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Bill Holbrook

Bill Holbrook (born 1958) is an American cartoonist and webcomic writer and artist, best known for his syndicated comic strip On the Fastrack.

Born in Los Angeles, Holbrook grew up in Huntsville, Alabama, and began drawing at an early age. While majoring in illustration and visual design at Auburn University, Holbrook served as art director of the student newspaper, doing editorial cartoons and a weekly comic strip. At the same time, his work was being published in the Huntsville Times and the Monroe Journal. After graduation in 1980, he joined the Atlanta Constitution as an editorial staff artist.

During a 1982 visit to relatives on the West Coast, Holbrook met Peanuts creator, Charles Schulz. Following his advice and encouragement, Holbrook created a strip in the fall of that year about a college graduate working in a rundown diner. It did not stir syndicate interest, but what he learned on the strip helped him when he created On the Fastrack.

Eleven days before On the Fastrack made its syndicated debut (March 19, 1984), Holbrook met Teri Peitso on a blind date. They were married on Pearl Harbor Day, 1985. They have two daughters, Chandler and Haviland. Peitso-Holbrook's novels have been nominated for both Edgar Awards and Agatha Awards. She is currently an assistant professor in literacy education at Georgia State University. The family lives in the Atlanta area.

On October 3, 1988, Holbrook began his second strip, Safe Havens, and his third strip, Kevin and Kell was launched in September 1995.

Comic strips
Every week Holbrook writes the story line for the next three weeks for one of his strips and draws the next three weeks' worth of strips for another. In 2010, characters from On the Fastrack and Safe Havens began appearing in both strips.
 * On the Fastrack - About the misadventures at Fastrack, Inc., On the Fastrack has been distributed by King Features Syndicate since 1984. It now appears in 75 newspapers nationwide.
 * Safe Havens - Initially about a day care center, this strip evolved into the adventures of Samantha Argus and her friends and is now syndicated nationally to over 50 newspapers.
 * Kevin and Kell - Originally an online-only strip but was also published in the Atlanta Journal-Constitution for some years, Kevin and Kell centers on the mixed marriage between a rabbit, Kevin and a grey wolf, Kell Dewclaw. The plot revolves around species-related humor, satire, and interpersonal conflict.
 * Duel In The Somme  - Holbrook illustrated a story by Ben Bova and Rob Balder in this strip about a romantic rivalry between a computer-simulation designer and his boss.

title: Bill Holbrook


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Bruce Campbell

Bruce Lorne Campbell (born June 22, 1958) is an American actor and filmmaker. He is known best for his role as Ash Williams in Sam Raimi's Evil Dead horror series, beginning with the short movie Within the Woods (1978). He has also featured in many low-budget cult movies such as Crimewave (1985), Maniac Cop (1988), Sundown: The Vampire in Retreat (1989), and Bubba Ho-Tep (2002).

Campbell had the main roles of the television series The Adventures of Brisco County, Jr. (1993–1994) and Jack of All Trades (2000), and a recurring role as Autolycus, King of Thieves in Hercules: The Legendary Journeys (1995–1999) and Xena: Warrior Princess (1995–1999). He played Sam Axe on the USA Network series Burn Notice (2007–2013) and reprised his role as Ash for the Starz series Ash vs. Evil Dead (2015–2018). He also appeared in The Escort (2015).

Campbell directed, produced, and featured in the documentaries Fanalysis (2002) and A Community Speaks (2004); co-wrote, directed, produced, and featured in the movie Man with the Screaming Brain (2005); and directed, produced, and featured in a parody of his career My Name Is Bruce (2007).

Campbell is known for frequent collaborations with the aforementioned Raimi, his brother Ted, Josh Becker, and Scott Spiegel.

Early life
Bruce Lorne Campbell was born in Royal Oak, Michigan, on June 22, 1958, the son of advertising executive and college professor Charles Newton Campbell and homemaker Joanne Louise (née Pickens). He is of English and Scottish ancestry, and has an older brother named Don and an older half-brother named Michael. His father was also an actor and director for local theater. Campbell began acting and making short Super 8 movies with friends as a teenager. After meeting future moviemaker Sam Raimi while the two attended Wylie E. Groves High School, they became good friends and collaborators. Campbell attended Western Michigan University and continued to pursue an acting career.

Film
Campbell and Raimi collaborated with a 30-minute Super 8 version of the first Evil Dead movie, titled Within the Woods (1978), which was initially used to attract investors. He and Raimi got together with family and friends to begin working on The Evil Dead (1981). While featuring as the protagonist, Campbell also participation with the production of the movie, receiving a co-executive producer credit. Raimi wrote, directed, and edited the movie, while Rob Tapert produced. After an endorsement by horror author Stephen King, the movie slowly began to receive attention and offers for distribution. Four years after its original release, it became the most popular movie in the UK. It was then distributed in the United States, resulting in the sequels Evil Dead II (1987) and Army of Darkness (1992).

Campbell was also drawn in the Marvel Zombie comics as his character, Ash Williams. He is featured in five comics, all in the series Marvel Zombies vs. Army of Darkness. In them, he fights alongside the Marvel heroes against the heroes and people who have become zombies (deadites) while in search of the Necronomicon (Book of the Names of the Dead). Campbell also played as Coach Boomer in the movie “Sky High”.

He has appeared in several of Raimi's movies other than the Evil Dead series, notably having cameo appearances in the director's Spider-Man film series. Campbell also joined the cast of Raimi's movie Darkman and The Quick and the Dead, though having no actual screen time in the latter movie's theatrical version. In March 2022, Campbell was announced to have a cameo in Raimi's Marvel Cinematic Universe film Doctor Strange in the Multiverse of Madness.

Campbell often performs quirky roles, such as Elvis Presley for the movie Bubba Ho-Tep. Along with Bubba Ho-Tep, he played a supporting role in Maniac Cop and Maniac Cop 2, and spoofed his career in the self-directed My Name is Bruce.

Other mainstream movies for Campbell include supporting or featured roles in the Coen Brothers movie The Hudsucker Proxy, the Michael Crichton adaptation Congo, the movie version of McHale's Navy, Escape From L.A. (the sequel to John Carpenter's Escape From New York), the Jim Carrey drama The Majestic and the 2005 Disney movie Sky High.

Campbell had a major voice role for the 2009 animated adaptation of the children's book Cloudy with a Chance of Meatballs, and a supporting voice role for Pixar's Cars 2.

Campbell produced the 2013 remake of The Evil Dead, along with Raimi and Rob Tapert, appearing in the movie's post-credits scene in a cameo role with the expectation he would reprise that role in Army of Darkness 2. The next year, the comedy metal band Psychostick released a song titled "Bruce Campbell" on their album IV: Revenge of the Vengeance that pays a comedic tribute to his past roles.

Campbell worked as an executive producer for the 2023 movie Evil Dead Rise.

Television

Other than cinema, Campbell has appeared in a number of television series. He featured in The Adventures of Brisco County, Jr. a boisterous science fiction comedy western created by Jeffrey Boam and Carlton Cuse that played for one season. He played a lawyer turned bounty hunter who was trying to hunt down John Bly, the man who killed his father. He featured in the television series Jack of All Trades, set on a fictional island occupied by the French in 1801. Campbell was also credited as co-executive producer, among others. The show was directed by Eric Gruendemann, and was produced by various people, including Sam Raimi. The show was broadcast for two seasons, from 2000 to 2001. He had a recurring role as "Bill Church Jr." based upon the character of Morgan Edge from the Superman comics on Lois & Clark: The New Adventures of Superman.

From 1996 to 1997, Campbell was a recurring guest actor of the television series Ellen as Ed Billik, who becomes Ellen's boss when she sells her bookstore in season four.

He is also known for his supporting role as the recurring character Autolycus ("King of Thieves") on both Hercules: The Legendary Journeys and Xena: Warrior Princess, which reunited him with producer Rob Tapert. Campbell played Hercules/Xena series producer Tapert in two episodes of Hercules set in the present. He directed a number of episodes of Hercules and Xena, including the Hercules series finale.

Campbell also obtained the main role of race car driver Hank Cooper for the Disney made-for-television remake of The Love Bug.

Campbell had a critically acclaimed dramatic guest role as a grief-stricken detective seeking revenge for his father's murder in a two-part episode of the fourth season of Homicide: Life on the Street. Campbell later played the part of a bigamous demon in The X-Files episode "Terms of Endearment". He also featured as Agent Jackman in the episode "Witch Way Now?" of the WB series Charmed, as well as playing a state police officer in an episode of the short-lived series American Gothic titled "Meet The Beetles".

Campbell co-featured in the television series Burn Notice, which was broadcast from 2007 to 2013 by USA Network. He portrayed Sam Axe, a beer-chugging, former Navy SEAL now working as an unlicensed private investigator and occasional mercenary with his old friend Michael Westen, the show's main character. When working undercover, his character frequently used the alias Chuck Finley, which Bruce later revealed was the name of one of his father's old co-workers. Campbell was the star of a 2011 Burn Notice made-for-television prequel focusing on Sam's Navy SEAL career, titled Burn Notice: The Fall of Sam Axe.

In 2014, Campbell played Santa Claus for an episode of The Librarians. Campbell played Ronald Reagan in season 2 of the FX original series Fargo. More recently Campbell reprised his role as Ashley "Ash" Williams in Ash vs Evil Dead, a series based upon the Evil Dead series that began his career. Ash vs Evil Dead began airing on Starz on October 31, 2015, and was renewed by the cable channel for second and third seasons, before being cancelled.

In January 2019, Travel Channel announced a new version of the Ripley's Believe It or Not! reality series, with Campbell serving as host and executive producer. The 10-episode season debuted on June 9, 2019.

Voice acting
Campbell is featured as a voice actor for several video games. He provides the voice of Ash in the four games based on the Evil Dead movies series: Evil Dead: Hail to the King, Evil Dead: A Fistful of Boomstick, Evil Dead: Regeneration and Evil Dead: The Game. He also provided voice talent in other titles such as Pitfall 3D: Beyond the Jungle, Spider-Man, Spider-Man 2, Spider-Man 3, The Amazing Spider-Man, and Dead by Daylight.

He provided the voice of main character Jake Logan for the PC game, Tachyon: The Fringe, the voice of main character Jake Burton for the PlayStation game Broken Helix and the voice of Magnanimous for Megas XLR. Campbell voiced the pulp adventurer Lobster Johnson in Hellboy: The Science of Evil and has done voice-over work for the Codemaster's game Hei$t, a game which was announced on January 28, 2010 to have been "terminated". He also provided the voice of The Mayor for the 2009 movie Cloudy With a Chance of Meatballs, the voice of Rod "Torque" Redline in Cars 2, the voice of Himcules in the 2003 Nickelodeon TV series My Life as a Teenage Robot, and the voice of Fugax in the 2006 movie The Ant Bully.

Despite the inclusion of his character "Ash Williams" in Telltale Games' Poker Night 2, Danny Webber voices the character in the game, instead of Bruce Campbell.

He has a voice in the online MOBA game, Tome: Immortal Arena in 2014. Campbell also provided voice-over and motion capture for Sgt. Lennox in the Exo Zombies mode of Call of Duty: Advanced Warfare.

Writing
In addition to acting and occasionally directing, Campbell has become a writer, starting with an autobiography, If Chins Could Kill: Confessions of a B Movie Actor, published in June 2001. The autobiography was a successful New York Times Best Seller. It describes Campbell's career to date as an actor in low-budget movies and television, providing his insight into "Blue-Collar Hollywood". The paperback version of the book adds details about the reactions of fans during book signings: "Whenever I do mainstream stuff, I think they're pseudo-interested, but they're still interested in seeing weirdo, offbeat stuff, and that's what I'm attracted to".

Campbell's next book Make Love! The Bruce Campbell Way was published on May 26, 2005. The book's plot involves him (depicted in a comical way) as the main character struggling to make it into the world of A-list movies. He later recorded an audio play adaptation of Make Love with fellow Michigan actors, including longtime collaborator Ted Raimi. This radio drama was released by the independent label Rykodisc and spans 6 discs with a 6-hour running time.

In addition to his books, Campbell also wrote a column for X-Ray Magazine in 2001, an issue of the popular comic series The Hire, and comic book adaptations of his Man with the Screaming Brain. Most recently he wrote the introduction to Josh Becker's The Complete Guide to Low-Budget Feature Filmmaking.

In late 2016, Campbell announced that he would be releasing a third book, Hail to the Chin: Further Confessions of a B Movie Actor, which will detail his life from where If Chins Could Kill ended. Hail to the Chin was released in August 2017, and accompanied by a book tour across the United States and Europe.

Campbell maintained a weblog on his official website, where he posted mainly about politics and the movie industry, though it has since been deleted.

Bruce Campbell Horror Film Festival
Since 2014, the Bruce Campbell Horror Film Festival, narrated and organized by Campbell, was held in the Muvico Theater in Rosemont, Illinois. The first festival was originally from August 21 to 25, 2014, presented by Wizard World, as part of the Chicago Comicon. The second festival was from August 20 to 23, 2015, with guests Tom Holland and Eli Roth. The third festival took place over four days in August 2016. Guests of the event were Sam Raimi, Robert Tapert and Doug Benson.

Personal life
Campbell married Christine Deveau in 1983, and they had two children before divorcing in 1989. He met costume designer Ida Gearon while working on Mindwarp, and they were married in 1992. They reside in Jacksonville, Oregon.

Campbell is also ordained and has performed marriage ceremonies.

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

title: Bruce Campbell


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Baron Aberdare

Baron Aberdare, of Duffryn in the County of Glamorgan, is a title in the Peerage of the United Kingdom. It was created on 23 August 1873 for the Liberal politician Henry Bruce. He served as Home Secretary from 1868 to 1873. His grandson, the third Baron, was a soldier, cricketer and tennis player and a member of the International Olympic Committee. His son, the fourth Baron, held office in the Conservative administration of Edward Heath and was later a Deputy Speaker of the House of Lords. Lord Aberdare was one of the ninety-two elected hereditary peers that were allowed to remain in the House of Lords after the passing of the House of Lords Act 1999. the title is held by his son, the fifth Baron, who succeeded in 2005 and was elected to the House of Lords in 2009.

Coat of arms
The heraldic blazon for the coat of arms of the family is: Or, a saltire gules, on a chief of the last a martlet of the field.

Baron Aberdare (1873)

 * Henry Austin Bruce, 1st Baron Aberdare (1815–1895)
 * Henry Campbell Bruce, 2nd Baron Aberdare (1851–1929)
 * Hon. Henry Lyndhurst Bruce (1881–1914), killed in action at Ypres
 * Clarence Napier Bruce, 3rd Baron Aberdare (1885–1957)
 * Morys George Lyndhurst Bruce, 4th Baron Aberdare (1919–2005)
 * Alastair John Lyndhurst Bruce, 5th Baron Aberdare (born 1947)

The heir apparent is the present holder's son, the Hon. Hector Morys Napier Bruce (born 1974).

title: Baron Aberdare


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Boy band

A boy band is a vocal group consisting of young male singers, usually in their teenage years or in their twenties at the time of formation. Generally, boy bands perform love songs marketed towards girls and young women. Many boy bands dance as well as sing, usually giving highly choreographed performances. South Korean boy bands usually also have designated rappers. Most boy band members do not play musical instruments, either in recording sessions or on-stage. They are similar in concept to their counterparts known as girl groups.

Some boy bands are formed on their own, but most are created by talent managers or record producers who hold auditions. The popularity of boy bands has peaked three times: first in the 1960s to '70s, with e.g. the Jackson 5 and the Osmonds; the second time during the late 1980s, the 1990s and the 2000s, when acts such as New Kids on the Block, Take That, Backstreet Boys, NSYNC, Boyzone, Five, A1, O-Zone and Westlife dominated global pop charts; and last time in the 2010s up to the present, with the emergence of groups such as Big Time Rush, the Wanted, One Direction, and K-pop acts such as BTS and Seventeen.

History
The term was not established until the late 1980s when Lou Pearlman decided to form a record company to promote a new singing and dancing group after becoming fascinated with the success of New Kids on the Block.

Although generally described as a rock band, the highest-selling band in history – the Beatles – have been described by several journalists as "the first" or "the original" boy band, "before anyone had thought of the term", exclusively due to the enthusiastic response they received from their young female audience.

"The Liverpool quartet known as the Beatles were not only the quintessential rock band, but many considered John Lennon, Paul McCartney, George Harrison and Ringo Star [sic] to be the original boy band – especially in the early 1960s when young girls would scream at the top of their lungs and pass out upon first sight of the 'Fab Four'."

Other critics, however, have pointed out that this assessment of the Beatles as a "boy band" could be applied to all other bands of the 1960s, saying, "if they were a (boy band), so was everyone else" and is countered by others, including Ringo Starr, who point out that, from the beginning, the Beatles wrote and exercised creative control over their own music, played their own instruments, were not manufactured by a record label, and did not feature the choreographed dance moves that later came to be associated with boy bands. The Beatles did, however, inspire the production of the 1966 television series The Monkees, which featured a music group of the same name, created for the show, that consisted of the four starring actors. The Monkees had a career as a rock and pop band after their songs from the TV series were released as successful records.

Late 1960s and 1970s: The Jackson 5 and the Osmonds
Although the term "boy band" was not commonly used then, the earliest predecessors of this format were groups such as the Jackson 5 and the Osmonds which helped form the template for boy bands. The Jackson 5 were a sibling group that established many musical conventions that boy bands follow. For instance, their music featured close harmonies from soul music and catchy pop hooks influenced as much as they were by Motown and acts like the Supremes. The group also incorporated choreographed dance moves to their performances. All members of the band sang, which is a common convention of a boy band, as opposed to having a front man and the rest on instruments; thus, no one person dominated the stage. Also a sibling group, The Osmonds first started singing barbershop music for local audiences, before being hired to perform at Disneyland early in their career. Their appearance in a televised Disney special earned them additional TV spots, such as The Andy Williams Show and The Jerry Lewis Show.

Late 1970s and 1980s: Menudo, New Edition, and New Kids on the Block
The Puerto Rican boy band Menudo, appealing to young Latina audiences, was founded in 1977. Menudo had a convention unique among boy bands: when a member turned 16, became too tall, or their voice changed, they were replaced. The members of Menudo were generally aged 12–16. Menudo had a large impact in Latin America and in Asia; Menudo fever there was compared to Beatlemania and it was nicknamed "Menudomania".

Boston group New Edition was formed in 1978 and reached their height of popularity in the 1980s, meaning they are often credited for starting the boy-band trend, even though the term "boy band" did not exist until the 1990s. Maurice Starr was influenced by New Edition and popularized it with his protégé New Kids on the Block (NKOTB), the first commercially successful modern boy band, which formed in 1984 and found international success in 1988. Starr's idea was to take the traditional template from the R&B genre (in this case his teenage band New Edition) and apply it to a pop genre.

Bros (abbreviation of the word "brothers") were a British boy band active in the late 1980s and early 1990s, consisting of twin brothers Matt and Luke Goss along with Craig Logan. Formed in 1986, they scored multiple top 10 hits between 1987 and 1989 and in 1988 became the first modern era–style boy band to have a multiple platinum-selling album in the UK, with Push, still one of the most successful boy-band albums in the UK. Other big boy bands in Britain during the late 1980s were Big Fun and Brother Beyond.

1990s: Boyz II Men, Take That, Backstreet Boys, NSYNC, Westlife, Seo Taiji and Boys and the birth of modern K-pop
The ongoing international success of New Kids on the Block inspired music managers in Europe to create their own acts, beginning with Nigel Martin-Smith's Take That in the UK (formed in 1990) and followed by Tom Watkins, who had success with Bros in the late 1980s and formed East 17 in 1991. East 17 were marketed and pitted against Take That as "rivals" with a rougher or harsher attitude, style and sound. Take That reformed in 2006 after a decade-long hiatus and became one of the most successful groups in British music chart history, with renewed chart success internationally, especially in Europe. Irish music manager Louis Walsh, who had witnessed the impact of these British boy bands, put out an advert for an "Irish Take That", thereby creating Boyzone in 1993. Let Loose (formed in 1993), MN8 and 911 (formed in 1995), and Damage (formed in 1996) were also successful boy bands in Britain; however, by the late 1990s all these bands had split up.

All these artists were very successful on both the singles and albums charts domestically and internationally; however, with the emergence of Britpop and the commercial co-option of indie rock, many boy bands were ridiculed by the British music press as having no artistic credibility, although some, such as East 17 and Take That, did write most of their own material. The media attention was then placed on the "Battle of Britpop", and the bands Oasis and Blur replaced the importance and rivalry of Take That and East 17 as the two new biggest bands in Britain. However, boy bands continued to find success in the late 1990s, such as Five, Another Level, Point Break and Westlife. In 1995 successful German music manager Frank Farian, who had been manager of Boney M and Milli Vanilli, put together Latin American band No Mercy who scored a few worldwide hits during the mid-90s.

Although being American and the sons of Tito Jackson, a member of the Jackson 5, 3T had several hits singles across Europe in the mid-1990s, despite limited success in the US, and finished the second biggest selling act of 1996 in Europe behind the Spice Girls. With the success of North American boy bands like New Kids on the Block in East Asia, Japanese entertainment company Johnny & Associates formed SMAP in 1992. The group enjoyed tremendous success, selling over 35 million records.

In 1992, after the disbandment of the heavy metal band Sinawe, in which he had a brief stint, Seo Taiji formed the boy band Seo Taiji and Boys (Korean: 서태지와 아이들) together with dancers Lee Juno and Yang Hyun-suk, which went on to become highly successful and created a craze at the time. Seo Taiji and Boys is credited with changing the South Korean music industry by pioneering the incorporation of rap and breakdance as well as the fusion of Korean music and various popular Western music genres in Korean popular music, and in turn creating the prototype for the modern hybrid K-pop genre or "rap-dance", as it was called at the time, and K-pop groups. They also left a lasting impact by explicitly putting social criticism at the forefront of their music, as well as paving the way for artistic freedom in South Korea by challenging censorship laws and the television networks hegemony over the music market. In 1995 the Korean Broadband is not 6 ft to a particular location casting Ethics Committee demanded that Seo Taiji and Boys change the lyrics for "Regret of the Times". As a result, Seo decided to release the song as a purely instrumental track. This incited protests and resulted in the abolishment of music pre-censorship in Korea. Seo Taiji also did not have to rely on television networks due to the fact that he owned his own studio. This autonomy allowed Seo to bring subcultures in Korea, such as heavy metal, to the forefront of popular culture and challenge pervasive social norms. The band's independent success diminished the power of the television networks to dictate which artists appeared on shows, and gave rise to the influence of record labels and talent agencies. In 1996, Seo Taiji and Boys disbanded. In April 1996, Billboard reported that the band's first three albums had each sold over 1.6 million copies, with the fourth nearing two million, making all four some of the best-selling albums of all time in South Korea to this day. Lee Juno became a record producer, and Yang Hyun-suk was successful in founding YG Entertainment, one of the three biggest record companies in the country. Seo Taiji returned to music two years later with a successful solo career as a rock artist; he rose to become one of the most prominent and influential cultural icons in South Korea and was dubbed "the President of culture". In 2017, Seo Taiji released a 25th Anniversary album with his greatest hits and remakes by prominent Korean artists, including the group BTS. He also held a joint celebratory concert with the latter, in which he acknowledged them as his spiritual successors in K-pop due to the socially conscious thematic similarities in their music as well their shared hip hop leanings, and metaphorically passed the torch, saying "This is your generation now".

In the early 1990s in North America, with New Kids on the Block's continued success and Color Me Badd also having success, boy bands became a continued staple of the Billboard charts. Continuing this success in the mid-1990s, most prominent boy bands were African American and had R&B and gospel elements, such as the groups All-4-One (formed in 1993) and Boyz II Men (formed in 1988). Boyz II Men are also the most successful boy band act on the U.S. Hot 100 as well as the Australian Singles Chart. Although they had success on the Billboard charts, they were not marketed towards youth but more towards adults. It was not until 1997 and the change to pop-oriented groups such as Backstreet Boys, 98 Degrees, NSYNC, the Moffatts, and Hanson that boy bands exploded commercially and dominated the market in the United States. This late 1990s marked the height of boy band popularity in North America, which has not been seen since.

Arguably the most successful boy band manager from the U.S. was Lou Pearlman, who founded commercially successful acts such as the Backstreet Boys in 1993, NSYNC and LFO in 1995, O-Town in 2000, and US5 in 2005. Backstreet Boys and NSYNC became the two biggest boy bands in the late 1990s until the early 2000s, and Backstreet Boys went on to become the best-selling boy band in history with over 100 million records sold.

In the late 1990s in the UK, producer Simon Cowell (noted in the U.S. for the American Idol/The X Factor franchise) is also known for having managed British boyband Five (formed in 1997) and Irish boyband Westlife (formed in 1998). Westlife was created by Irishman Louis Walsh as a replacement for Boyzone and was initially managed by a former member of the band Ronan Keating. Westlife would eventually overtake Take That in number one's tally in the UK although Take That's overall UK sales are still higher. In 2012, the Official Charts Company revealed the biggest selling singles artists in British music chart history with Take That placed 15th overall and the highest selling boyband act (9.3 million), followed by Boyzone at 29 (7.1 million) and Westlife at 34 (6.8 million). Even though Cowell is known to have managed several successful boy bands, he is also infamous for passing on signing two of the biggest boybands to emerge from the 1990s and 2000s, Take That and Busted.

2000s: Backstreet Boys, NSYNC, Westlife and Jonas Brothers
With the continued success of Backstreet Boys and *NSYNC, American and British groups like 98 Degrees, Westlife, O-Town, A1, Blue, and Busted gained quick popularity both domestically and internationally. International boy bands would also occasionally spring up, such as the Moldovan band O-Zone (better known today as an Internet meme), and Overground. American Christian boy band Plus One also enjoyed brief remarkable success during this time.

At the height of boy band popularity in North America, MTV created their own parody boyband, 2gether. Like the Monkees in the 1960s, they were a manufactured act composed of actors. 2gether played off of the idea that every successful boy band must have five distinct personality types: the bad boy, the shy one, the young one, the older brother type, and a heart throb.

Since 2001, the dominance of traditional boy bands on pop charts began to fade in the western hemisphere, although Gil Kaufman of MTV has described "new boy bands" that are "more likely to resemble My Chemical Romance, Sum 41, and Simple Plan.

In 2001, Taiwanese boy band F4 (called JVKV since 2007) blew up big as a result of the success of their TV drama Meteor Garden. According to Forbes, F4 has sold 3.5 million copies of their first two albums all over Asia as of July 2003.

With their success, many other Taiwanese boy bands emerged around this time, such as 5566 and Fahrenheit. In South Korea, Shinhwa also spread hallyu wave throughout Asia such as Japan, Thailand, Singapore, Taiwan, Hong Kong and China. Also in 2001, a new all-male pop band and dance group boyband hailing from Japan called Exile debuted under Avex Group's label Rhythm Zone with 14 members, putting them on par with Super Junior, a South Korean boy band, who at the time, had had 13 members at its peak.

Japanese boy band Arashi has sold over 30 million copies of their records since their first release in 1999. They had the yearly best-selling single in Japan in 2008 and 2009. In 2003 SMAP released the single "Sekai ni Hitotsu Dake no Hana" that has become the third best-selling single ever in Japan, with over three million copies sold.

In North America, the Jonas Brothers rose to fame from promotion on the Disney Channel in 2008. Other boy bands like JLS and Mindless Behavior also emerged and experienced remarkable success around this time. However, apart from them, boy bands have not seen the commercial boom experienced in the genre from the mid to late nineties in North America.

The mid 2000s, especially the United Kingdom and the rest of Europe, saw the continued longevity of nineties boy bands such as Backstreet Boys and Westlife (before they disbanded in 2012), and the successful comeback of Take That in 2005, Boyzone in 2007, and New Kids on the Block in 2008. Some sections of the press have referred to these acts, particularly those who have reformed after a previous split, such as Take That, Boyzone, and 98 Degrees, as 'man bands'.

2010s and 2020s: Big Time Rush, One Direction and rise of K-pop
In the early 2010s, there was somewhat of a resurgence of boy band popularity in countries where the trend had not maintained, with the emergence of new boy bands like Big Time Rush, the Wanted, and One Direction and the formation of supergroup NKOTBSB which comprised members of New Kids on the Block and Backstreet Boys. NKOTBSB's success inspired boy bands who were fairly popular during the 1990s and 2000s to make a comeback, such as A1, Blue, 98 Degrees, Five, 911, and O-Town. Like 2gether and the Monkees, Big Time Rush was a manufactured act created for a television show. One Direction were often credited as sparking a resurgence in the popularity and interest boy bands alongside being credited with forming part of a new "British Invasion" in the United States. Their Where We Are Tour was the highest-grossing tour by a vocal group in history and after the release of their fourth album, Four, they became the only group in the 58-year history of the Billboard 200 to have their first four albums debut at number one.

In Southeast Asia, local boy bands also emerged as a result of the continued success of Korean and Japanese boy bands. After the debut of the Philippines supergroup SB19 in 2018, the group appeared at number six on Billboard Year-End Social 50 chart, making them the first Southeast Asian act to reach the top 10 of the magazine's annual chart.

In South Korea, boy bands have been commercially successful. On the Circle Chart year-end albums chart of 2022, 7 of the top 10 and 13 of the top 20 albums are by boy bands or by subunits/members of boy bands. Seventeen's  FML is the best-selling album of all time in South Korea, with more than 6.2 million copies sold, and BTS's Love Yourself: Her became the first album released since 2001 to sell more than 1 million copies.

In 2013, Billboard started covering music releases in K-pop, though K-pop had been entering the charts as early as 2009. By 2017, BTS crossed into the international music market, furthering the Korean Wave in the United States and becoming the first Korean group to receive a certification by the Recording Industry Association of America (RIAA) with their single "Mic Drop". The band is the first Korean act to top the U.S. Billboard 200 with their studio album Love Yourself: Tear (2018) and have since hit the top of the U.S. charts with their albums Love Yourself: Answer (2018), Map of the Soul: Persona (2019), Map of the Soul: 7 (2020), Be (2020) and Proof. Love Yourself: Answer also broke South Korea's Gaon Album Chart's all-time monthly record previously set by Love Yourself: Tear and became the first Korean album certified Gold in the United States. SuperM later became the first K-pop group to debut at No. 1 in the U.S. Billboard 200. In 2020, BTS "Dynamite" debuted atop the Billboard Hot 100, making them the first all-South Korean act in Hot 100 history to debut at number one. It garnered the band their first Grammy nomination, for Best Pop Duo/Group Performance at 63rd Annual Grammy Awards, making them the first K-pop act to be nominated for one.

In Japan, Arashi was the best-selling music artist in Japan from 2013 through 2017 by value of sales and also having the yearly best-selling album in the country in 2010, 2011, 2013, 2015 and 2016. Other successful Japanese boy bands in this decade include Sandaime J Soul Brothers, the second best-selling music artist of 2016 in the country and Kanjani Eight, the fifth best-selling music artist of that year in Japan.

In Norway, the boy band Ballinciaga gained commercial success in 2022 with dance and party songs like "Dans På Bordet" and "Beklager (Guttaklubben)". The group is also known for keeping their identities anonymous by wearing pink-colored masks in the public.

Key factors of the concept
Seen as important to a "boy band" group's commercial success is the group's image, carefully controlled by managing all aspects of the group's attire, promotional materials (which are frequently supplied to teen magazines), and music videos. The key factor of a boy band is being trendy. This means that the band conforms to the most recent fashion and musical trends in the popular music scene. Typically, each member of the group will have some distinguishing feature and be portrayed as having a particular personality stereotype, such as "the baby", "the bad boy", or "the shy one". While managing the portrayal of popular musicians is as old as popular music, the particular pigeonholing of band members is a defining characteristic of boy and girl bands. In K-pop, officially designated positions within the group are common, such as "leader", "maknae" (Korean: 막내, English: "the youngest"), "visual", "center" "vocalist", "rapper" and "dancer". The latter three are based on the members' specialized skills and are further divided into "main-", "lead-" and "sub-" (vocalist/rapper/dancer) positions, with the members occupying the "main" positions often being considered the most skilled and having the most parts in songs or being highlighted during solo dance parts. The "leader" is the spokesperson who represents the group in public, and is in charge of mediating between group members, as well as between the group and the label.

In most cases, their music is written, arranged and produced by a producer who works with the band at all times and controls the group's sound – if necessary, to the point of hiring session singers to record guide vocals for each member of the group to sing individually if the members cannot harmonize well together. However, for clarity of each voice, recording each voice individually is most commonly the norm with most modern vocal groups. In recent years, auto-tune has become a popular tool in vocal producing, some boy bands have come under fire for that reason. Some have also come under fire for lip syncing in their performances as well, for example New Kids on the Block.

A typical boy band performance features elaborately choreographed dancing, with the members taking turns singing and/or rapping. Boy bands generally do not compose or produce their own material, unless the members lobby hard enough for creative control. However, some bands were created around the talent of a songwriter within the group like Gary Barlow of Take That or Tony Mortimer of East 17. It is not uncommon to find extra songs on an album written by one or more of the band members; however, their producers rarely use these as singles.

Since the 21st century, however, boy bands have been expected to write or at least contribute in some part lyrically to songs. Apart from the groups mentioned above who all had at least one primary songwriter from their beginning, other groups soon caught up. At the close of the nineties, groups like Backstreet Boys and *NSYNC who had previously used writers like Max Martin during their early albums began writing their own songs. Newer groups from late 2000s such as JLS have all made a point from early interviews that they write their own songs and hold their own image as this is an important part of marketing. Some bands like The Wanted have even spent time learning the craft of songwriting. There has also been a rising trend of so-called "songwriter-" or "producer idols" (Korean: Hangul 작곡돌, rev. Rom. jakgok-dol) in K-pop since the early 2000s. Nowadays, it is not uncommon for groups to have at least one member who is heavily involved in the songwriting and producing of the groups' music. In many cases, these members are the rappers in the group, who have often gained songwriting and producing experience while being active as amateur or underground rappers before joining the group. There is also a higher expectation for rappers to write their own lyrics due to self-expression being a core value of the hip-hop genre. There are cases of "producer idols" writing or producing for other artists outside of their solo or respective group work as well, such as BTS' RM and Suga.

Individuals can also go on to achieve greater success as a solo artist coming out of a boy band having used the groups popularity to build on. Usually this signals the end of the group until potential future reunions. Examples of this include Justin Timberlake from NSYNC, and Robbie Williams from Take That. Some boy band members have gone on to successful careers elsewhere in the media. In K-pop, it is expected and common practice for members to embark on solo endeavors as musical artists or in other entertainment sectors, such as acting, or as variety personalities, alongside their group career after a few years. At the latest, this happens around the time the eldest member reaches the age of 28 (in exceptional cases 30) and is drafted for mandatory military service, forcing the group into a temporary hiatus of at least 18 months. The other members then often go on to pursue solo endeavors and reconvene as a group while no member is serving, or after all members have completed their service.

Music genres
Although most boy bands consist of R&B or pop influences, other music genres, most notably country music and folk music, are also represented. South 65 and Marshall Dyllon, for example, were both country music boy bands. Il Divo, created by Simon Cowell in 2004, are a vocal group that performs operatic pop in several (mainly Italian) languages. Since then operatic/classical boy bands have become quite popular and common, especially in the UK. Since 2001, there has been some crossover with power pop and pop punk from bands that play live instruments. Just recently some boy bands decided to go back to their original doo-wop roots, most notably, The Overtones.

Controversy
Since the 2000s, groups such as Backstreet Boys and LFO have disliked the term "boy band" and have preferred to be known as a "male vocal group". Being categorized among boy bands was also the main reason the Moffatts split up. Boy bands have been accused by the music press of emphasizing the appearance and marketing of the group above the quality of music, deliberately trying to appeal to a preteen audience and for conforming to trends instead of being original. Such criticisms can become extremely scathing. Boy bands are often seen as being short-lived, although some acts such as The Jackson 5, Backstreet Boys, Human Nature, New Edition, SMAP, Shinhwa, Take That and Westlife have sustained lasting careers.

title: Boy band


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B-tree

In computer science, a B-tree is a self-balancing tree data structure that maintains sorted data and allows searches, sequential access, insertions, and deletions in logarithmic time. The B-tree generalizes the binary search tree, allowing for nodes with more than two children. Unlike other self-balancing binary search trees, the B-tree is well suited for storage systems that read and write relatively large blocks of data, such as databases and file systems.

History
B-trees were invented by Rudolf Bayer and Edward M. McCreight while working at Boeing Research Labs, for the purpose of efficiently managing index pages for large random-access files. The basic assumption was that indices would be so voluminous that only small chunks of the tree could fit in main memory. Bayer and McCreight's paper Organization and maintenance of large ordered indices was first circulated in July 1970 and later published in Acta Informatica.

Bayer and McCreight never explained what, if anything, the B stands for; Boeing, balanced, between, broad, bushy, and Bayer have been suggested. McCreight has said that "the more you think about what the B in B-trees means, the better you understand B-trees".

Definition
According to Knuth's definition, a B-tree of order m is a tree which satisfies the following properties:

 * 1) Every node has at most m children.
 * 2) Every node, except for the root and the leaves, has at least ⌈m/2⌉ children.
 * 3) The root node has at least two children unless it is a leaf.
 * 4) All leaves appear on the same level.
 * 5) A non-leaf node with k children contains k−1 keys.

Each internal node's keys act as separation values which divide its subtrees. For example, if an internal node has 3 child nodes (or subtrees) then it must have 2 keys: a1 and a2. All values in the leftmost subtree will be less than a1, all values in the middle subtree will be between a1 and a2, and all values in the rightmost subtree will be greater than a2.

 * Internal nodes
 * Internal nodes (also known as inner nodes) are all nodes except for leaf nodes and the root node. They are usually represented as an ordered set of elements and child pointers. Every internal node contains a maximum of U children and a minimum of L children. Thus, the number of elements is always 1 less than the number of child pointers (the number of elements is between L−1 and U−1). U must be either 2L or 2L−1; therefore each internal node is at least half full. The relationship between U and L implies that two half-full nodes can be joined to make a legal node, and one full node can be split into two legal nodes (if there's room to push one element up into the parent). These properties make it possible to delete and insert new values into a B-tree and adjust the tree to preserve the B-tree properties.

 * The root node
 * The root node's number of children has the same upper limit as internal nodes, but has no lower limit. For example, when there are fewer than L−1 elements in the entire tree, the root will be the only node in the tree with no children at all.

 * Leaf nodes
 * In Knuth's terminology, the "leaf" nodes are the actual data objects / chunks. The internal nodes that are one level above these leaves are what would be called the "leaves" by other authors: these nodes only store keys (at most m-1, and at least m/2-1 if they are not the root) and pointers (one for each key) to nodes carrying the data objects / chunks.

A B-tree of depth n+1 can hold about U times as many items as a B-tree of depth n, but the cost of search, insert, and delete operations grows with the depth of the tree. As with any balanced tree, the cost grows much more slowly than the number of elements.

Some balanced trees store values only at leaf nodes, and use different kinds of nodes for leaf nodes and internal nodes. B-trees keep values in every node in the tree except leaf nodes.

Differences in terminology
The literature on B-trees is not uniform in its terminology.

Bayer and McCreight (1972), Comer (1979), and others define the order of B-tree as the minimum number of keys in a non-root node. Folk and Zoellick points out that terminology is ambiguous because the maximum number of keys is not clear. An order 3 B-tree might hold a maximum of 6 keys or a maximum of 7 keys. Knuth (1998) avoids the problem by defining the order to be the maximum number of children (which is one more than the maximum number of keys).

The term leaf is also inconsistent. Bayer and McCreight (1972) considered the leaf level to be the lowest level of keys, but Knuth considered the leaf level to be one level below the lowest keys. There are many possible implementation choices. In some designs, the leaves may hold the entire data record; in other designs, the leaves may only hold pointers to the data record. Those choices are not fundamental to the idea of a B-tree.

For simplicity, most authors assume there are a fixed number of keys that fit in a node. The basic assumption is the key size is fixed and the node size is fixed. In practice, variable length keys may be employed.

Node structure
As with other trees, B-trees can be represented as a collection of three types of nodes: root, internal (a.k.a. interior), and leaf.

Note the following variable definitions:

 * $K$: Maximum number of potential search keys for each node in a B-tree. (this value is constant over the entire tree).
 * $$pt_i$$: The pointer to a child node which starts a sub-tree.
 * $$pr_i$$: The pointer to a record which stores the data.
 * $$k_i$$: The search key at the zero-based node index $$i$$.

In B-trees, the following properties are maintained for these nodes:

 * If $k_i$ exists in any node in a B+ tree, then $$k_{i-1}$$ exists in that node where $$i \ge 1$$.
 * All leaf nodes have the same number of ancestors (i.e., they are all at the same depth).

Each internal node in a B-tree has the following format: Each leaf node in a B-tree has the following format: The node bounds are summarized in the table below:

Insertion and deletion
In order to maintain the predefined range of child nodes, internal nodes may be joined or split.

Usually, the number of keys is chosen to vary between $$d$$ and $$2d$$, where $$d$$ is the minimum number of keys, and $$d+1$$ is the minimum degree or branching factor of the tree. The factor of 2 will guarantee that nodes can be split or combined.

If an internal node has $$2d$$ keys, then adding a key to that node can be accomplished by splitting the hypothetical $$2d+1$$ key node into two $$d$$ key nodes and moving the key that would have been in the middle to the parent node. Each split node has the required minimum number of keys. Similarly, if an internal node and its neighbor each have $$d$$ keys, then a key may be deleted from the internal node by combining it with its neighbor. Deleting the key would make the internal node have $$d-1$$ keys; joining the neighbor would add $$d$$ keys plus one more key brought down from the neighbor's parent. The result is an entirely full node of $$2d$$ keys.

A B-tree is kept balanced after insertion by splitting a would-be overfilled node, of $$2d+1$$ keys, into two $$d$$-key siblings and inserting the mid-value key into the parent. Depth only increases when the root is split, maintaining balance. Similarly, a B-tree is kept balanced after deletion by merging or redistributing keys among siblings to maintain the $$d$$-key minimum for non-root nodes. A merger reduces the number of keys in the parent potentially forcing it to merge or redistribute keys with its siblings, and so on. The only change in depth occurs when the root has two children, of $$d$$ and (transitionally) $$d-1$$ keys, in which case the two siblings and parent are merged, reducing the depth by one.

This depth will increase slowly as elements are added to the tree, but an increase in the overall depth is infrequent, and results in all leaf nodes being one more node farther away from the root.

Comparison to other trees
Because a range of child nodes is permitted, B-trees do not need re-balancing as frequently as other self-balancing search trees, but may waste some space, since nodes are not entirely full.

B-trees have substantial advantages over alternative implementations when the time to access the data of a node greatly exceeds the time spent processing that data, because then the cost of accessing the node may be amortized over multiple operations within the node. This usually occurs when the node data are in secondary storage such as disk drives. By maximizing the number of keys within each internal node, the height of the tree decreases and the number of expensive node accesses is reduced. In addition, rebalancing of the tree occurs less often. The maximum number of child nodes depends on the information that must be stored for each child node and the size of a full disk block or an analogous size in secondary storage. While 2–3 B-trees are easier to explain, practical B-trees using secondary storage need a large number of child nodes to improve performance.

Variants
The term B-tree may refer to a specific design or it may refer to a general class of designs. In the narrow sense, a B-tree stores keys in its internal nodes but need not store those keys in the records at the leaves. The general class includes variations such as the B+ tree, the B* tree and the B*+ tree.
 * In the B+ tree, the internal nodes do not store any pointers to records, thus all pointers to records are stored in the leaf nodes. In addition, a leaf node may include a pointer to the next leaf node to speed sequential access. Because B+ tree internal nodes have fewer pointers, each node can hold more keys, causing the tree to be shallower, and thus, faster to search.
 * The B* tree balances more neighboring internal nodes to keep the internal nodes more densely packed. This variant ensures non-root nodes are at least 2/3 full instead of 1/2. As the most costly part of operation of inserting the node in B-tree is splitting the node, B*-trees are created to postpone splitting operation as long as they can. To maintain this, instead of immediately splitting up a node when it gets full, its keys are shared with a node next to it. This spill operation is less costly to do than split, because it requires only shifting the keys between existing nodes, not allocating memory for a new one. For inserting, first it is checked whether the node has some free space in it, and if so, the new key is just inserted in the node. However, if the node is full (it has $m − 1$ keys, where $m$ is the order of the tree as maximum number of pointers to subtrees from one node), it needs to be checked whether the right sibling exists and has some free space. If the right sibling has $j < m − 1$ keys, then keys are redistributed between the two sibling nodes as evenly as possible. For this purpose, $m - 1$ keys from the current node, the new key inserted, one key from the parent node and $j$ keys from the sibling node are seen as an ordered array of $m + j + 1$ keys. The array becomes split by half, so that $\floor{(m + j + 1)/2}$ lowest keys stay in the current node, the next (middle) key is inserted in the parent and the rest go to the right sibling. (The newly inserted key might end up in any of the three places.) The situation when right sibling is full, and left isn't is analogous. When both the sibling nodes are full, then the two nodes (current node and a sibling) are split into three and one more key is shifted up the tree, to the parent node. If the parent is full, then spill/split operation propagates towards the root node. Deleting nodes is somewhat more complex than inserting however.
 * The B*+ tree combines the main B+ tree and B* tree features together.
 * B-trees can be turned into order statistic trees to allow rapid searches for the Nth record in key order, or counting the number of records between any two records, and various other related operations.

Time to search a sorted file
Sorting and searching algorithms can be characterized by the number of comparison operations that must be performed using order notation. A binary search of a sorted table with $N$ records, for example, can be done in roughly $⌈ log_{2} N ⌉$ comparisons. If the table had 1,000,000 records, then a specific record could be located with at most 20 comparisons: $⌈ log_{2} (1,000,000) ⌉ = 20$.

Large databases have historically been kept on disk drives. The time to read a record on a disk drive far exceeds the time needed to compare keys once the record is available due to seek time and a rotational delay. The seek time may be 0 to 20 or more milliseconds, and the rotational delay averages about half the rotation period. For a 7200 RPM drive, the rotation period is 8.33 milliseconds. For a drive such as the Seagate ST3500320NS, the track-to-track seek time is 0.8 milliseconds and the average reading seek time is 8.5 milliseconds. For simplicity, assume reading from disk takes about 10 milliseconds.

The time to locate one record out of a million in the example above would take 20 disk reads times 10 milliseconds per disk read, which is 0.2 seconds.

The search time is reduced because individual records are grouped together in a disk block. A disk block might be 16 kilobytes. If each record is 160 bytes, then 100 records could be stored in each block. The disk read time above was actually for an entire block. Once the disk head is in position, one or more disk blocks can be read with little delay. With 100 records per block, the last 6 or so comparisons don't need to do any disk reads—the comparisons are all within the last disk block read.

To speed up the search further, the time to do the first 13 to 14 comparisons (which each required a disk access) must be reduced.

An index speeds the search
A B-tree index can be used to improve performance. A B-tree index creates a multi-level tree structure that breaks a database down into fixed-size blocks or pages. Each level of this tree can be used to link those pages via an address location, allowing one page (known as a node, or internal page) to refer to another with leaf pages at the lowest level. One page is typically the starting point of the tree, or the "root". This is where the search for a particular key would begin, traversing a path that terminates in a leaf. Most pages in this structure will be leaf pages which refer to specific table rows.

Because each node (or internal page) can have more than two children, a B-tree index will usually have a shorter height (the distance from the root to the farthest leaf) than a Binary Search Tree. In the example above, initial disk reads narrowed the search range by a factor of two. That can be improved by creating an auxiliary index that contains the first record in each disk block (sometimes called a sparse index). This auxiliary index would be 1% of the size of the original database, but it can be searched quickly. Finding an entry in the auxiliary index would tell us which block to search in the main database; after searching the auxiliary index, we would have to search only that one block of the main database—at a cost of one more disk read.

In the above example the index would hold 10,000 entries and would take at most 14 comparisons to return a result. Like the main database, the last six or so comparisons in the auxiliary index would be on the same disk block. The index could be searched in about eight disk reads, and the desired record could be accessed in 9 disk reads.

Creating an auxiliary index can be repeated to make an auxiliary index to the auxiliary index. That would make an aux-aux index that would need only 100 entries and would fit in one disk block.

Instead of reading 14 disk blocks to find the desired record, we only need to read 3 blocks. This blocking is the core idea behind the creation of the B-tree, where the disk blocks fill-out a hierarchy of levels to make up the index. Reading and searching the first (and only) block of the aux-aux index which is the root of the tree identifies the relevant block in aux-index in the level below. Reading and searching that aux-index block identifies the relevant block to read, until the final level, known as the leaf level, identifies a record in the main database. Instead of 150 milliseconds, we need only 30 milliseconds to get the record.

The auxiliary indices have turned the search problem from a binary search requiring roughly $log_{2} N$ disk reads to one requiring only $log_{b} N$ disk reads where $b$ is the blocking factor (the number of entries per block: $b = 100$ entries per block in our example; $log_{100} 1,000,000 = 3$ reads).

In practice, if the main database is being frequently searched, the aux-aux index and much of the aux index may reside in a disk cache, so they would not incur a disk read. The B-tree remains the standard index implementation in almost all relational databases, and many nonrelational databases use them too.

Insertions and deletions
If the database does not change, then compiling the index is simple to do, and the index need never be changed. If there are changes, managing the database and its index require additional computation.

Deleting records from a database is relatively easy. The index can stay the same, and the record can just be marked as deleted. The database remains in sorted order. If there are a large number of lazy deletions, then searching and storage become less efficient.

Insertions can be very slow in a sorted sequential file because room for the inserted record must be made. Inserting a record before the first record requires shifting all of the records down one. Such an operation is just too expensive to be practical. One solution is to leave some spaces. Instead of densely packing all the records in a block, the block can have some free space to allow for subsequent insertions. Those spaces would be marked as if they were "deleted" records.

Both insertions and deletions are fast as long as space is available on a block. If an insertion won't fit on the block, then some free space on some nearby block must be found and the auxiliary indices adjusted. The best case is that enough space is available nearby so that the amount of block reorganization can be minimized. Alternatively, some out-of-sequence disk blocks may be used.

Advantages of B-tree usage for databases
The B-tree uses all of the ideas described above. In particular, a B-tree:
 * keeps keys in sorted order for sequential traversing
 * uses a hierarchical index to minimize the number of disk reads
 * uses partially full blocks to speed up insertions and deletions
 * keeps the index balanced with a recursive algorithm

In addition, a B-tree minimizes waste by making sure the interior nodes are at least half full. A B-tree can handle an arbitrary number of insertions and deletions.

Best case and worst case heights
Let h ≥ –1 be the height of the classic B-tree (see for the tree height definition). Let n ≥ 0 be the number of entries in the tree. Let m be the maximum number of children a node can have. Each node can have at most m−1 keys.

It can be shown (by induction for example) that a B-tree of height h with all its nodes completely filled has n = mh+1–1 entries. Hence, the best case height (i.e. the minimum height) of a B-tree is:
 * $$h_{\mathrm{min}} = \lceil \log_{m} (n+1) \rceil -1$$

Let $$d$$ be the minimum number of children an internal (non-root) node must have. For an ordinary B-tree, $$ d = \left\lceil m/2 \right\rceil. $$

Comer (1979) and Cormen et al. (2001) give the worst case height (the maximum height) of a B-tree as
 * $$h_{\mathrm{max}} = \left\lfloor \log_{d}\frac{n+1}{2} \right\rfloor .$$

Search
Searching is similar to searching a binary search tree. Starting at the root, the tree is recursively traversed from top to bottom. At each level, the search reduces its field of view to the child pointer (subtree) whose range includes the search value. A subtree's range is defined by the values, or keys, contained in its parent node. These limiting values are also known as separation values.

Binary search is typically (but not necessarily) used within nodes to find the separation values and child tree of interest.

Insertion

All insertions start at a leaf node. To insert a new element, search the tree to find the leaf node where the new element should be added. Insert the new element into that node with the following steps:

 * 1) If the node contains fewer than the maximum allowed number of elements, then there is room for the new element. Insert the new element in the node, keeping the node's elements ordered.
 * 2) Otherwise the node is full, evenly split it into two nodes so:
 * 3) A single median is chosen from among the leaf's elements and the new element that is being inserted.
 * 4) Values less than the median are put in the new left node and values greater than the median are put in the new right node, with the median acting as a separation value.
 * 5) The separation value is inserted in the node's parent, which may cause it to be split, and so on. If the node has no parent (i.e., the node was the root), create a new root above this node (increasing the height of the tree).

If the splitting goes all the way up to the root, it creates a new root with a single separator value and two children, which is why the lower bound on the size of internal nodes does not apply to the root. The maximum number of elements per node is U−1. When a node is split, one element moves to the parent, but one element is added. So, it must be possible to divide the maximum number U−1 of elements into two legal nodes. If this number is odd, then U=2L and one of the new nodes contains (U−2)/2 = L−1 elements, and hence is a legal node, and the other contains one more element, and hence it is legal too. If U−1 is even, then U=2L−1, so there are 2L−2 elements in the node. Half of this number is L−1, which is the minimum number of elements allowed per node.

An alternative algorithm supports a single pass down the tree from the root to the node where the insertion will take place, splitting any full nodes encountered on the way pre-emptively. This prevents the need to recall the parent nodes into memory, which may be expensive if the nodes are on secondary storage. However, to use this algorithm, we must be able to send one element to the parent and split the remaining U−2 elements into two legal nodes, without adding a new element. This requires U = 2L rather than U = 2L−1, which accounts for why some textbooks impose this requirement in defining B-trees.

Deletion
There are two popular strategies for deletion from a B-tree.

 * 1) Locate and delete the item, then restructure the tree to retain its invariants, OR
 * 2) Do a single pass down the tree, but before entering (visiting) a node, restructure the tree so that once the key to be deleted is encountered, it can be deleted without triggering the need for any further restructuring

The algorithm below uses the former strategy.

There are two special cases to consider when deleting an element:

 * 1) The element in an internal node is a separator for its child nodes
 * 2) Deleting an element may put its node under the minimum number of elements and children

The procedures for these cases are in order below.

Deletion from a leaf node

 * 1) Search for the value to delete.
 * 2) If the value is in a leaf node, simply delete it from the node.
 * 3) If underflow happens, rebalance the tree as described in section "Rebalancing after deletion" below.

Deletion from an internal node
Each element in an internal node acts as a separation value for two subtrees, therefore we need to find a replacement for separation. Note that the largest element in the left subtree is still less than the separator. Likewise, the smallest element in the right subtree is still greater than the separator. Both of those elements are in leaf nodes, and either one can be the new separator for the two subtrees. Algorithmically described below:

 * 1) Choose a new separator (either the largest element in the left subtree or the smallest element in the right subtree), remove it from the leaf node it is in, and replace the element to be deleted with the new separator.
 * 2) The previous step deleted an element (the new separator) from a leaf node. If that leaf node is now deficient (has fewer than the required number of nodes), then rebalance the tree starting from the leaf node.

Rebalancing after deletion
Rebalancing starts from a leaf and proceeds toward the root until the tree is balanced. If deleting an element from a node has brought it under the minimum size, then some elements must be redistributed to bring all nodes up to the minimum. Usually, the redistribution involves moving an element from a sibling node that has more than the minimum number of nodes. That redistribution operation is called a rotation. If no sibling can spare an element, then the deficient node must be merged with a sibling. The merge causes the parent to lose a separator element, so the parent may become deficient and need rebalancing. The merging and rebalancing may continue all the way to the root. Since the minimum element count doesn't apply to the root, making the root be the only deficient node is not a problem. The algorithm to rebalance the tree is as follows:
 * If the deficient node's right sibling exists and has more than the minimum number of elements, then rotate left
 * Copy the separator from the parent to the end of the deficient node (the separator moves down; the deficient node now has the minimum number of elements)
 * Replace the separator in the parent with the first element of the right sibling (right sibling loses one node but still has at least the minimum number of elements)
 * The tree is now balanced
 * Otherwise, if the deficient node's left sibling exists and has more than the minimum number of elements, then rotate right
 * Copy the separator from the parent to the start of the deficient node (the separator moves down; deficient node now has the minimum number of elements)
 * Replace the separator in the parent with the last element of the left sibling (left sibling loses one node but still has at least the minimum number of elements)
 * The tree is now balanced
 * Otherwise, if both immediate siblings have only the minimum number of elements, then merge with a sibling sandwiching their separator taken off from their parent
 * Copy the separator to the end of the left node (the left node may be the deficient node or it may be the sibling with the minimum number of elements)
 * Move all elements from the right node to the left node (the left node now has the maximum number of elements, and the right node – empty)
 * Remove the separator from the parent along with its empty right child (the parent loses an element)
 * If the parent is the root and now has no elements, then free it and make the merged node the new root (tree becomes shallower)
 * Otherwise, if the parent has fewer than the required number of elements, then rebalance the parent

 * Note: The rebalancing operations are different for B+ trees (e.g., rotation is different because parent has copy of the key) and B*-tree (e.g., three siblings are merged into two siblings).

Sequential access
While freshly loaded databases tend to have good sequential behaviour, this behaviour becomes increasingly difficult to maintain as a database grows, resulting in more random I/O and performance challenges.

Initial construction
A common special case is adding a large amount of pre-sorted data into an initially empty B-tree. While it is quite possible to simply perform a series of successive inserts, inserting sorted data results in a tree composed almost entirely of half-full nodes. Instead, a special "bulk loading" algorithm can be used to produce a more efficient tree with a higher branching factor.

When the input is sorted, all insertions are at the rightmost edge of the tree, and in particular any time a node is split, we are guaranteed that no more insertions will take place in the left half. When bulk loading, we take advantage of this, and instead of splitting overfull nodes evenly, split them as unevenly as possible: leave the left node completely full and create a right node with zero keys and one child (in violation of the usual B-tree rules).

At the end of bulk loading, the tree is composed almost entirely of completely full nodes; only the rightmost node on each level may be less than full. Because those nodes may also be less than half full, to re-establish the normal B-tree rules, combine such nodes with their (guaranteed full) left siblings and divide the keys to produce two nodes at least half full. The only node which lacks a full left sibling is the root, which is permitted to be less than half full.

In filesystems
In addition to its use in databases, the B-tree (or ) is also used in filesystems to allow quick random access to an arbitrary block in a particular file. The basic problem is turning the file block $$i$$ address into a disk block address.

Some operating systems require the user to allocate the maximum size of the file when the file is created. The file can then be allocated as contiguous disk blocks. In that case, to convert the file block address $$i$$ into a disk block address, the operating system simply adds the file block address $$i$$ to the address of the first disk block constituting the file. The scheme is simple, but the file cannot exceed its created size.

Other operating systems allow a file to grow. The resulting disk blocks may not be contiguous, so mapping logical blocks to physical blocks is more involved.

MS-DOS, for example, used a simple File Allocation Table (FAT). The FAT has an entry for each disk block, and that entry identifies whether its block is used by a file and if so, which block (if any) is the next disk block of the same file. So, the allocation of each file is represented as a linked list in the table. In order to find the disk address of file block $$i$$, the operating system (or disk utility) must sequentially follow the file's linked list in the FAT. Worse, to find a free disk block, it must sequentially scan the FAT. For MS-DOS, that was not a huge penalty because the disks and files were small and the FAT had few entries and relatively short file chains. In the FAT12 filesystem (used on floppy disks and early hard disks), there were no more than 4,080 entries, and the FAT would usually be resident in memory. As disks got bigger, the FAT architecture began to confront penalties. On a large disk using FAT, it may be necessary to perform disk reads to learn the disk location of a file block to be read or written.

TOPS-20 (and possibly TENEX) used a 0 to 2 level tree that has similarities to a B-tree. A disk block was 512 36-bit words. If the file fit in a 512 (29) word block, then the file directory would point to that physical disk block. If the file fit in 218 words, then the directory would point to an aux index; the 512 words of that index would either be NULL (the block isn't allocated) or point to the physical address of the block. If the file fit in 227 words, then the directory would point to a block holding an aux-aux index; each entry would either be NULL or point to an aux index. Consequently, the physical disk block for a 227 word file could be located in two disk reads and read on the third.

Apple's filesystem HFS+ and APFS, Microsoft's NTFS, AIX (jfs2) and some Linux filesystems, such as Bcachefs, Btrfs and ext4, use B-trees.

B*-trees are used in the HFS and Reiser4 file systems.

DragonFly BSD's HAMMER file system uses a modified B+-tree.

Performance
A B-tree grows slower with growing data amount, than the linearity of a linked list. Compared to a skip list, both structures have the same performance, but the B-tree scales better for growing n. A T-tree, for main memory database systems, is similar but more compact.

Access concurrency
Lehman and Yao showed that all the read locks could be avoided (and thus concurrent access greatly improved) by linking the tree blocks at each level together with a "next" pointer. This results in a tree structure where both insertion and search operations descend from the root to the leaf. Write locks are only required as a tree block is modified. This maximizes access concurrency by multiple users, an important consideration for databases and/or other B-tree-based ISAM storage methods. The cost associated with this improvement is that empty pages cannot be removed from the btree during normal operations. (However, see for various strategies to implement node merging, and source code at. )

United States Patent 5283894, granted in 1994, appears to show a way to use a 'Meta Access Method' to allow concurrent B+ tree access and modification without locks. The technique accesses the tree 'upwards' for both searches and updates by means of additional in-memory indexes that point at the blocks in each level in the block cache. No reorganization for deletes is needed and there are no 'next' pointers in each block as in Lehman and Yao.

Parallel algorithms
Since B-trees are similar in structure to red-black trees, parallel algorithms for red-black trees can be applied to B-trees as well.

Maple tree
A Maple tree is a B-tree developed for use in the Linux kernel to reduce lock contention in virtual memory management.

title: B-tree