Dial-up Internet access is a form of Internet access that uses the facilities of the public switched telephone network (PSTN) to establish a connection to an Internet service provider (ISP) by dialing a telephone number on a conventional telephone line. The user's computer orrouter uses an attached modem to encode and decode information into and from audio frequency signals, respectively. Despite the proliferation of high-speed Internet access (broadband), dial-up Internet access may be used where other forms are not available or the cost is too high, such as in some rural or remote areas.

Dial-up Internet has been around since the 1980s via public providers such as NSFNET-linked universities and was first offered 

In computer networks and telecommunications, a dedicated line is a communications cable or other facility dedicated to a specific application, in contrast with a shared resourcesuch as the telephone network or the Internet.

In practice, such services may not be provided by a single, discrete, end-to-end cable, but they do provide guarantees of constant bandwidth availability and near-constantlatency, properties that cannot be guaranteed for more public systems. Such properties add a considerable premium to the price charged.

As more general-purpose systems have improved, dedicated lines have been steadily replaced by intranets and the public Internet, but they are still useful for time-critical, high-bandwidth applications such as video transmission.

"Database Software" redirects here. For the computer program, see Europress.

A database is an organized collection of data.^[1] It is the collection of schemas, tables, queries, reports, views and other objects. The data is typically organized to model aspects of reality in a way that supports processes requiring information, such as modelling the availability of rooms in hotels in a way that supports finding a hotel with vacancies.

A database management system (DBMS) is a computer software application that interacts with the user, other applications, and the database itself to capture and analyze data. A general-purpose DBMS is designed to allow the definition, creation, querying, update, and administration of databases. Well-known DBMSs include MySQL, PostgreSQL,Microsoft SQL Server, Oracle, Sybase and IBM DB2. A database is not generally portable across different DBMSs, but different DBMS can interoperate by using standards such as SQL and ODBC or JDBC to allow a single application to work with more than one DBMS. Database management systems are often classified according to the database modelthat they support; the most popular database systems since the 1980s have all supported the relational model as represented by the SQL language.^{[disputed – discuss]} Sometimes a 

Cyberspace is "the notional environment in which communication over computer networks occurs."^[1] The word became popular in the 1990s when the uses of the Internet, networking, and digital communication were all growing dramatically and the term "cyberspace" was able to represent the many new ideas and phenomena that were emerging.^[2]

The parent term of cyberspace is "cybernetics", derived from the Ancient Greek κυβερνήτης (kybernētēs, steersman, governor, pilot, or rudder), a word introduced by Norbert Wiener for his pioneering work in electronic communication and control science.

As a social experience, individuals can interact, exchange ideas, share information, provide social support, conduct business, direct actions, create artistic media, play games, engage in political discussion, and so on, using this global network. They are sometimes referred to as cybernauts. The term cyberspace has become a conventional means to describe anything associated with the Internetand the diverse Internet culture. The United States government recognizes the interconnected information technology and the interdependent network of information technology infrastructures operating across this medium as part of the US national critical infrastructure. Amongst individuals on cyberspace, there is believed to be a code of shared rules and ethics mutually beneficial for all to follow, referred to as cyberethics. Many view the right to privacy as most important to a functional code of cyberethics.^[3] Such moral responsibilities go hand in hand when working online with global networks, specifically, when opinions are involved with online social experiences.^[4]

According to Chip Morningstar and F. Randall Farmer, cyberspace is defined more by the social interactions involved rather than its technical implementation.^[5] In their view, the computational medium in cyberspace is an augmentation of the communication channel between real people; the core characteristic of cyberspace is that it offers an environment that consists of many participants with the ability to affect and influence each other. They derive this concept from the observation that people seek richness, complexity, and depth within a virtual world.

An HTTP cookie (also called web cookie, Internet cookie, browser cookie or simply cookie), is a small piece of data sent from a website and stored in the user's web browser while the user is browsing it. Every time the user loads the website, the browser sends the cookie back to the server to notify the user's previous activity.^[1] Cookies were designed to be a reliable mechanism for websites to remember stateful information (such as items added in the shopping cart in an online store) or to record the user's browsing activity (including clicking particular buttons, logging in, or recording which pages were visited in the past). Cookies can also store passwords and form content a user has previously entered, such as a credit card number or an address.

The tracking cookies, and especially third-party tracking cookies, are commonly used as ways to compile long-term records of individuals' browsing histories – a potential privacy concern that prompted European^[2] and U.S. law makers to take action in 2011.^[3][4]

Other kinds of cookies perform essential functions in the modern web. Perhaps most importantly, authentication cookies are the most common method used by web servers to know whether the user is logged in or not, and which account they are logged in with. Without such a mechanism, the site would not know whether to send a page containing sensitive information, or require the user to authenticate themselves by logging in. The security of an authentication cookie generally depends on the security of the issuing website and the user's web browser, and on whether the cookie data is encrypted. Security vulnerabilities may allow a cookie's data to be read by a hacker, used to gain access to user data, or used to gain access (with the user's credentials) to the website to which the cookie belongs (see cross-site scripting and cross-site request forgery for 

The term chat room, or chatroom, is primarily used to describe any form of synchronous conferencing, occasionally even asynchronous conferencing. The term can thus mean any technology ranging from real-time online chat and online interaction with strangers (e.g., online forums) to fully immersive graphical social environments.

The primary use of a chat room is to share information via text with a group of other users. Generally speaking, the ability to converse with multiple people in the same conversation differentiates chat rooms from instant messaging programs, which are more typically designed for one-to-one communication. The users in a particular chat room are generally connected via a shared interest or other similar connection, and chat rooms exist catering for a wide range of subjects. New technology has enabled the use of file sharing and webcams to be included in some programs. This can be considered a chat room.

Real-time communication between two users via computer. Once a chat has been initiated, either user can enter text by typing on thekeyboard and the entered text will appear on the other user'smonitor. Most networks and online services offer a chat feature.

A typical chain letter consists of a message that attempts to convince the recipient to make a number of copies of the letter and then pass them on to as many recipients as possible. In reality, the "chain" is actually a geometrically progressing pyramid that cannot be sustained indefinitely. Common methods used in chain letters include emotionally manipulative stories, get-rich-quick pyramid schemes, and the exploitation of superstition to threaten the recipient with bad luck or even physical violence or death if he or she "breaks the chain" and refuses to adhere to the conditions set out in the letter. Chain letters started as actual letters that one received in the mail. Today, chain letters are generally no longer actual letters. They are sent through email messages, postings on social network sites, and text messages.

There are two main types of chain letters:

1. Hoaxes - Hoaxes attempt to trick or defraud users. A hoax could be malicious, instructing users to delete a file necessary to the operating system by claiming it is a virus. It could also be a scam that convinces users to send money or personal information. Phishing attacks could fall into this.
2. Urban legends - Urban legends are designed to be redistributed and usually warn users of a threat or claim to be notifying them of important or urgent information. Another common form are the emails that promise users monetary rewards for forwarding the message or suggest that they are signing something that will be submitted to a particular group. Urban legends usually have no negative effect aside from wasted time.

In the United States, chain letters that request money or other items of value and promise a substantial return to the participants (such as the infamous Make Money Fast scheme) are illegal.^[1]

Some colleges and military bases have passed regulations stating that in the private mail of college students and military personnel, respectively, chain letters are not authorized and will be thrown out. However, it is often difficult to distinguish chain letters from genuine correspondence.

In most computer systems, a byte is a unit of data that is eight binary digits long. A byte is the unit most computers use to represent a character such as a letter, number, or typographic symbol (for example, "g", "5", or "?"). A byte can also hold a string of bits that need to be used in some larger unit for application purposes (for example, the stream of bits that constitute a visual image for a program that displays images or the string of bits that constitutes the machine code of a computer program).

A software bug is an error, flaw, failure, or fault in a computer program or system that causes it to produce an incorrect or unexpected result, or to behave in unintended ways. Most bugs arise from mistakes and errors made by people in either a program'ssource code or its design, or in frameworks and operating systems used by such programs, and a few are caused by compilersproducing incorrect code. A program that contains a large number of bugs, and/or bugs that seriously interfere with its functionality, is said to be buggy or defective. Reports detailing bugs in a program are commonly known as bug reports, defect reports, fault reports, problem reports, trouble reports, change requests, and so forth.

Bugs trigger errors that can in turn have a wide variety of ripple effects, with varying levels of inconvenience to the user of the program. Some bugs have only a subtle effect on the program's functionality, and may thus lie undetected for a long time. More serious bugs may cause the program to crash or freeze. Others qualify as security bugs and might for example enable a malicious user to bypass access controls in order to obtain unauthorized privileges.

The results of bugs may be extremely serious. Bugs in the code controlling the Therac-25 radiation therapy machine were directly responsible for some patient deaths in the 1980s. In 1996, the European Space Agency's US$1 billion prototype Ariane 5 rocket had to be destroyed less than a minute after launch, due to a bug in the on-board guidance computer program. In June 1994, a Royal Air Force Chinook helicopter crashed into the Mull of Kintyre, killing 29. This was initially dismissed as pilot error, but an investigation byComputer Weekly uncovered sufficient evidence to convince a House of Lords inquiry that it may have been caused by a software bug in the aircraft's engine control computer.^[1]

In 2002, a study commissioned by the US Department of Commerce' National Institute of Standards and Technology concluded that "software bugs, or errors, are so prevalent and so detrimental that they cost the US economy an estimated $59 billion annually, or about 0.6 percent of the gross domestic product".^[2]

Bounce rate (sometimes confused with exit rate)^[1] is an Internet marketing term used in web traffic analysis. It represents the percentage of visitors who enter the site and then leave ("bounce") rather than continuing on to view other pages within the same site.

Bounce rate is a measure of the effectiveness of a website in encouraging visitors to continue with their visit. It is expressed as a percentage and represents the proportion of visits that end on the first page of the website that the visitor sees.^[2]

"Favorites" redirects here. For other uses, see Favorites (disambiguation).

The bookmarks menu in Mozilla Firefox—both a live (Wikinews) and a static (Wikipedia) bookmark are depicted.

In the context of the World Wide Web, a bookmark is a Uniform Resource Identifier (URI) that is stored for later retrieval in any of various storage formats. All modern web browsers include bookmark features.^{[citation needed]} Bookmarks are calledfavorites or Internet shortcuts in Internet Explorer, and by virtue of that browser's large market share, these terms have been synonymous with bookmark since the first browser war.^[1] Bookmarks are normally accessed through a menu in the user's web browser, and folders are commonly used for organization. In addition to bookmarking methods within most browsers, many external applications offer bookmark management.

Bookmarks have been incorporated in browsers since the Mosaic browser in 1993.^[2] Bookmark lists were called Hotlists in Mosaic^[3] and in previous versions of Opera; this term has faded from common use. Other early web browsers such asViolaWWW and Cello also had bookmarking features.

With the advent of social bookmarking, shared bookmarks have become a means for users sharing similar interests to pool web resources, or to store their bookmarks in such a way that they are not tied to one specific computer or browser. Web-based bookmarking services let users save bookmarks on a remote web server, accessible from anywhere.

Newer browsers have expanded the "bookmark" feature to include variations on the concept of saving links. Mozilla Firefox introduced live bookmarks in 2004,^[4] which resemble standard bookmarks but contain a list of links to recent articles supplied by a news site or weblog, which is regularly updated via RSS feeds. "Bookmarklets" are JavaScriptprograms stored as bookmarks that can be clicked to perform a function.

For other uses, see Bitmap (disambiguation).

In computing, a bitmap is a mapping from some domain (for example, a range of integers) to bits, that is, values which are zero or one. It is also called a bit array or bitmap index.

Bitmap image downsampled from an Inkscape vectorial image

In computer graphics, when the domain is a rectangle (indexed by two coordinates) a bitmap gives a way to store a binary image, that is, an image in which each pixel is either black or white (or any two colors).

The more general term pixmap refers to a map of pixels, where each one may store more than two colors, thus using more than one bit per pixel. Often bitmap is used for this as well. In some contexts, the term bitmap implies one bit per pixel, while pixmap is used for images with multiple bits per pixel.^[1][2]

A bitmap is a type of memory organization or image file format used to store digital images. The term bitmap comes from the computer programming terminology, meaning just a map of bits, a spatially mapped array of bits. Now, along with pixmap, it commonly refers to the similar concept of a spatially mapped array of pixels. Raster images in general may be referred to as bitmaps or pixmaps, whether synthetic or photographic, in files or memory.

Many graphical user interfaces use bitmaps in their built-in graphics subsystems;^[3] for example, the Microsoft Windows and OS/2 platforms' GDI subsystem, where the specific format used is the Windows and OS/2 bitmap file format, usually named with the file extension of .BMP (or .DIB for device-independent bitmap). Besides BMP, other file formats that store literal bitmaps include InterLeaved Bitmap (ILBM), Portable Bitmap (PBM), X Bitmap (XBM), and Wireless Application Protocol Bitmap (WBMP). Similarly, most other image file formats, such as JPEG, TIFF, PNG, and GIF, also store bitmap images (as opposed to vector graphics), but they are not usually referred to as bitmaps, since they use compressed formats internally.

binary

In mathematics and digital electronics, a binary number is a number expressed in the binary numeral system or base-2 numeral system which represents numeric values using two different symbols: typically 0 (zero) and 1 (one). The base-2 system is apositional notation with a radix of 2. Because of its straightforward implementation in digital electronic circuitry using logic gates, the binary system is used internally by almost all modern computers and computer-based devices. Each digit is referred to as a bit.

For other uses, see Baud (disambiguation).

In telecommunication and electronics, baud (/ˈbɔːd/, unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second or pulses per second. It is the number of distinct symbol changes (signaling events) made to the transmission medium per second in a digitally modulated signal or a line code.

Digital data modem manufacturers commonly define the baud as the modulation rate of data transmission and express it as bits per second.^[1]

Baud is related to gross bit rate expressed as bits per second.

This article is about the concept in computing and networking. For use in signal and wireless communications, see Bandwidth (signal processing). For other uses, seeBandwidth (disambiguation).

In computing, bandwidth is the bit-rate of available or consumed information capacity expressed typically in metric multiples of bits per second. Variously, bandwidth may be characterized as network bandwidth,^[1] data bandwidth,^[2] or digital bandwidth.^[3][4]

This definition of bandwidth is in contrast to the field of signal processing, wireless communications, modem data transmission, digital communications, and electronics, in whichbandwidth is used to refer to analog signal bandwidth measured in hertz, meaning the frequency range between lowest and highest attainable frequency while meeting a well-defined impairment level in signal power.

However, the actual bit rate that can be achieved depends not only on the signal bandwidth, but also on the noise on the channel.

For other uses, see Archive (disambiguation).

For the Wikipedia coordination point on archived pages, see Wikipedia:Historical archive.

For details on how to archive a talk page, see Help:Archiving a talk page.

"Digital archive" redirects here. It is not to be confused with Digital library. For other uses, see digital archiving.

Shelved record boxes of an archive.

An archive is an accumulation of historical records or the physical place they are located.^[1] Archives contain primary source documents that have accumulated over the course of an individual or organization's lifetime, and are kept to show the function of that person or organization. Professional archivists and historians generally understand archives to be records that have been naturally and necessarily generated as a product of regular legal, commercial, administrative or social activities. They have been metaphorically defined as "the secretions of an organism",^[2] and are distinguished from documents that have been consciously written or created to communicate a particular message to posterity.

In general, archives consist of records that have been selected for permanent or long-term preservation on grounds of their enduring cultural, historical, or evidentiary value. Archival records are normally unpublished and almost always unique, unlike books or magazines for which many identical copies exist. This means that archives are quite distinct from libraries with regard to their functions and organization, although archival collections can often be found within library buildings.^[3]

A person who works in archives is called an archivist. The study and practice of organizing, preserving, and providing access to information and materials in archives is calledarchival science. The physical place of storage can be referred to as an archive (more usual in the UK), an archives (more usual in the USA), or a repository.^[4]

When referring to historical records or the places they are kept, the plural form archives is chiefly used.^[5] The computing use of the term 'archive' should not be confused with the record-keeping meaning of the term.

applet

In computing, an applet is any small application that performs one specific task that runs within the scope of a dedicated widget engine or a larger program, often as a plug-in.^[1][2] The term is frequently used to refer to a Java applet, a program written in the Java programming language that is designed to be placed on a web page. Applets are typical examples of transient and auxiliary applications that don't monopolize the user's attention. Applets are not full-featured application programs, and are intended to be easily accessible.



credited by owner 

anti virus

Antivirus" redirects here. For the antiviral medication, see Antiviral drug.

ClamTk, an open source antivirus based on theClamAV antivirus engine, originally developed by Tomasz Kojm in 2001.

Antivirus or anti-virus software (often abbreviated as AV), sometimes known as anti-malware software, is computer software used to prevent, detect and remove malicious software.

Antivirus software was originally developed to detect and remove computer viruses, hence the name. However, with the proliferation of other kinds of malware, antivirus software started to provide protection from other computer threats. In particular, modern antivirus software can protect from: malicious Browser Helper Objects (BHOs), browser hijackers,ransomware, keyloggers, backdoors, rootkits, trojan horses, worms, malicious LSPs, dialers, fraudtools, adware andspyware.^[1] Some products also include protection from other computer threats, such as infected and malicious URLs, spam,scam and phishing attacks, online identity (privacy), online banking attacks, social engineering techniques, Advanced 

credited by owner