INSTALASI OPEN OFFICE CALC

Openoffice.Org Calc atau dikenal dengan sebutan CALC saja adalah Perangkat lunak pengolah data angka, teks ataupun formula numerik. Program ini memudahkan pengguna untuk memanipulasi data mentah yang biasanya berupa tabulasi data menjadi sebuah laporan data yang menarik dan mudah dipahami karena ditampilkan menjadi grafik yang menarik.


Untuk mengintal open office calc sangat mudah sekali.Ini dia caranya :

1. bagi yang belum memiliki open office calc installer (atahanna , hehhehehe) tinggal download saja di http://download.openoffice.org/.

2. setelah didownload lalu instal dehh ...

3. simpan aplikasi open office calc ini misalnya di direktori C

4. tunggu beberapa saat untuk melakukan unpacking

5. lalu klik next pada kotak dialog Openoffice.org 32 - intalation wizard

6. masukkan user name kita

7. pilih tipe etup complete

8. lalu klik instal

9. tunggu beberapa saat untuk penginstalan

10. klik finish

11. setelah itu akan muncul kotak perintah restart, maka klik yes

12. instalasi selesai dan siap digunakan

.... ^-^ enjoyy ...

Algorithm

In mathematics, computer science, and related subjects, an algorithm (derived from the name of mathematician al-Khwārizmī and transformed to match the Greek "arithmos"-number) is an effective method for solving a problem expressed as a finite sequence of steps. Algorithms are used for calculation, data processing, and many other fields. (In more advanced or abstract settings, the instructions do not necessarily constitute a finite sequence, and even not necessarily a sequence; see, e.g., "nondeterministic algorithm".)

Each algorithm is a list of well-defined instructions for completing a task. Starting from an initial state, the instructions describe a computation that proceeds through a well-defined series of successive states, eventually terminating in a final ending state. The transition from one state to the next is not necessarily deterministic; some algorithms, known as randomized algorithms, incorporate randomness.

A partial formalization of the concept began with attempts to solve the Entscheidungsproblem (the "decision problem") posed by David Hilbert in 1928. Subsequent formalizations were framed as attempts to define "effective calculability" or "effective method" those formalizations included the Gödel–Herbrand–Kleene recursive functions of 1930, 1934 and 1935, Alonzo Church's lambda calculus of 1936, Emil Post's "Formulation 1" of 1936, and Alan Turing's Turing machines of 1936–7 and 1939.

The adjective "continuous" when applied to the word "algorithm" can mean:

1. An algorithm operating on data that represents continuous quantities, even though this data is represented by discrete approximations – such algorithms are studied in numerical analysis; or
2. An algorithm in the form of a differential equation that operates continuously on the data, running on an analog computer
   
   
    While there is no generally accepted formal definition of "algorithm," an informal definition could be "a process that performs some sequence of operations." For some people, a program is only an algorithm if it stops eventually. For others, a program is only an algorithm if it stops before a given number of calculation steps.
   A prototypical example of an algorithm is Euclid's algorithm to determine the maximum common divisor of two integers.
   We can derive clues to the issues involved and an informal meaning of the word from the following quotation from Boolos & Jeffrey (1974, 1999) (boldface added):
   No human being can write fast enough, or long enough, or small enough† ( †"smaller and smaller without limit ...you'd be trying to write on molecules, on atoms, on electrons") to list all members of an enumerably infinite set by writing out their names, one after another, in some notation. But humans can do something equally useful, in the case of certain enumerably infinite sets: They can give explicit instructions for determining the nth member of the set, for arbitrary finite n. Such instructions are to be given quite explicitly, in a form in which they could be followed by a computing machine, or by a human who is capable of carrying out only very elementary operations on symbols
   The term "enumerably infinite" means "countable using integers perhaps extending to infinity." Thus Boolos and Jeffrey are saying that an algorithm implies instructions for a process that "creates" output integers from an arbitrary "input" integer or integers that, in theory, can be chosen from 0 to infinity. Thus we might expect an algorithm to be an algebraic equation such as y = m + n — two arbitrary "input variables" m and n that produce an output y. As we see in Algorithm characterizations — the word algorithm implies much more than this, something on the order of (for our addition example):
   Precise instructions (in language understood by "the computer") for a "fast, efficient, good" process that specifies the "moves" of "the computer" (machine or human, equipped with the necessary internally contained information and capabilities) to find, decode, and then munch arbitrary input integers/symbols m and n, symbols + and = ... and (reliably, correctly, "effectively") produce, in a "reasonable" time, output-integer y at a specified place and in a specified format.
   The concept of algorithm is also used to define the notion of decidability. That notion is central for explaining how formal systems come into being starting from a small set of axioms and rules. In logic, the time that an algorithm requires to complete cannot be measured, as it is not apparently related with our customary physical dimension. From such uncertainties, that characterize ongoing work, stems the unavailability of a definition of algorithm that suits both concrete (in some sense) and abstract usage of the term.
   Formalization
   Algorithms are essential to the way computers process information. Many computer programs contain algorithms that specify the specific instructions a computer should perform (in a specific order) to carry out a specified task, such as calculating employees' paychecks or printing students' report cards. Thus, an algorithm can be considered to be any sequence of operations that can be simulated by a Turing-complete system. Authors who assert this thesis include Minsky (1967), Savage (1987) and Gurevich (2000):
   Minsky: "But we will also maintain, with Turing . . . that any procedure which could "naturally" be called effective, can in fact be realized by a (simple) machine. Although this may seem extreme, the arguments . . . in its favor are hard to refute".
   Gurevich: "...Turing's informal argument in favor of his thesis justifies a stronger thesis: every algorithm can be simulated by a Turing machine ... according to Savage [1987], an algorithm is a computational process defined by a Turing machine".
   Typically, when an algorithm is associated with processing information, data is read from an input source, written to an output device, and/or stored for further processing. Stored data is regarded as part of the internal state of the entity performing the algorithm. In practice, the state is stored in one or more data structures.
   For some such computational process, the algorithm must be rigorously defined: specified in the way it applies in all possible circumstances that could arise. That is, any conditional steps must be systematically dealt with, case-by-case; the criteria for each case must be clear (and computable).
   Because an algorithm is a precise list of precise steps, the order of computation will always be critical to the functioning of the algorithm. Instructions are usually assumed to be listed explicitly, and are described as starting "from the top" and going "down to the bottom", an idea that is described more formally by flow of control.
   So far, this discussion of the formalization of an algorithm has assumed the premises of imperative programming. This is the most common conception, and it attempts to describe a task in discrete, "mechanical" means. Unique to this conception of formalized algorithms is the assignment operation, setting the value of a variable. It derives from the intuition of "memory" as a scratchpad. There is an example below of such an assignment.
   For some alternate conceptions of what constitutes an algorithm see functional programming and logic programming .
   [Termination
   Some writers restrict the definition of algorithm to procedures that eventually finish. In such a category Kleene places the "decision procedure or decision method or algorithm for the question".Others, including Kleene, include procedures that could run forever without stopping; such a procedure has been called a "computational method" or "calculation procedure or algorithm (and hence a calculation problem) in relation to a general question which requires for an answer, not yes or no, but the exhibiting of some object".
   Minsky makes the pertinent observation, in regards to determining whether an algorithm will eventually terminate (from a particular starting state):
   But if the length of the process isn't known in advance, then "trying" it may not be decisive, because if the process does go on forever—then at no time will we ever be sure of the answer.
   As it happens, no other method can do any better, as was shown by Alan Turing with his celebrated result on the undecidability of the so-called halting problem. There is no algorithmic procedure for determining whether or not arbitrary algorithms terminate from given starting states. The analysis of algorithms for their likelihood of termination is called termination analysis.
   See the examples of (im-)"proper" subtraction at partial function for more about what can happen when an algorithm fails for certain of its input numbers—e.g., (i) non-termination, (ii) production of "junk" (output in the wrong format to be considered a number) or no number(s) at all (halt ends the computation with no output), (iii) wrong number(s), or (iv) a combination of these. Kleene proposed that the production of "junk" or failure to produce a number is solved by having the algorithm detect these instances and produce e.g., an error message (he suggested "0"), or preferably, force the algorithm into an endless loop. Davis (1958) does this to his subtraction algorithm—he fixes his algorithm in a second example so that it is proper subtraction and it terminates. Along with the logical outcomes "true" and "false" Kleene (1952) also proposes the use of a third logical symbol "u" — undecided — thus an algorithm will always produce something when confronted with a "proposition". The problem of wrong answers must be solved with an independent "proof" of the algorithm e.g., using induction:
   We normally require auxiliary evidence for this [that the algorithm correctly defines a mu recursive function], e.g, in the form of an inductive proof that, for each argument value, the computation terminates with a unique value.
   Expressing algorithms
   Algorithms can be expressed in many kinds of notation, including natural languages, pseudocode, flowcharts, programming languages or control tables (processed by interpreters). Natural language expressions of algorithms tend to be verbose and ambiguous, and are rarely used for complex or technical algorithms. Pseudocode, flowcharts and control tables are structured ways to express algorithms that avoid many of the ambiguities common in natural language statements, while remaining independent of a particular implementation language. Programming languages are primarily intended for expressing algorithms in a form that can be executed by a computer, but are often used as a way to define or document algorithms.
   There is a wide variety of representations possible and one can express a given Turing machine program as a sequence of machine tables (see more at finite state machine and state transition table), as flowcharts (see more at state diagram), or as a form of rudimentary machine code or assembly code called "sets of quadruples" (see more at Turing machine).
   Sometimes it is helpful in the description of an algorithm to supplement small "flow charts" (state diagrams) with natural-language and/or arithmetic expressions written inside "block diagrams" to summarize what the "flow charts" are accomplishing.
   Representations of algorithms are generally classed into three accepted levels of Turing machine description:
   • 1 High-level description:
   "...prose to describe an algorithm, ignoring the implementation details. At this level we do not need to mention how the machine manages its tape or head."
   • 2 Implementation description:
   "...prose used to define the way the Turing machine uses its head and the way that it stores data on its tape. At this level we do not give details of states or transition function."
   • 3 Formal description:
   Most detailed, "lowest level", gives the Turing machine's "state table".
   For an example of the simple algorithm "Add m+n" described in all three levels see Algorithm examples.
   Computer algorithms
   In computer systems, an algorithm is basically an instance of logic written in software by software developers to be effective for the intended "target" computer(s), in order for the software on the target machines to do something. For instance, if a person is writing software that is supposed to print out a PDF document located at the operating system folder "/My Documents" at computer drive "D:" every Friday at 10 pm, they will write an algorithm that specifies the following actions: "If today's date (computer time) is 'Friday,' open the document at 'D:/My Documents' and call the 'print' function". While this simple algorithm does not look into whether the printer has enough paper or whether the document has been moved into a different location, one can make this algorithm more robust and anticipate these problems by rewriting it as a formal CASE statement or as a (carefully crafted) sequence of IF-THEN-ELSE statements.For example the CASE statement might appear as follows (there are other possibilities):
   CASE 1: IF today's date is NOT Friday THEN exit this CASE instruction ELSE
   CASE 2: IF today's date is Friday AND the document is located at 'D:/My Documents' AND there is paper in the printer THEN print the document (and exit this CASE instruction) ELSE
   CASE 3: IF today's date is Friday AND the document is NOT located at 'D:/My Documents' THEN display 'document not found' error message (and exit this CASE instruction) ELSE
   CASE 4: IF today's date is Friday AND the document is located at 'D:/My Documents' AND there is NO paper in the printer THEN (i) display 'out of paper' error message and (ii) exit.
   Note that CASE 3 includes two possibilities: (i) the document is NOT located at 'D:/My Documents' AND there's paper in the printer OR (ii) the document is NOT located at 'D:/My Documents' AND there's NO paper in the printer.
   The sequence of IF-THEN-ELSE tests might look like this:
   TEST 1: IF today's date is NOT Friday THEN done ELSE TEST 2:
   TEST 2: IF the document is NOT located at 'D:/My Documents' THEN display 'document not found' error message ELSE TEST 3:
   TEST 3: IF there is NO paper in the printer THEN display 'out of paper' error message ELSE print the document.
   These examples' logic grants precedence to the instance of "NO document at 'D:/My Documents' ". Also observe that in a well-crafted CASE statement or sequence of IF-THEN-ELSE statements the number of distinct actions—4 in these examples: do nothing, print the document, display 'document not found', display 'out of paper' – equals the number of cases.
   Given unlimited memory, a computational machine with the ability to execute either a set of CASE statements or a sequence of IF-THEN-ELSE statements is Turing complete. Therefore, anything that is computable can be computed by this machine. This form of algorithm is fundamental to computer programming in all its forms (see more at McCarthy formalism).
   Implementation
   Most algorithms are intended to be implemented as computer programs. However, algorithms are also implemented by other means, such as in a biological neural network (for example, the human brain implementing arithmetic or an insect looking for food), in an electrical circuit, or in a mechanical device.
   
   

Konversi CD Fisik ke CD VIrtual

Banyak sekali aplikasi untuk menkonversi CD tapi yang paling mudah bisa didownload yaitu alcohol52.
Cara konversinya gampang banget.
1. Instal Alcohol52
2. Setelah keluar tampilan Alcohol, masukan CD Fisik ke CDRom Drive.
3. Klik Capture ISO Image . Maka akan tampil program-program yang ada pada CD Fisik.
3. Drag program tersebut pada hard disk komputer virtual .
5.Selesai ....

Ayo Bikin Komputer Virtual: Part 2. Setting Virtual PC

Hola ......
Di postingan sebelumnya saya telah menulis cara instalasi virtual PC. Sekarang saya akan menulis setting virtual PCnya. Untuk setting yang ini hmmm gampang sich tapi agak rumit (bingung) . hmm pokoknya gitu dech.

1. klik start pada taskbar lalu klik microsoft virtual. Maka akan ada tampilan Virtual PC Console seperti gambar di bawah ini :

 Untuk mensetting Virtual PC klik new.
2. Selanjutnya akan ada tampilan new virtual machine wizard. Lalu klik saja next.

3. Pilih opsi create a virtual machine lalu klik next.

4. Tuliskan nama kita pada kotak name and location . Lalu klik next.

5. Pilih Windows XP sebagai Operating System komputer virtual kita karena e karena Windows XP itu tidak makan banyak memory so performanya lebih oke dibandingkan Window7 apalagi Vista. Lalu klik next.

5. Pada saat tampil tampilan pemilihan memory yang digunakan, pilih opsi adjusting RAM agar kita dapat mengaturnya sendiri karena rekomendasi 128 MB itu terlalu kurang bagi komputer virtual kita. Lalu atur busur panahnya sehingga memorynya itu setengah dari memory komputer kita. Lalu klik next.

6. pilih opsi a new virtual machine. Lalu klik next.

7. klik next

8. finish.

9. setelah itu maka akan tampil lagi Virtual PC Console. Klik start.

  

     Setelah itu pastikan CD WinXP ada pada CDRom Drive. Klik CD pada menu bar Virtual PC Console lalu klik Capture ISO Image, lalu browse CD Windows XP kita. Maka Proses instalasi Windows XP dimulai.
10. Maka akan ada tampilan seperti dibawah ini.

 Tekan tombol enter pada keyboard.

    Tekan F8 pada keyboard

  Tekan Enter pada keyboard

 Tekan enter.

    Tunggu beberapa saat setup.

           Saat tampilan seperti dibawah ini klik next saja

  Lalu atur Waktu lokal

11. Komputer Virtual sudah jadi ...

12. Tambahin Virtual Machine Additions. Klik pada menu Action dan pilih Install or Update Virtual Machine Additions terus nanti akan ada warning maka klik saja continue dan terus install dech . Setelah install selesai, restart komputer virtual kita.

 13. Selanjutnya kita membuat shared folder agar file dari host dapat berbagi ke guest  atau sebaliknya. Dengan cara klik edit pada menu bar klik setting lalu klik shared folder. 

kita juga dapat mendapatkan file dari host ke guest dengan cara mendrag file itu ke komputer virtual kita.
note : cara memindahkan kursor dari guest ke host dengan cara menekan tombol alt sebelah kanan pada keyboard.

INI DIA KOMPUTER VIRTUAL SAYA

KALAU KAMU ??????

Ayo Bikin Komputer Virtual : part 1.Install MS Virtual PC

      Nah, untukmembuat komputer virtual pastikan di komputer kita sudah terinstal Microsoft Virtual PC. Kalau belum,ya kita harus mendownload installernya di http://www.microsoft.com/windows/downloads/virtualpc/default.mspx. udah gitu kita instal deh.

     Instal gampang kok tinggal klik next next aja abis itu finish deh. untuk lebih jelasnya kita lihat steps berikut ini :

1. kita cek dulu jenis system type komputer kita. kalau 32bit maka gunakan WinPC32, kalau 64bit gunakan WinPC64, khusus untuk windows 7 gunakan WinPC7.  

   Karena komputer saya system typenya 32 bit jadi saya instal WinPC32.

2. instal MS virtualnya. 

klik next...

ga usah dibaca dech perjanjiannya langsung pilih I accept the terms.. next aja..

next..

 klik instal..

      lalu akan terlihat tampilan seperti di atas. tunggu sesaat, abis itu akan muncul seperti gambar di bawah ini .

 

   klik finish .lalu akan tampil virtual PC Console.

Sampai sini sudah mengerti ? hahahah? udah kayak guru aja aku. kalau sudah begini komputer kita sudah memiliki fasilitas untukmembuat komputer virtual. tapi belum selesai lho, selanjutnya kita akan mensetting virtual PC yang akan saya posting di postingan selanjutnya.

to be continued ..... : D

Ayo bikin Komputer Virtual

Barangkali temen-temen masih ada yang aneh apa sich sebenernya computer virtual itu ? yang pasti sich bukan computer jadi-jadian kan? Kalo begitu apa donk ? Hmm … menurut Mbah Gugel virtualisasi ini adalah suatu teknik menyembunyikan karakteristik fisik dari sumber daya computer. Sebenarnya kata-kata Mbah Gugel itu rumit banget. Tapi aku ambil kesimpulan aja bahwa computer virtual itu bisa dikatakan sebuah computer di dalam computer. Di mana computer virtual mulai dari system operasi, aplikasi, dll dibuat sama seperti computer asli. Jadi kata orang awam computer virtual ini seperti computer jadi-jadian (penulis juga sempet jadi orang awam tersebut)

Nah, computer virtual ini khusus buat anak-anak kelas XI asuhan Pak Dodi, kudu bin wajib buat bikin computer virtual ini karena selain sebagai kurikulum tambahan dari kurikulum Cambridge juga nantinya computer virtual ini digunakan sebagai media penyimpanan tugas-tugas kita sampai semester 2.  So.. otomatis ntar akhir semester 2, computer virtual ini akan dikumpulkan dalam bentuk DVD. 

The World Wide Web, abbreviated as WWW and commonly known as the Web, is a system of interlinked hypertext documents accessed via the Internet. With a web browser, one can view web pages that may contain text, images, videos, and other multimedia and navigate between them by using hyperlinks. Using concepts from earlier hypertext systems, English engineer and computer scientist Sir Tim Berners-Lee, now the Director of the World Wide Web Consortium, wrote a proposal in March 1989 for what would eventually become the World Wide Web.^[1] At CERN in Geneva, Switzerland, Berners-Lee and Belgian computer scientist Robert Cailliau proposed in 1990 to use "HyperText [...] to link and access information of various kinds as a web of nodes in which the user can browse at will", and publicly introduced the project in December.
"The World-Wide Web (W3) was developed to be a pool of human knowledge, and human culture, which would allow collaborators in remote sites to share their ideas and all aspects of a common project."

1 History 2 Function 2.1 Linking 2.2 Dynamic updates of web pages 2.3 WWW prefix 3 Privacy 4 Security 5 Standards 6 Accessibility 7 Internationalization 8 Statistics 9 Speed issues 10 Caching 11 See also 12 Notes 13 References 14 External links

History

Main article: History of the World Wide Web

Arthur C. Clarke predicted in Popular Science in May 1970 that satellites would one day "bring the accumulated knowledge of the world to our fingertips" using an office console that would combine the functionality of the xerox, telephone, TV and a small computer so as to allow both data transfer and video conferencing around the globe.
In March 1989, Tim Berners-Lee wrote a proposal that referenced ENQUIRE, a database and software project he had built in 1980, and described a more elaborate information management system.
With help from Robert Cailliau, he published a more formal proposal (on November 12, 1990) to build a "Hypertext project" called "WorldWideWeb" (one word, also "W3") as a "web" of "hypertext documents" to be viewed by "browsers" using a client–server architecture. This proposal estimated that a read-only web would be developed within three months and that it would take six months to achieve "the creation of new links and new material by readers, [so that] authorship becomes universal" as well as "the automatic notification of a reader when new material of interest to him/her has become available." See Web 2.0 and RSS/Atom, which have taken a little longer to mature.
The proposal had been modeled after the Dynatext SGML reader by Electronic Book Technology, a spin-off from the Institute for Research in Information and Scholarship at Brown University. The Dynatext system, licensed by CERN, was technically advanced and was a key player in the extension of SGML ISO 8879:1986 to Hypermedia within HyTime, but it was considered too expensive and had an inappropriate licensing policy for use in the general high energy physics community, namely a fee for each document and each document alteration.
A NeXT Computer was used by Berners-Lee as the world's first web server and also to write the first web browser, WorldWideWeb, in 1990. By Christmas 1990, Berners-Lee had built all the tools necessary for a working Web:the first web browser (which was a web editor as well); the first web server; and the first web pages, which described the project itself. On August 6, 1991, he posted a short summary of the World Wide Web project on the alt.hypertext newsgroup. This date also marked the debut of the Web as a publicly available service on the Internet. The first server outside Europe was set up at SLAC to host the SPIRES-HEP database. Accounts differ substantially as to the date of this event. The World Wide Web Consortium says December 1992,^[10] whereas SLAC itself claims 1991.^[11][12] This is supported by a W3C document entitled A Little History of the World Wide Web.^[13]
The crucial underlying concept of hypertext originated with older projects from the 1960s, such as the Hypertext Editing System (HES) at Brown University, Ted Nelson's Project Xanadu, and Douglas Engelbart's oN-Line System (NLS). Both Nelson and Engelbart were in turn inspired by Vannevar Bush's microfilm-based "memex", which was described in the 1945 essay "As We May Think".^{[citation needed]}
Berners-Lee's breakthrough was to marry hypertext to the Internet. In his book Weaving The Web, he explains that he had repeatedly suggested that a marriage between the two technologies was possible to members of both technical communities, but when no one took up his invitation, he finally tackled the project himself. In the process, he developed a system of globally unique identifiers for resources on the Web and elsewhere: the Universal Document Identifier (UDI), later known as Uniform Resource Locator (URL) and Uniform Resource Identifier (URI); the publishing language HyperText Markup Language (HTML); and the Hypertext Transfer Protocol (HTTP).^[14]
The World Wide Web had a number of differences from other hypertext systems that were then available. The Web required only unidirectional links rather than bidirectional ones. This made it possible for someone to link to another resource without action by the owner of that resource. It also significantly reduced the difficulty of implementing web servers and browsers (in comparison to earlier systems), but in turn presented the chronic problem of link rot. Unlike predecessors such as HyperCard, the World Wide Web was non-proprietary, making it possible to develop servers and clients independently and to add extensions without licensing restrictions. On April 30, 1993, CERN announced^[15] that the World Wide Web would be free to anyone, with no fees due. Coming two months after the announcement that the Gopher protocol was no longer free to use, this produced a rapid shift away from Gopher and towards the Web. An early popular web browser was ViolaWWW, which was based upon HyperCard.
Scholars generally agree that a turning point for the World Wide Web began with the introduction^[16] of the Mosaic web browser^[17] in 1993, a graphical browser developed by a team at the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign (NCSA-UIUC), led by Marc Andreessen. Funding for Mosaic came from the U.S. High-Performance Computing and Communications Initiative, a funding program initiated by the High Performance Computing and Communication Act of 1991, one of several computing developments initiated by U.S. Senator Al Gore.^[18] Prior to the release of Mosaic, graphics were not commonly mixed with text in web pages and the Web's popularity was less than older protocols in use over the Internet, such as Gopher and Wide Area Information Servers (WAIS). Mosaic's graphical user interface allowed the Web to become, by far, the most popular Internet protocol.
The World Wide Web Consortium (W3C) was founded by Tim Berners-Lee after he left the European Organization for Nuclear Research (CERN) in October, 1994. It was founded at the Massachusetts Institute of Technology Laboratory for Computer Science (MIT/LCS) with support from the Defense Advanced Research Projects Agency (DARPA), which had pioneered the Internet; a year later, a second site was founded at INRIA (a French national computer research lab) with support from the European Commission DG InfSo; and in 1996, a third continental site was created in Japan at Keio University. By the end of 1994, while the total number of websites was still minute compared to present standards, quite a number of notable websites were already active, many of which are the precursors or inspiration for today's most popular services.
Connected by the existing Internet, other websites were created around the world, adding international standards for domain names and HTML. Since then, Berners-Lee has played an active role in guiding the development of web standards (such as the markup languages in which web pages are composed), and in recent years has advocated his vision of a Semantic Web. The World Wide Web enabled the spread of information over the Internet through an easy-to-use and flexible format. It thus played an important role in popularizing use of the Internet.Although the two terms are sometimes conflated in popular use, World Wide Web is not synonymous with Internet. The Web is an application built on top of the Internet.

Function

The terms Internet and World Wide Web are often used in every-day speech without much distinction. However, the Internet and the World Wide Web are not one and the same. The Internet is a global system of interconnected computer networks. In contrast, the Web is one of the services that runs on the Internet. It is a collection of interconnected documents and other resources, linked by hyperlinks and URLs. In short, the Web is an application running on the Internet. Viewing a web page on the World Wide Web normally begins either by typing the URL of the page into a web browser, or by following a hyperlink to that page or resource. The web browser then initiates a series of communication messages, behind the scenes, in order to fetch and display it.
First, the server-name portion of the URL is resolved into an IP address using the global, distributed Internet database known as the Domain Name System (DNS). This IP address is necessary to contact the Web server. The browser then requests the resource by sending an HTTP request to the Web server at that particular address. In the case of a typical web page, the HTML text of the page is requested first and parsed immediately by the web browser, which then makes additional requests for images and any other files that complete the page image. Statistics measuring a website's popularity are usually based either on the number of page views or associated server 'hits' (file requests) that take place.
While receiving these files from the web server, browsers may progressively render the page onto the screen as specified by its HTML, Cascading Style Sheets (CSS), or other page composition languages. Any images and other resources are incorporated to produce the on-screen web page that the user sees. Most web pages contain hyperlinks to other related pages and perhaps to downloadable files, source documents, definitions and other web resources. Such a collection of useful, related resources, interconnected via hypertext links is dubbed a web of information. Publication on the Internet created what Tim Berners-Lee first called the WorldWideWeb (in its original CamelCase, which was subsequently discarded) in November 1990.

Over time, many web resources pointed to by hyperlinks disappear, relocate, or are replaced with different content. This makes hyperlinks obsolete, a phenomenon referred to in some circles as link rot and the hyperlinks affected by it are often called dead links. The ephemeral nature of the Web has prompted many efforts to archive web sites. The Internet Archive, active since 1996, is one of the best-known efforts.

Dynamic updates of web pages

Main article: Ajax (programming)

JavaScript is a scripting language that was initially developed in 1995 by Brendan Eich, then of Netscape, for use within web pages.The standardized version is ECMAScript.To overcome some of the limitations of the page-by-page model described above, some web applications also use Ajax (asynchronous JavaScript and XML). JavaScript is delivered with the page that can make additional HTTP requests to the server, either in response to user actions such as mouse-clicks, or based on lapsed time. The server's responses are used to modify the current page rather than creating a new page with each response. Thus the server only needs to provide limited, incremental information. Since multiple Ajax requests can be handled at the same time, users can interact with a page even while data is being retrieved. Some web applications regularly poll the server to ask if new information is available.

WWW prefix

Many domain names used for the World Wide Web begin with www because of the long-standing practice of naming Internet hosts (servers) according to the services they provide. The hostname for a web server is often www, as it is ftp for an FTP server, and news or nntp for a USENET news server. These host names appear as Domain Name System (DNS) subdomain names, as in www.example.com. The use of such subdomain names is not required by any technical or policy standard; indeed, the first ever web server was called nxoc01.cern.cand many web sites exist without a www subdomain but most established websites prefer to use them, or they use some other name such as "www2", "secure", etc. Most web servers are set up such that both the domain root (e.g., example.com) and the www subdomain (e.g., www.example.com) refer to the same site; others require one form or the other, or they may map to different web sites.
www is a very useful tool for load-balancing incoming web traffic by creating a CNAME_record that point to a cluster of load balancing servers. Since only a subdomain can be cname'ed the same result can not be achieved by using just the domain root.
When a user submits an incomplete website address to a web browser in its address bar input field, some web browsers automatically try adding the prefix "www" to the beginning of it and possibly ".com", ".org" and ".net" at the end, depending on what might be missing. For example, entering 'microsoft' may be transformed to http://www.microsoft.com/ and 'openoffice' to http://www.openoffice.org. This feature started appearing in early versions of Mozilla Firefox, when it still had the working title 'Firebird' in early 2003. It is reported that Microsoft was granted a US patent for the same idea in 2008, but only for mobile devices.
The scheme specifier (http:// or https://) in URIs refer to the Hypertext Transfer Protocol and to HTTP Secure and so define the communication protocol to be used for the request and response. The HTTP protocol is fundamental to the operation of the World Wide Web, and the encryption involved in HTTPS adds an essential layer if confidential information such as passwords or banking information are to be exchanged over the public Internet. Web browsers usually prepend this scheme to URLs too, if omitted. Berners-Lee has acknowledged that the two forward slashes (//) were originally unnecessary.
In overview, RFC 2396 defines Uniform Resource Indicators to have the following form:

<scheme>://<authority><path>?<query>#<fragment>

Here <authority> is for example the web server (e.g., www.example.com), <path> identifies the web page on that server, from just '/' for the root page to longer paths in the form common on Unix-like operating systems. The web server processes the <query>, which can be data sent via a form, e.g., terms sent to a search engine, and the returned page present the result. Finally, <fragment> is not sent to the web server. It identifies a tag to which the browser positions the page.
In English, www is pronounced by individually pronouncing the name of characters (double-u double-u double-u). Although some technical users pronounce it dub-dub-dub this is not widespread. The English writer Douglas Adams once quipped in The Independent on Sunday (1999): "The World Wide Web is the only thing I know of whose shortened form takes three times longer to say than what it's short for," with Stephen Fry later pronouncing it in his "Podgrammes" series of podcasts as "wuh wuh wuh." In Mandarin Chinese, World Wide Web is commonly translated via a phono-semantic matching to wàn wéi wǎng (万维网), which satisfies www and literally means "myriad dimensional net", a translation that very appropriately reflects the design concept and proliferation of the World Wide Web. Tim Berners-Lee's web-space states that World Wide Web is officially spelled as three separate words, each capitalized, with no intervening hyphens.

Privacy

Computer users, who save time and money, and who gain conveniences and entertainment, may or may not have surrendered the right to privacy in exchange for using a number of technologies including the Web. Worldwide, more than a half billion people have used a social network service,and of Americans who grew up with the Web, half created an online profile and are part of a generational shift that could be changing norms. Facebook progressed from U.S. college students to a 70% non-U.S. audience, and in 2009 estimated that only 20% of its members use privacy settings In 2010 (six years after co-founding the company), Mark Zuckerberg wrote, "we will add privacy controls that are much simpler to use".
Privacy representatives from 60 countries have resolved to ask for laws to complement industry self-regulation, for education for children and other minors who use the Web, and for default protections for users of social networks. They also believe data protection for personally identifiable information benefits business more than the sale of that information.Users can opt-in to features in browsers to clear their personal histories locally and block some cookies and advertising networks but they are still tracked in websites' server logs, and particularly web beacons. Berners-Lee and colleagues see hope in accountability and appropriate use achieved by extending the Web's architecture to policy awareness, perhaps with audit logging, reasoners and appliances.
In exchange for providing free content, vendors hire advertisers who spy on Web users and base their business model on tracking them.Since 2009, they buy and sell consumer data on exchanges (lacking a few details that could make it possible to de-anonymize, or identify an individual). Hundreds of millions of times per day, Lotame Solutions captures what users are typing in real time, and sends that text to OpenAmplify who then tries to determine, to quote a writer at The Wall Street Journal, "what topics are being discussed, how the author feels about those topics, and what the person is going to do about them".
Microsoft backed away in 2008 from its plans for strong privacy features in Internet Explorer, leaving its users (60% of the world's Web users) open to advertisers who may make assumptions about them based on only one click when they visit a websit Among services paid for by advertising, Yahoo! could collect the most data about users of commercial websites, about 2,500 bits of information per month about each typical user of its site and its affiliated advertising network sites. Yahoo! was followed by MySpace with about half that potential and then by AOL–TimeWarner, Google, Facebook, Microsoft, and eBay.

Security

The Web has become criminals' preferred pathway for spreading malware. Cybercrime carried out on the Web can include identity theft, fraud, espionage and intelligence gathering. Web-based vulnerabilities now outnumber traditional computer security concerns,and as measured by Google, about one in ten web pages may contain malicious code. Most Web-based attacks take place on legitimate websites, and most, as measured by Sophos, are hosted in the United States, China and Russia. The most common of all malware threats is SQL injection attacks against websites.Through HTML and URIs the Web was vulnerable to attacks like cross-site scripting (XSS) that came with the introduction of JavaScri and were exacerbated to some degree by Web 2.0 and Ajax web design that favors the use of scripts. Today by one estimate, 70% of all websites are open to XSS attacks on their users.
Proposed solutions vary to extremes. Large security vendors like McAfee already design governance and compliance suites to meet post-9/11 regulations, and some, like Finjan have recommended active real-time inspection of code and all content regardless of its source.Some security vendors like Commtouch monitor new threats and provide reporting tools for malware outbreaks, spam, and zombie trends along with real-time outbreak monitors.
Some have argued that for enterprise to see security as a business opportunity rather than a cost center,"ubiquitous, always-on digital rights management" enforced in the infrastructure by a handful of organizations must replace the hundreds of companies that today secure data and networks. Jonathan Zittrain has said users sharing responsibility for computing safety is far preferable to locking down the Internet.

Standards

Main article: Web standards

Many formal standards and other technical specifications and software define the operation of different aspects of the World Wide Web, the Internet, and computer information exchange. Many of the documents are the work of the World Wide Web Consortium (W3C), headed by Berners-Lee, but some are produced by the Internet Engineering Task Force (IETF) and other organizations.
Usually, when web standards are discussed, the following publications are seen as foundational:

• Recommendations for markup languages, especially HTML and XHTML, from the W3C. These define the structure and interpretation of hypertext documents.
• Recommendations for stylesheets, especially CSS, from the W3C.
• Standards for ECMAScript (usually in the form of JavaScript), from Ecma International.
• Recommendations for the Document Object Model, from W3C.

Additional publications provide definitions of other essential technologies for the World Wide Web, including, but not limited to, the following:

• Uniform Resource Identifier (URI), which is a universal system for referencing resources on the Internet, such as hypertext documents and images. URIs, often called URLs, are defined by the IETF's RFC 3986 / STD 66: Uniform Resource Identifier (URI): Generic Syntax, as well as its predecessors and numerous URI scheme-defining RFCs;
• HyperText Transfer Protocol (HTTP), especially as defined by RFC 2616: HTTP/1.1 and RFC 2617: HTTP Authentication, which specify how the browser and server authenticate each other.

Accessibility

Main article: Web accessibility

Access to the Web is for everyone regardless of disability including visual, auditory, physical, speech, cognitive, or neurological. Accessibility features also help others with temporary disabilities like a broken arm or the aging population as their abilities change.^[62] The Web is used for receiving information as well as providing information and interacting with society, making it essential that the Web be accessible in order to provide equal access and equal opportunity to people with disabilities.^[63] Tim Berners-Lee once noted, "The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect."^[62] Many countries regulate web accessibility as a requirement for websites.^[64] International cooperation in the W3C Web Accessibility Initiative led to simple guidelines that web content authors as well as software developers can use to make the Web accessible to persons who may or may not be using assistive technology.^[62][65]

Internationalization

The W3C Internationalization Activity assures that web technology will work in all languages, scripts, and cultures.^[66] Beginning in 2004 or 2005, Unicode gained ground and eventually in December 2007 surpassed both ASCII and Western European as the Web's most frequently used character encoding.^[67] Originally RFC 3986 allowed resources to be identified by URI in a subset of US-ASCII. RFC 3987 allows more characters—any character in the Universal Character Set—and now a resource can be identified by IRI in any language.^[68]

[edit] Statistics

According to a 2001 study, there were massively more than 550 billion documents on the Web, mostly in the invisible Web, or deep Web.^[69] A 2002 survey of 2,024 million Web pages^[70] determined that by far the most Web content was in English: 56.4%; next were pages in German (7.7%), French (5.6%), and Japanese (4.9%). A more recent study, which used Web searches in 75 different languages to sample the Web, determined that there were over 11.5 billion Web pages in the publicly indexable Web as of the end of January 2005.^[71] As of March 2009^[update], the indexable web contains at least 25.21 billion pages.^[72] On July 25, 2008, Google software engineers Jesse Alpert and Nissan Hajaj announced that Google Search had discovered one trillion unique URLs.^[73] As of May 2009^[update], over 109.5 million websites operated.^[74] Of these 74% were commercial or other sites operating in the .com generic top-level domain.^[74]

Speed issues

Frustration over congestion issues in the Internet infrastructure and the high latency that results in slow browsing has led to a pejorative name for the World Wide Web: the World Wide Wait.^[75] Speeding up the Internet is an ongoing discussion over the use of peering and QoS technologies. Other solutions to reduce the congestion can be found at W3C.^[76] Standard guidelines for ideal Web response times are:^[77]

• 0.1 second (one tenth of a second). Ideal response time. The user doesn't sense any interruption.
• 1 second. Highest acceptable response time. Download times above 1 second interrupt the user experience.
• 10 seconds. Unacceptable response time. The user experience is interrupted and the user is likely to leave the site or system.

Caching

If a user revisits a Web page after only a short interval, the page data may not need to be re-obtained from the source Web server. Almost all web browsers cache recently obtained data, usually on the local hard drive. HTTP requests sent by a browser will usually only ask for data that has changed since the last download. If the locally cached data are still current, it will be reused. Caching helps reduce the amount of Web traffic on the Internet. The decision about expiration is made independently for each downloaded file, whether image, stylesheet, JavaScript, HTML, or whatever other content the site may provide. Thus even on sites with highly dynamic content, many of the basic resources only need to be refreshed occasionally. Web site designers find it worthwhile to collate resources such as CSS data and JavaScript into a few site-wide files so that they can be cached efficiently. This helps reduce page download times and lowers demands on the Web server.
There are other components of the Internet that can cache Web content. Corporate and academic firewalls often cache Web resources requested by one user for the benefit of all. (See also Caching proxy server.) Some search engines also store cached content from websites. Apart from the facilities built into Web servers that can determine when files have been updated and so need to be re-sent, designers of dynamically generated Web pages can control the HTTP headers sent back to requesting users, so that transient or sensitive pages are not cached. Internet banking and news sites frequently use this facility. Data requested with an HTTP 'GET' is likely to be cached if other conditions are met; data obtained in response to a 'POST' is assumed to depend on the data that was POSTed and so is not cached.