Mainframe computers or mainframes are computers used by large organizations for critical applications. They are larger and have more processing power than some other classes of computers: minicomputers, servers and personal computers; the term referred to the large cabinets called "main frames" that housed the central processing unit and main memory of early computers. The term was used to distinguish high-end commercial machines from less powerful units. Most large-scale computer system architectures were established in the 1960s, but continue to evolve. Mainframe computers are used as servers. Modern mainframe design is characterized less by raw computational speed and more by: Redundant internal engineering resulting in high reliability and security Extensive input-output facilities with the ability to offload to separate engines Strict backward compatibility with older software High hardware and computational utilization rates through virtualization to support massive throughput. Hot-swapping of hardware, such as processors and memory.
Their high stability and reliability enable these machines to run uninterrupted for long periods of time, with mean time between failures measured in decades. Mainframes have high availability, one of the primary reasons for their longevity, since they are used in applications where downtime would be costly or catastrophic; the term reliability and serviceability is a defining characteristic of mainframe computers. Proper planning and implementation is required to realize these features. In addition, mainframes are more secure than other computer types: the NIST vulnerabilities database, US-CERT, rates traditional mainframes such as IBM Z, Unisys Dorado and Unisys Libra as among the most secure with vulnerabilities in the low single digits as compared with thousands for Windows, UNIX, Linux. Software upgrades require setting up the operating system or portions thereof, are non-disruptive only when using virtualizing facilities such as IBM z/OS and Parallel Sysplex, or Unisys XPCL, which support workload sharing so that one system can take over another's application while it is being refreshed.
In the late 1950s, mainframes had only a rudimentary interactive interface, used sets of punched cards, paper tape, or magnetic tape to transfer data and programs. They operated in batch mode to support back office functions such as payroll and customer billing, most of which were based on repeated tape-based sorting and merging operations followed by line printing to preprinted continuous stationery; when interactive user terminals were introduced, they were used exclusively for applications rather than program development. Typewriter and Teletype devices were common control consoles for system operators through the early 1970s, although supplanted by keyboard/display devices. By the early 1970s, many mainframes acquired interactive user terminals operating as timesharing computers, supporting hundreds of users along with batch processing. Users gained access through keyboard/typewriter terminals and specialized text terminal CRT displays with integral keyboards, or from personal computers equipped with terminal emulation software.
By the 1980s, many mainframes supported graphic display terminals, terminal emulation, but not graphical user interfaces. This form of end-user computing became obsolete in the 1990s due to the advent of personal computers provided with GUIs. After 2000, modern mainframes or phased out classic "green screen" and color display terminal access for end-users in favour of Web-style user interfaces; the infrastructure requirements were drastically reduced during the mid-1990s, when CMOS mainframe designs replaced the older bipolar technology. IBM claimed that its newer mainframes reduced data center energy costs for power and cooling, reduced physical space requirements compared to server farms. Modern mainframes can run multiple different instances of operating systems at the same time; this technique of virtual machines allows applications to run as if they were on physically distinct computers. In this role, a single mainframe can replace higher-functioning hardware services available to conventional servers.
While mainframes pioneered this capability, virtualization is now available on most families of computer systems, though not always to the same degree or level of sophistication. Mainframes can add or hot swap system capacity without disrupting system function, with specificity and granularity to a level of sophistication not available with most server solutions. Modern mainframes, notably the IBM zSeries, System z9 and System z10 servers, offer two levels of virtualization: logical partitions and virtual machines. Many mainframe customers run two machines: one in their primary data center, one in their backup data center—fully active active, or on standby—in case there is a catastrophe affecting the first building. Test, development and production workload for applications and databases can run on a single machine, except for large demands where the capacity of one machine might be limiting; such a two-mainframe installation can support continuous business service, avoiding both planned and unplanned outages.
In practice many customers use multiple mainframes linked either by Parallel Sysplex and shared DASD, or with shared, geographically dispersed storage provided by EMC or
The decade of the 1970s saw significant changes in television programming in both the United Kingdom and the United States. The trends included the decline of the "family sitcoms" and rural-oriented programs to more contemporary shows and "young and urban" sitcoms in the United States and the permanent establishment of colour television in the United Kingdom. In 1967, BBC Two had started trials of their new colour service, it was rolled out over the next few years. BBC One and ITV followed suit in 1969, so by 1970 the viewer had three colour channels from which to choose: BBC1, BBC2 and ITV. Although U. S. imports occupied a significant proportion of airtime, there was a substantial amount of high quality in-house production too. The BBC, supported by its licence fee and with no advertisers to placate, continued fulfilling its brief to entertain and inform; the Play for Today was a continuation of the Wednesday Play. As the title implied, it presented TV drama which had relevance to current social and economic issues, done in a way calculated to intrigue or shock the viewer.
As well as using established writers, it was an apprenticeship for new ones who were trying to make a name for themselves. In style, the plays could go from documentary realism to the futuristic or surrealist. Potter went on to write Pennies from one of the landmarks of 1970's television drama, it had the now familiar elements of Potter's style: sexual explicitness, fantasy song and dance scenes, all overlaying a dark and pessimistic view of human motivation. The series was a success, but the BBC was not yet ready for Brimstone and Treacle, a story of the rape of a physically and mentally handicapped young woman. After viewing it, the BBC's Director Of Programs Alasdair Milne, pronouncing it to be "brilliantly written... but nauseating", withdrew it, it would not be shown on British television until 1987. Things had begun to change in the 1960s, with Till Death Us Do Part, the series continued during 1972–75; the rantings of Alf Garnett on race, religion and anything else at all touched a nerve.
Although the show was in fact poking fun at right-wing bigotry, not everyone got the joke. Some — including, Mary Whitehouse — complained about the language and resented the racial epithets like "wog" and "coon" and the attitudes underlying them. Others missing the point of the show adopted Alf as their hero, thinking he was uttering truths that others didn't dare to — oblivious to the fact that he never got the best of any argument and was shown up to be stupid and ill-informed; the series provoked controversy in the media, for millions it became a common gossiping point at work or in the pub. Many popular British situation comedies were gentle, not challenging portrayals of middle-class life, avoiding or only hinting at controversial issues. Set in a hotel in Torquay, Fawlty Towers was a massive success for the BBC, despite only twelve episodes being made. More nostalgic in tone were Last of the Summer Wine, about the escapades of pensioners in a Yorkshire town, Dad's Army, about a Home Guard unit during World War II and It Ain't Half Hot Mum about a Royal Artillery Concert Party stationed in India/later Burma during World War II.
A more diverse view of society was offered by series like Porridge, a comedy about prison life, Rising Damp, set in a lodging house inhabited by two students, a lonely spinster and a lecherous landlord. Taking a softer approach to race than Till Death Us Do Part, ITV's Mind Your Language represented several foreign nations personified as English language students attending an evening class. Despite LWT ending the show after its third series in objection to the undeniable stereotyping, Mind Your Language did return for a fourth series in the 1980s. In police dramas, there was a move towards increasing realism. Dixon of Dock Green continued until 1976, but it was a nostalgic look back to an earlier time when police officers were depicted as a mix of strict but fair law enforcer, kindly social worker. On the other hand, detective series such as Softly, Softly began to show police work done by fallible human beings with their own personal failings and weaknesses frustrated by the constraints under which they worked.
Such series showed crime at the level of petty larceny and fraud, being tackled by ordinary coppers on the beat. Serious organised crime, on the other hand, was the province of various elite units, one show in the 1970s set a new standard; the Sweeney presented a hard, gritty picture of an armed police unit — members of Scotland Yard's elite Flying Squad. Violence was routine. In police dramas, through most of the 1970s however, corruption was rare, the detection rate was unrealistically high, the criminals arrested were always convicted on solid evidence. Although the officers in The S
American Samoa sent a team to the 2008 Summer Olympics in Beijing, China. The U. S. territory selected four athletes to compete in three sports: swimming and judo. The dependency's participation in Beijing marked its seventh participation in any Olympic game since its debut at the 1988 Summer Olympics in Seoul, its sixth participation at any Summer Olympic games. Of the four American Samoan athletes who participated in Beijing, all four were first-time Olympians and born outside American Samoa and none of the four advanced past the qualification or preliminary rounds of their events. More women participated in the 2008 American Samoan Olympic delegation than in any one delegation in its Olympic history. Judoka Silulu A'etonu was the territory's flagbearer at the ceremonies. American Samoa is a territory of the United States that lies in the South Pacific Ocean to the far east of Australia; the dependency's debut at the Olympics was at the 1988 Summer Olympics in Seoul. Between 1988 and 2008, American Samoa sent a delegation to participate at seven Olympic games, not missing a single Summer Olympics since its first time in the competition.
In 2008, American Samoa's delegation was composed of four athletes, including two women, the greatest number of women to have competed for American Samoa at any one games. Silulu A'etonu, a first-time Olympian and a judoka, was American Samoa's flagbearer at the ceremonies. Nineteen-year-old Los Angeles area-born athlete Shanahan Sanitoa participated on American Samoa's behalf at the Beijing Olympics, he was the only American Samoan Olympian involved in any field event. His appearance in Beijing marked the first time he appeared in an Olympic games, he participated in the fifth heat during the August 14 qualification round, completing the event in 12.60 seconds and placing last in his heat of eight athletes. Danny D'Souza of the Seychelles ranked just ahead of Sanitoa; the leaders of Sanitoa's heat included Nigeria's Olusoji Fasuba. Overall, the American Samoan runner ranked last out of the 80 athletes who participated in the qualification round, he did not progress to rounds. KeyNote–Ranks given for track events are within the athlete's heat only Q = Qualified for the next round q = Qualified for the next round as a fastest loser or, in field events, by position without achieving the qualifying target NR = National record N/A = Round not applicable for the event Bye = Athlete not required to compete in round Men Guam-born 24-year-old judoka Silulu A'etonu was the only American Samoan participating in a judo event at the Beijing Olympics.
She had not participated in any Olympic games. The judoka represented American Samoa in the women's half-middleweight weight class. During the August 12 Round of 32, Aetonu faced Germany's Anna von Harnier. Von Harnier defeated A`etonu by scoring ippon, she did not advance to rounds. Women Then 19 year-old West Point student Stewart Glenister, born in Fort Knox, competed on American Samoa's behalf at the Beijing Olympics in the men's 50 meters freestyle, he was the only American Samoan in the event, did not compete at any Olympic games. During the August 14 preliminary round, Glenister competed in the fourth heat, finished the race in 25.45 seconds. He placed first in his heat of displacing Palestine's Hamza Abdo. Overall, he ranked 71 out of the 97 participating athletes, did not advance. 32 year-old San Luis Obispo-born swimmer Virginia Farmer represented American Samoa at the Beijing Olympics. Farmer was the only American Samoan in her event. Additionally, prior to Beijing, she had not participated in any Olympic games or event.
The preliminary round for the event took place on August 15, Virginia Farmer participated in the fourth heat. She finished the race in 28.82 seconds, ranking third behind Swaziland's Senele Dlamini and ahead of Bolivia's Katerine Moreno. The leader of Virginia's heat was Mozambique's Ximene Gomes. Out of the 92 participating athletes, Farmer ranked 62nd, she did not progress to rounds. MenWomen