written, the system will have to be rebooted. Upon reboot, the file system will replay the log as normal, and replay the "winners" (transactions with a commit block, including the invalid transaction above, which happened to be tagged with a valid commit block). The unfinished disk write above will thus proceed, but using corrupt journal data. The file system will thus mistakenly overwrite normal data with corrupt data while replaying the journal. If checksums had been used, where the blocks of the "fake winner" transaction were tagged with a mutual checksum, the file system could have known better and not replayed the corrupt data onto the disk. Journal checksumming has been added to ext4.

Filesystems going through the device mapper interface (including software RAID and LVM implementations) may not support barriers, and will issue a warning if that mount option is used. There are also some disks that do not properly implement the write cache flushing extension necessary for barriers to work, which causes a similar warning. In these situations, where barriers are not supported or practical, reliable write ordering is possible by turning off the disk's write cache and using the data=journal mount option. Turning off the disk's write cache may be required even when barriers are available.

Applications like databases expect a call to fsync to flush pending writes to disk, and the barrier implementation doesn't always clear the drive's write cache in response to that call. There is also a potential issue with the barrier implementation related to error handling during events, such as a drive failure. It is also known that sometimes some virtualization technologies do not properly forward fsync or flush commands to the underlying devices (files, volumes, disk) from a guest operating system. Similarly, some hard disks or controllers implement cache flushing incorrectly or not at all, but still advertise that it is supported, and do not return any error when it is used. There are so many ways to handle fsync and write cache handling incorrectly, it is safer to assume that cache flushing does not work unless it is explicitly tested, regardless of how reliable individual components are believed to be.

Near-time extinction due to date-stamp limitation
Ext3 stores dates as Unix time using four bytes in the file header. 32 bits does not give enough scope to continue processing files beyond January 18, 2038 - the Year 2038 problem.

ext4

On June 28, 2006, Theodore Ts'o, the principal developer of ext3, announced an enhanced version, called ext4. On October 11, 2008, the patches that mark ext4 as stable code were merged in the Linux 2.6.28 source code repositories, marking the end of the development phase and recommending its adoption. In 2008, Ts'o stated that although ext4 has improved features such as being much faster than ext3, it is not a major advance, it uses old technology, and is a stop-gap; Ts'o believes that Btrfs is the better direction, because "it offers improvements in scalability, reliability, and ease of management". Btrfs also has "a number of the same design ideas that reiser3/4 had".

title: Ext3


text:
Talk:Causality

Article issues and classification

 * The article is tagged with "citation needed" (April 2016 and April 2020), a 2017 "section needs additional citations", and a June 2016 "vague" tag. There are unsourced sentences, subsections, and sections.
 * The "See also" section (with an astounding 10 subsections) has 78 entries that go far beyond any "reasonable number".
 * The B-class criteria #1 states; The article is suitably referenced, with inline citations. It has reliable sources, and any important or controversial material which is likely to be challenged is cited. Reassess the article to C-class.
 * There are 10 entries in the "External links". Three seems to be an acceptable number and of course, everyone has their favorite to add for four. The problem is that none is needed for article promotion.

 * ELpoints #3) states: Links in the "External links" section should be kept to a minimum. A lack of external links or a small number of external links is not a reason to add external links.
 * LINKFARM states: There is nothing wrong with adding one or more useful content-relevant links to the external links section of an article; however, excessive lists can dwarf articles and detract from the purpose of Wikipedia. On articles about topics with many fansites, for example, including a link to one major fansite may be appropriate.
 * WP:ELMIN: Minimize the number of links. -- Otr500 (talk) 12:11, 27 February 2023 (UTC)

Philosophy
कारन कार्य नियम कि व्यख्या करे 2409:408A:217:D857:0:0:24CF:80B0 (talk) 16:44, 20 November 2023 (UTC)

Philosophy
कारन कार्य नियम कि व्यख्या करे 2409:408A:217:D857:0:0:24CF:80B0 (talk) 16:44, 20 November 2023 (UTC)

title: Talk:Causality