1.
Computer security
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A vulnerability is a system susceptibility or flaw. Many vulnerabilities are documented in the Common Vulnerabilities and Exposures database, an exploitable vulnerability is one for which at least one working attack or exploit exists. They may exist for a number of reasons, including by original design or from poor configuration, denial of service attacks are designed to make a machine or network resource unavailable to its intended users. An unauthorized user gaining physical access to a computer is most likely able to copy data from it. They may also compromise security by making operating system modifications, installing software worms, keyloggers, even when the system is protected by standard security measures, these may be able to be by-passed by booting another operating system or tool from a CD-ROM or other bootable media. Disk encryption and Trusted Platform Module are designed to prevent these attacks, eavesdropping is the act of surreptitiously listening to a private conversation, typically between hosts on a network. For instance, programs such as Carnivore and NarusInsight have been used by the FBI, spoofing, in general, is a fraudulent or malicious practice in which communication is sent from an unknown source disguised as a source known to the receiver. Spoofing is most prevalent in communication mechanisms lack a high level of security. Tampering describes a malicious modification of products, so-called Evil Maid attacks and security services planting of surveillance capability into routers are examples. Privilege escalation describes a situation where an attacker with some level of restricted access is able to, without authorization, elevate their privileges or access level. So for example a computer user may be able to fool the system into giving them access to restricted data. Phishing is the attempt to acquire sensitive information such as usernames, passwords, phishing is typically carried out by email spoofing or instant messaging, and it often directs users to enter details at a fake website whose look and feel are almost identical to the legitimate one. Preying on a victims trust, phishing can be classified as a form of social engineering and this is done using multiple transparent or opaque layers. The attacker is basically hijacking the clicks meant for the top level page and routing them to some other irrelevant page, a similar technique can be used to hijack keystrokes. Social engineering aims to convince a user to disclose secrets such as passwords, card numbers, etc. by, for example, impersonating a bank, a common scam involves fake CEO emails sent to accounting and finance departments. In early 2016, the FBI reported that the scam has cost US businesses more than $2bn in about two years, Computer security is critical in almost any industry which uses computers. However, computers can be protected through well built software and hardware, by having strong internal interactions of properties, software complexity can prevent software crash and security failure. In-store payment systems and ATMs have also been tampered with in order to gather customer account data, computers control functions at many utilities, including coordination of telecommunications, the power grid, nuclear power plants, and valve opening and closing in water and gas networks
2.
Access control
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Security, access control is the selective restriction of access to a place or other resource. The act of accessing may mean consuming, entering, or using, permission to access a resource is called authorization. Locks and login credentials are two mechanisms of access control. Geographical access control may be enforced by personnel, or with a such as a turnstile. There may be fences to avoid circumventing this access control, an alternative of access control in the strict sense is a system of checking authorized presence, see e. g. Ticket controller. A variant is exit control, e. g. of a shop or a country, the term access control refers to the practice of restricting entrance to a property, a building, or a room to authorized persons. Physical access control can be achieved by a human, through means such as locks and keys. Within these environments, physical key management may also be employed as a means of managing and monitoring access to mechanically keyed areas or access to certain small assets. Physical access control is a matter of who, where, an access control system determines who is allowed to enter or exit, where they are allowed to exit or enter, and when they are allowed to enter or exit. Historically, this was accomplished through keys and locks. When a door is locked, only someone with a key can enter through the door, mechanical locks and keys do not allow restriction of the key holder to specific times or dates. Mechanical locks and keys do not provide records of the key used on any specific door, when a mechanical key is lost or the key holder is no longer authorized to use the protected area, the locks must be re-keyed. Electronic access control uses computers to solve the limitations of mechanical locks, a wide range of credentials can be used to replace mechanical keys. The electronic access control system grants access based on the credential presented, when access is granted, the door is unlocked for a predetermined time and the transaction is recorded. When access is refused, the door locked and the attempted access is recorded. The system will monitor the door and alarm if the door is forced open or held open too long after being unlocked. When a credential is presented to a reader, the reader sends the information, usually a number, to a control panel. The control panel compares the number to an access control list, grants or denies the presented request
3.
Computer
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A computer is a device that can be instructed to carry out an arbitrary set of arithmetic or logical operations automatically. The ability of computers to follow a sequence of operations, called a program, such computers are used as control systems for a very wide variety of industrial and consumer devices. The Internet is run on computers and it millions of other computers. Since ancient times, simple manual devices like the abacus aided people in doing calculations, early in the Industrial Revolution, some mechanical devices were built to automate long tedious tasks, such as guiding patterns for looms. More sophisticated electrical machines did specialized analog calculations in the early 20th century, the first digital electronic calculating machines were developed during World War II. The speed, power, and versatility of computers has increased continuously and dramatically since then, conventionally, a modern computer consists of at least one processing element, typically a central processing unit, and some form of memory. The processing element carries out arithmetic and logical operations, and a sequencing, peripheral devices include input devices, output devices, and input/output devices that perform both functions. Peripheral devices allow information to be retrieved from an external source and this usage of the term referred to a person who carried out calculations or computations. The word continued with the same meaning until the middle of the 20th century, from the end of the 19th century the word began to take on its more familiar meaning, a machine that carries out computations. The Online Etymology Dictionary gives the first attested use of computer in the 1640s, one who calculates, the Online Etymology Dictionary states that the use of the term to mean calculating machine is from 1897. The Online Etymology Dictionary indicates that the use of the term. 1945 under this name, theoretical from 1937, as Turing machine, devices have been used to aid computation for thousands of years, mostly using one-to-one correspondence with fingers. The earliest counting device was probably a form of tally stick, later record keeping aids throughout the Fertile Crescent included calculi which represented counts of items, probably livestock or grains, sealed in hollow unbaked clay containers. The use of counting rods is one example, the abacus was initially used for arithmetic tasks. The Roman abacus was developed from used in Babylonia as early as 2400 BC. Since then, many forms of reckoning boards or tables have been invented. In a medieval European counting house, a checkered cloth would be placed on a table, the Antikythera mechanism is believed to be the earliest mechanical analog computer, according to Derek J. de Solla Price. It was designed to calculate astronomical positions and it was discovered in 1901 in the Antikythera wreck off the Greek island of Antikythera, between Kythera and Crete, and has been dated to circa 100 BC
4.
Identity document
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An identity document is any document which may be used to prove a persons identity. If issued in a small, standard credit card size form, some countries issue formal identity documents, while others may require identity verification using informal documents. When the identity document incorporates a persons photograph, it may be called photo ID, in the absence of a formal identity document, a drivers license may be accepted in many countries for identity verification. Some countries do not accept drivers licenses for identification, often because in countries they do not expire as documents. Most countries accept passports as a form of identification, some countries require all people to have an identity document available at any time. Many countries require all foreigners to have a passport or occasionally a national identity card from their country available at any time if they do not have a permit in the country. The identity document is used to connect a person to information about the person, the photo and the possession of it is used to connect the person with the document. A unique national identification number is the most secure way, a version of the passport considered to be the earliest identity document inscribed into law was introduced by King Henry V of England with the Safe Conducts Act 1414. For the next 500 years and before World War I, most people did not have or need an identity document, both Australia and Great Britain, for example, introduced the requirement for a photographic passport in 1915 after the so-called Lody spy scandal. The shape and size of identity cards were standardized in 1985 by ISO/IEC7810, some modern identity documents are smart cards including a difficult-to-forge embedded integrated circuit, that were standardized in 1988 by ISO/IEC7816. New technologies allow identity cards to contain information, such as photographs, face, hand or iris measurements. Electronic identity cards are available in countries including Belgium, Croatia, Estonia, Finland, Guatemala, Hong Kong, Malaysia, Morocco, Portugal. Law enforcement officials claim that identity cards make surveillance and the search for criminals easier, in countries that dont have a national identity card, there is, however, concern about the projected large costs and potential abuse of high-tech smartcards. There is debate in these countries about whether such cards and their centralised database would constitute an infringement of privacy, most criticism is directed towards the enhanced possibilities of extensive abuse of centralised and comprehensive databases storing sensitive data. None of the countries listed above mandate possession of identity documents, for example, all vehicle drivers must have a driving licence, and young people may need to use specially issued proof of age cards when purchasing alcohol. Arguments for identity documents as such, In order to avoid mismatching people, Every human being already carries their own personal identification in the form of DNA, which is extremely hard to falsify or to discard. For example, in Sweden private companies such as banks refused to issue ID cards to individuals without a Swedish card and this forced the government to start issuing national cards. It is also hard to control information usage by private companies
5.
Authentication
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Authentication is the act of confirming the truth of an attribute of a single piece of data claimed true by an entity. In other words, authentication often involves verifying the validity of at least one form of identification, Authentication is relevant to multiple fields. In art, antiques and anthropology, a problem is verifying that a given artifact was produced by a certain person or in a certain place or period of history. In computer science, verifying a persons identity is required to allow access to confidential data or systems. With autographed sports memorabilia, this could involve someone attesting that they witnessed the object being signed, a vendor selling branded items implies authenticity, while he or she may not have evidence that every step in the supply chain was authenticated. The second type of authentication is comparing the attributes of the object itself to what is known about objects of that origin. For example, an art expert might look for similarities in the style of painting, check the location and form of a signature, or compare the object to an old photograph. The physics of sound and light, and comparison with a physical environment, can be used to examine the authenticity of audio recordings, photographs. Documents can be verified as being created on ink or paper readily available at the time of the implied creation. Attribute comparison may be vulnerable to forgery, in art and antiques, certificates are of great importance for authenticating an object of interest and value. Certificates can, however, also be forged, and the authentication of these poses a problem. For instance, the son of Han van Meegeren, the well-known art-forger, forged the work of his father and provided a certificate for its provenance as well, see the article Jacques van Meegeren. Criminal and civil penalties for fraud, forgery, and counterfeiting can reduce the incentive for falsification, currency and other financial instruments commonly use this second type of authentication method. The third type of authentication relies on documentation or other external affirmations, in criminal courts, the rules of evidence often require establishing the chain of custody of evidence presented. This can be accomplished through a written evidence log, or by testimony from the police detectives, some antiques are accompanied by certificates attesting to their authenticity. Signed sports memorabilia is usually accompanied by a certificate of authenticity and these external records have their own problems of forgery and perjury, and are also vulnerable to being separated from the artifact and lost. In computer science, a user can be access to secure systems based on user credentials that imply authenticity. A network administrator can give a user a password, or provide the user with a key card or other device to allow system access
6.
User (computing)
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A user is a person who uses a computer or network service. Users generally use a system or a product without the technical expertise required to fully understand it. Power users use advanced features of programs, though they are not necessarily capable of computer programming, a user often has a user account and is identified to the system by a username. Other terms for username include login name, screenname, nickname and handle, some software products provide services to other systems and have no direct end users. End users are the ultimate users of a software product. The term is used to abstract and distinguish those who use the software from the developers of the system. This abstraction is primarily useful in designing the user interface, in user-centered design, personas are created to represent the types of users. It is sometimes specified for each persona which types of user interfaces it is comfortable with, in this context, graphical user interfaces are usually preferred to command-line interfaces for the sake of usability. The end-user development discipline blurs the distinction between users and developers. It designates activities or techniques in which people who are not professional developers create automated behavior, systems whose actor is another system or a software agent have no direct end users. To log in to an account, a user is required to authenticate oneself with a password or other credentials for the purposes of accounting, security, logging. Once the user has logged on, the system will often use an identifier such as an integer to refer to them, rather than their username. In Unix systems, the username is correlated with an identifier or user id. Computer systems operate in one of two based on what kind of users they have, Single-user systems do not have a concept of several user accounts. Multi-user systems have such a concept, and require users to identify themselves using the system. Each user account on a system typically has a home directory, in which to store files pertaining exclusively to that users activities. User accounts often contain a public profile, which contains basic information provided by the accounts owner. Various computer operating-systems and applications expect/enforce different rules for the formats of user names, in some cases, a user may be better known by their username than by their real name, such as CmdrTaco, founder of the website Slashdot
7.
Multi-factor authentication
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Two-factor authentication is a method of confirming a users claimed identity by utilizing a combination of two different components. Two-factor authentication is a type of multi-factor authentication, a good example from everyday life is the withdrawing of money from a cash machine, only the correct combination of a bank card and a PIN allows the transaction to be carried out. The use of multiple factors to prove ones identity is based on the premise that an unauthorized actor is unlikely to be able to supply the factors required for access. Knowledge factors are the most commonly used form of authentication, in this form, the user is required to prove knowledge of a secret in order to authenticate. A password is a word or string of characters that is used for user authentication. This is the most commonly used mechanism of authentication, many multi-factor authentication techniques rely on password as one factor of authentication. Variations include both longer ones formed from words and the shorter, purely numeric, personal identification number commonly used for ATM access. Traditionally, passwords are expected to be memorized, many secret questions such as Where were you born. Are poor examples of a factor because they may be known to a wide group of people. Possession factors have been used for authentication for centuries, in the form of a key to a lock, the basic principle is that the key embodies a secret which is shared between the lock and the key, and the same principle underlies possession factor authentication in computer systems. A security token is an example of a possession factor, disconnected tokens have no connections to the client computer. They typically use a screen to display the generated authentication data. Connected tokens are devices that are connected to the computer to be used. There are a number of different types, including card readers, wireless tags and these are factors associated with the user, and are usually biometric methods, including fingerprint readers, retina scanners or voice recognition. The major drawback of authentication performed including something that the user possesses is that the token must be carried around by the user. Loss and theft are a risk, there are also costs involved in procuring and subsequently replacing tokens of this kind. In addition, there are inherent conflicts and unavoidable trade-offs between usability and security, to authenticate themselves, people can use their personal access license plus a one-time-valid, dynamic passcode consisting of digits. The code can be sent to their device by SMS or via a special app
8.
Fingerprint
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A fingerprint in its narrow sense is an impression left by the friction ridges of a human finger. The recovery of fingerprints from a scene is an important method of forensic science. Fingerprints are easily deposited on surfaces by the natural secretions of sweat from the eccrine glands that are present in epidermal ridges. These are sometimes referred to as Chanced Impressions, in a wider use of the term, fingerprints are the traces of an impression from the friction ridges of any part of a human or other primate hand. A print from the sole of the foot can also leave an impression of friction ridges, deliberate impressions of fingerprints may be formed by ink or other substances transferred from the peaks of friction ridges on the skin to a relatively smooth surface such as a fingerprint card. Fingerprint records normally contain impressions from the pad on the last joint of fingers and thumbs, human fingerprints are detailed, nearly unique, difficult to alter, and durable over the life of an individual, making them suitable as long-term markers of human identity. Fingerprint analysis, in use since the early 20th century, has led to many crimes being solved and this means that many criminals consider gloves essential. In 2015, the identification of sex by use of a fingerprint test has been reported. A friction ridge is a portion of the epidermis on the digits. These are sometimes known as epidermal ridges which are caused by the interface between the dermal papillae of the dermis and the interpapillary pegs of the epidermis. These ridges may also assist in gripping surfaces and may improve surface contact in wet conditions. Before computerisation, manual filing systems were used in large fingerprint repositories, manual classification systems were based on the general ridge patterns of several or all fingers. This allowed the filing and retrieval of paper records in large collections based on friction ridge patterns alone, the most popular systems used the pattern class of each finger to form a key to assist lookup in a filing system. Classification systems include the Roscher system, the Juan Vucetich system, in the Henry system of classification, there are three basic fingerprint patterns, loop, whorl, and arch, which constitute 60–65%, 30–35%, and 5% of all fingerprints respectively. Ulnar loops start on the pinky-side of the finger, the closer to the ulna. Radial loops start on the thumb-side of the finger, the closer to the radius. Whorls may also have sub-group classifications including plain whorls, accidental whorls, double loop whorls, peacocks eye, composite, other common fingerprint patterns include the tented arch, the plain arch, and the central pocket loop. The system used by most experts, although complex, is similar to the Henry System of Classification
9.
Website
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A website is a collection of related web pages, including multimedia content, typically identified with a common domain name, and published on at least one web server. A website may be accessible via a public Internet Protocol network, such as the Internet, or a local area network. Websites have many functions and can be used in various fashions, a website can be a website, a commercial website for a company. Websites are typically dedicated to a topic or purpose, ranging from entertainment and social networking to providing news. All publicly accessible websites collectively constitute the World Wide Web, while private websites, Web pages, which are the building blocks of websites, are documents, typically composed in plain text interspersed with formatting instructions of Hypertext Markup Language. They may incorporate elements from other websites with suitable markup anchors, Web pages are accessed and transported with the Hypertext Transfer Protocol, which may optionally employ encryption to provide security and privacy for the user. The users application, often a web browser, renders the page content according to its HTML markup instructions onto a display terminal. Hyperlinking between web pages conveys to the reader the site structure and guides the navigation of the site, Some websites require user registration or subscription to access content. As of 2016 end users can access websites on a range of devices, including desktop and laptop computers, tablet computers, smartphones, the World Wide Web was created in 1990 by the British CERN physicist Tim Berners-Lee. On 30 April 1993, CERN announced that the World Wide Web would be free to use for anyone, before the introduction of HTML and HTTP, other protocols such as File Transfer Protocol and the gopher protocol were used to retrieve individual files from a server. These protocols offer a directory structure which the user navigates and chooses files to download. Documents were most often presented as text files without formatting. Websites have many functions and can be used in various fashions, a website can be a website, a commercial website. Websites can be the work of an individual, a business or other organization, any website can contain a hyperlink to any other website, so the distinction between individual sites, as perceived by the user, can be blurred. Websites are written in, or converted to, HTML and are accessed using a software interface classified as a user agent. Web pages can be viewed or otherwise accessed from a range of computer-based and Internet-enabled devices of various sizes, including computers, laptops, PDAs. A website is hosted on a system known as a web server. These terms can refer to the software that runs on these systems which retrieves
10.
Web browser
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A web browser is a software application for retrieving, presenting and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier that may be a web page, image, hyperlinks present in resources enable users easily to navigate their browsers to related resources. Although browsers are primarily intended to use the World Wide Web, the most popular web browsers are Google Chrome, Microsoft Edge, Safari, Opera and Firefox. The first web browser was invented in 1990 by Sir Tim Berners-Lee, Berners-Lee is the director of the World Wide Web Consortium, which oversees the Webs continued development, and is also the founder of the World Wide Web Foundation. His browser was called WorldWideWeb and later renamed Nexus, the first commonly available web browser with a graphical user interface was Erwise. The development of Erwise was initiated by Robert Cailliau, andreesens browser sparked the internet boom of the 1990s. The introduction of Mosaic in 1993 – one of the first graphical web browsers – led to an explosion in web use, Microsoft responded with its Internet Explorer in 1995, also heavily influenced by Mosaic, initiating the industrys first browser war. Bundled with Windows, Internet Explorer gained dominance in the web browser market, Internet Explorer usage share peaked at over 95% by 2002. Opera debuted in 1996, it has never achieved widespread use and it is also available on several other embedded systems, including Nintendos Wii video game console. In 1998, Netscape launched what was to become the Mozilla Foundation in an attempt to produce a competitive browser using the open source software model, as of August 2011, Firefox has a 28% usage share. Apples Safari had its first beta release in January 2003, as of April 2011, the most recent major entrant to the browser market is Chrome, first released in September 2008. Chromes take-up has increased year by year, by doubling its usage share from 8% to 16% by August 2011. This increase seems largely to be at the expense of Internet Explorer, in December 2011, Chrome overtook Internet Explorer 8 as the most widely used web browser but still had lower usage than all versions of Internet Explorer combined. Chromes user-base continued to grow and in May 2012, Chromes usage passed the usage of all versions of Internet Explorer combined, by April 2014, Chromes usage had hit 45%. Internet Explorer was deprecated in Windows 10, with Microsoft Edge replacing it as the web browser. The ways that web browser makers fund their development costs has changed over time, the first web browser, WorldWideWeb, was a research project. In addition to being freeware, Netscape Navigator and Opera were also sold commercially, Internet Explorer, on the other hand, was bundled free with the Windows operating system, and therefore it was funded partly by the sales of Windows to computer manufacturers and direct to users. Internet Explorer also used to be available for the Mac, in this respect, IE may have contributed to Windows and Microsoft applications sales in another way, through lock-in to Microsofts browser
11.
HTTP cookie
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An HTTP cookie is a small piece of data sent from a website and stored on the users computer by the users web browser while the user is browsing. Cookies were designed to be a mechanism for websites to remember stateful information or to record the users browsing activity. They can also be used to remember pieces of information that the user previously entered into form fields such as names, addresses, passwords. 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, the security of an authentication cookie generally depends on the security of the issuing website and the users web browser, and on whether the cookie data is encrypted. Security vulnerabilities may allow a cookies data to be read by a hacker, used to access to user data. Lawmakers to take action in 2011, European law requires all websites targeting European Union member states gain informed consent from users before storing non-essential cookies on their device. The term cookie was coined by web browser programmer Lou Montulli and it was derived from the term magic cookie, which is a packet of data a program receives and sends back unchanged, used by Unix programmers. Magic cookie in turn derives from fortune cookie, a cookie with an embedded message, magic cookies were already used in computing when computer programmer Lou Montulli had the idea of using them in web communications in June 1994. At the time, he was an employee of Netscape Communications, vint Cerf and John Klensin represented MCI in technical discussions with Netscape Communications. MCI did not want its servers to have to retain partial transaction states, cookies provided a solution to the problem of reliably implementing a virtual shopping cart. Together with John Giannandrea, Montulli wrote the initial Netscape cookie specification the same year, version 0. 9beta of Mosaic Netscape, released on October 13,1994, supported cookies. The first use of cookies was checking whether visitors to the Netscape website had already visited the site, Montulli applied for a patent for the cookie technology in 1995, and US5774670 was granted in 1998. Support for cookies was integrated in Internet Explorer in version 2, the introduction of cookies was not widely known to the public at the time. In particular, cookies were accepted by default, and users were not notified of their presence, the general public learned about cookies after the Financial Times published an article about them on February 12,1996. In the same year, cookies received a lot of media attention, cookies were discussed in two U. S. Federal Trade Commission hearings in 1996 and 1997. The development of the formal cookie specifications was already ongoing, in particular, the first discussions about a formal specification started in April 1995 on the www-talk mailing list. A special working group within the Internet Engineering Task Force was formed, two alternative proposals for introducing state in HTTP transactions had been proposed by Brian Behlendorf and David Kristol respectively
12.
Hotspot (Wi-Fi)
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A hotspot is a physical location where people may obtain Internet access, typically using Wi-Fi technology, via a wireless local area network using a router connected to an internet service provider. Public hotspots may be found in a number of businesses for use of customers in developed urban areas throughout the world. Many hotels offer wifi access to guests, either in guest rooms or in the lobby, Hotspots differ from wireless access points, which are the hardware devices used to provide a wireless network service. Private hotspots allow Internet access to a device via another device which may have access via say a mobile device. Public access wireless local area networks were first proposed by Henrik Sjödin at the NetWorld+Interop conference in The Moscone Center in San Francisco in August 1993, Sjödin did not use the term hotspot but referred to publicly accessible wireless LANs. The first commercial venture to attempt to create a local area access network was a firm founded in Richardson. The founders of the venture, Mark Goode, Greg Jackson, the firm was one of the first to sign such public access locations as Starbucks, American Airlines, and Hilton Hotels. The company was sold to Deutsche Telecom in 2001, who converted the name of the firm into T-Mobile Hotspot. It was then that the term entered the popular vernacular as a reference to a location where a publicly accessible wireless LAN is available. ABI Research reported there was a total of 4.9 million global Wi-Fi hotspots in 2012 and projected that number would surpass 6.3 million by the end of 2013. The latest Wireless Broadband Alliance Industry Report outlines a scenario for the Wi-Fi market. Collectively, WBA operator members serve more than 1 billion subscribers, the public can use a laptop or other suitable portable device to access the wireless connection provided. Of the estimated 150 million laptops,14 million PDAs, and other emerging Wi-Fi devices sold per year for the last few years, most include the Wi-Fi feature. For venues that have broadband Internet access, offering wireless access is as simple as configuring one access point, in conjunction with a router, a single wireless router combining these functions may suffice. More than 10,900 hotspots are on trains, planes and airports, the region with the largest number of public hotspots is Europe, followed by North America and Asia. Security is a concern in connection with Hotspots. There are three possible attack vectors, first, there is the wireless connection between the client and the access point. This needs to be encrypted, so that the connection cannot be eavesdropped or attacked by a man-in-the-middle-attack, second, there is the Hotspot itself
13.
Screensaver
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A screensaver is a computer program that blanks the screen or fills it with moving images or patterns when the computer is not in use. Initially designed to prevent phosphor burn-in on CRT and plasma monitors, screensavers are now used primarily for entertainment. Decades before the first computers using this technology were invented, Robert A, many modern television operating systems, media players and other digital entertainment systems include optional screensavers. Some screensavers also offer functions like automated workstation password protection during inactivity or disk scan with installed antivirus software. Before the advent of LCD screens, most computer screens were based on cathode ray tubes, cathode ray televisions, oscilloscopes and other devices that use CRTs are all susceptible to phosphor burn-in, as are plasma displays to some extent. Screen-saver programs were designed to avoid these effects by automatically changing the images on the screen during periods of user inactivity. For CRTs used in public, such as ATMs and railway ticketing machines, blanking the screen is out of the question as the machine would appear to be out of service. In these applications, burn-in can be prevented by shifting the position of the display contents every few seconds, LCD computer monitors, including the display panels used in laptop computers, are not susceptible to burn-in because the image is not directly produced by phosphors. For these reasons, screensavers today are primarily for decorative/entertainment purposes and they usually feature moving images or patterns and sometimes sound effects. One increasingly popular application is for screensavers to activate a useful background task and this allows applications to use resources only when the computer would be otherwise idle. The first screensaver was allegedly written for the original IBM PC by John Socha, best known for creating the Norton Commander, the screensaver, named scrnsave, was published in the December 1983 issue of the Softalk magazine. It simply blanked the screen three minutes of inactivity. The first screensaver that allowed users to change the time was released on Apples Lisa. The Atari 400 and 800s screens would also go through random screensaver-like color changes if they were left inactive for too long, the user had no control over this. These computers, released in 1979, are technically earlier screen savers, and prior to these computers, the 1977 Atari VCS/2600 gaming console included color cycling in games like Combat or Breakout, in order to prevent burn-in of game images to 1970s-era televisions. In addition, the first model of the TI-30 calculator from 1976 featured a screensaver and this was chiefly used to save battery power, as the LED display was more power intensive than later LCD models. These are examples of screensavers in ROM or the firmware of a computer, today with the help of modern graphics technologies there is a wide variety of screensavers. Because of 3D computer graphics, which provide realistic environments, 3D screensavers are available, screensavers are usually designed and coded using a variety of programming languages as well as graphics interfaces
14.
Time-sharing
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In computing, time-sharing is the sharing of a computing resource among many users by means of multiprogramming and multi-tasking at the same time. Its introduction in the 1960s and emergence as the prominent model of computing in the 1970s represented a major shift in the history of computing. The earliest computers were expensive devices, and very slow in comparison to later models. These programs might take hours, or even weeks, to run, as computers grew in speed, run times dropped, and soon the time taken to start up the next program became a concern. Batch processing methodologies evolved to decrease these dead periods by queuing up programs so that as soon as one program completed, to support a batch processing operation, a number of comparatively inexpensive card punch or paper tape writers were used by programmers to write their programs offline. When typing was complete, the programs were submitted to the operations team, important programs were started quickly, how long before less important programs were started was unpredictable. When the program run was completed, the output was returned to the programmer. The complete process might take days, during which time the programmer might never see the computer, the alternative of allowing the user to operate the computer directly was generally far too expensive to consider. This was because users might have long periods of entering code while the computer remained idle and this situation limited interactive development to those organizations that could afford to waste computing cycles, large universities for the most part. Programmers at the universities decried the behaviors that batch processing imposed and they experimented with new ways to interact directly with the computer, a field today known as human–computer interaction. Time-sharing was developed out of the realization that any single user would make inefficient use of a computer. Given an optimal size, the overall process could be very efficient. Similarly, small slices of time spent waiting for disk, tape, in a paper published in December 1958 by W. F. Bauer, he wrote that The computers would handle a number of problems concurrently. Implementing a system able to take advantage of this was initially difficult, batch processing was effectively a methodological development on top of the earliest systems. Since computers still ran single programs for single users at any time, developing a system that supported multiple users at the same time was a completely different concept. The state of each user and their programs would have to be kept in the machine and this would take up computer cycles, and on the slow machines of the era this was a concern. However, as computers rapidly improved in speed, and especially in size of memory in which users states were retained. The first project to implement a system was initiated by John McCarthy at MIT in 1959, initially planned on a modified IBM704
15.
Bulletin board system
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A bulletin board system, or BBS, is a computer server running software that allows users to connect to the system using a terminal program. Many BBSes also offer on-line games, in users can compete with each other. Bulletin board systems were in many ways a precursor to the form of the World Wide Web, social networks. Low-cost, high-performance modems drove the use of services and BBSes through the early 1990s. Infoworld estimated there were 60,000 BBSes serving 17 million users in the United States alone in 1994, over the next year, many of the leading BBS software providers went bankrupt and tens of thousands of BBSes disappeared. Today, BBSing survives largely as a hobby in most parts of the world. Most BBSes are now accessible over Telnet and typically offer free email accounts, FTP services, IRC, some offer access through packet switched networks, or packet radio connections. A precursor to the bulletin board system was Community Memory, started in August 1973 in Berkeley. Useful microcomputers did not exist at that time, and modems were both expensive and slow, Community Memory therefore ran on a mainframe computer and was accessed through terminals located in several San Francisco Bay Area neighborhoods. The poor quality of the original modem connecting the terminals to the mainframe prompted a user to invent the Pennywhistle modem, Community Memory allowed the user to type messages into a computer terminal after inserting a coin, and offered a pure bulletin board experience with public messages only. It did offer the ability to tag messages with keywords, which the user could use in searches, the system acted primarily in the form of a buy and sell system with the tags taking the place of the more traditional classifications. But users found ways to express themselves outside these bounds, unfortunately, the system was expensive to operate, and when their host machine became unavailable and a new one could not be found, the system closed in January 1975. Similar functionality was available to most mainframe users, which might be considered a sort of ultra-local BBS when used in this fashion. Commercial systems, expressly intended to offer features to the public, became available in the late 1970s. Early modems were very simple devices using acoustic couplers to handle telephone operation. The user would first pick up the phone, dial a number, disconnecting at the end of a call required the user to pick up the handset and return it to the phone. With the introduction of microcomputers with expansion slots, like the S-100 bus machines and Apple II, it possible for the modem to communicate instructions. A number of modems of this sort were available by the late 1970s
16.
Home computer
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Home computers were a class of microcomputers entering the market in 1977, and becoming common during the 1980s. They were marketed to consumers as affordable and accessible computers that, however, a home computer often had better graphics and sound than contemporaneous business computers. Their most common uses were playing games, but they were also regularly used for word processing, doing homework. Home computers were usually not electronic kits, home computers were already manufactured in stylish metal or plastic enclosures. There were, however, commercial kits like the Sinclair ZX80 which were home and home-built computers since the purchaser could assemble the unit from a kit. For example, using a typical 1980s home computer as a home automation appliance would require the computer to be powered on at all times. Personal finance and database use required tedious data entry, by contrast, advertisements in the specialty computer press often simply listed specifications. Since most systems shipped with the BASIC programming language included on the system ROM, many users found programming to be a fun and rewarding experience, and an excellent introduction to the world of digital technology. Often the only difference may be the outlet through which they are purchased. Another change from the computer era is that the once-common endeavour of writing ones own software programs has almost vanished from home computer use. As early as 1965, some projects such as Jim Sutherlands ECHO IV explored the possible utility of a computer in the home. In 1969, the Honeywell Kitchen Computer was marketed as a gift item, and would have inaugurated the era of home computing. Computers became affordable for the public in the 1970s due to the mass production of the microprocessor starting in 1971. Early microcomputers such as the Altair 8800 had front-mounted switches and diagnostic lights to control and indicate internal system status, while two early home computers could be bought either in kit form or assembled, most home computers were only sold pre-assembled. The keyboard - a feature lacking on the Altair - was usually built into the case as the motherboard. Ports for plug-in peripheral devices such as a display, cassette tape recorders, joysticks. Usually the manufacturer would sell peripheral devices designed to be compatible with their computers as extra cost accessories, peripherals were not often interchangeable between different brands of home computer, or even between successive models of the same brand. To save the cost of a monitor, the home computer would often connect through an RF modulator to the family TV set
17.
Personal computer
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A personal computer is a multi-purpose electronic computer whose size, capabilities, and price make it feasible for individual use. PCs are intended to be operated directly by a end-user, rather than by an expert or technician. In the 2010s, PCs are typically connected to the Internet, allowing access to the World Wide Web, personal computers may be connected to a local area network, either by a cable or a wireless connection. In the 2010s, a PC may be, a multi-component desktop computer, designed for use in a location a laptop computer, designed for easy portability or a tablet computer. In the 2010s, PCs run using a system, such as Microsoft Windows, Linux. The very earliest microcomputers, equipped with a front panel, required hand-loading of a program to load programs from external storage. Before long, automatic booting from permanent read-only memory became universal, in the 2010s, users have access to a wide range of commercial software, free software and free and open-source software, which are provided in ready-to-run or ready-to-compile form. Since the early 1990s, Microsoft operating systems and Intel hardware have dominated much of the computer market, first with MS-DOS. Alternatives to Microsofts Windows operating systems occupy a minority share of the industry and these include Apples OS X and free open-source Unix-like operating systems such as Linux and Berkeley Software Distribution. Advanced Micro Devices provides the alternative to Intels processors. PC is an initialism for personal computer, some PCs, including the OLPC XOs, are equipped with x86 or x64 processors but not designed to run Microsoft Windows. PC is used in contrast with Mac, an Apple Macintosh computer and this sense of the word is used in the Get a Mac advertisement campaign that ran between 2006 and 2009, as well as its rival, Im a PC campaign, that appeared in 2008. Since Apples transition to Intel processors starting 2005, all Macintosh computers are now PCs, the “brain” may one day come down to our level and help with our income-tax and book-keeping calculations. But this is speculation and there is no sign of it so far, in the history of computing there were many examples of computers designed to be used by one person, as opposed to terminals connected to mainframe computers. Using the narrow definition of operated by one person, the first personal computer was the ENIAC which became operational in 1946 and it did not meet further definitions of affordable or easy to use. An example of an early single-user computer was the LGP-30, created in 1956 by Stan Frankel and used for science and it came with a retail price of $47, 000—equivalent to about $414,000 today. Introduced at the 1965 New York Worlds Fair, the Programma 101 was a programmable calculator described in advertisements as a desktop computer. It was manufactured by the Italian company Olivetti and invented by the Italian engineer Pier Giorgio Perotto, the Soviet MIR series of computers was developed from 1965 to 1969 in a group headed by Victor Glushkov
18.
Windows NT
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Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It is a processor-independent, multiprocessing, multi-user operating system, the first version of Windows NT was Windows NT3.1 and was produced for workstations and server computers. It was intended to complement consumer versions of Windows that were based on MS-DOS, gradually, the Windows NT family was expanded into Microsofts general-purpose operating system product line for all personal computers, deprecating the Windows 9x family. NT was formerly expanded to New Technology but no longer carries any specific meaning, starting with Windows 2000, NT was removed from the product name and is only included in the product version string. NT was the first purely 32-bit version of Windows, whereas its consumer-oriented counterparts, Windows 3. 1x and it is a multi-architecture operating system. Initially, it supported several CPU architectures, including IA-32, MIPS, DEC Alpha, PowerPC, the latest versions support x86 and ARM. This lineage is made clear in Cutlers foreword to Inside Windows NT by Helen Custer and it has been suggested that Dave Cutler intended the initialism WNT as a play on VMS, incrementing each letter by one. However, the project was intended as a follow-on to OS/2 and was referred to as NT OS/2 before receiving the Windows brand. One of the original NT developers, Mark Lucovsky, states that the name was taken from the original target processor—the Intel i860, the letters were dropped from the names of releases from Windows 2000 onwards, though Microsoft described that product as being Built on NT Technology. A main design goal of NT was hardware and software portability, the idea was to have a common code base with a custom Hardware Abstraction Layer for each platform. However, support for MIPS, Alpha, and PowerPC was later dropped in Windows 2000, broad software compatibility was achieved with support for several API personalities, including Windows API, POSIX, and OS/2 APIs – the latter two were phased out starting with Windows XP. Partial MS-DOS compatibility was achieved via an integrated DOS Virtual Machine – although this feature is being phased out in the x86-64 architecture, NT supported per-object access control lists allowing a rich set of security permissions to be applied to systems and services. NT supported Windows network protocols, inheriting the previous OS/2 LAN Manager networking, Windows NT3.1 was the first version of Windows to use 32-bit flat virtual memory addressing on 32-bit processors. Its companion product, Windows 3.1, used segmented addressing, notably, in Windows NT3. x, several I/O driver subsystems, such as video and printing, were user-mode subsystems. In Windows NT4, the video, server, and printer spooler subsystems were moved into kernel mode, NTFS, a journaled, secure file system, was created for NT. Windows NT also allows for other file systems, starting with versions 3.1. Windows NT introduced its own model, the Windows NT driver model. With Windows 2000, the Windows NT driver model was enhanced to become the Windows Driver Model, which was first introduced with Windows 98, but was based on the NT driver model
19.
OS/2
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OS/2 is a series of computer operating systems, initially created by Microsoft and IBM, then later developed by IBM exclusively. The name stands for Operating System/2, because it was introduced as part of the generation change release as IBMs Personal System/2 line of second-generation personal computers. The first version of OS/2 was released in December 1987 and newer versions were released until December 2001, OS/2 was intended as a protected mode successor of PC DOS. Because of this heritage, OS/2 shares similarities with Unix, Xenix, IBM discontinued its support for OS/2 on 31 December 2006. Since then, it has been updated, maintained and marketed under the name eComStation, in 2015 it was announced that a new OEM distribution of OS/2 would be released that was to be called ArcaOS. The development of OS/2 began when IBM and Microsoft signed the Joint Development Agreement in August 1985 and it was code-named CP/DOS and it took two years for the first product to be delivered. OS/21.0 was announced in April 1987 and released in December, the original release is textmode-only, and a GUI was introduced with OS/21.1 about a year later. OS/2 features an API for controlling the display and handling keyboard. In addition, development tools include a subset of the video, a task-switcher named Program Selector is available through the Ctrl-Esc hotkey combination, allowing the user to select among multitasked text-mode sessions. Communications and database-oriented extensions were delivered in 1988, as part of OS/21.0 Extended Edition, SNA, X. 25/APPC/LU6.2, LAN Manager, Query Manager, SQL. The promised graphical user interface, Presentation Manager, was introduced with OS/21.1 in October,1988 and it had a similar user interface to Windows 2.1, which was released in May of that year. The Extended Edition of 1.1, sold only through IBM sales channels, introduced distributed database support to IBM database systems, in 1989, Version 1.2 introduced Installable Filesystems and notably the HPFS filesystem. HPFS provided a number of improvements over the older FAT file system, including long filenames, in addition, extended attributes were also added to the FAT file system. The Extended Edition of 1.2 introduced TCP/IP and Ethernet support, OS/2 and Windows-related books of the late 1980s acknowledged the existence of both systems and promoted OS/2 as the system for the future. The collaboration between IBM and Microsoft unravelled in 1990, between the releases of Windows 3.0 and OS/21.3, during this time, Windows 3.0 became a tremendous success, selling millions of copies in its first year. Much of its success was because Windows 3.0 was bundled with most new computers, OS/2, on the other hand, was available only as an expensive stand-alone software package. In addition, OS/2 lacked device drivers for many devices such as printers. Windows, on the hand, supported a much larger variety of hardware
20.
Linux
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Linux is a Unix-like computer operating system assembled under the model of free and open-source software development and distribution. The defining component of Linux is the Linux kernel, an operating system kernel first released on September 17,1991 by Linus Torvalds, the Free Software Foundation uses the name GNU/Linux to describe the operating system, which has led to some controversy. Linux was originally developed for computers based on the Intel x86 architecture. Because of the dominance of Android on smartphones, Linux has the largest installed base of all operating systems. Linux is also the operating system on servers and other big iron systems such as mainframe computers. It is used by around 2. 3% of desktop computers, the Chromebook, which runs on Chrome OS, dominates the US K–12 education market and represents nearly 20% of the sub-$300 notebook sales in the US. Linux also runs on embedded systems – devices whose operating system is built into the firmware and is highly tailored to the system. This includes TiVo and similar DVR devices, network routers, facility automation controls, televisions, many smartphones and tablet computers run Android and other Linux derivatives. The development of Linux is one of the most prominent examples of free, the underlying source code may be used, modified and distributed—commercially or non-commercially—by anyone under the terms of its respective licenses, such as the GNU General Public License. Typically, Linux is packaged in a known as a Linux distribution for both desktop and server use. Distributions intended to run on servers may omit all graphical environments from the standard install, because Linux is freely redistributable, anyone may create a distribution for any intended use. The Unix operating system was conceived and implemented in 1969 at AT&Ts Bell Laboratories in the United States by Ken Thompson, Dennis Ritchie, Douglas McIlroy, first released in 1971, Unix was written entirely in assembly language, as was common practice at the time. Later, in a key pioneering approach in 1973, it was rewritten in the C programming language by Dennis Ritchie, the availability of a high-level language implementation of Unix made its porting to different computer platforms easier. Due to an earlier antitrust case forbidding it from entering the computer business, as a result, Unix grew quickly and became widely adopted by academic institutions and businesses. In 1984, AT&T divested itself of Bell Labs, freed of the legal obligation requiring free licensing, the GNU Project, started in 1983 by Richard Stallman, has the goal of creating a complete Unix-compatible software system composed entirely of free software. Later, in 1985, Stallman started the Free Software Foundation, by the early 1990s, many of the programs required in an operating system were completed, although low-level elements such as device drivers, daemons, and the kernel were stalled and incomplete. Linus Torvalds has stated that if the GNU kernel had been available at the time, although not released until 1992 due to legal complications, development of 386BSD, from which NetBSD, OpenBSD and FreeBSD descended, predated that of Linux. Torvalds has also stated that if 386BSD had been available at the time, although the complete source code of MINIX was freely available, the licensing terms prevented it from being free software until the licensing changed in April 2000
21.
Logbook
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A logbook is a record of important events in the management, operation, and navigation of a ship. It is essential to navigation, and must be filled in at least daily. The term originally referred to a book for recording readings from the chip log, the readings of the log have been recorded in equal times to give the distance traveled with respect to a given start position. The term logbook has spread to a variety of other endeavors. Now, a virtual or electronic logbook is used for record-keeping for complex machines such as nuclear plants or particle accelerators. In military terms, a logbook is a series of official, each document is marked with the time of an event or action of significance. Most national shipping authorities and admiralties specify that logbooks are kept to provide a record of events, and to help crews navigate should radio, radar or the GPS fail. Examination of the detail in a log is often an important part of the investigative process for official maritime inquiries. Logbook entries are sometimes of importance in legal cases involving maritime commercial disputes. Changes may be made to the rough log but the log is considered permanent. Alterations or corrections in an official logbook must be initialled by the keeper of the logbook. The V5C car registration document in the UK is often referred to as the logbook, in the fishing industry, a logbook is used to record catch data as part of the fisheries regulations. It is then submitted to the authorities of the vessels flag state. For amateur radio the logbook is where the hams register their QSO, there are several programs to help radio operators in the management of their logbook. Pilots of aircraft must maintain a pilot logbook to record their time spent flying, in scuba diving, the logbook documents the experience of a diver by logging a divers dives. The Hornblower series mentions logs to explain plot development, or to make the more realistic. In Star Trek, the Captains log, a form of log, is used to fill in the audience as to the events in progress. This is part of a log system that includes personal logs and other officers official logs
22.
Chip log
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A chip log, also called common log, ship log, or just log, is a navigation tool mariners use to estimate the speed of a vessel through water. The word knot, to mean nautical mile per hour, derives from this measurement method, all nautical instruments that measure the speed of a ship through water are known as logs. This nomenclature dates back to the days of sail, when sailors tossed a log attached to a rope knotted at regular intervals off the stern of a ship, sailors counted the number of knots that passed through their hands in a given time to determine the ships speed. They had to know the speed to navigate using dead reckoning, today, sailors and aircraft pilots still use the written term knot to express speed, although the modern term is a respelling of naut, an abbreviation of nautical mile. A chip log consists of a board attached to a line. The log-line has a number of knots at uniform intervals, the log-line is wound on a reel so the user can easily pay it out. The shape is a circle, or quadrant, and the log-line attaches to the board with a bridle of three lines that connect to the vertex and to the two ends of the quadrants arc. To ensure the log submerges and orients correctly in the water and this provides more resistance in the water, and a more accurate and repeatable reading. The bridle attaches in such a way that a tug on the log-line makes one or two of the bridles lines release, so a sailor can retrieve the log. A navigator who needed to know the speed of the vessel had a sailor drop the log over the ships stern, the log acted as a drogue, remaining roughly in place while the vessel moved away. The sailor let the log-line run out for a time while counting the knots that passed over. The length of log-line passing determined the reading, the first known device that measured speed is often claimed to be the Dutchmans Log. However this invention is attributed to the Portuguese Bartolomeu Crescêncio, who designed it in the end of the 15th century or in the beginning of the 16th century. A sailor threw a floating object overboard and used a sandglass to measure the time it took to pass two points on deck. However, the first reference to a Dutchmans log is in 1623—later than the ship log, the Dutchmans log could be used with a brass tobacco box, rectangular with rounded ends. This box had tables on it to convert log timing to speed, mariners have used the log for a long time. The first known description of the device in print is in A Regiment for the Sea by William Bourne, Bourne devised a half-minute sandglass for timing. At the time, a mile was reckoned as 5,000 feet, so in 30 seconds at one mile per hour, initially, the log-line was not knotted and sailors measured the length directly on the line
23.
Guestbook
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A guestbook is a paper or electronic means for a visitor to acknowledge a visit to a site, physical or web-based, and leave details such as their name, postal or electronic address, and any comments. Such paper-based ledgers or books are traditional in churches, at weddings, funerals, B&Bs, museums, schools, institutions, some private homes keep visitors books. On the web, a guestbook is a system that allows visitors of a website to leave a public comment. It is possible in some guestbooks for visitors to express their thoughts about the website or its subject, generally, they do not require the poster to create a user account, as it is an informal method of dropping off a quick message. The purpose of a website guestbook is to display the kind of visitors the site gets, including the part of the world they reside in and this allows the webmaster to assess and improve their site. A guestbook is generally a script, which is usually hosted and written in a language such as Perl, PHP. Many free guestbook hosts and scripts exist, drop top guest book Guestbook spam
24.
Style guide
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A style guide is a set of standards for the writing and design of documents, either for general use or for a specific publication, organization, or field. A style guide establishes and enforces style to improve communication, to do that, it ensures consistency within a document and across multiple documents and enforces best practice in usage and in language composition, visual composition, orthography and typography. For academic and technical documents, a guide may also enforce the best practice in ethics, pedagogy, Style guides vary widely in scope and size. This variety in scope and length is enabled by the cascading of one style over another, in a way analogous to how styles cascade in web development, a short style guide is often called a style sheet. A comprehensive guide tends to be long and is called a style manual or manual of style. Most house styles, in turn, cascade over an industry-wide or profession-wide style manual that is more comprehensive. This, of course, may be subject to national variety such as the different varieties of American English and British English, some style guides focus on specific topic areas such as graphic design, including typography. Website style guides cover a publications visual and technical aspects along with text, Style guides that cover usage may suggest ways of describing people that avoid racism, sexism, and homophobia. Guides in specific scientific and technical fields cover nomenclature, which specifies names or classifying labels that are preferred because they are clear, standardized, most style guides are revised periodically to accommodate changes in conventions and usage. The frequency of updating and the control are determined by the subject matter. For style manuals in reference work format, new editions typically appear every 1 to 20 years, for example, the AP Stylebook is revised annually, and the Chicago, APA, and ASA manuals are in their 16th, 6th, and 4th editions, respectively. Many house styles and individual project styles change more frequently, especially for new projects, several basic style guides for technical and scientific communication have been defined by international standards organizations. One example is ISO215 Documentation — Presentation of contributions to periodicals, the European Union publishes an Interinstitutional style guide—encompassing 24 languages across the European Union. This manual is obligatory for all those employed by the institutions of the EU who are involved in preparing EU documents, Style Manual, For Authors, Editors and Printers by Snooks & Co for the Department of Finance and Administration. CP Stylebook, Guide to newspaper style in Canada maintained by the Canadian Press, 4th ed. Oxford University Press,2015. Based on Fowlers Modern English Usage, by Henry Watson Fowler, the Kings English, by Henry Watson Fowler and Francis George Fowler. The Complete Plain Words, by Sir Ernest Gowers, Usage and Abusage, by Eric Partridge. The BBC News Style Guide, by the British Broadcasting Corporation, the Economist Style Guide, by The Economist
25.
Windows 8
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Windows 8 is a personal computer operating system developed by Microsoft as part of the Windows NT family of operating systems. Development of Windows 8 started before the release of its predecessor, Windows 7 and it was announced at CES2011, and followed by the release of three pre-release versions from September 2011 to May 2012. The operating system was released to manufacturing on August 1,2012, Windows 8 added support for USB3.0, Advanced Format hard drives, near field communications, and cloud computing. Windows 8 was released to a critical reception. Despite these shortcomings,60 million Windows 8 licenses were sold through January 2013, on October 17,2013, Microsoft released Windows 8.1. It addressed some aspects of Windows 8 that were criticized by reviewers and early adopters, Windows 8 was ultimately succeeded by Windows 10 in July 2015. Support for Windows 8 RTM ended on January 12,2016, per Microsoft lifecycle policies regarding service packs, Windows 8.1 must be installed to maintain support, Windows 8 development started before Windows 7 had shipped in 2009. Three milestone releases of Windows 8 leaked to the general public, milestone 1, Build 7850, was leaked on April 12,2011. It was the first build where the text of a window was written centered instead of aligned to the left and it was also probably the first appearance of the Metro-style font, and its wallpaper had the text shhh. Lets not leak our hard work, however, its detailed build number reveals that the build was created on September 22,2010. The leaked copy was Enterprise edition, the OS still reads as Windows 7. Milestone 2, Build 7955, was leaked on April 25,2011, the traditional Blue Screen of Death was replaced by a new black screen, although this was later scrapped. This build introduced a new ribbon in Windows Explorer, Build 7959, with minor changes but the first 64-bit version, was leaked on May 1,2011. The Windows 7 logo was replaced with text displaying Microsoft Confidential. On June 17,2011, build 7989 64-bit edition was leaked and it introduced a new boot screen featuring the same fish as the default Windows 7 Beta wallpaper, which was later scrapped, and the circling dots as featured in the final. It also had the text Welcome below them, although this was also scrapped, on June 1,2011, Microsoft unveiled Windows 8s new user interface, as well as additional features at both Computex Taipei and the D9, All Things Digital conference in California. The Building Windows 8 blog launched on August 15,2011, featuring details surrounding Windows 8s features, Microsoft unveiled more Windows 8 features and improvements on the first day of the Build conference on September 13,2011. Microsoft released the first public build of Windows 8, Windows Developer Preview at the event
26.
OpenID
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OpenID is an open standard and decentralized authentication protocol. The BBC, IBM, PayPal, and Steam, although some of those organizations also have their own authentication management, Facebook did use OpenID in the past, but moved to Facebook Connect. Users create accounts by selecting an OpenID identity provider, and then use those accounts to sign onto any website which accepts OpenID authentication, the OpenID standard provides a framework for the communication that must take place between the identity provider and the OpenID acceptor. An extension to the standard facilitates the transfer of user attributes, such as name and gender, the OpenID protocol does not rely on a central authority to authenticate a users identity. Moreover, neither services nor the OpenID standard may mandate a specific means by which to authenticate users, the current version of OpenID is OpenID Connect 1.0, finalized and published in February 2014, and updated with corrections in November 2014. As of March 2016, there are over 1 billion OpenID enabled accounts on the Internet, an end-user is the entity that wants to assert a particular identity. A relying party is a web site or application that wants to verify the end-users identifier, other terms for this party include service provider or the now obsolete consumer. An identity provider, or OpenID provider is a service that specializes in registering OpenID URLs or XRIs, OpenID enables an end-user to communicate with a relying party. This communication is done through the exchange of an identifier or OpenID, an Identity provider provides the OpenID authentication. The exchange is enabled by a user-agent, which is the used by the end-user to communicate with the relying party. The relying party typically transforms the OpenID into a canonical URL form, with OpenID1.0, the relying party then requests the HTML resource identified by the URL and reads an HTML link tag to discover the OpenID providers URL. The relying party also discovers whether to use a delegated identity, all communication is relayed through the end-users user-agent without explicitly notifying the end-user. Checkid_setup, in which the end-user communicates with the OpenID provider via the same user-agent used to access the relying party, the checkid_immediate mode can fall back to the checkid_setup mode if the operation cannot be automated. First, the party and the OpenID provider establish a shared secret, referenced by an associate handle. If using the mode, the relying party redirects the end-users user-agent to the OpenID provider so the end-user can authenticate directly with the OpenID provider. If the end-user accepts the OpenID providers request to trust the relying party and that relying party must then confirm that the credentials really came from the OpenID provider. In contrast, a stateless or dumb relying party must make one more background request to ensure that the data indeed came from the OpenID provider. After the OpenID has been verified, authentication is considered successful, the relying party typically then stores the end-users OpenID along with the end-users other session information
27.
Password
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A password is a word or string of characters used for user authentication to prove identity or access approval to gain access to a resource, which is to be kept secret from those not allowed access. The use of passwords is known to be ancient, sentries would challenge those wishing to enter an area or approaching it to supply a password or watchword, and would only allow a person or group to pass if they knew the password. Despite the name, there is no need for passwords to be words, indeed passwords which are not actual words may be harder to guess. Some passwords are formed from words and may more accurately be called a passphrase. The terms passcode and passkey are sometimes used when the information is purely numeric. Passwords are generally enough to be easily memorized and typed. Most organizations specify a policy that sets requirements for the composition and usage of passwords, typically dictating minimum length, required categories. Some governments have national authentication frameworks that define requirements for user authentication to government services, the easier a password is for the owner to remember generally means it will be easier for an attacker to guess. Others argue longer passwords provide more security than shorter passwords with a variety of characters. In The Memorability and Security of Passwords, Jeff Yan et al. examine the effect of advice given to users about a choice of password. Combining two or more unrelated words and altering some of the letters to special characters or numbers is another good method, but a single dictionary word is not. Asking users to use letters and digits will often lead to easy-to-guess substitutions such as E →3 and I →1. Similarly typing the password one keyboard row higher is a trick known to attackers. The overall system must, of course, be designed for security, with protection against computer viruses, man-in-the-middle attacks. Physical security issues are also a concern, from deterring shoulder surfing to more sophisticated physical threats such as video cameras and keyboard sniffers. And, of course, passwords should be chosen so that they are hard for an attacker to guess, see password strength and computer security. Nowadays, it is a practice for computer systems to hide passwords as they are typed. The purpose of this measure is to avoid reading the password
28.
Personal identification number
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A personal identification number is a numeric password used to authenticate a user to a system. PINs may be used with banking systems to authenticate the identity of the cardholder, usually, both a private PIN and public user identifier is required to authenticate a user to the system. In these situations, typically the user is required to provide a user identifier or token. Upon receiving the user ID and PIN, the system looks up the PIN based upon the user ID, the user is granted access only when the number entered matches with the number stored in the system. Hence, despite the name, a PIN does not personally identify the user, PINs may also be used in contexts other than ATM or POS transactions, such as door access, Internet transactions, or to log in to a restricted website. In such cases, the PIN may simply be a password, the PIN originated with the introduction of the ATM in 1967, as an efficient way for banks to dispense cash to their customers. The first ATM system was that of Barclays in London, in 1967, it accepted cheques with machine-readable encoding, rather than cards,1972, Lloyds Bank issued the first bank card to feature an information-encoding magnetic strip, using a PIN for security. In 2006, James Goodfellow, the inventor who patented the first personal identification number, was awarded an OBE in the Queens Birthday Honours, there are several main methods of validating PINs. The operations discussed below are usually performed within a security module. One of the earliest ATM models was the IBM3624, which used the IBM method to generate what is termed a natural PIN, the natural PIN is generated by encrypting the primary account number, using an encryption key generated specifically for the purpose. This key is sometimes referred to as the PIN generation key and this PIN is directly related to the primary account number. To validate the PIN, the issuing bank regenerates the PIN using the above method, natural PINs can not be user selectable because they are derived from the PAN. If the card is reissued with a new PAN, a new PIN must be generated, natural PINs allow banks to issue PIN reminder letters as the PIN can be generated. To allow user selectable PINs it is possible to store a PIN offset value, the offset is found by subtracting natural PIN from the customer selected PIN using modulo 10. For example, if the natural PIN is 1234, and the wishes to have a PIN of 2345. The offset can be stored either on the track data. To validate the PIN, the issuing bank calculates the natural PIN as in the method, then adds the offset. The VISA method is used by many card schemes and is not VISA-specific, the VISA method generates a PIN verification value
29.
Wayback Machine
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The Internet Archive launched the Wayback Machine in October 2001. It was set up by Brewster Kahle and Bruce Gilliat, and is maintained with content from Alexa Internet, the service enables users to see archived versions of web pages across time, which the archive calls a three dimensional index. Since 1996, the Wayback Machine has been archiving cached pages of websites onto its large cluster of Linux nodes and it revisits sites every few weeks or months and archives a new version. Sites can also be captured on the fly by visitors who enter the sites URL into a search box, the intent is to capture and archive content that otherwise would be lost whenever a site is changed or closed down. The overall vision of the machines creators is to archive the entire Internet, the name Wayback Machine was chosen as a reference to the WABAC machine, a time-traveling device used by the characters Mr. Peabody and Sherman in The Rocky and Bullwinkle Show, an animated cartoon. These crawlers also respect the robots exclusion standard for websites whose owners opt for them not to appear in search results or be cached, to overcome inconsistencies in partially cached websites, Archive-It. Information had been kept on digital tape for five years, with Kahle occasionally allowing researchers, when the archive reached its fifth anniversary, it was unveiled and opened to the public in a ceremony at the University of California, Berkeley. Snapshots usually become more than six months after they are archived or, in some cases, even later. The frequency of snapshots is variable, so not all tracked website updates are recorded, Sometimes there are intervals of several weeks or years between snapshots. After August 2008 sites had to be listed on the Open Directory in order to be included. As of 2009, the Wayback Machine contained approximately three petabytes of data and was growing at a rate of 100 terabytes each month, the growth rate reported in 2003 was 12 terabytes/month, the data is stored on PetaBox rack systems manufactured by Capricorn Technologies. In 2009, the Internet Archive migrated its customized storage architecture to Sun Open Storage, in 2011 a new, improved version of the Wayback Machine, with an updated interface and fresher index of archived content, was made available for public testing. The index driving the classic Wayback Machine only has a bit of material past 2008. In January 2013, the company announced a ground-breaking milestone of 240 billion URLs, in October 2013, the company announced the Save a Page feature which allows any Internet user to archive the contents of a URL. This became a threat of abuse by the service for hosting malicious binaries, as of December 2014, the Wayback Machine contained almost nine petabytes of data and was growing at a rate of about 20 terabytes each week. Between October 2013 and March 2015 the websites global Alexa rank changed from 162 to 208, in a 2009 case, Netbula, LLC v. Chordiant Software Inc. defendant Chordiant filed a motion to compel Netbula to disable the robots. Netbula objected to the motion on the ground that defendants were asking to alter Netbulas website, in an October 2004 case, Telewizja Polska USA, Inc. v. Echostar Satellite, No.02 C3293,65 Fed. 673, a litigant attempted to use the Wayback Machine archives as a source of admissible evidence, Telewizja Polska is the provider of TVP Polonia and EchoStar operates the Dish Network
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Integrated Authority File
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The Integrated Authority File or GND is an international authority file for the organisation of personal names, subject headings and corporate bodies from catalogues. It is used mainly for documentation in libraries and increasingly also by archives, the GND is managed by the German National Library in cooperation with various regional library networks in German-speaking Europe and other partners. The GND falls under the Creative Commons Zero license, the GND specification provides a hierarchy of high-level entities and sub-classes, useful in library classification, and an approach to unambiguous identification of single elements. It also comprises an ontology intended for knowledge representation in the semantic web, available in the RDF format
