king of the kings(mani kant)

The Merchant of Venice

2008-01-24T03:07:00.002-08:00

The Merchant of Venice

From Mani Kant

Shylock and Portia (1835) by Thomas Sully

The Merchant of Venice is a play written by William Shakespeare sometime between 1596 and 1598. Although classified as a comedy in the First Folio, and while it shares certain aspects with Shakespeare's other romantic comedies, the play is perhaps more remembered for its dramatic scenes (particularly the trial scene), and is best known for the character of Shylock.

The title character is the merchant Antonio, not the more famous villain, the Jewish moneylender Shylock, who is the play's most prominent figure. Although Shylock is a tormented character, he is also a tormentor, so whether he is to be viewed with disdain or sympathy is up to the audience (as influenced by the interpretation of the play's director and lead actors). As a result, The Merchant of Venice is often classified as one of Shakespeare's problem plays.

[edit] Date and text

Title page of the first quarto (1600)

The date of composition for The Merchant of Venice is believed to be between 1596 and 1598. The play was mentioned by Francis Meres in 1598, so it must have been familiar on the stage by that date. Solanio's reference to his ship the "Andrew" (I,i,27) is thought to be an allusion to the Spanish ship St. Andrew captured by the English at Cadiz in 1596. A date of 1596–97 is considered consistent with the play's style.

The play was entered in the Register of the Stationers Company, the method at that time of obtaining copyright for a new play, by James Roberts on July 22, 1598 under the title The Merchant of Venice, otherwise called The Jew of Venice. On October 28, 1600 Roberts transferred his right to the play to the stationer Thomas Hayes; Hayes published the first quarto before the end of the year. It was printed again in a pirated edition in 1619, as part of William Jaggard's so-called False Folio. (Afterward, Thomas Hayes' son and heir Laurence Hayes asked for and was granted a confirmation of his right to the play, on July 8, 1619.) The 1600 edition is the basis of the text published in the First Folio (1623) and is regarded as being generally accurate and reliable.

No further performances are recorded between 1605 and 1701. In the latter year George Granville staged a successful adaptation, titled The Jew of Venice, with Thomas Betterton as Bassanio. This version (which featured a masque) was popular, and was acted for the next forty years. Granville cut the Gobbos in line with neoclassical decorum; he added a jail scene between Shylock and Antonio, and a more extended scene of toasting at a banquet scene. Thomas Doggett was Shylock, playing the role comically, perhaps even farcically. Rowe expressed doubts about this interpretation as early as 1709; however, Doggett's success in the role meant that later productions would feature the troupe clown as Shylock.

In 1741 Charles Macklin returned to the original text in a very successful production at Drury Lane, paving the way for Edmund Kean seventy years later (see below).^[1]

[edit] Performance

[edit] Shylock on stage

Jacob Adler and others report that the tradition of playing Shylock sympathetically began in the first half of the 19th century with Edmund Kean^[2], and that previously the role had been played "by a comedian as a repulsive clown or, alternatively, as a monster of unrelieved evil." Kean's Shylock established his reputation as an actor.^[3]

From Kean's time forward, all of the actors who have famously played the role, with the exception of Edwin Booth, who played Shylock as a simple villain, have chosen a sympathetic approach to the character; even Booth's father, Junius Brutus Booth, played the role sympathetically. Henry Irving was among the most notable late 19th century Shylocks, and Jacob Adler certainly the most notable of the early 20th century. Adler played the role in Yiddish-language translation, first in Manhattan's Lower East Side, and later on Broadway, where, to great acclaim, he performed the role in Yiddish in an otherwise English-language production.^[4]

Kean and Irving presented a Shylock justified in wanting his revenge; Adler's Shylock evolved over the years he played the role, first as a stock Shakespearean villain, then as a man whose better nature was overcome by a desire for revenge, and finally as a man who operated not from revenge but from pride. In a 1902 interview with Theater magazine, Adler pointed out that Shylock is a wealthy man, "rich enough to forego the interest on three thousand ducats" and that Antonio is "far from the chivalrous gentleman he is made to appear. He has insulted the Jew and spat on him, yet he comes with hypocritical politeness to borrow money of him." Shylock's fatal flaw is to depend on the law, but "would he not walk out of that courtroom head erect, the very apotheosis of defiant hatred and scorn?"^[5]

Some modern productions take further pains to show how Shylock's thirst for vengeance has some justification. For instance in the 2004 film adaptation directed by Michael Radford and starring Al Pacino as Shylock, the film begins with text and a montage of how the Jewish community is cruelly abused by the bigoted Christian population of the city. One of the last shots of the film also brings attention to the fact that, as a convert, Shylock would have been cast out of the Jewish community in Venice, no longer allowed to live in the ghetto, and would still not be accepted by the Christians, as they would feel that Shylock was yet the Jew he once was.

[edit] Synopsis

Portia by Henry Woods

Bassanio, a young Venetian, would like to travel to Belmont to woo the beautiful and wealthy heiress Portia. He approaches his friend Antonio, a merchant, for three thousand ducats needed to subsidize his traveling expenditures as a suitor for three months. As all of Antonio's ships and merchandise are busy at sea, Antonio approaches the Jewish moneylender/usurer Shylock for a loan.

Shylock, who hates Antonio because he had insulted and spat on him for being a Jew a week previously, proposes a condition. If Antonio is unable to repay the loan at the specified date, Shylock will be free to take a pound of Antonio's flesh closest to his heart. Although Bassanio does not want Antonio to accept such a risky condition, Antonio, surprised by what he sees as the moneylender's generosity (no "usance" — interest — is asked for), accedes and signs the contract. With money at hand, Bassanio leaves for Belmont with another friend Gratiano.

At Belmont, Portia has no lack of suitors. Portia's father, however, has left a will stipulating each of her suitors must choose correctly from one of three caskets – one each of gold, silver, and lead – before he could win Portia's hand. In order to be granted an opportunity to marry Portia, each suitor must agree in advance to live out his life as a bachelor were he to select wrongly. The suitor who correctly looks past the outward appearance of the caskets will find Portia's portrait inside and win her hand.

After two suitors, the Princes of Morocco and Aragon, choose incorrectly, Bassanio makes the correct choice, that of the leaden casket. The other two contain mocking verses, including the famous phrase all that glisters [glistens] is not gold.

At Venice, all ships bearing Antonio's goods are reported lost at sea, leaving him unable to satisfy the bond. Shylock is even more determined to exact revenge from Christians after his daughter Jessica flees his home to convert to Christianity and elope with the Christian Lorenzo, taking a substantial amount of Shylock's wealth with her. With the bond at hand, Shylock has Antonio arrested and brought before court.

At Belmont, Portia and Bassanio have just been married, along with his friend Gratiano and Portia's handmaid Nerissa. He receives a letter telling him that Antonio has defaulted on his loan from Shylock. Shocked, Bassanio and Gratiano leave for Venice immediately, with money from Portia, to save Antonio's life. Unknown to Bassanio and Gratiano, Portia and Nerissa leave Belmont to seek the counsel of Portia's cousin, Bellario, a lawyer, at Padua.

The dramatic center of the play comes in the court of the Duke of Venice. Shylock refuses Bassanio's offer, despite Bassanio increasing the repayment to 6000 ducats (twice the specified loan). He demands the pound of flesh from Antonio. The Duke, wishing to save Antonio but unwilling to set a dangerous legal precedent of nullifying a contract, refers the case to Balthasar, a young male "doctor of the law" who is actually Portia in disguise, with "his" lawyer's clerk, who is Nerissa in disguise. Portia asks Shylock to show mercy in a famous speech (The quality of mercy is not strained—IV,i,185), but Shylock refuses. Thus the court allows Shylock to extract the pound of flesh.

At the very moment Shylock is about to cut Antonio with his knife, Portia points out a flaw in the contract (see Quibble (plot device)). The bond only allows Shylock to remove the flesh, not blood, of Antonio. If Shylock were to shed any drop of Antonio's blood in doing so, his "lands and goods" will be forfeited under Venetian laws.

Defeated, Shylock accedes to accept monetary payment for the defaulted bond, but is denied. Portia pronounces none should be given, and for his attempt to take the life of a citizen, Shylock's property will be forfeited, half to the government and half to Antonio, and his life will be at the mercy of the Duke. The Duke pardons his life before Shylock can beg for it, and Antonio asks for his share "in use" (that is, reserving the principal amount while taking only the income) until Shylock's death, when the principal will be given to Lorenzo and Jessica. At Antonio's request, the Duke grants remission of the state's half of forfeiture, but in return, Shylock is forced to convert to Christianity and to make a will (or "deed of gift") bequeathing his entire estate to Lorenzo and Jessica (IV,i).

Bassanio does not recognize his disguised wife. He offers to give "him" a present. First she declines, but after he insists, Portia requests his ring and his gloves. He gives the gloves away without a second thought, but gives the ring only after much persuasion from Antonio, as earlier in the play he promised his wife never to lose, sell or give it away. Nerrisa also tries to retrieve her ring from Gratiano,

At Belmont, Portia and Nerissa taunt their husbands before revealing they were really the lawyer and his clerk in disguise.

After all the other characters make amends, all ends happily (except for Shylock) as Antonio learns that three of his ships were not stranded and have returned safely after all.

[edit] Themes

Shylock and Jessica by Maurycy Gottlieb

[edit] Shylock and the anti-Semitism debate

This section may contain original research or unverified claims.
Please help Wikipedia by adding references. See the talk page for details.(October 2007)

The play is frequently staged today, but is potentially troubling to modern audiences due to its central themes, which can easily appear anti-Semitic. Critics still argue over whether the play is itself anti-semitic, or that it is merely a play about anti-Semitism, or whether the foreign setting, including Shylock's ethnicity, is a literary device used to couch uncomfortable truths.

[edit] The anti-Semitic reading

English society in the Elizabethan era has been described as anti-Semitic.^[6] English Jews had been expelled in the Middle Ages and were not permitted to return until the rule of Oliver Cromwell. Jews were often presented on the Elizabethan stage in hideous caricature, with hooked noses and bright red wigs, and were usually depicted as avaricious usurers; an example is Christopher Marlowe's play The Jew of Malta, which features a comically wicked Jewish villain called Barabas. They were usually characterized as evil, deceptive, and greedy.

During the 1600s in Venice and in some other places, Jews were required to wear a red hat at all times in public to make sure that they were easily identified. If they did not comply with this rule they could face the death penalty. Jews also had to live in a ghetto protected by Christians, supposedly for their own safety. The Jews were expected to pay their guards. ^[7]

Readers may see Shakespeare's play as a continuation of this anti-Semitic tradition. The title page of the Quarto indicates that the play was sometimes known as The Jew of Venice in its day, which suggests that it was seen as similar to Marlowe's The Jew of Malta. One interpretation of the play's structure is that Shakespeare meant to contrast the mercy of the main Christian characters with the vengefulness of a Jew, who lacks the religious grace to comprehend mercy. Similarly, it is possible that Shakespeare meant Shylock's forced conversion to Christianity to be a "happy ending" for the character, as it 'redeems' Shylock both from his unbelief and his specific sin of wanting to kill Antonio. This reading of the play would certainly fit with the anti-Semitic trends present in Elizabethan England.

[edit] The sympathetic reading

Many modern readers and theatregoers have read the play as a plea for tolerance as Shylock is a sympathetic character. Shylock's 'trial' at the end of the play is a mockery of justice, with Portia acting as a judge when she has no real right to do so. Thus, Shakespeare is not calling into question Shylock's intentions, but the fact that the very people who berated Shylock for being dishonest have had to resort to trickery in order to win. Shakespeare puts one of his most eloquent speeches into the mouth of this "villain":

Hath not a Jew eyes? Hath not a Jew hands, organs, dimensions, senses, affections, passions; fed with the same food, hurt with the same weapons, subject to the same diseases, heal'd by the same means, warm'd and cool'd by the same winter and summer as a Christian is? If you prick us, do we not bleed? If you tickle us, do we not laugh? If you poison us, do we not die? And if you wrong us, shall we not revenge? If we are like you in the rest, we will resemble you in that. If a Jew wrong a Christian, what is his humility? Revenge. If a Christian wrong a Jew, what should his sufferance be by Christian example? Why, revenge. The villainy you teach me, I will execute, and it shall go hard but I will better the instruction.

—Act III, scene I

[edit] Influence on anti-semitism

Regardless of what Shakespeare's own intentions may have been, the play has been made use of by Anti-semites throughout history. One must note that the end of the title in the 1619 edition "With the Extreme Cruelty of Shylock the Jew…" must aptly describe how Shylock was viewed by the English public. The Nazis used the usurious Shylock for their propaganda. Shortly after Kristallnacht in 1938, "The Merchant of Venice" was broadcast for propagandistic ends over the German airwaves. Productions of the play followed in Lübeck (1938), Berlin (1940), and elsewhere within the Nazi Territory.^[8]

The depiction of Jews in English Literature throughout the centuries bears the close imprint of Shylock. With slight variations much of English literature up until the 20th century depicts the Jew as "a monied, cruel, lecherous, avaricious outsider tolerated only because of his golden hoard". ^[9]

[edit] Character study

It is difficult to know whether the sympathetic reading of Shylock is entirely due to changing sensibilities among readers, or whether Shakespeare, a writer who clearly delighted in creating complex, multi-faceted characters, deliberately intended this reading.

One reason for this interpretation is that Shylock's painful status in Venetian society is emphasised. To some critics, Shylock's celebrated "Hath not a Jew eyes" speech (see above) redeems him and even makes him into something of a tragic figure. In the speech, Shylock argues that he is no different from the Christian characters. Detractors note that Shylock ends the speech with a tone of revenge: "if you wrong us, shall we not revenge?" However, those who see the speech as sympathetic point out that Shylock says he learned the desire for revenge from the Christian characters: "If a Christian wrong a Jew, what should his sufferance be by Christian example? Why, revenge. The villainy you teach me, I will execute, and it shall go hard but I will better the instruction."

Even if Shakespeare did not intend the play to be read this way, the fact that it retains its power on stage for audiences who may perceive its central conflicts in radically different terms is an illustration of the subtlety of Shakespeare's characterizations.

[edit] Religious interpretations

Sir Herbert Beerbohm Tree as Shylock, painted by Charles Buchel (1895–1935).

Sympathy for Shylock can be derived from an understanding of the difference between the concept of forgiveness of sins in Judaism and Christianity. In Christianity, like in Judaism, forgiveness comes only to those who "truly repent"; this repentance comes about through faith in Christ, and does not involve any specific ritual. (See Justification.) In Judaism, Jews who seek to atone for their sins (Teshuvah) are called to a deep reckoning and soul-searching, of which confession, though of paramount importance, is but one aspect. Judaism draws heavily on the exhortations of the prophets, most notably Isaiah and Jeremiah, that the repentance be an intensely personal experience; any and all associated ritual is but the means of formalizing the deeper, inner dimension of Teshuvah.^[10] This theme is brought out with particular force in the ritual of Yom Kippur, the annual Day of Atonement.

According to this interpretation, Shylock is the most morally upright character (of the main characters) in the play. Supporters of this interpretation tend to describe the other main characters in negative terms: Antonio as a repressed homosexual (immoral by the standards of the day); Bassanio as a prodigal who does no work except capitalize on his looks and live off of other people, and who ends up with Portia, who, at the end, realizes that Bassanio only ever wanted her money despite all his charms; and Jessica as an ungrateful daughter who steals her father's possessions and runs away to marry Lorenzo, a proselytizing hypocrite.

Directors such as John Neville who support this interpretation tend to show the '"young love" story in which Jessica escapes her father to marry Lorenzo, ending unhappily, a reading that may be justified by careful reading of the text.

In this reading, though the play is light and funny on the surface, the Christian characters' lives are collapsing because of their immoral behavior and disrespect for duty to God and the law. Meanwhile, Shylock does not deceive, trick, lie, kill, steal, or do anything mischievous. The promise of a pound of flesh upon default of the loan was something Antonio freely agreed to. Still it can hardly be moral for Shylock to demand a pound of flesh from Antonio. Shylock knows this will kill Antonio, but according to this theory his desire for vengeance is not only justified but in a sense moral as well.

Some actors who are trained in early modern drama will, for the above reason, identify the Merchant of Venice as not an anti-Jewish play, but an anti-Christian play. This is not reflected in the history of the production and is a recent phenomenon. This does not necessarily mean that Shakespeare himself was anti-Christian, but rather that he was using the story of Shylock to attack prevailing hypocrisies.

[edit] A Catholic reading

In 2004 Clare Asquith published her analysis of Shakespeare's writing from the perspective of Catholics toiling under the nascent Reformation movement in England, in her book^[11]Shadowplay. Asquith maintains that Shakespeare was a recusant Catholic whose sympathies are covertly woven within his works. Queen Elizabeth I was the third monarch to reign over the Church of England's split from Rome (succeeding her Catholic half-sister Queen Mary who had attempted to undo their younger half-brother Edward's consolidation of Henry VIII's original schism). Asquith's thesis posits that the dramatis personae mask actual persons in the politics of England at the end of the 16th century. Portia can be seen to represent Queen Elizabeth I herself, while Shylock represents a patriarch of the Puritan merchant classes who had suffered under Queen Mary's persecutions. The relevance of the legal setting to the plot calls to mind the conviction that Christ's new Law of Love fulfills the Old Covenant, the natural law revealed to Moses (defended by Shylock in the speech quoted above) whereby an eye-for-an-eye is a reasonable measure, superior to the lawlessness of barbarian rape and pillage, but inferior to peaceful reconciliation dispensed with Christ-like mercy.

The question remains, does Portia dispense a Christian portion of Divine mercy? The final act contains many allusions to Catholic rituals for the celebration of solemnities in the three days before Easter, the Triduum, banned in England at the time the play was published, but still celebrated elsewhere in Catholic Europe, certainly in Venice. As Asquith^[11] points out

"The opening love-duet between Lorenzo and Jessica in Act V repeats the phrase "in such a night" eight times: exactly the same number that the phrase "this is the night" is repeated in the great Easter hymn, the Exultet. "

Catholics in England continued to be persecuted for more than two centuries before regaining their religious freedoms, albeit with concessions to the civil rights of their Irish brethren, under the second Catholic Relief Act. Antonio is reprieved by Portia's comprehension of the Christian Mystery: Christ the Pascal Lamb shed blood for us all, justice does not require a second blood-shedding.

[edit] Sexuality in the play

This section may contain original research or unverified claims.
Please help Wikipedia by adding references. See the talk page for details.(October 2007)

[edit] Antonio, Bassanio and homosexuality

Antonio's unexplained depression—"In sooth I know not why I am so sad"—and utter devotion to Bassanio has led some critics to theorize that he is suffering from unrequited love for Bassanio and is depressed because Bassanio is coming to an age where he will marry a woman. In his plays and poetry Shakespeare often depicted strong male bonds of varying homosociality, which has led some critics to infer that Bassanio returns Antonio's affections despite his obligation to marry^{[citation needed]}:

ANTONIO: Commend me to your honorable wife:

Tell her the process of Antonio's end,

Say how I lov'd you, speak me fair in death;

And, when the tale is told, bid her be judge

Whether Bassanio had not once a love.

BASSANIO: But life itself, my wife, and all the world

Are not with me esteemed above thy life;

I would lose all, ay, sacrifice them all

Here to this devil, to deliver you. (IV,i)

In his essay "Brothers and Others", published in The Dyer's Hand, W.H. Auden describes Antonio as "a man whose emotional life, though his conduct may be chaste, is concentrated upon a member of his own sex." Antonio's feelings for Bassanio are likened to a couplet from Shakespeare's Sonnets: "But since she pricked thee out for women's pleasure,/ Mine be thy love, and my love's use their treasure." Antonio, says Auden, embodies the words on Portia's leaden casket: "Who chooseth me, must give and hazard all he hath." Antonio has taken this potentially fatal turn because he despairs, not only over the loss of Bassanio in marriage, but also because Bassanio cannot requite what Antonio feels for him. Antonio's frustrated devotion is a form of idolatry: the right to live is yielded for the sake of the loved one. There is one other such idolator in the play: Shylock himself. "Shylock, however unintentionally, did, in fact, hazard all for the sake of destroying the enemy he hated; and Antonio, however unthinkingly he signed the bond, hazarded all to secure the happiness of the man he loved." Both Antonio and Shylock, agreeing to put Antonio's life at a forfeit, stand outside the normal bounds of society. There was, states Auden, a traditional "association of sodomy with usury" with which Shakespeare was likely familiar. (Auden sees the theme of usury in the play as a comment on human relations in a mercantile society.)

Other interpreters of the play regard Auden's conception of Antonio's sexual desire for Bassanio as questionable. Michael Radford, director of the 2004 film version starring Al Pacino, explained that although the film contains a scene where Antonio and Bassanio actually kiss, the friendship between the two is platonic, in line with the prevailing view of male friendship at the time. Jeremy Irons, in an interview, concurs with the director's view and states that he did not "play Antonio as gay".

[edit] Bassanio, Portia and fidelity

Portia and Bassanio marry, with the promise that he will never give up her ring. The ring is a symbol of marital fidelity. The Elizabethans were obsessed with wifely fidelity, and a whole subgenre of jokes were devoted to the subject.^{[citation needed]} An Elizabethan audience may have seen the significance of Bassanio giving Portia's "ring" back to her as an emblem of his potential for fidelity.

[edit] Adaptations and cultural references

[edit] Film adaptations

The Shakespeare play has inspired several movies.

1914—silent movie directed by Lois Weber
- Weber, who also stars as Portia, became the first woman to direct a full-length feature film in America with this film.
- The Merchant of Venice at the Internet Movie Database
1973—television film directed by John Sichel
- The cast included Sir Laurence Olivier as Shylock, Anthony Nicholls as Antonio, Jeremy Brett as Bassanio, Joan Plowright as Portia, Louise Purnell as Jessica.
- The Merchant of Venice at the Internet Movie Database
1980—A BBC television film directed by Jack Gold
- The cast included Warren Mitchell as Shylock and John Rhys-Davies as Salerio
- The Merchant of Venice at the Internet Movie Database
1996—A Channel 4 television film directed by Alan Horrox
- The cast included Paul McGann as Bassanio and Haydn Gwynne as Portia
- The Merchant of Venice at the Internet Movie Database
2001—A BBC television film directed by Trevor Nunn
- Royal National Theatre production starring Henry Goodman as Shylock
- The Merchant of Venice at the Internet Movie Database
2004—The Merchant of Venice directed by Michael Radford.
- The cast included Al Pacino as Shylock, Jeremy Irons as Antonio, Joseph Fiennes as Bassanio, Lynn Collins as Portia, Zuleikha Robinson as Jessica.
- The Merchant of Venice at the Internet Movie Database
2007(?)— The Merchant of Venice (2007 film) written by John Logan (writer)
- The cast will include Sir Ian McKellen and Patrick Stewart and be set in a Las Vegas casino.^[12]
- Filming to start in late 2006.

[edit] Cultural references

Arnold Wesker's play The Merchant tells the same story from Shylock's point of view. In this retelling, Shylock and Antonio are fast friends, and make the bond as a joke against the Christian establishment. Shylock is manipulated into the position of having to enforce it, and is grateful when Portia cuts the knot by showing that the wording is ambiguous and unenforceable.

One of the four short stories comprising Alan Isler's Op Non Cit is also told from Shylock's point of view. In this story, Antonio was a boy of Jewish origin kidnapped at an early age by priests...

[edit] Pastime

The device of three caskets with riddles has been used for logic games in works like What is the name of this book? by Raymond Smullyan. The coffers make assertions about the truthfulness of their and the other inscriptions (e.g. the golden casket has the portrait, two of the caskets are lying"), to discover the portrait of Portia, and the reader of the pastime has to find which is telling truth.

[edit] Notes

^ F. E. Halliday, A Shakespeare Companion 1564–1964, Baltimore, Penguin, 1964; pp. 261, 311–12.
^ Adler erroneously dates this from 1847 (at which time Kean was already dead); the Cambridge Student Guide to The Merchant of Venice dates Kean's performance to a more likely 1814.
^ Adler 1999, 341.
^ Adler 1999, 342–44.
^ Adler 1999, 344–350
^ Philipe Burrin, Nazi Anti-Semitism: From Prejudice to Holocaust. The New Press, 2005, ISBN 1-56584-969-8, p. 17.

It was not until the twelfth century that in northern Europe (England, Germany, and France), a region until then peripheral but at this point expanding fast, a form of Judeophobia developed that was considerably more violent because of a new dimension of imagined behaviors, including accusations that Jews engaged in ritual murder, profanation of the host, and the poisoning of wells. With the preduces of the day against Jews, atheists and non christians in general Jews found it hard to fit in with society. Some say that these attitudes provided the foundations of anti-semitism in the 20th century. "
^ http://www.jewishvirtuallibrary.org/jsource/vjw/Venice.html
^ Lecture by James Shapiro: "Shakespeare and the Jews"
^ The Fictive Jew in the Literature of England 1890-1920 David Mirsky in the Samuel K. Mirsky Memorial Volume.
^ http://www.crosscurrents.org/blumenthal.htm
^ ^a ^b ASQUITH, Clare, Shakespeare’s Catholic Code.
^ Chris Hastings. "The Merchant moves from Venice to Vegas", Daily Telegraph, 2005-08-07.

[edit] References

Adler, Jacob, A Life on the Stage: A Memoir, translated and with commentary by Lulla Rosenfeld, Knopf, New York, 1999, ISBN 0-679-41351-0.
Rob Smith, Cambridge Student Guide to The Merchant of Venice. ISBN 0-521-00816-6.

[edit] External links

Wikisource has original text related to this article:

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SparkNotes: Study Guide
Filmschatten — film The Merchant of Venice (1910) online
Lesson plans for The Merchant of Venice at Web English Teacher
Overview of Clare Asquith's analysis of the Merchant of Venice, as an example of Shakespeare's works containing hidden references to persecution of Roman Catholicism, published in her 2005 book Shadowplay.

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Growth

Although the basic applications and guidelines that make the Internet possible had existed for almost a decade, the network did not gain a public face until the 1990s. On August 6, 1991, CERN, which straddles the border between France and Switzerland, publicized the new World Wide Web project. The Web was invented by English scientist Tim Berners-Lee in 1989.

An early popular web browser was ViolaWWW based upon HyperCard. It was eventually replaced in popularity by the Mosaic web browser. In 1993, the National Center for Supercomputing Applications at the University of Illinois released version 1.0 of Mosaic, and by late 1994 there was growing public interest in the previously academic/technical Internet. By 1996 usage of the word "Internet" had become commonplace, and consequently, so had its misuse as a reference to the World Wide Web.

Meanwhile, over the course of the decade, the Internet successfully accommodated the majority of previously existing public computer networks (although some networks, such as FidoNet, have remained separate). During the 1990s, it was estimated that the Internet grew by 100% per year, with a brief period of explosive growth in 1996 and 1997.^[1] This growth is often attributed to the lack of central administration, which allows organic growth of the network, as well as the non-proprietary open nature of the Internet protocols, which encourages vendor interoperability and prevents any one company from exerting too much control over the network.^{[citation needed]}

University Students Appreciation and Contributions

New findings in the field of communications during the 1960s, 1970s and 1980s were quickly adopted by universities across the United States.

Examples of early university Internet communities are Cleveland FreeNet, Blacksburg Electronic Village and NSTN in Nova Scotia ( [1] ). Students took up the opportunity of free communications and saw this new phenomenon as a tool of liberation. Personal computers and the Internet would free them from corporations and governments (Nelson, Jennings, Stallman).

Graduate students played a huge part in the creation of ARPANET. In the 1960’s, the network working group, which did most of the design for ARPANET’s protocols was composed mainly of graduate students.

Today's Internet

The Opera Community rack. From the top, user file storage (content of files.myopera.com), "bigma" (the master MySQL database server), and two IBM blade centers containing multi-purpose machines (Apache front ends, Apache back ends, slave MySQL database servers, load balancers, file servers, cache servers and sync masters).

Aside from the complex physical connections that make up its infrastructure, the Internet is facilitated by bi- or multi-lateral commercial contracts (e.g., peering agreements), and by technical specifications or protocols that describe how to exchange data over the network. Indeed, the Internet is essentially defined by its interconnections and routing policies.

As of September 30, 2007, 1.244 billion people use the Internet according to Internet World Stats. Writing in the Harvard International Review, philosopher N.J.Slabbert, a writer on policy issues for the Washington DC-based Urban Land Institute, has asserted that the Internet is fast becoming a basic feature of global civilization, so that what has traditionally been called "civil society" is now becoming identical with information technology society as defined by Internet use. Some suggest that as low as 2% of the World's population regularly accesses the internet.^[2] "http://www.edchange.org/multicultural/quiz/quiz_key.pdf"

Internet protocols

For more details on this topic, see Internet Protocols.

In this context, there are three layers of protocols:

At the lower level (OSI layer 3) is IP (Internet Protocol), which defines the datagrams or packets that carry blocks of data from one node to another. The vast majority of today's Internet uses version four of the IP protocol (i.e. IPv4), and although IPv6 is standardized, it exists only as "islands" of connectivity, and there are many ISPs without any IPv6 connectivity. [2]. ICMP (Internet Control Message Protocol) also exists at this level. ICMP is connectionless; it is used for control, signaling, and error reporting purposes.

TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) exist at the next layer up (OSI layer 4); these are the protocols by which data is transmitted. TCP makes a virtual 'connection', which gives some level of guarantee of reliability. UDP is a best-effort, connectionless transport, in which data packets that are lost in transit will not be re-sent.

The application protocols sit on top of TCP and UDP and occupy layers 5, 6, and 7 of the OSI model. These define the specific messages and data formats sent and understood by the applications running at each end of the communication. Examples of these protocols are HTTP, FTP, and SMTP.

Internet structure

There have been many analyses of the Internet and its structure. For example, it has been determined that the Internet IP routing structure and hypertext links of the World Wide Web are examples of scale-free networks.

Similar to the way the commercial Internet providers connect via Internet exchange points, research networks tend to interconnect into large subnetworks such as:

GEANT
GLORIAD
The Internet2 Network (formally known as the Abilene Network)
JANET (the UK's national research and education network)

These in turn are built around relatively smaller networks. See also the list of academic computer network organizations

In network diagrams, the Internet is often represented by a cloud symbol, into and out of which network communications can pass.

ICANN

ICANN headquarters in Marina Del Rey, California, United States

For more details on this topic, see ICANN.

The Internet Corporation for Assigned Names and Numbers (ICANN) is the authority that coordinates the assignment of unique identifiers on the Internet, including domain names, Internet Protocol (IP) addresses, and protocol port and parameter numbers. A globally unified namespace (i.e., a system of names in which there is at most one holder for each possible name) is essential for the Internet to function. ICANN is headquartered in Marina del Rey, California, but is overseen by an international board of directors drawn from across the Internet technical, business, academic, and non-commercial communities. The US government continues to have the primary role in approving changes to the root zone file that lies at the heart of the domain name system. Because the Internet is a distributed network comprising many voluntarily interconnected networks, the Internet, as such, has no governing body. ICANN's role in coordinating the assignment of unique identifiers distinguishes it as perhaps the only central coordinating body on the global Internet, but the scope of its authority extends only to the Internet's systems of domain names, IP addresses, protocol ports and parameter numbers.

On November 16, 2005, the World Summit on the Information Society, held in Tunis, established the Internet Governance Forum (IGF) to discuss Internet-related issues.

Language

For more details on this topic, see English on the Internet.

Further information: Unicode

The prevalent language for communication on the Internet is English. This may be a result of the Internet's origins, as well as English's role as the lingua franca. It may also be related to the poor capability of early computers, largely originating in the United States, to handle characters other than those in the English variant of the Latin alphabet.

After English (31% of Web visitors) the most-requested languages on the World Wide Web are Chinese 16%, Spanish 9%, Japanese 7%, German 5% and French 5% (from Internet World Stats, updated June 30, 2007).

By continent, 37% of the world's Internet users are based in Asia, 27% in Europe, 19% in North America, and 9% in Latin America and the Carribean ([3] updated September 30, 2007).

The Internet's technologies have developed enough in recent years, especially in the use of Unicode, that good facilities are available for development and communication in most widely used languages. However, some glitches such as mojibake (incorrect display of foreign language characters, also known as kryakozyabry) still remain.

Internet and the workplace

The Internet is allowing greater flexibility in working hours and location, especially with the spread of unmetered high-speed connections and Web applications.

The Internet viewed on mobile devices

The Internet can now be accessed virtually anywhere by numerous means. Mobile phones, datacards, handheld game consoles and cellular routers allow users to connect to the Internet from anywhere there is a cellular network supporting that device's technology.

Common uses of the Internet

E-mail

For more details on this topic, see E-mail.

The concept of sending electronic text messages between parties in a way analogous to mailing letters or memos predates the creation of the Internet. Even today it can be important to distinguish between Internet and internal e-mail systems. Internet e-mail may travel and be stored unencrypted on many other networks and machines out of both the sender's and the recipient's control. During this time it is quite possible for the content to be read and even tampered with by third parties, if anyone considers it important enough. Purely internal or intranet mail systems, where the information never leaves the corporate or organization's network, are much more secure, although in any organization there will be IT and other personnel whose job may involve monitoring, and occasionally accessing, the email of other employees not addressed to them.

The World Wide Web

For more details on this topic, see World Wide Web.

Graphic representation of less than 0.0001% of the WWW, representing some of the hyperlinks

Many people use the terms Internet and World Wide Web (or just the Web) interchangeably, but, as discussed above, the two terms are not synonymous.

The World Wide Web is a huge set of interlinked documents, images and other resources, linked by hyperlinks and URLs. These hyperlinks and URLs allow the web-servers and other machines that store originals, and cached copies, of these resources to deliver them as required using HTTP (Hypertext Transfer Protocol). HTTP is only one of the communication protocols used on the Internet.

Web services also use HTTP to allow software systems to communicate in order to share and exchange business logic and data.

Software products that can access the resources of the Web are correctly termed user agents. In normal use, web browsers, such as Internet Explorer and Firefox access web pages and allow users to navigate from one to another via hyperlinks. Web documents may contain almost any combination of computer data including photographs, graphics, sounds, text, video, multimedia and interactive content including games, office applications and scientific demonstrations.

Through keyword-driven Internet research using search engines, like Yahoo!, and Google, millions of people worldwide have easy, instant access to a vast and diverse amount of online information. Compared to encyclopedias and traditional libraries, the World Wide Web has enabled a sudden and extreme decentralization of information and data.

It is also easier, using the Web, than ever before for individuals and organisations to publish ideas and information to an extremely large audience. Anyone can find ways to publish a web page or build a website for very little initial cost. Publishing and maintaining large, professional websites full of attractive, diverse and up-to-date information is still a difficult and expensive proposition, however.

Many individuals and some companies and groups use "web logs" or blogs, which are largely used as easily-updatable online diaries. Some commercial organizations encourage staff to fill them with advice on their areas of specialization in the hope that visitors will be impressed by the expert knowledge and free information, and be attracted to the corporation as a result. One example of this practice is Microsoft, whose product developers publish their personal blogs in order to pique the public's interest in their work.

Collections of personal web pages published by large service providers remain popular, and have become increasingly sophisticated. Whereas operations such as Angelfire and GeoCities have existed since the early days of the Web, newer offerings from, for example, Facebook and MySpace currently have large followings. These operations often brand themselves as social network services rather than simply as web page hosts.

Advertising on popular web pages can be lucrative, and e-commerce or the sale of products and services directly via the Web continues to grow.

In the early days, web pages were usually created as sets of complete and isolated HTML text files stored on a web server. More recently, web sites are more often created using content management system (CMS) or wiki software with, initially, very little content. Users of these systems, who may be paid staff, members of a club or other organisation or members of the public, fill the underlying databases with content using editing pages designed for that purpose, while casual visitors view and read this content in its final HTML form. There may or may not be editorial, approval and security systems built into the process of taking newly entered content and making it available to the target visitors.

Remote access

Further information: Remote access

The Internet allows computer users to connect to other computers and information stores easily, wherever they may be across the world. They may do this with or without the use of security, authentication and encryption technologies, depending on the requirements.

This is encouraging new ways of working from home, collaboration and information sharing in many industries. An accountant sitting at home can audit the books of a company based in another country, on a server situated in a third country that is remotely maintained by IT specialists in a fourth. These accounts could have been created by home-working book-keepers, in other remote locations, based on information e-mailed to them from offices all over the world. Some of these things were possible before the widespread use of the Internet, but the cost of private, leased lines would have made many of them infeasible in practice.

An office worker away from his desk, perhaps the other side of the world on a business trip or a holiday, can open a remote desktop session into their normal office PC using a secure Virtual Private Network (VPN) connection via the Internet. This gives the worker complete access to all of their normal files and data, including e-mail and other applications, while away from the office.

This concept is also referred to by some network security people as the Virtual Private Nightmare, because it extends the secure perimeter of a corporate network into its employees' homes; this has been the source of some notable security breaches, but also provides security for the workers.

Collaboration

See also: Collaborative software

The low cost and nearly instantaneous sharing of ideas, knowledge, and skills has made collaborative work dramatically easier. Not only can a group cheaply communicate and test, but the wide reach of the Internet allows such groups to easily form in the first place, even among niche interests. An example of this is the free software movement in software development which produced GNU and Linux from scratch and has taken over development of Mozilla and OpenOffice.org (formerly known as Netscape Communicator and StarOffice). Films such as Zeitgeist, Loose Change and Endgame have had extensive coverage on the internet, while being virtually ignored in the mainstream media.

Internet 'chat', whether in the form of IRC 'chat rooms' or channels, or via instant messaging systems allow colleagues to stay in touch in a very convenient way when working at their computers during the day. Messages can be sent and viewed even more quickly and conveniently than via e-mail. Extension to these systems may allow files to be exchanged, 'whiteboard' drawings to be shared as well as voice and video contact between team members.

Version control systems allow collaborating teams to work on shared sets of documents without either accidentally overwriting each other's work or having members wait until they get 'sent' documents to be able to add their thoughts and changes.

File sharing

For more details on this topic, see File sharing.

A computer file can be e-mailed to customers, colleagues and friends as an attachment. It can be uploaded to a Web site or FTP server for easy download by others. It can be put into a "shared location" or onto a file server for instant use by colleagues. The load of bulk downloads to many users can be eased by the use of "mirror" servers or peer-to-peer networks.

In any of these cases, access to the file may be controlled by user authentication; the transit of the file over the Internet may be obscured by encryption and money may change hands before or after access to the file is given. The price can be paid by the remote charging of funds from, for example a credit card whose details are also passed—hopefully fully encrypted—across the Internet. The origin and authenticity of the file received may be checked by digital signatures or by MD5 or other message digests.

These simple features of the Internet, over a world-wide basis, are changing the basis for the production, sale, and distribution of anything that can be reduced to a computer file for transmission. This includes all manner of print publications, software products, news, music, film, video, photography, graphics and the other arts. This in turn has caused seismic shifts in each of the existing industries that previously controlled the production and distribution of these products.

Internet collaboration technology enables business and project teams to share documents, calendars and other information. Such collaboration occurs in a wide variety of areas including scientific research, software development, conference planning, political activism and creative writing.

Streaming media

Many existing radio and television broadcasters provide Internet 'feeds' of their live audio and video streams (for example, the BBC). They may also allow time-shift viewing or listening such as Preview, Classic Clips and Listen Again features. These providers have been joined by a range of pure Internet 'broadcasters' who never had on-air licenses. This means that an Internet-connected device, such as a computer or something more specific, can be used to access on-line media in much the same way as was previously possible only with a television or radio receiver. The range of material is much wider, from pornography to highly specialized technical Web-casts. Podcasting is a variation on this theme, where—usually audio—material is first downloaded in full and then may be played back on a computer or shifted to a digital audio player to be listened to on the move. These techniques using simple equipment allow anybody, with little censorship or licensing control, to broadcast audio-visual material on a worldwide basis.

Webcams can be seen as an even lower-budget extension of this phenomenon. While some webcams can give full frame rate video, the picture is usually either small or updates slowly. Internet users can watch animals around an African waterhole, ships in the Panama Canal, the traffic at a local roundabout or their own premises, live and in real time. Video chat rooms, video conferencing, and remote controllable webcams are also popular. Many uses can be found for personal webcams in and around the home, with and without two-way sound.

YouTube, sometimes described as an internet phenomenon because of the vast amount of users and how rapidly the sites popularity has grown. Youtube was founded in February 15, 2005. It is now the leading website for free streaming video. It uses a flash based web player which streams video files in the format FLV. Users are able to watch videos without signing up however if users do sign up they are able to upload an unlimited amount of videos and they are given their own personal profile. It is currently estimated that there are 64,000,000 videos on Youtube and it is also currently estimated that 825,000 new videos are uploaded every day.

Voice telephony (VoIP)

For more details on this topic, see VoIP.

VoIP stands for Voice over IP, where IP refers to the Internet Protocol that underlies all Internet communication. This phenomenon began as an optional two-way voice extension to some of the Instant Messaging systems that took off around the year 2000. In recent years many VoIP systems have become as easy to use and as convenient as a normal telephone. The benefit is that, as the Internet carries the actual voice traffic, VoIP can be free or cost much less than a normal telephone call, especially over long distances and especially for those with always-on Internet connections such as cable or ADSL.

Thus VoIP is maturing into a viable alternative to traditional telephones. Interoperability between different providers has improved and the ability to call or receive a call from a traditional telephone is available. Simple inexpensive VoIP modems are now available that eliminate the need for a PC.

Voice quality can still vary from call to call but is often equal to and can even exceed that of traditional calls.

Remaining problems for VoIP include emergency telephone number dialling and reliability. Currently a few VoIP providers provide an emergency service but it is not universally available. Traditional phones are line powered and operate during a power failure, VoIP does not do so without a backup power source for the electronics.

Most VoIP providers offer unlimited national calling but the direction in VoIP is clearly toward global coverage with unlimited minutes for a low monthly fee.

VoIP has also become increasingly popular within the gaming world, as a form of communication between players. Popular gaming VoIP clients include Ventrilo and Teamspeak, and there are others available also. The PlayStation 3 and Xbox 360 also offer VoIP chat features.

Censorship

For more details on this topic, see Internet censorship.

Some governments, such as those of Cuba, Iran, North Korea, Myanmar, the People's Republic of China, and Saudi Arabia, restrict what people in their countries can access on the Internet, especially political and religious content. This is accomplished through software that filters domains and content so that they may not be easily accessed or obtained without elaborate circumvention.

In Norway, Denmark, Finland and Sweden, major Internet service providers have voluntarily (possibly to avoid such an arrangement being turned into law) agreed to restrict access to sites listed by police. While this list of forbidden URLs is only supposed to contain addresses of known child pornography sites, the content of the list is secret.^{[citation needed]}

Many countries, including the United States, have enacted laws making the possession or distribution of certain material, such as child pornography, illegal, but do not use filtering software.

There are many free and commercially available software programs with which a user can choose to block offensive Web sites on individual computers or networks, such as to limit a child's access to pornography or violence. See Content-control software.

Internet access

For more details on this topic, see Internet access.

Wikibooks has a book on the topic of

Online linux connect

Common methods of home access include dial-up, landline broadband (over coaxial cable, fiber optic or copper wires), Wi-Fi, satellite and 3G technology cell phones.

Public places to use the Internet include libraries and Internet cafes, where computers with Internet connections are available. There are also Internet access points in many public places such as airport halls and coffee shops, in some cases just for brief use while standing. Various terms are used, such as "public Internet kiosk", "public access terminal", and "Web payphone". Many hotels now also have public terminals, though these are usually fee-based. These terminals are widely accessed for various usage like ticket booking, bank deposit, online payment etc. Wi-Fi provides wireless access to computer networks, and therefore can do so to the Internet itself. Hotspots providing such access include Wi-Fi-cafes, where a would-be user needs to bring their own wireless-enabled devices such as a laptop or PDA. These services may be free to all, free to customers only, or fee-based. A hotspot need not be limited to a confined location. The whole campus or park, or even the entire city can be enabled. Grassroots efforts have led to wireless community networks. Commercial WiFi services covering large city areas are in place in London, Vienna, Toronto, San Francisco, Philadelphia, Chicago and Pittsburgh. The Internet can then be accessed from such places as a park bench.^[3]

Apart from Wi-Fi, there have been experiments with proprietary mobile wireless networks like Ricochet, various high-speed data services over cellular phone networks, and fixed wireless services.

High-end mobile phones such as smartphones generally come with Internet access through the phone network. Web browsers such as Opera are available on these advanced handsets, which can also run a wide variety of other Internet software. More mobile phones have Internet access than PCs, though this is not as widely used. An Internet access provider and protocol matrix differentiates the methods used to get online.

Leisure

The Internet has been a major source of leisure since before the World Wide Web, with entertaining social experiments such as MUDs and MOOs being conducted on university servers, and humor-related Usenet groups receiving much of the main traffic. Today, many Internet forums have sections devoted to games and funny videos; short cartoons in the form of Flash movies are also popular. Over 6 million people use blogs or message boards as a means of communication and for the sharing of ideas.

The pornography and gambling industries have both taken full advantage of the World Wide Web, and often provide a significant source of advertising revenue for other Web sites. Although many governments have attempted to put restrictions on both industries' use of the Internet, this has generally failed to stop their widespread popularity.

One main area of leisure on the Internet is multiplayer gaming. This form of leisure creates communities, bringing people of all ages and origins to enjoy the fast-paced world of multiplayer games. These range from MMORPG to first-person shooters, from role-playing games to online gambling. This has revolutionized the way many people interact and spend their free time on the Internet.

While online gaming has been around since the 1970s, modern modes of online gaming began with services such as GameSpy and MPlayer, which players of games would typically subscribe to. Non-subscribers were limited to certain types of gameplay or certain games.

Many use the Internet to access and download music, movies and other works for their enjoyment and relaxation. As discussed above, there are paid and unpaid sources for all of these, using centralized servers and distributed peer-to-peer technologies. Discretion is needed as some of these sources take more care over the original artists' rights and over copyright laws than others.

Many use the World Wide Web to access news, weather and sports reports, to plan and book holidays and to find out more about their random ideas and casual interests.

People use chat, messaging and email to make and stay in touch with friends worldwide, sometimes in the same way as some previously had pen pals. Social networking Web sites like Myspace and Facebook many others like them also put and keep people in contact for their enjoyment.

The Internet has seen a growing number of Internet operating systems, where users can access their files, folders, and settings via the Internet. An example of an opensource webOS is Eyeos.

Cyberslacking has become a serious drain on corporate resources; the average UK employee spends 57 minutes a day surfing the Web at work, according to a study by Peninsula Business Services [4].

Complex architecture

Many computer scientists see the Internet as a "prime example of a large-scale, highly engineered, yet highly complex system".^[4] The Internet is extremely heterogeneous. (For instance, data transfer rates and physical characteristics of connections vary widely.) The Internet exhibits "emergent phenomena" that depend on its large-scale organization. For example, data transfer rates exhibit temporal self-similarity. Further adding to the complexity of the Internet is the ability of more than one computer to use the Internet through only one node, thus creating the possibility for a very deep and hierarchal based sub-network that can theoretically be extended infinitely (disregarding the programmatic limitations of the IPv4 protocol). However, since principles of this architecture date back to the 1960s, it might not be a solution best suited to modern needs, and thus the possibility of developing alternative structures is currently being looked into.^[5]

According to a June 2007 article in Discover Magazine, the combined weight of all the electrons moved within the internet in a day is 0.2 millionths of an ounce.^[6] Others have estimated this at nearer 2 ounces (50 grams).^[7]

Marketing

The Internet has also become a large market for companies; some of the biggest companies today have grown by taking advantage of the efficient nature of low-cost advertising and commerce through the Internet, also known as e-commerce. It is the fastest way to spread information to a vast number of people simultaneously. The Internet has also subsequently revolutionized shopping—for example; a person can order a CD online and receive it in the mail within a couple of days, or download it directly in some cases. The Internet has also greatly facilitated personalized marketing which allows a company to market a product to a specific person or a specific group of people more so than any other advertising medium.

Examples of personalized marketing include online communities such as MySpace, Friendster, Orkut, Facebook and others which thousands of Internet users join to advertise themselves and make friends online. Many of these users are young teens and adolescents ranging from 13 to 25 years old. In turn, when they advertise themselves they advertise interests and hobbies, which online marketing companies can use as information as to what those users will purchase online, and advertise their own companies' products to those users.

Further information: Disintermediation#Impact of Internet-related disintermediation upon various industries and Travel agency#The Internet threat

The name Internet

For more details on this topic, see Internet capitalization conventions.

Look up Internet, internet in Wiktionary, the free dictionary.

Internet is traditionally written with a capital first letter, as it is a proper noun. The Internet Society, the Internet Engineering Task Force, the Internet Corporation for Assigned Names and Numbers, the World Wide Web Consortium, and several other Internet-related organizations use this convention in their publications.

Many newspapers, newswires, periodicals, and technical journals capitalize the term (Internet). Examples include The New York Times, the Associated Press, Time, The Times of India, Hindustan Times, and Communications of the ACM.

Others assert that the first letter should be in lower case (internet), and that the specific article “the” is sufficient to distinguish “the internet” from other internets. A significant number of publications use this form, including The Economist, the Canadian Broadcasting Corporation, the Financial Times, The Guardian, The Times, and The Sydney Morning Herald. As of 2005, many publications using internet appear to be located outside of North America—although one U.S. news source, Wired News, has adopted the lower-case spelling.

Historically, Internet and internet have had different meanings, with internet meaning “an interconnected set of distinct networks,” and Internet referring to the world-wide, publicly-available IP internet. Under this distinction, "the Internet" is the familiar network via which websites exist, however "an internet" can exist between any two remote locations.^[8] Any group of distinct networks connected together is an internet; each of these networks may or may not be part of the Internet. The distinction was evident in many RFCs, books, and articles from the 1980s and early 1990s (some of which, such as RFC 1918, refer to "internets" in the plural), but has recently fallen into disuse.^{[citation needed]} Instead, the term intranet is generally used for private networks, whether they are connected to the Internet or not. See also: extranet.

Some people use the lower-case term as a medium (like radio or newspaper, e.g. I've found it on the internet), and first letter capitalized as the global network.

Find more about Internet on Wikipedia's sister projects:
	Dictionary definitions
	Textbooks
	Quotations
	Source texts
	Images and media
	News stories
	Learning resources

Notes

^ Coffman, K. G; Odlyzko, A. M. (1998-10-02). "The size and growth rate of the Internet". AT&T Labs. Retrieved on 2007-05-21.
^ Slabbert,N.J. The Technologies of Peace, Harvard International Review, June 2006.
^ "Toronto Hydro to Install Wireless Network in Downtown Toronto". Bloomberg.com. Retrieved 19-Mar-2006.
^ Walter Willinger, Ramesh Govindan, Sugih Jamin, Vern Paxson, and Scott Shenker (2002). Scaling phenomena in the Internet. In Proceedings of the National Academy of Sciences, 99, suppl. 1, 2573–2580.
^ "Internet Makeover? Some argue it's time". The Seattle Times, April 16, 2007.
^ "How Much Does The Internet Weigh?". Discover Magazine, June 2007.
^ How Much Does The Internet Weigh? - The Unbearable Lightness Of Fact Checking
^ What is the Internet?

References

Media Freedom Internet Cookbook by the OSCE Representative on Freedom of the Media Vienna, 2004
Living Internet—Internet history and related information, including information from many creators of the Internet
First Monday peer-reviewed journal on the Internet
How Much Does The Internet Weigh? by Stephen Cass, Discover 2007
Rehmeyer, Julie J. 2007. Mapping a medusa: The Internet spreads its tentacles. Science News 171(June 23):387-388. Available at http://www.sciencenews.org/articles/20070623/fob2.asp .
Sohn, Emily. 2006. Internet generation. Science News for Kids (Oct. 25). Available at http://www.sciencenewsforkids.org/articles/20061025/Feature1.asp .
Castells, M. 1996. Rise of the Network Society. 3 vols. Vol. 1. Cambridge, MA: Blackwell Publishers.
Castells, M. (2001), “Lessons from the History of Internet”, in “The Internet Galaxy”, Ch. 1, pp 9-35. Oxford Univ. Press.

External links

Laptops

2008-01-24T03:00:00.000-08:00

Laptop

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An ultraportable IBM X31 with 12" screen on an IBM T43 Thin & Light laptop with a 14" screen

QWERTY keyboard on 2007 Sony VAIO laptop

A laptop computer, or simply laptop (also notebook computer, notebook, notepad, and incorrectly labtop;), is a small mobile computer, which usually weighs 2-18 pounds (around 1 to 8 kilograms), depending on size, materials, and other factors.

Laptops usually run on a single main battery or from an external AC/DC adapter which can charge the battery while also supplying power to the computer itself. Many computers also have a 3 volt cell to run the clock and other processes in the event of a power failure.

As Personal computers, laptops are capable of the same tasks as a desktop computer, although they are typically less powerful for the same price. They contain components that are similar to their desktop counterparts and perform the same functions, but are miniaturized and optimized for mobile use and efficient power consumption. Laptops usually have liquid crystal displays and most of them use different memory modules for their random access memory (RAM), for instance, SO-DIMM in lieu of the larger DIMMs. In addition to a built-in keyboard, they may utilize a touchpad (also known as a trackpad) or a pointing stick for input, though an external keyboard or mouse can usually be attached.

[hide]

[edit] Categories

Thin-and-lights: Laptops usually weighing in between 4 and 6 lb (1.8–2.7 kg) with a screen size of between 12 and 14 inches (30–35 cm) diagonally.

Mainstream: Laptops weighing in between 5 and 7 lb (2.3–3.2 kg), with a screen size of 14.1 inches and 15.4 inches (35 and 39 cm).

Desktop replacement computers: Powerful laptops meant to be mainly used in a fixed location and infrequently carried out due to their weight and size; the latter provides more space for powerful components and a big screen, usually measuring 17–20 inches (43–51 cm). Desktop replacements tend to have limited battery life, rarely exceeding three hours, because the hardware is not optimized for efficient power usage. Sometimes called a luggable laptop. An example of a desktop replacement computers are gaming notebooks, which are designed to handle 3D graphic-intensive processing for gamers.

[edit] Related devices

Laptops can be understood as a particular point on the continuum of more or less portable computing devices: the point at which the device is large enough to use substantially the same software as a desktop machine, but small enough to support mobile computing. Other points on the continuum include:

Transportable, also called portable computers: Computers which can easily be moved from place to place, but cannot be used while in transit, usually because they require AC power. The most famous example is the Osborne 1. A transportable, like a laptop, can run desktop software; but it does not support mobile computing.

Tablets: Computers shaped like slates or (paper) notebooks, with touchscreen interfaces include a magnetized stylus and software for allowing input to be recognized by the touch screen. As of 2007, the most common subcategory is the Tablet PC, which is essentially a laptop with a touchscreen. Some tablets have no keyboard; others, called "convertibles", have a screen which can be rotated 180 degrees and folded on top of the keyboard. Tablets may have limited functionality in certain applications that require an actual physical keyboard for typing, but are otherwise capable of carrying out most tasks that an ordinary laptop would be able to perform.

Internet tablets: Internet appliances in tablet form. An internet tablet supports mobile computing. Internet tablets usually use Linux and they are able to run some applications, but they cant replace a computer. Internet tablets feature MP3, video, internet browser, chat, and picture viewer.

Personal digital assistants (PDAs): Small computers, usually pocket-sized, usually with limited functionality. A PDA supports mobile computing, but almost never runs any desktop software.

Handheld computers: A high-end PDA or small tablet.

Smart phone: A hand held or PDA with an integrated cellphone.

Boundaries that separate these categories are blurry at times. For example, the OQO UPC is a PDA-sized tablet PC; the Apple eMate had the clamshell form factor of a laptop, but ran PDA software. The HP Omnibook line of laptops included some devices small enough to be called handheld computers. The hardware of the Nokia 770 internet tablet is essentially the same as that of a PDA such as the Zaurus 6000; the only reason it's not called a PDA is that it doesn't have PIM software. On the other hand, both the 770 and the Zaurus can run some desktop Linux software, usually with modifications.

An opened Osborne 1 computer, ready for use. The keyboard sits on the inside of the lid.

[edit] History

Before laptop/notebook computers were technically feasible, similar ideas had been proposed, most notably Alan Kay's Dynabook concept, developed at Xerox PARC in the early 1970s.

The first commercially available portable computer was the Osborne 1 in 1981, which used the CP/M operating system. Although it was large and heavy compared to today's laptops, with a tiny CRT monitor, it had a near-revolutionary impact on business, as professionals were able to take their computer and data with them for the first time. This and other "luggables" were inspired by what was probably the first portable computer, the Xerox NoteTaker, again developed at Xerox PARC, in 1976; however, only ten prototypes were built. The Osborne was about the size of a portable sewing machine, and importantly could be carried on a commercial aircraft. However, it was not possible to run the Osborne on batteries: it had to be plugged into mains.

In 1982 Kaypro introduced the Kaypro II, a CP/M-based competitor to the Osborne 1. The Kaypro II featured a display nearly twice as big as the Osborne's and double-sided floppy drives with twice the storage capacity.

A more enduring success was the Compaq Portable, the first product from Compaq, introduced in 1983, by which time the IBM Personal Computer had become the standard platform. Although scarcely more portable than the Osborne machines, and also requiring AC power to run, it ran MS-DOS and was the first true IBM clone (IBM's own later Portable Computer, which arrived in 1984, was notably less IBM PC-compatible than the Compaq^{[citation needed]}).

Another significant machine announced in 1981, although first sold widely in 1983, was the Epson HX-20. A simple handheld computer, it featured a full-transit 68-key keyboard, rechargeable nickel-cadmium batteries, a small (120 x 32-pixel) dot-matrix LCD display with 4 lines of text, 20 characters per line text mode, a 24 column dot matrix printer, a Microsoft BASIC interpreter, and 16 KB of RAM (expandable to 32 KB).

However, arguably the first true laptop was the GRiD Compass 1101, designed by Bill Moggridge in 1979-1980, and released in 1982. Enclosed in a magnesium case, it introduced the now familiar clamshell design, in which the flat display folded shut against the keyboard. The computer could be run from batteries, and was equipped with a 320×200-pixel plasma display and 384 kibibyte bubble memory. It was not IBM-compatible, and its high price (US$8,000–10,000) limited it to specialized applications. However, it was used heavily by the U.S. military, and by NASA on the Space Shuttle during the 1980s. The GRiD's manufacturer subsequently earned significant returns on its patent rights as its innovations became commonplace. GRiD Systems Corp. was later bought by the Tandy (now RadioShack) Corporation.

Two other noteworthy early laptops were the Sharp PC-5000 and the Gavilan SC, announced in 1983 but first sold in 1984. The Gavilan was notably the first computer to be marketed as a "laptop". It was also equipped with a pioneering touchpad-like pointing device, installed on a panel above the keyboard. Like the GRiD Compass, the Gavilan and the Sharp were housed in clamshell cases, but they were partly IBM-compatible, although primarily running their own system software. Both had LCD displays, and could connect to optional external printers. The Dulmont Magnum, launched internationally in 1984, was an Australian portable similar in layout to the Gavilan, which used the Intel 80186 processor.^[1]

The year 1983 also saw the launch of what was probably the biggest-selling early laptop, the Kyocera Kyotronic 85, which owed much to the design of the previous Epson HX-20. Although it was at first a slow seller in Japan, it was quickly licensed by Tandy Corporation, Olivetti, and NEC, which saw its potential and marketed it respectively as TRS-80 Model 100 line (or Tandy 100), Olivetti M-10, NEC PC-8201.^[2] The machines ran on standard AA batteries. The Tandy's built-in programs, including a BASIC interpreter, a text editor, and a terminal program, were supplied by Microsoft, and are thought to have been written in part by Bill Gates himself. The computer was not a clamshell, but provided a tiltable 8×40-character LCD screen above a full-travel keyboard. With its internal modem, it was a highly portable communications terminal. Due to its portability, good battery life (and ease of replacement), reliability (it had no moving parts), and low price (as little as US$300), the model was highly regarded, becoming a favorite among journalists. It weighed less than 2 kg with dimensions of 30×21.5×4.5 centimeters (12×8½×1¾ in). Initial specifications included 8 kilobytes of RAM (expandable to 24 KB) and a 3 MHz processor. The machine was in fact about the size of a paper notebook, but the term had yet to come into use and it was generally described as a "portable" computer.

Possibly the first commercial IBM-compatible laptop was the Kaypro 2000, introduced in 1985. With its brushed aluminum clamshell case, it was remarkably similar in design to modern laptops. It featured a 25 line by 80 character LCD display, a detachable keyboard, and a pop-up 90 mm (3.5 inch) floppy drive.

Also among the first commercial IBM-compatible laptops were the IBM PC Convertible, introduced in 1986, and two Toshiba models, the T1000 and T1200, introduced in 1987. Although limited floppy-based DOS machines, with the operating system stored in read-only memory, the Toshiba models were small and light enough to be carried in a backpack, and could be run off lead-acid batteries. These also introduced the now-standard "resume" feature to DOS-based machines: the computer could be paused between sessions, without having to be restarted each time.

The first laptops successful on a large scale came in large part due to a Request For Proposal (RFP) by the U.S. Air Force in 1987. This contract would eventually lead to the purchase of over 200,000 laptops. Competition to supply this contract was fiercely contested and the major PC companies of the time; IBM, Toshiba, Compaq, NEC, and Zenith Data Systems (ZDS), rushed to develop laptops in an attempt to win this deal. ZDS, which had earlier won a landmark deal with the IRS for its Z-171, was awarded this contract for its SupersPort series. The SupersPort series was originally launched with an Intel 8086 processor, dual floppy disk drives, a backlit, blue and white STN LCD screen, and a NiCD battery pack. Later models featured an Intel 80286 processor and a 20 MB hard disk drive. On the strength of this deal, ZDS became the world's largest laptop supplier in 1987 and 1988. ZDS partnered with Tottori Sanyo in the design and manufacturing of these laptops. This relationship is notable because it was the first deal between a major brand and an Asian original equipment manufacturer.

Another notable computer was the Cambridge Z88, designed by Clive Sinclair, introduced in 1988. About the size of an A4 sheet of paper as well, it ran on standard batteries, and contained basic spreadsheet, word processing, and communications programs. It anticipated the future miniaturization of the portable computer; and, as a ROM-based machine with a small display, can—like the TRS-80 Model 100—also be seen as a forerunner of the personal digital assistant.

By the end of the 1980s, laptop computers were becoming popular among business people. The NEC UltraLite, released in mid-1989, was perhaps the first notebook computer, weighing just over 2 kg; in lieu of a floppy or hard drive, it contained a 2 mebibyte RAM drive, but this reduced its utility as well as its size. The first notebook computers to include hard drives were those of the Compaq LTE series, introduced toward the end of that year. Truly the size of a notebook, they also featured grayscale backlit displays with CGA resolution.

The Macintosh Portable, Apple's first attempt at a battery-powered computer

The first Apple Computer machine designed to be used on the go was the 1989 Macintosh Portable (although an LCD screen had been an option for the transportable Apple IIc in 1984). Actually a "luggable", the Mac Portable was praised for its clear active matrix display and long battery life, but was a poor seller due to its bulk. In the absence of a true Apple laptop, several compatible machines such as the Outbound Laptop were available for Mac users; however, for copyright reasons, the user had to supply a set of Mac ROMs, which usually meant having to buy a new or used Macintosh as well.

The Apple PowerBook series, introduced in October 1991, pioneered changes that are now de facto standards on laptops, such as the placement of the keyboard, room for palm rest, and the inclusion of a built-in pointing device (a trackball). The following year, IBM released its ThinkPad 700C, featuring a similar design (though with a distinctive red TrackPoint pointing device).

Later PowerBooks introduced the first 256-color displays (PowerBook 165c, 1993), and first true touchpad, first 16-bit sound recording, and first built-in Ethernet network adapter (PowerBook 500, 1994).

In 1994, IBM released RS/6000 N40 PowerPC laptop running AIX (Operating system based on UNIX), manufactured by Tadpole. Tadpole also manufactured laptops based on SPARC and DEC Alpha CPUs.

The summer of 1995 was a significant turning point in the history of notebook computing. In August of that year Microsoft introduced Windows 95. It was the first time that Microsoft had placed much of the power management control in the operating system. Prior to this point each brand used custom BIOS, drivers and in some cases, ASICs, to optimize the battery life of its machines. This move by Microsoft was controversial in the eyes of notebook designers because it greatly reduced their ability to innovate; however, it did serve its role in simplifying and stabilizing certain aspects of notebook design. Windows 95 also ushered in the importance of the CD-ROM drive in mobile computing and initiated the shift to the Intel Pentium processor as the base platform for notebooks. The Gateway Solo was the first notebook introduced with a Pentium processor and a CD-ROM. By also featuring a removable hard disk drive and floppy drive it was the first three-spindle (optical, floppy, and hard disk drive) notebook computer. The Gateway Solo was extremely successful within the consumer segment of the market. In roughly the same time period the Dell Latitude, Toshiba Satellite, and IBM ThinkPad were reaching great success with Pentium-based two-spindle (hard disk and floppy disk drive) systems directed toward the corporate market.

A 1997 Micron laptop

As technology improved during the 1990s, the usefulness and popularity of laptops increased. Correspondingly prices went down. Several developments specific to laptops were quickly implemented, improving usability and performance. Among them were:

Improved battery technology. The heavy lead-acid batteries were replaced with lighter and more efficient technologies, first nickel cadmium or NiCD, then nickel metal hydride (NiMH) and then lithium ion battery and lithium polymer.

Power-saving processors. While laptops in 1991 were limited to the 80286 processor because of the energy demands of the more powerful 80386, the introduction of the Intel 386SL processor, designed for the specific power needs of laptops, marked the point at which laptop needs were included in CPU design. The 386SL integrated a 386SX core with a memory controller and this was paired with an I/O chip to create the SL chipset. It was more integrated than any previous solution although its cost was higher. It was heavily adopted by the major notebook brands of the time. Intel followed this with the 486SL chipset which used the same architecture. However, Intel had to abandon this design approach as it introduced its Pentium series. Early versions of the mobile Pentium required TAB mounting (also used in LCD manufacturing) and this initially limited the number of companies capable of supplying notebooks. However, Intel did eventually migrate to more standard chip packaging. One limitation of notebooks has always been the difficulty in upgrading the processor which is a common attribute of desktops. Intel did try to solve this problem with the introduction of the MMC for mobile computing. The MMC was a standard module upon which the CPU and external cache memory could sit. It gave the notebook buyer the potential to upgrade his CPU at a later date, eased the manufacturing process somewhat, and was also used in some cases to skirt U.S. import duties as the CPU could be added to the chassis after it arrived in the U.S. Intel stuck with MMC for a few generations but ultimately could not maintain the appropriate speed and data integrity to the memory subsystem through the MMC connector.

Improved liquid crystal displays, in particular active-matrix TFT (Thin-Film Transistor) LCD technology. Early laptop screens were black and white, blue and white, or grayscale, STN (Super Twist Nematic) passive-matrix LCDs prone to heavy shadows, ghosting and blurry movement (some portable computer screens were sharper monochrome plasma displays, but these drew too much current to be powered by batteries). Color STN screens were used for some time although their viewing quality was poor. By about 1991, two new color LCD technologies hit the mainstream market in a big way; Dual STN and TFT. The Dual STN screens solved many of the viewing problems of STN at a very affordable price and the TFT screens offered excellent viewing quality although initially at a steep price. DSTN continued to offer a significant cost advantage over TFT until the mid-90s before the cost delta dropped to the point that DSTN was no longer used in notebooks. Improvements in production technology meant displays became larger, sharper, had higher native resolutions, faster response time and could display color with great accuracy, making them an acceptable substitute for a traditional CRT monitor.

Improved storage technology. Early laptops and portables had only floppy disk drives. As thin, high-capacity hard disk drives with higher reliability and shock resistance and lower power consumption became available, users could store their work on laptop computers and take it with them. The 3.5" HDD was created initially as a response to the needs of notebook designers that needed smaller, lower power consumption products. With continuing pressure to shrink the notebook size even further, the 2.5" HDD was introduced. One Laptop Per Child (OLPC) and other new laptops use Flash (non volatile, non mechanical memory device) instead of the mechanical hard disk.

Improved connectivity. Internal modems and standard serial, parallel, and PS/2 ports on IBM PC-compatible laptops made it easier to work away from home; the addition of network adapters and, from 1997, USB, as well as, from 1999, Wi-Fi, made laptops as easy to use with peripherals as a desktop computer. Several laptops also have built in 3 Gbit/s Broadband wireless modem.

Other peripherals such as video camera and fingerprint sensor.

[edit] Parts

Hard disk from a Dell Latitude

Most modern laptops feature 12 inch (30 cm) or larger active matrix displays with resolutions of 1024×768 pixels and above, and have a PC Card (formerly PCMCIA) or ExpressCard expansion bay for expansion cards. Internal hard disks are physically smaller—2.5 inch (60 mm)—compared to the standard desktop 3.5 inch (90 mm) drive, and usually have lower performance and power consumption. Video and sound chips are usually integrated. This tends to limit the use of laptops for gaming and entertainment, two fields which have constantly escalating hardware demands.^{[citation needed]} However, higher end laptops can come with dedicated graphics processors, such as the Dell Inspiron E1505 and E1705, which can be bought with an ATI Mobility Radeon X1300 or similar. These mobile graphics processors tend to have less performance than their desktop counterparts, but this is because they have been optimized for lower power usage.

There is a wide range of laptop specific processors available from Intel (Pentium M, Celeron, Intel Core and Intel Core 2) and from AMD (Athlon, Turion 64, and Sempron) and also from VIA (C3 and C7-M). Motorola and IBM developed and manufactured the chips for the former PowerPC-based Apple laptops (iBook and PowerBook). Generally, laptop processors are less powerful than their desktop counterparts, due to the need to save energy and reduce heat dissipation. However, the PowerPC G3 and G4 processor generations were able to offer almost the same performance as their desktop versions, limited mostly by other factors, such as the system bus bandwidth; recently, though, with the introduction of the G5s, they have been far outstripped. At one point, the Pismo G3, at up to 500 MHz, was faster than the fastest desktop G3 (then the B&W G3), which ran at 450 MHz.

Some parts for a modern laptop have no corresponding part in a desktop computer. For example, current models use lithium ion and more recently lithium polymer batteries, which have largely replaced the older nickel metal-hydride technology. Typical battery life for most laptops is two to five hours with light-duty use, but may drop to as little as one hour with intensive use. Batteries gradually deteriorate over time and eventually need to be replaced in one to five years, depending on the charging and discharging pattern.

A memory module removed from a high-performance Alienware laptop

Docking stations became another common laptop accessories in the early 1990s. They typically were quite large and offered 3.5" and 5.25" storage bays, one to three expansion slots (typically AT style), and a host of connectors. The mating between the laptop and docking station was typically through a large, high-speed, proprietary connector. The most common use was in a corporate computing environment where the company had standardized on a common network card and this same card was placed into the docking station. These stations were very large and quite expensive. As the need to additional storage and expansion slots became less critical because of the high integration inside the laptop itself, the emergence of the Port Replicator as a major accessory commenced. The Port Replicator was often a passive device that simply mated to the connectors on the back of the notebook and allowed the user to quickly connect their laptop so VGA, PS/2, RS-232, etc. devices were instantly attached. As higher speed ports like USB and Firewire became commonplace, the Port Replication was accomplished by a small cable connected to one of the USB 2.0 or FireWire ports on the notebooks. Wireless Port Replicators followed.

Virtually all laptops can be powered from an external AC converter. This device typically adds half a kilogram (1 lb) to the overall "transport weight" of the equipment.

A pointing stick or touchpad is used to control the position of the cursor on the screen. The pointing stick is usually a rubber dot that is located between the G, H and B keys on the laptop keyboard. To navigate the cursor, pressure is applied in the direction intended to move. The touchpad is touch-sensitive and the cursor can be navigated by moving the finger on the pad.

Intel, Asus, Compal, Quanta and other laptop manufacturers have created Common Building Block standard for laptop parts.

[edit] Disadvantages

[edit] Parts standardization and compatibility issues

Current compatibility problems in the laptop trade are reflective of the early era of personal computers, when there were many different manufacturers, each and every one of them having their own systems and incompatibility was more a norm. While there are accepted world standards of form factors for all the peripherals and add-in PC cards used in the desktop computers, there are still no firm worldwide standards relating to today's laptops' internal form factors, such as supply of electric voltage, motherboard layouts, internal adapters used in connecting the hard disk, optical drive, LCD cable, keyboard and floppy drive to the main board. Most affected by this are users uneducated in the relevant fields, especially if they attempt to connect their laptops with incompatible hardware or power adapters.

Some parts, such as hard drives and memory are commodity items and are interchangeable. However, other parts such as motherboards, keyboards, and batteries are proprietary in design and are only interchangeable within a manufacters brand and/or model line.

A significant point to note is that the vast majority of laptops on the market are manufactured by a small handful of ODMs.^[3] The ODM matters more than the OEM. Major relationships include:

Quanta sells to (among others) HP/Compaq, Dell, Toshiba, Sony, Fujitsu, Acer, NEC, Gateway and IBM - note that Quanta is currently (as of August, 2007) the largest manufacturer of notebook computers in the world
Compal sells to Toshiba, HP/Compaq, Acer, and Dell
Wistron sells to HP/Compaq, Dell, IBM, NEC, and Acer
Arima sells to HP/Compaq, NEC, and Dell
Uniwill/ECS sells to IBM, Fujitsu, and Dell
Asus sells to Apple (iBook), Sony, and Samsung
Inventec sells to HP/Compaq, Toshiba, and BenQ

[edit] Durability Issues

Due to their portablility and tight integration, Laptops are more subject to wear and physical damage than desktops. Components such as batteries, screen hinges, power jacks, and power cords are commonly subject to deterioration due to ordinary use. A liquid spill onto the keyboard, which is rather minor mishap with a desktop system can damage costly components such as the motherboard or LCD panel. Dropping a laptop can damage the LCD screen if not break apart its body. The repair costs of a failed motherboard or LCD panel may exceed the purchase value of the laptop.

Some manufacturers have mitigated some of these problems by selling "ruggedized" laptops. These often have a special drain in the keyboard that safely routes all of the water out through a hole in the bottom of the case. Additionally, the bodies of these laptops are typically made of magnesium alloy instead of plastic, and hard drives are often braced to greatly increase their chances of surviving a waist-high fall.

[edit] Upgradeability

Laptops' upgradeability is severely limited, both for technical and economic reasons. As of 2006, there is no industry-wide standard form factor for laptops. Each major laptop vendor pursues its own proprietary design and construction, with the result that laptops are difficult to upgrade and exhibit high repair costs. With few exceptions, laptop components can rarely be swapped between laptops of competing manufacturers, or even between laptops from the different product-lines of the same manufacturer. Standard feature peripherals (such as audio, video, USB, 1394, WiFi, Bluetooth) are generally integrated on the main PCB (motherboard), and thus upgrades often require using external ports, card slots, or wireless peripherals. Other components, such as RAM modules, hard drives, and batteries are typically user-upgradeable.

Many laptops have removable CPUs, although support for other CPUs is restricted to the specific models supported by the laptop motherboard. The socketed CPUs are perhaps for the manufacturer's convenience, rather than the end-user, as few manufacturers try new CPUs in last year's laptop model with an eye toward selling upgrades rather than new laptops. In many other laptops, the CPU is soldered and non-replaceable. ^[4]

Many laptops also include an internal MiniPCI slot, often occupied by a WiFi or Bluetooth card, but as with the CPU, the internal slot is often restricted in the range of cards that can be installed. The widespread adoption of USB mitigates I/O connectivity to a great degree, although the user must carry the USB peripheral as a separate item.

NVidia and ATI have proposed a standardized interface for laptop GPU upgrades (such as an MXM), but again, choices are limited compared to the desktop PCIe/AGP after-market.

On January 2007, Asus announced XG Station external video card for laptops. XG Station is connected to the laptops using USB-2 and Express card interface.

On February 2007, there is a new standard for external PCI Express cable and connector. Future laptops can be expanded using external PCI Express backplane and chassis.

[edit] Performance

A modern mid-range HP Laptop.

For a given price range (and manufacturing base), laptop computational power has traditionally trailed that of desktops. This is partly due to most laptops sharing RAM between the program memory and the graphics adapter. By virtue of their usage goals, laptops prioritize energy efficiency and compactness over absolute performance. Desktop computers and their modular components are built to fit much bigger standard enclosures, along with the expectation of AC line power. As such, energy efficiency and portability for desktops are secondary design goals compared to absolute performance.

For typical home (personal use) applications, where the computer spends the majority of its time sitting idle for the next user input, laptops of the thin-client type or larger are generally fast enough to achieve the required performance. 3D gaming, multimedia (video) encoding and playback, and analysis-packages (database, math, engineering, financial, etc.) are areas where desktops still offer the casual user a compelling advantage.

With the advent of dual-core processors and perpendicular recording, laptops are beginning to close the performance gap with desktops. Intel's Core 2 line of processors is efficient enough to be used in portable computers, and many manufacturers such as Apple and Dell are building Core 2 based laptops. Also, many high end laptop computers feature mobility versions of graphics cards, eliminating the performance losses associated with integrated graphics.

[edit] Health issues

Laptop coaster preventing heating of lap and improving laptop airflow.

A study by State University of New York researchers says heat generated from laptops can significantly elevate the temperature of the scrotum, potentially putting sperm count at risk. The small study, which included little more than two dozen men ages 13 to 35, found that the sitting position required to balance a laptop can raise scrotum temperature by as much as 2.1 °C (3.8 °F). Heat from the laptop itself can raise the temperature by another 0.7 °C (1.4 °F), bringing the potential total increase to 2.8 °C (5.2 °F). However, further research is needed to determine whether this directly affects sterility in men. ^[5] A common practical solution to this problem is to place the laptop on a table or desk.

Because of their small keyboard, the use of laptops can cause RSI, and for this reason laptops have docks that are used with ergonomic keyboards to prevent injury. Some health standards require that ergonomic keyboards be used in workplaces.

[edit] Security

Laptops are generally prized targets of theft, and theft of laptops can lead to more serious problems such as identity theft from stolen credit card numbers.^[6] Most laptops have a Kensington security slot to chain the computer to a desk with a third party security cable. In addition to this, modern operating systems and software may have disk encryption functionality that renders the data on the laptop's hard drive unreadable without a key, providing the laptop was not turned on while stolen.

[edit] Major brands and manufacturers

Major brands

Acer - TravelMate, Extensa, Ferrari and Aspire
Apple - MacBook, MacBook Air and MacBook Pro
Compaq - Evo, Armada, LTE, and Presario
Dell - Inspiron, Latitude, Precision, Vostro and XPS
Gateway
Hewlett-Packard - HP Pavilion and HP Omnibook
Lenovo - ThinkPad and 3000 series
Panasonic - Toughbook, Let's Note (available in Japan only)
Sony - VAIO, C series, FJ Series: ,N series, Sz series, FZ series, Ar series
Toshiba - Dynabook, Equium, Portege, Tecra, Satellite, Qosmio, Libretto

ODM brands

Gaming

Alienware - Area 51m, Alienware Sentia and Aurora m
Falcon Northwest - DR6800, TL2
Vigor Gaming - Atlantis, Augustus, Artorius, and Aegis
Voodoo PC - Envy

Other brands

Acorn Computers - Deskbook, Desknote and Solonote
AVADirect
Averatec
BenQ
Everex
Fujitsu Siemens - Lifebook, FMV - BiBlo, Amilo
Gericom
HCL
Hypersonic
Hyundai
Jetta (electronics company) - Jetbook
LG - Xnote
LinuxCertified - Linux laptop
MDG Computers
Medion
Micro-Star International (MSI)
NEC - VERSA, LaVie
Neo - Empiriva, Endura
Packard Bell - EasyNote
Samsung - Sens
Seanix - Seanix
Sharp - Mebius
Zenith
Zepto

[edit] See also

Wikimedia Commons has media related to:

Laptop

NEC UltraLite

[edit] External links

How to Add RAM to a Laptop, (How Stuff Works).

[edit] References

^ http://www.old-computers.com/museum/doc.asp?c=764
^ See TRS-80 Model 100 / 102 at old-computers.com
^ Notebook OEM/ODM relationships. Retrieved on 2007-06-28.
^ Thus, there is no practical way to update it on models which already feature the latest processor for their motherboard.
^ Sheynkin, Y.; Jung M;Yoo P;Schulsinger D;Komaroff E (2004-12-9). "Increase in scrotal temperature in laptop computer users". Human Reproduction 20 (2): 452-5. Epub. Retrieved on 2006-12-14.
^ TuxMobil's page with a list of information and protection devices

[hide] v • d • e Computer sizes
Supercomputer	Minisupercomputer
Mainframe	Mainframe computer
Minicomputer	Superminicomputer
Desktop computer	Microcomputer · Home computer · Personal computer · Workstation · Server
Cart computer	Cart computer
Portable computer	Portable computer
Mobile computing	Desktop replacement computer · Laptop · Subnotebook · Tablet PC Mobile device: Ultra-Mobile PC · Electronic organizer · Pocket computer · Handheld game console · Portable data terminal · Mobile data terminal · Wearable computer Personal digital assistant: Handheld PC · Pocket PC Calculator: Graphing calculator Information appliance: Smartphone
Others	Embedded system · Wireless sensor network · Smartdust · Nanocomputer

Computers

2008-01-24T02:54:00.000-08:00

Computer

From Mani Kant

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This article is about the machine. For the magazine, see Computer (magazine). For the profession, see human computer.

The NASA Columbia Supercomputer.

A computer in a wristwatch.

A computer is a machine that manipulates data according to a list of instructions.

Computers take numerous physical forms. The first devices that resemble modern computers date to the mid-20th century (around 1940 - 1945), although the computer concept and various machines similar to computers existed earlier. Early electronic computers were the size of a large room, consuming as much power as several hundred modern personal computers.^[1] Modern computers are based on comparatively tiny integrated circuits and are millions to billions of times more capable while occupying a fraction of the space.^[2] Today, simple computers may be made small enough to fit into a wristwatch and be powered from a watch battery. Personal computers in various forms are icons of the Information Age and are what most people think of as "a computer"; however, the most common form of computer in use today is the embedded computer. Embedded computers are small, simple devices that are used to control other devices — for example, they may be found in machines ranging from fighter aircraft to industrial robots, digital cameras, and children's toys.

The ability to store and execute lists of instructions called programs makes computers extremely versatile and distinguishes them from calculators. The Church–Turing thesis is a mathematical statement of this versatility: any computer with a certain minimum capability is, in principle, capable of performing the same tasks that any other computer can perform. Therefore, computers with capability and complexity ranging from that of a personal digital assistant to a supercomputer are all able to perform the same computational tasks given enough time and storage capacity.

History of computing

Main article: History of computer hardware

The Jacquard loom was one of the first programmable devices.

It is difficult to identify any one device as the earliest computer, partly because the term "computer" has been subject to varying interpretations over time. Originally, the term "computer" referred to a person who performed numerical calculations (a human computer), often with the aid of a mechanical calculating device.

The history of the modern computer begins with two separate technologies - that of automated calculation and that of programmability.

Examples of early mechanical calculating devices included the abacus, the slide rule and arguably the astrolabe and the Antikythera mechanism (which dates from about 150-100 BC). The end of the Middle Ages saw a re-invigoration of European mathematics and engineering, and Wilhelm Schickard's 1623 device was the first of a number of mechanical calculators constructed by European engineers. However, none of those devices fit the modern definition of a computer because they could not be programmed.

Hero of Alexandria (c. 10 – 70 AD) built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums that might be considered to be a means of deciding which parts of the mechanism performed which actions - and when.^[3] This is the essence of programmability. In 1801, Joseph Marie Jacquard made an improvement to the textile loom that used a series of punched paper cards as a template to allow his loom to weave intricate patterns automatically. The resulting Jacquard loom was an important step in the development of computers because the use of punched cards to define woven patterns can be viewed as an early, albeit limited, form of programmability.

It was the fusion of automatic calculation with programmability that produced the first recognisable computers. In 1837, Charles Babbage was the first to conceptualize and design a fully programmable mechanical computer that he called "The Analytical Engine".^[4] Due to limited finances, and an inability to resist tinkering with the design, Babbage never actually built his Analytical Engine.

Large-scale automated data processing of punched cards was performed for the U.S. Census in 1890 by tabulating machines designed by Herman Hollerith and manufactured by the Computing Tabulating Recording Corporation, which later became IBM. By the end of the 19th century a number of technologies that would later prove useful in the realization of practical computers had begun to appear: the punched card, Boolean algebra, the vacuum tube (thermionic valve) and the teleprinter.

During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated analog computers, which used a direct mechanical or electrical model of the problem as a basis for computation. However, these were not programmable and generally lacked the versatility and accuracy of modern digital computers.

*Defining characteristics of five early digital computers*
Computer	First operation	Place	Decimal/Binary	Electronic	Programmable	Turing complete
Zuse Z3	May 1941	Germany	binary	No	By punched film stock	Yes (1998)
Atanasoff–Berry Computer	Summer 1941	USA	binary	Yes	No	No
Colossus	December 1943 / January 1944	UK	binary	Yes	Partially, by rewiring	No
Harvard Mark I – IBM ASCC	1944	USA	decimal	No	By punched paper tape	Yes (1998)
ENIAC	1944	USA	decimal	Yes	Partially, by rewiring	Yes
ENIAC	1948	USA	decimal	Yes	By Function Table ROM	Yes

A succession of steadily more powerful and flexible computing devices were constructed in the 1930s and 1940s, gradually adding the key features that are seen in modern computers. The use of digital electronics (largely invented by Claude Shannon in 1937) and more flexible programmability were vitally important steps, but defining one point along this road as "the first digital electronic computer" is difficult (Shannon 1940). Notable achievements include:

EDSAC was one of the first computers to implement the stored program (von Neumann) architecture.

Konrad Zuse's electromechanical "Z machines". The Z3 (1941) was the first working machine featuring binary arithmetic, including floating point arithmetic and a measure of programmability. In 1998 the Z3 was proved to be Turing complete, therefore being the world's first operational computer.
The non-programmable Atanasoff–Berry Computer (1941) which used vacuum tube based computation, binary numbers, and regenerative capacitor memory.
The secret British Colossus computer (1944), which had limited programmability but demonstrated that a device using thousands of tubes could be reasonably reliable and electronically reprogrammable. It was used for breaking German wartime codes.
The Harvard Mark I (1944), a large-scale electromechanical computer with limited programmability.
The U.S. Army's Ballistics Research Laboratory ENIAC (1946), which used decimal arithmetic and is sometimes called the first general purpose electronic computer (since Konrad Zuse's Z3 of 1941 used electromagnets instead of electronics). Initially, however, ENIAC had an inflexible architecture which essentially required rewiring to change its programming.

Several developers of ENIAC, recognizing its flaws, came up with a far more flexible and elegant design, which came to be known as the stored program architecture or von Neumann architecture. This design was first formally described by John von Neumann in the paper "First Draft of a Report on the EDVAC", published in 1945. A number of projects to develop computers based on the stored program architecture commenced around this time, the first of these being completed in Great Britain. The first to be demonstrated working was the Manchester Small-Scale Experimental Machine (SSEM) or "Baby". However, the EDSAC, completed a year after SSEM, was perhaps the first practical implementation of the stored program design. Shortly thereafter, the machine originally described by von Neumann's paper—EDVAC—was completed but did not see full-time use for an additional two years.

Nearly all modern computers implement some form of the stored program architecture, making it the single trait by which the word "computer" is now defined. By this standard, many earlier devices would no longer be called computers by today's definition, but are usually referred to as such in their historical context. While the technologies used in computers have changed dramatically since the first electronic, general-purpose computers of the 1940s, most still use the von Neumann architecture. The design made the universal computer a practical reality.

Microprocessors are miniaturized devices that often implement stored program CPUs.

Vacuum tube-based computers were in use throughout the 1950s, but were largely replaced in the 1960s by transistor-based devices, which were smaller, faster, cheaper, used less power and were more reliable. These factors allowed computers to be produced on an unprecedented commercial scale. By the 1970s, the adoption of integrated circuit technology and the subsequent creation of microprocessors such as the Intel 4004 caused another leap in size, speed, cost and reliability. By the 1980s, computers had become sufficiently small and cheap to replace simple mechanical controls in domestic appliances such as washing machines. Around the same time, computers became widely accessible for personal use by individuals in the form of home computers and the now ubiquitous personal computer. In conjunction with the widespread growth of the Internet since the 1990s, personal computers are becoming as common as the television and the telephone and almost all modern electronic devices contain a computer of some kind.

Stored program architecture

Main articles: Computer program and Computer programming

The defining feature of modern computers which distinguishes them from all other machines is that they can be programmed. That is to say that a list of instructions (the program) can be given to the computer and it will store them and carry them out at some time in the future.

In most cases, computer instructions are simple: add one number to another, move some data from one location to another, send a message to some external device, etc. These instructions are read from the computer's memory and are generally carried out (executed) in the order they were given. However, there are usually specialized instructions to tell the computer to jump ahead or backwards to some other place in the program and to carry on executing from there. These are called "jump" instructions (or branches). Furthermore, jump instructions may be made to happen conditionally so that different sequences of instructions may be used depending on the result of some previous calculation or some external event. Many computers directly support subroutines by providing a type of jump that "remembers" the location it jumped from and another instruction to return to the instruction following that jump instruction.

Program execution might be likened to reading a book. While a person will normally read each word and line in sequence, they may at times jump back to an earlier place in the text or skip sections that are not of interest. Similarly, a computer may sometimes go back and repeat the instructions in some section of the program over and over again until some internal condition is met. This is called the flow of control within the program and it is what allows the computer to perform tasks repeatedly without human intervention.

Comparatively, a person using a pocket calculator can perform a basic arithmetic operation such as adding two numbers with just a few button presses. But to add together all of the numbers from 1 to 1,000 would take thousands of button presses and a lot of time—with a near certainty of making a mistake. On the other hand, a computer may be programmed to do this with just a few simple instructions. For example:

        mov      #0,sum     ; set sum to 0
       mov      #1,num     ; set num to 1
loop:   add      num,sum    ; add num to sum
       add      #1,num     ; add 1 to num
       cmp      num,#1000  ; compare num to 1000
       ble      loop       ; if num <= 1000, go back to 'loop'
       halt                ; end of program. stop running

Once told to run this program, the computer will perform the repetitive addition task without further human intervention. It will almost never make a mistake and a modern PC can complete the task in about a millionth of a second.^[5]

However, computers cannot "think" for themselves in the sense that they only solve problems in exactly the way they are programmed to. An intelligent human faced with the above addition task might soon realize that instead of actually adding up all the numbers one can simply use the equation

and arrive at the correct answer (500,500) with little work.^[6] In other words, a computer programmed to add up the numbers one by one as in the example above would do exactly that without regard to efficiency or alternative solutions.

Programs

A 1970s punched card containing one line from a FORTRAN program. The card reads: "Z(1) = Y + W(1)" and is labelled "PROJ039" for identification purposes.

In practical terms, a computer program might include anywhere from a dozen instructions to many millions of instructions for something like a word processor or a web browser. A typical modern computer can execute billions of instructions every second and nearly never make a mistake over years of operation.

Large computer programs may take teams of computer programmers years to write and the probability of the entire program having been written completely in the manner intended is unlikely. Errors in computer programs are called bugs. Sometimes bugs are benign and do not affect the usefulness of the program, in other cases they might cause the program to completely fail (crash), in yet other cases there may be subtle problems. Sometimes otherwise benign bugs may be used for malicious intent, creating a security exploit. Bugs are usually not the fault of the computer. Since computers merely execute the instructions they are given, bugs are nearly always the result of programmer error or an oversight made in the program's design.^[7]

In most computers, individual instructions are stored as machine code with each instruction being given a unique number (its operation code or opcode for short). The command to add two numbers together would have one opcode, the command to multiply them would have a different opcode and so on. The simplest computers are able to perform any of a handful of different instructions, the more complex computers have several hundred to choose from—each with a unique numerical code. Since the computer's memory is able to store numbers, it can also store the instruction codes. This leads to the important fact that entire programs (which are just lists of instructions) can be represented as lists of numbers and can themselves be manipulated inside the computer just as if they were numeric data. The fundamental concept of storing programs in the computer's memory alongside the data they operate on is the crux of the von Neumann, or stored program, architecture. In some cases, a computer might store some or all of its program in memory that is kept separate from the data it operates on. This is called the Harvard architecture after the Harvard Mark I computer. Modern von Neumann computers display some traits of the Harvard architecture in their designs, such as in CPU caches.

While it is possible to write computer programs as long lists of numbers (machine language) and this technique was used with many early computers,^[8] it is extremely tedious to do so in practice, especially for complicated programs. Instead, each basic instruction can be given a short name that is indicative of its function and easy to remember—a mnemonic such as ADD, SUB, MULT or JUMP. These mnemonics are collectively known as a computer's assembly language. Converting programs written in assembly language into something the computer can actually understand (machine language) is usually done by a computer program called an assembler. Machine languages and the assembly languages that represent them (collectively termed low-level programming languages) tend to be unique to a particular type of computer. For instance, an ARM architecture computer (such as may be found in a PDA or a hand-held videogame) cannot understand the machine language of an Intel Pentium or the AMD Athlon 64 computer that might be in a PC.^[9]

Though considerably easier than in machine language, writing long programs in assembly language is often difficult and error prone. Therefore, most complicated programs are written in more abstract high-level programming languages that are able to express the needs of the computer programmer more conveniently (and thereby help reduce programmer error). High level languages are usually "compiled" into machine language (or sometimes into assembly language and then into machine language) using another computer program called a compiler.^[10] Since high level languages are more abstract than assembly language, it is possible to use different compilers to translate the same high level language program into the machine language of many different types of computer. This is part of the means by which software like video games may be made available for different computer architectures such as personal computers and various video game consoles.

The task of developing large software systems is an immense intellectual effort. It has proven, historically, to be very difficult to produce software with an acceptably high reliability, on a predictable schedule and budget. The academic and professional discipline of software engineering concentrates specifically on this problem.

Example

A traffic light showing red.

Suppose a computer is being employed to drive a traffic light. A simple stored program might say:

Turn off all of the lights
Turn on the red light
Wait for sixty seconds
Turn off the red light
Turn on the green light
Wait for sixty seconds
Turn off the green light
Turn on the yellow light
Wait for two seconds
Turn off the yellow light
Jump to instruction number (2)

With this set of instructions, the computer would cycle the light continually through red, green, yellow and back to red again until told to stop running the program.

However, suppose there is a simple on/off switch connected to the computer that is intended to be used to make the light flash red while some maintenance operation is being performed. The program might then instruct the computer to:

Turn off all of the lights
Turn on the red light
Wait for sixty seconds
Turn off the red light
Turn on the green light
Wait for sixty seconds
Turn off the green light
Turn on the yellow light
Wait for two seconds
Turn off the yellow light
If the maintenance switch is NOT turned on then jump to instruction number 2
Turn on the red light
Wait for one second
Turn off the red light
Wait for one second
Jump to instruction number 11

In this manner, the computer is either running the instructions from number (2) to (11) over and over or its running the instructions from (11) down to (16) over and over, depending on the position of the switch.^[11]

How computers work

Main articles: Central processing unit and Microprocessor

A general purpose computer has four main sections: the arithmetic and logic unit (ALU), the control unit, the memory, and the input and output devices (collectively termed I/O). These parts are interconnected by busses, often made of groups of wires.

The control unit, ALU, registers, and basic I/O (and often other hardware closely linked with these) are collectively known as a central processing unit (CPU). Early CPUs were composed of many separate components but since the mid-1970s CPUs have typically been constructed on a single integrated circuit called a microprocessor.

Control unit

Main articles: CPU design and Control unit

The control unit (often called a control system or central controller) directs the various components of a computer. It reads and interprets (decodes) instructions in the program one by one. The control system decodes each instruction and turns it into a series of control signals that operate the other parts of the computer.^[12] Control systems in advanced computers may change the order of some instructions so as to improve performance.

A key component common to all CPUs is the program counter, a special memory cell (a register) that keeps track of which location in memory the next instruction is to be read from.^[13]

Diagram showing how a particular MIPS architecture instruction would be decoded by the control system.

The control system's function is as follows—note that this is a simplified description, and some of these steps may be performed concurrently or in a different order depending on the type of CPU:

Read the code for the next instruction from the cell indicated by the program counter.
Decode the numerical code for the instruction into a set of commands or signals for each of the other systems.
Increment the program counter so it points to the next instruction.
Read whatever data the instruction requires from cells in memory (or perhaps from an input device). The location of this required data is typically stored within the instruction code.
Provide the necessary data to an ALU or register.
If the instruction requires an ALU or specialized hardware to complete, instruct the hardware to perform the requested operation.
Write the result from the ALU back to a memory location or to a register or perhaps an output device.
Jump back to step (1).

Since the program counter is (conceptually) just another set of memory cells, it can be changed by calculations done in the ALU. Adding 100 to the program counter would cause the next instruction to be read from a place 100 locations further down the program. Instructions that modify the program counter are often known as "jumps" and allow for loops (instructions that are repeated by the computer) and often conditional instruction execution (both examples of control flow).

It is noticeable that the sequence of operations that the control unit goes through to process an instruction is in itself like a short computer program - and indeed, in some more complex CPU designs, there is another yet smaller computer called a microsequencer that runs a microcode program that causes all of these events to happen.

Arithmetic/logic unit (ALU)

Main article: Arithmetic logic unit

The ALU is capable of performing two classes of operations: arithmetic and logic.

The set of arithmetic operations that a particular ALU supports may be limited to adding and subtracting or might include multiplying or dividing, trigonometry functions (sine, cosine, etc) and square roots. Some can only operate on whole numbers (integers) whilst others use floating point to represent real numbers—albeit with limited precision. However, any computer that is capable of performing just the simplest operations can be programmed to break down the more complex operations into simple steps that it can perform. Therefore, any computer can be programmed to perform any arithmetic operation—although it will take more time to do so if its ALU does not directly support the operation. An ALU may also compare numbers and return boolean truth values (true or false) depending on whether one is equal to, greater than or less than the other ("is 64 greater than 65?").

Logic operations involve Boolean logic: AND, OR, XOR and NOT. These can be useful both for creating complicated conditional statements and processing boolean logic.

Superscalar computers contain multiple ALUs so that they can process several instructions at the same time. Graphics processors and computers with SIMD and MIMD features often provide ALUs that can perform arithmetic on vectors and matrices.

Memory

Main article: Computer storage

Magnetic core memory was popular main memory for computers through the 1960s until it was completely replaced by semiconductor memory.

A computer's memory can be viewed as a list of cells into which numbers can be placed or read. Each cell has a numbered "address" and can store a single number. The computer can be instructed to "put the number 123 into the cell numbered 1357" or to "add the number that is in cell 1357 to the number that is in cell 2468 and put the answer into cell 1595". The information stored in memory may represent practically anything. Letters, numbers, even computer instructions can be placed into memory with equal ease. Since the CPU does not differentiate between different types of information, it is up to the software to give significance to what the memory sees as nothing but a series of numbers.

In almost all modern computers, each memory cell is set up to store binary numbers in groups of eight bits (called a byte). Each byte is able to represent 256 different numbers; either from 0 to 255 or -128 to +127. To store larger numbers, several consecutive bytes may be used (typically, two, four or eight). When negative numbers are required, they are usually stored in two's complement notation. Other arrangements are possible, but are usually not seen outside of specialized applications or historical contexts. A computer can store any kind of information in memory as long as it can be somehow represented in numerical form. Modern computers have billions or even trillions of bytes of memory.

The CPU contains a special set of memory cells called registers that can be read and written to much more rapidly than the main memory area. There are typically between two and one hundred registers depending on the type of CPU. Registers are used for the most frequently needed data items to avoid having to access main memory every time data is needed. Since data is constantly being worked on, reducing the need to access main memory (which is often slow compared to the ALU and control units) greatly increases the computer's speed.

Computer main memory comes in two principal varieties: random access memory or RAM and read-only memory or ROM. RAM can be read and written to anytime the CPU commands it, but ROM is pre-loaded with data and software that never changes, so the CPU can only read from it. ROM is typically used to store the computer's initial start-up instructions. In general, the contents of RAM is erased when the power to the computer is turned off while ROM retains its data indefinitely. In a PC, the ROM contains a specialized program called the BIOS that orchestrates loading the computer's operating system from the hard disk drive into RAM whenever the computer is turned on or reset. In embedded computers, which frequently do not have disk drives, all of the software required to perform the task may be stored in ROM. Software that is stored in ROM is often called firmware because it is notionally more like hardware than software. Flash memory blurs the distinction between ROM and RAM by retaining data when turned off but being rewritable like RAM. However, flash memory is typically much slower than conventional ROM and RAM so its use is restricted to applications where high speeds are not required.^[14]

In more sophisticated computers there may be one or more RAM cache memories which are slower than registers but faster than main memory. Generally computers with this sort of cache are designed to move frequently needed data into the cache automatically, often without the need for any intervention on the programmer's part.

Input/output (I/O)

Main article: Input/output

Hard disks are common I/O devices used with computers.

I/O is the means by which a computer receives information from the outside world and sends results back. Devices that provide input or output to the computer are called peripherals. On a typical personal computer, peripherals include input devices like the keyboard and mouse, and output devices such as the display and printer. Hard disk drives, floppy disk drives and optical disc drives serve as both input and output devices. Computer networking is another form of I/O.

Often, I/O devices are complex computers in their own right with their own CPU and memory. A graphics processing unit might contain fifty or more tiny computers that perform the calculations necessary to display 3D graphics^{[citation needed]}. Modern desktop computers contain many smaller computers that assist the main CPU in performing I/O.

Multitasking

Main article: Computer multitasking

While a computer may be viewed as running one gigantic program stored in its main memory, in some systems it is necessary to give the appearance of running several programs simultaneously. This is achieved by having the computer switch rapidly between running each program in turn. One means by which this is done is with a special signal called an interrupt which can periodically cause the computer to stop executing instructions where it was and do something else instead. By remembering where it was executing prior to the interrupt, the computer can return to that task later. If several programs are running "at the same time", then the interrupt generator might be causing several hundred interrupts per second, causing a program switch each time. Since modern computers typically execute instructions several orders of magnitude faster than human perception, it may appear that many programs are running at the same time even though only one is ever executing in any given instant. This method of multitasking is sometimes termed "time-sharing" since each program is allocated a "slice" of time in turn.

Before the era of cheap computers, the principle use for multitasking was to allow many people to share the same computer.

Seemingly, multitasking would cause a computer that is switching between several programs to run more slowly - in direct proportion to the number of programs it is running. However, most programs spend much of their time waiting for slow input/output devices to complete their tasks. If a program is waiting for the user to click on the mouse or press a key on the keyboard, then it will not take a "time slice" until the event it is waiting for has occurred. This frees up time for other programs to execute so that many programs may be run at the same time without unacceptable speed loss.

Multiprocessing

Main article: Multiprocessing

Cray designed many supercomputers that used multiprocessing heavily.

Some computers may divide their work between one or more separate CPUs, creating a multiprocessing configuration. Traditionally, this technique was utilized only in large and powerful computers such as supercomputers, mainframe computers and servers. However, multiprocessor and multi-core (multiple CPUs on a single integrated circuit) personal and laptop computers have become widely available and are beginning to see increased usage in lower-end markets as a result.

Supercomputers in particular often have highly unique architectures that differ significantly from the basic stored-program architecture and from general purpose computers.^[15] They often feature thousands of CPUs, customized high-speed interconnects, and specialized computing hardware. Such designs tend to be useful only for specialized tasks due to the large scale of program organization required to successfully utilize most of a the available resources at once. Supercomputers usually see usage in large-scale simulation, graphics rendering, and cryptography applications, as well as with other so-called "embarrassingly parallel" tasks.

Networking and the Internet

Main articles: Computer networking and Internet

Visualization of a portion of the routes on the Internet.

Computers have been used to coordinate information in multiple locations since the 1950s. The U.S. military's SAGE system was the first large-scale example of such a system, which led to a number of special-purpose commercial systems like Sabre.

In the 1970s, computer engineers at research institutions throughout the United States began to link their computers together using telecommunications technology. This effort was funded by ARPA (now DARPA), and the computer network that it produced was called the ARPANET. The technologies that made the Arpanet possible spread and evolved. In time, the network spread beyond academic and military institutions and became known as the Internet. The emergence of networking involved a redefinition of the nature and boundaries of the computer. Computer operating systems and applications were modified to include the ability to define and access the resources of other computers on the network, such as peripheral devices, stored information, and the like, as extensions of the resources of an individual computer. Initially these facilities were available primarily to people working in high-tech environments, but in the 1990s the spread of applications like e-mail and the World Wide Web, combined with the development of cheap, fast networking technologies like Ethernet and ADSL saw computer networking become almost ubiquitous. In fact, the number of computers that are networked is growing phenomenally. A very large proportion of personal computers regularly connect to the Internet to communicate and receive information. "Wireless" networking, often utilizing mobile phone networks, has meant networking is becoming increasingly ubiquitous even in mobile computing environments.

Further topics

Hardware

Main article: Computer hardware

The term hardware covers all of those parts of a computer that are tangible objects. Circuits, displays, power supplies, cables, keyboards, printers and mice are all hardware.

**History of computing hardware**
First Generation (Mechanical/Electromechanical)	Calculators	Antikythera mechanism, Difference Engine, Norden bombsight
First Generation (Mechanical/Electromechanical)	Programmable Devices	Jacquard loom, Analytical Engine, Harvard Mark I, Z3
Second Generation (Vacuum Tubes)	Calculators	Atanasoff–Berry Computer, IBM 604, UNIVAC 60, UNIVAC 120
Second Generation (Vacuum Tubes)	Programmable Devices	ENIAC, EDSAC, EDVAC, UNIVAC I, IBM 701, IBM 702, IBM 650, Z22
Third Generation (Discrete transistors and SSI, MSI, LSI Integrated circuits)	Mainframes	IBM 7090, IBM 7080, System/360, BUNCH
	Minicomputer	PDP-8, PDP-11, System/32, System/36
Fourth Generation (VLSI integrated circuits)	Minicomputer	VAX, IBM System i
	4-bit microcomputer	Intel 4004, Intel 4040
	8-bit microcomputer	Intel 8008, Intel 8080, Motorola 6800, Motorola 6809, MOS Technology 6502, Zilog Z80
	16-bit microcomputer	8088, Zilog Z8000, WDC 65816/65802
	32-bit microcomputer	80386, Pentium, 68000, ARM architecture
	64-bit microcomputer^[16]	x86-64, PowerPC, MIPS, SPARC
	Embedded computer	8048, 8051
	Personal computer	Desktop computer, Home computer, Laptop computer, Personal digital assistant (PDA), Portable computer, Tablet computer, Wearable computer
Theoretical/experimental	Quantum computer, Chemical computer, DNA computing, Optical computer, Spintronics based computer

**Other Hardware Topics**
Peripheral device (Input/output)	Input	Mouse, Keyboard, Joystick, Image scanner
	Output	Monitor, Printer
	Both	Floppy disk drive, Hard disk, Optical disc drive, Teleprinter
Computer busses	Short range	RS-232, SCSI, PCI, USB
Computer busses	Long range (Computer networking)	Ethernet, ATM, FDDI

Software

Main article: Computer software

Software refers to parts of the computer which do not have a material form, such as programs, data, protocols, etc. When software is stored in hardware that cannot easily be modified (such as BIOS ROM in an IBM PC compatible), it is sometimes called "firmware" to indicate that it falls into an uncertain area somewhere between hardware and software.

**Computer software**
Operating system	Unix/BSD	UNIX System V, AIX, HP-UX, Solaris (SunOS), IRIX, List of BSD operating systems
	GNU/Linux	List of Linux distributions, Comparison of Linux distributions
	Microsoft Windows	Windows 95, Windows 98, Windows NT, Windows XP, Windows Vista, Windows CE
	DOS	86-DOS (QDOS), PC-DOS, MS-DOS, FreeDOS
	Mac OS	Mac OS classic, Mac OS X
	Embedded and real-time	List of embedded operating systems
	Experimental	Amoeba, Oberon/Bluebottle, Plan 9 from Bell Labs
Library	Multimedia	DirectX, OpenGL, OpenAL
Library	Programming library	C standard library, Standard template library
Data	Protocol	TCP/IP, Kermit, FTP, HTTP, SMTP
Data	File format	HTML, XML, JPEG, MPEG, PNG
User interface	Graphical user interface (WIMP)	Microsoft Windows, GNOME, KDE, QNX Photon, CDE, GEM
User interface	Text user interface	Command line interface, shells
Application	Office suite	Word processing, Desktop publishing, Presentation program, Database management system, Scheduling & Time management, Spreadsheet, Accounting software
	Internet Access	Browser, E-mail client, Web server, Mail transfer agent, Instant messaging
	Design and manufacturing	Computer-aided design, Computer-aided manufacturing, Plant management, Robotic manufacturing, Supply chain management
	Graphics	Raster graphics editor, Vector graphics editor, 3D modeler, Animation editor, 3D computer graphics, Video editing, Image processing
	Audio	Digital audio editor, Audio playback, Mixing, Audio synthesis, Computer music
	Software Engineering	Compiler, Assembler, Interpreter, Debugger, Text Editor, Integrated development environment, Performance analysis, Revision control, Software configuration management
	Educational	Edutainment, Educational game, Serious game, Flight simulator
	Games	Strategy, Arcade, Puzzle, Simulation, First-person shooter, Platform, Massively multiplayer, Interactive fiction
	Misc	Artificial intelligence, Antivirus software, Malware scanner, Installer/Package management systems, File manager

Programming languages

Programming languages provide various ways of specifying programs for computers to run. Unlike natural languages, programming languages are designed to permit no ambiguity and to be concise. They are purely written languages and are often difficult to read aloud. They are generally either translated into machine language by a compiler or an assembler before being run, or translated directly at run time by an interpreter. Sometimes programs are executed by a hybrid method of the two techniques. There are thousands of different programming languages—some intended to be general purpose, others useful only for highly specialized applications.

**Programming Languages**
Lists of programming languages	Timeline of programming languages, Categorical list of programming languages, Generational list of programming languages, Alphabetical list of programming languages, Non-English-based programming languages
Commonly used Assembly languages	ARM, MIPS, x86
Commonly used High level languages	BASIC, C, C++, C#, COBOL, Fortran, Java, Lisp, Pascal
Commonly used Scripting languages	Bourne script, JavaScript, Python, Ruby, PHP, Perl

Professions and organizations

As the use of computers has spread throughout society, there are an increasing number of careers involving computers. Following the theme of hardware, software and firmware, the brains of people who work in the industry are sometimes known irreverently as wetware or "meatware".

**Computer-related professions**
Hardware-related	Electrical engineering, Electronics engineering, Computer engineering, Telecommunications engineering, Optical engineering, Nanoscale engineering
Software-related	Computer science, Human-computer interaction, Information technology, Software engineering, Scientific computing, Web design, Desktop publishing

The need for computers to work well together and to be able to exchange information has spawned the need for many standards organizations, clubs and societies of both a formal and informal nature.

**Organizations**
Standards groups	ANSI, IEC, IEEE, IETF, ISO, W3C
Professional Societies	ACM, ACM Special Interest Groups, IET, IFIP
Free/Open source software groups	Free Software Foundation, Mozilla Foundation, Apache Software Foundation

Notes

^ In 1946, ENIAC consumed an estimated 174 kW. By comparison, a typical personal computer may use around 400 W; over four hundred times less. (Kempf 1961)
^ Early computers such as Colossus and ENIAC were able to process between 5 and 100 operations per second. A modern "commodity" microprocessor (as of 2007) can process billions of operations per second, and many of these operations are more complicated and useful than early computer operations.
^ Heron of Alexandria. Retrieved on 2008-01-15.
^ The Analytical Engine should not be confused with Babbage's difference engine which was a non-programmable mechanical calculator.
^ This program was written similarly to those for the PDP-11 minicomputer and shows some typical things a computer can do. All the text after the semicolons are comments for the benefit of human readers. These have no significance to the computer and are ignored. (Digital Equipment Corporation 1972)
^ Attempts are often made to create programs that can overcome this fundamental limitation of computers. Software that mimics learning and adaptation is part of artificial intelligence.
^ It is not universally true that bugs are solely due to programmer oversight. Computer hardware may fail or may itself have a fundamental problem that produces unexpected results in certain situations. For instance, the Pentium FDIV bug caused some Intel microprocessors in the early 1990s to produce inaccurate results for certain floating point division operations. This was caused by a flaw in the microprocessor design and resulted in a partial recall of the affected devices.
^ Even some later computers were commonly programmed directly in machine code. Some minicomputers like the DEC PDP-8 could be programmed directly from a panel of switches. However, this method was usually used only as part of the booting process. Most modern computers boot entirely automatically by reading a boot program from some non-volatile memory.
^ However, there is sometimes some form of machine language compatibility between different computers. An x86-64 compatible microprocessor like the AMD Athlon 64 is able to run most of the same programs that an Intel Core 2 microprocessor can, as well as programs designed for earlier microprocessors like the Intel Pentiums and Intel 80486. This contrasts with very early commercial computers, which were often one-of-a-kind and totally incompatible with other computers.
^ High level languages are also often interpreted rather than compiled. Interpreted languages are translated into machine code on the fly by another program called an interpreter.
^ Although this is a simple program, it contains a software bug. If the traffic signal is showing red when someone switches the "flash red" switch, it will cycle through green once more before starting to flash red as instructed. This bug is quite easy to fix by changing the program to repeatedly test the switch throughout each "wait" period—but writing large programs that have no bugs is exceedingly difficult.
^ The control unit's rule in interpreting instructions has varied somewhat in the past. While the control unit is solely responsible for instruction interpretation in most modern computers, this is not always the case. Many computers include some instructions that may only be partially interpreted by the control system and partially interpreted by another device. This is especially the case with specialized computing hardware that may be partially self-contained. For example, EDVAC, the first modern stored program computer to be designed, used a central control unit that only interpreted four instructions. All of the arithmetic-related instructions were passed on to its arithmetic unit and further decoded there.
^ Instructions often occupy more than one memory address, so the program counters usually increases by the number of memory locations required to store one instruction.
^ Flash memory also may only be rewritten a limited number of times before wearing out, making it less useful for heavy random access usage. (Verma 1988)
^ However, it is also very common to construct supercomputers out of many pieces of cheap commodity hardware; usually individual computers connected by networks. These so-called computer clusters can often provide supercomputer performance at a much lower cost than customized designs. While custom architectures are still used for most of the most powerful supercomputers, there has been a proliferation of cluster computers in recent years. (TOP500 2006)
^ Most major 64-bit instruction set architectures are extensions of earlier designs. All of the architectures listed in this table existed in 32-bit forms before their 64-bit incarnations were introduced.

About me

2008-01-24T02:47:00.000-08:00

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king of the kings(mani kant)

The Merchant of Venice

The Merchant of Venice

From Mani Kant

Contents

[edit] Date and text

[edit] Performance

[edit] Shylock on stage

[edit] Synopsis

[edit] Themes

[edit] Shylock and the anti-Semitism debate

[edit] The anti-Semitic reading

[edit] The sympathetic reading

[edit] Influence on anti-semitism

[edit] Character study

[edit] Religious interpretations

[edit] A Catholic reading

[edit] Sexuality in the play

[edit] Antonio, Bassanio and homosexuality

[edit] Bassanio, Portia and fidelity

[edit] Adaptations and cultural references

[edit] Film adaptations

[edit] Cultural references

[edit] Pastime

[edit] Notes

[edit] References

[edit] External links

Internet

Internet

From Mani Kant

Contents

Terminology

History

Growth

Today's Internet

Internet protocols

Internet structure

ICANN

Language

Internet and the workplace

The Internet viewed on mobile devices

Common uses of the Internet

E-mail

The World Wide Web

Remote access

Collaboration

File sharing

Streaming media

Voice telephony (VoIP)

Censorship

Internet access

Leisure

Complex architecture

Marketing

The name Internet

See also

Major aspects and issues

Functions

Underlying infrastructure

Regulatory bodies

Notes

References

External links

Laptops

Laptop

From Mani kant

Contents

[edit] Categories

[edit] Related devices

[edit] History

[edit] Parts

[edit] Disadvantages

[edit] Parts standardization and compatibility issues

[edit] Durability Issues

[edit] Upgradeability

[edit] Performance

[edit] Health issues

[edit] Security

[edit] Major brands and manufacturers

[edit] See also