In computing, a keyboard is an input device, partially modeled after the typewriter keyboard, which uses an arrangement of buttons or keys, which act as mechanical levers or electronic switches. A keyboard typically has characters engraved or printed on the keys and each press of a key typically corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence. While most keyboard keys produce letters, numbers or signs (characters), other keys or simultaneous key presses can produce actions or computer commands.
In normal usage, the keyboard is used to type text and numbers into a word processor, text editor or other program. In a modern computer, the interpretation of keypresses is generally left to the software. A computer keyboard distinguishes each physical key from every other and reports all keypresses to the controlling software. Keyboards are also used for computer gaming, either with regular keyboards or by using keyboards with special gaming features, which can expedite frequently used keystroke combinations. A keyboard is also used to give commands to the operating system of a computer, such as Windows' Control-Alt-Delete combination, which brings up a task window or shuts down the machine.

Types

Standard
Standard keyboards, such as the 101-key US traditional keyboard 104-key Windows keyboards, include alphabetic characters, punctuation symbols, numbers and a variety of function keys. The internationally-common 102/105 key keyboards have a smaller 'left shift' key and an additional key with some more symbols between that and the letter to its right (usually Z or Y).

Laptop-size
Keyboards on laptops and notebook computers usually have a shorter travel distance for the keystroke and a reduced set of keys. As well, they may not have a numerical keypad, and the function keys may be placed in locations that differ from their placement on a standard, full-sized keyboard.
Gaming and multimedia
Keyboards with extra keys, such as multimedia keyboards, have special keys for accessing music, web and other oft-used programs, a mute button, volume buttons or knob and standby (sleep) button. Gaming keyboards have extra function keys, which can be programmed with keystroke macros. For example, 'ctrl+shift+y' could be a keystroke that is frequently used in a certain computer game. Shortcuts marked on color-coded keys are used for some software applications and for specialized for uses including word processing, video editing, graphic design and audio editing.

Thumb-sized
Smaller keyboards have been introduced for laptops, PDAs, cellphones or users who have a limited workspace. The size of a standard keyboard is dictated by the practical consideration that the keys must be large enough to be easily pressed by fingers. To reduce the size of the keyboard, the numeric keyboard to the right of the alphabetic keyboard can be removed, or the size of the keys can be reduced, which makes it harder to enter text.
Another way to reduce the size of the keyboard is to reduce the number of keys and use chording keyer, i.e. pressing several keys simultaneously. For example, the GKOS keyboard has been designed for small wireless devices. Other two-handed alternatives more akin to a game controller, such as the AlphaGrip, are also used as a way to input data and text. Another way to reduce the size of a keyboard is to use smaller buttons and pack them closer together. Such keyboards, often called a "thumbboard" (thumbing) are used in some personal digital assistants such as the Palm Treo and BlackBerry and some Ultra-Mobile PCs such as the OQO.

Numeric
Numeric keyboards contain only numbers, mathematical symbols for addition, subtraction, multiplication, and division, a decimal point, and several function keys (e.g. End, Delete, etc.). They are often used to facilitate data entry with smaller keyboard-equipped laptops or with smaller keyboards that do not have a numeric keypad.

Barack Hussein Obama was born Aug. 4, 1961, in Honolulu, Hawaii. His father, Barack Obama, Sr., was born of Luo ethnicity in Nyanza Province, Kenya. He grew up herding goats with his own father, who was a domestic servant to the British. Although reared among Muslims, Obama, Sr., became an atheist at some point.
Obama’s mother, Ann Dunham, grew up in Wichita, Kansas. Her father worked on oil rigs during the Depression. After the Japanese attack on Pearl Harbor, he signed up for service in World War II and marched across Europe in Patton’s army. Dunham’s mother went to work on a bomber assembly line. After the war, they studied on the G. I. Bill, bought a house through the Federal Housing Program, and moved to Hawaii.
Meantime, Barack’s father had won a scholarship that allowed him to leave Kenya pursue his dreams in Hawaii. At the time of his birth, Obama’s parents were students at the East–West Center of the University of Hawaii at Manoa.
Obama’s parents separated when he was two years old and later divorced. Obama’s father went to Harvard to pursue Ph. D. studies and then returned to Kenya.
His mother married Lolo Soetoro, another East–West Center student from Indonesia. In 1967, the family moved to Jakarta, where Obama’s half-sister Maya Soetoro–Ng was born. Obama attended schools in Jakarta, where classes were taught in the Indonesian language.
Four years later when Barack (commonly known throughout his early years as "Barry") was ten, he returned to Hawaii to live with his maternal grandparents, Madelyn and Stanley Dunham, and later his mother (who died of ovarian cancer in 1995).
He was enrolled in the fifth grade at the esteemed Punahou Academy, graduating with honors in 1979. He was only one of three black students at the school. This is where Obama first became conscious of racism and what it meant to be an African–American.
In his memoir, Obama described how he struggled to reconcile social perceptions of his multiracial heritage. He saw his biological father (who died in a 1982 car accident) only once (in 1971) after his parents divorced. And he admitted using alcohol, marijuana and cocaine during his teenage years.
After high school, Obama studied at Occidental College in Los Angeles for two years. He then transferred to Columbia University in New York, graduating in 1983 with a degree in political science.

After working at Business International Corporation (a company that provided international business information to corporate clients) and NYPIRG, Obama moved to Chicago in 1985. There, he worked as a community organizer with low-income residents in Chicago’s Roseland community and the Altgeld Gardens public housing development on the city’s South Side.
It was during this time that Obama, who said he "was not raised in a religious household," joined the Trinity United Church of Christ. He also visited relatives in Kenya, which included an emotional visit to the graves of his father and paternal grandfather.
Obama entered Harvard Law School in 1988. In February 1990, he was elected the first African–American editor of the Harvard Law Review. Obama graduated magna cum laude in 1991.
After law school, Obama returned to Chicago to practice as a civil rights lawyer, joining the firm of Miner, Barnhill & Galland. He also taught at the University of Chicago Law School. And he helped organize voter registration drives during Bill Clinton’s 1992 presidential campaign.
Obama published an autobiography in 1995 Dreams From My Father: A Story of Race and Inheritance. And he won a Grammy for the audio version of the book.
Obama’s advocacy work led him to run for the Illinois State Senate as a Democrat. He was elected in 1996 from the south side neighborhood of Hyde Park.
During these years, Obama worked with both Democrats and Republicans in drafting legislation on ethics, expanded health care services and early childhood education programs for the poor. He also created a state earned-income tax credit for the working poor. And after a number of inmates on death row were found innocent, Obama worked with law enforcement officials to require the videotaping of interrogations and confessions in all capital cases.
In 2000, Obama made an unsuccessful Democratic primary run for the U. S. House of Representatives seat held by four-term incumbent candidate Bobby Rush.
Following the 9/11 attacks, Obama was an early opponent of President George W. Bush’s push to war with Iraq. Obama was still a state senator when he spoke against a resolution authorizing the use of force against Iraq during a rally at Chicago’s Federal Plaza in October 2002.

"I am not opposed to all wars. I'm opposed to dumb wars," he said. "What I am opposed to is the cynical attempt by Richard Perle and Paul Wolfowitz and other arm-chair, weekend warriors in this Administration to shove their own ideological agendas down our throats, irrespective of the costs in lives lost and in hardships borne."
"He's a bad guy," Obama said, referring to Iraqi dictator Saddam Hussein. "The world, and the Iraqi people, would be better off without him. But I also know that Saddam poses no imminent and direct threat to the United States, or to his neighbors, that the Iraqi economy is in shambles, that the Iraqi military a fraction of its former strength, and that in concert with the international community he can be contained until, in the way of all petty dictators, he falls away into the dustbin of history."
"I know that even a successful war against Iraq will require a U. S. occupation of undetermined length, at undetermined cost, with undetermined consequences," Obama continued. "I know that an invasion of Iraq without a clear rationale and without strong international support will only fan the flames of the Middle East, and encourage the worst, rather than best, impulses of the Arab world, and strengthen the recruitment arm of al-Qaeda."
The war with Iraq began in 2003 and Obama decided to run for the U.S. Senate open seat vacated by Republican Peter Fitzgerald. In the 2004 Democratic primary, he won 52 percent of the vote, defeating multimillionaire businessman Blair Hull and Illinois Comptroller Daniel Hynes.
That summer, he was invited to deliver the keynote speech in support of John Kerry at the 2004 Democratic National Convention in Boston. Obama emphasized the importance of unity, and made veiled jabs at the Bush administration and the diversionary use of wedge issues.
"We worship an awesome God in the blue states, and we don't like federal agents poking around our libraries in the red states," he said. "We coach Little League in the blue states, and yes, we've got some gay friends in the red states. There are patriots who opposed the war in Iraq, and there are patriots who supported the war in Iraq. We are one people, all of us pledging allegiance to the Stars and Stripes, all of us defending the United States of America."

After the convention, Obama returned to his U.S. Senate bid in Illinois. His opponent in the general election was suppose to be Republican primary winner Jack Ryan, a wealthy former investment banker. However, Ryan withdrew from the race in June 2004, following public disclosure of unsubstantiated sexual allegations by Ryan's ex wife, actress Jeri Ryan.
In August 2004, diplomat and former presidential candidate Alan Keyes, who was also an African-American, accepted the Republican nomination to replace Ryan. In three televised debates, Obama and Keyes expressed opposing views on stem cell research, abortion, gun control, school vouchers and tax cuts.
In the November 2004 general election, Obama received 70% of the vote to Keyes's 27%, the largest electoral victory in Illinois history. Obama became only the third African-American elected to the U.S. Senate since Reconstruction.
Sworn into office January 4, 2005, Obama partnered with Republican Sen. Richard Lugar of Indiana on a bill that expanded efforts to destroy weapons of mass destruction in Eastern Europe and Russia. Then with Republican Sen. Tom Corburn of Oklahoma, he created a website that tracks all federal spending.
Obama was also the first to raise the threat of avian flu on the Senate floor, spoke out for victims of Hurricane Katrina, pushed for alternative energy development and championed improved veterans´ benefits. He also worked with Democrat Russ Feingold of Wisconsin to eliminate gifts of travel on corporate jets by lobbyists to members of Congress.
His second book, The Audacity of Hope: Thoughts on Reclaiming the American Dream, was published in October 2006.
In February 2007, Obama made headlines when he announced his candidacy for the 2008 Democratic presidential nomination. He was locked in a tight battle with former first lady and current U.S. Senator from New York, Hillary Rodham Clinton until he became the presumptive nominee on June 3, 2008. On November 4th, 2008, Obama defeated Republican presidential nominee John McCain for the position of U.S. President. He is now the 44th president of the United States.
Obama met his wife, Michelle, in 1988 when he was a summer associate at the Chicago law firm of Sidley & Austin. They were married in October 1992 and live in Kenwood on Chicago's South Side with their daughters, Malia (born 1998) and Sasha (born 2001).

Indian Railways ,abbreviated as IR,is the state-owned railway company of India, which owns and operates most of the country's rail transport. It is overseen by the Ministry of Railways of the Government of India.
Indian Railways has one of the largest and busiest rail networks in the world, transporting over 18 million passengers and more than 2 million tonnes of freight daily.It is the world's largest commercial or utility employer, with more than 1.4 million employees.

The railways traverse the length and breadth of the country, covering 6,909 stations over a total route length of more than 63,327 kilometres (39,350 mi). As to rolling stock, IR owns over 200,000 (freight) wagons, 50,000 coaches and 8,000 locomotives.
Railways were first introduced to India in 1853. By 1947, the year of India's independence, there were forty-two rail systems. In 1951 the systems were nationalised as one unit, becoming one of the largest networks in the world. IR operates both long distance and suburban rail systems on a multi-gauge network of broad, metre and narrow gauges. It also owns locomotive and coach production facilities.

At the beginning of the twentieth century India had a multitude of rail services with diverse ownership and management, operating on broad, metre and narrow gauge networks.

In 1900 the government took over the GIPR network, while the company continued to manage it. With the arrival of the First World War, the railways were used to transport troops and foodgrains to the port city of Bombay and Karachi en route to UK, Mesopotamia, East Africa etc. By the end of the First World War, the railways had suffered immensely and were in a poor state. In 1923, both GIPR and EIR were nationalized with the state assuming both ownership and management control.

The Second World War severely crippled the railways as rolling stock was diverted to the Middle East, and the railway workshops were converted into munitions workshops.At the time of independence in 1947, about 40 per cent of the railways then went to newly-created nation of Pakistan.[citation needed] A total of forty-two separate railway systems, including thirty-two lines owned by the former Indian princely states, were amalgamated as a single unit which was christened as the Indian Railways. The existing rail networks were abandoned in favour of zones in 1951 and a total of six zones came into being in 1952.

As the economy of India improved, almost all railway production units were 'indigenised' (produced in India). By 1985, steam locomotives were phased out in favour of diesel and electric locomotives. The entire railway reservation system was streamlined with computerisation between 1987 and 1995.

A visual display unit, often called simply a monitor or display, is a piece of electrical equipment which displays images generated from the video output of devices such as computers, without producing a permanent record. Most newer monitors typically consist of a TFT LCD, with older monitors based around a cathode ray tube (CRT). Almost all of the mainstream new monitors being sold on market now are LCD. The monitor comprises the display device, simple circuitry to generate and format a picture from video sent by the signals source, and usually an enclosure. Within the signal source, either as an integral section or a modular component, there is a display adapter to generate video in a format compatible with the monitor.

Diagonal size

The size of a display is typically given as the distance between two opposite screen corners. One problem with this method is that it does not distinguish between the aspect ratios of monitors with identical diagonal sizes, in spite of the fact that a shape of a given diagonal span's area decreases as it becomes less square. For example, a 4:3 21" monitor has an area of ~211 square inches, while a 16:9 21" widescreen has an area of only ~188 square inches.
This method of measurement is from the first types of CRT television, when round picture tubes were in common use. Being circular, they only needed to use their diameter to describe their tube size. When round tubes were used to display rectangular images, the diagonal measurement was equivalent to the round tube's diameter. This method continued even when CRT tubes were manufactured as rounded rectangles.
Another historically problematic practice is the direct measurement of a monitor's imaging element as its quoted size in publicity and advertising materials. Especially on CRT displays, a substantial portion of the imaging element is concealed behind the case's bezel or shroud in order to hide areas outside the monitor's safe area due to overscan. Seen as deceptive, widespread consumer objection and lawsuits eventually forced most manufacturers to instead measure viewable size

A USB flash drive consists of a NAND-type flash memory data storage device integrated with a USB (universal serial bus) interface. USB flash drives are typically removable and rewritable, much smaller than a floppy disk (1 to 4 inches or 2.5 to 10 cm), and most USB flash drives weigh less than an ounce (28g).[1] Storage capacities typically range from 64 MB to 128 GB[2] with steady improvements in size and price per gigabyte. Some allow 1 million write or erase cycles[3][4] and have 10-year data retention,[5] connected by USB 1.1 or USB 2.0.
USB flash drives offer potential advantages over other portable storage devices, particularly the floppy disk. They have a more compact shape, operate faster, hold much more data, have a more durable design, and operate more reliably due to their lack of moving parts. Additionally, it has become increasingly common for computers to be sold without floppy disk drives. USB ports, on the other hand, appear on almost every current[update] mainstream PC and laptop. These types of drives use the USB mass storage standard, supported natively by modern operating systems such as Windows, Mac OS X, Linux, and other Unix-like systems. USB drives with USB 2.0 support can also operate faster than an optical disc drive, while storing a larger amount of data in a much smaller space.
Nothing actually moves in a flash drive: the term drive persists because computers read and write flash-drive data using the same system commands as for a mechanical disk drive, with the storage appearing to the computer operating system and user interface as just another drive.[4]
A flash drive consists of a small printed circuit board protected inside a plastic, metal, or rubberized case, robust enough for carrying with no additional protection—in a pocket or on a key chain, for example. The USB connector is protected by a removable cap or by retracting into the body of the drive, although it is not likely to be damaged if exposed (but it may damages other items, for example a bag it is placed in). Most flash drives use a standard type-A USB connection allowing plugging into a port on a personal computer, but drives for other interfaces also exist.

A motherboard is the central printed circuit board (PCB) in some complex electronic systems, such as modern personal computers. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple computers, the logic board. It is also sometimes casually shortened to mobo.

History

Prior to the advent of the microprocessor, a computer was usually built in a card-cage case or mainframe with components connected by a backplane consisting of a set of slots themselves connected with wires; in very old designs the wires were discrete connections between card connector pins, but printed-circuit boards soon became the standard practice. The central processing unit, memory and peripherals were housed on individual printed circuit boards which plugged into the backplane.
During the late 1980s and 1990s, it became economical to move an increasing number of peripheral functions onto the motherboard.In the late 1980s, motherboards began to include single ICs (called Super I/O chips) capable of supporting a set of low-speed peripherals: keyboard, mouse, floppy disk drive, serial ports, and parallel ports. As of the late 1990s, many personal computer motherboards support a full range of audio, video, storage, and networking functions without the need for any expansion cards at all; higher-end systems for 3D gaming and computer graphics typically retain only the graphics card as a separate component.
The early pioneers of motherboard manufacturing were Micronics, Mylex, AMI, DTK, Hauppauge, Orchid Technology, Elitegroup, DFI, and a number of Taiwan-based manufacturers.
Popular personal computers such as the Apple II and IBM PC had published schematic diagrams and other documentation which permitted rapid reverse-engineering and third-party replacement motherboards. Usually intended for building new computers compatible with the exemplars, many motherboards offered additional performance or other features and were used to upgrade the manufacturer's original equipment.
The term mainboard is archaically applied to devices with a single board and no additional expansions or capability. In modern terms this would include embedded systems, and controlling boards in televisions, washing machines etc. A motherboard specifically refers to a printed circuit with the capability to add/extend its performance/capabilities with the addition of "daughterboards".