File sharing is the practice of distributing or providing access to digital media, such as computer programs, documents or electronic books. File sharing may be achieved in a number of ways. Common methods of storage and dispersion include manual sharing utilizing removable media, centralized servers on computer networks, World Wide Web-based hyperlinked documents, the use of distributed peer-to-peer networking. Peer-to-peer file sharing is based on the peer-to-peer application architecture. Shared files on the computers of other users are indexed on directory servers. P2P technology was used by popular services like Limewire; the most popular protocol for P2P sharing is BitTorrent. Cloud-based file syncing and sharing services implement automated file transfers by updating files from a dedicated sharing directory on each user's networked devices. Files placed in this folder are accessible through a website and mobile app, can be shared with other users for viewing or collaboration; such services have become popular via consumer-oriented file hosting services such as Dropbox and Google Drive.
Rsync is a more traditional program released in 1996 which synchronizes files on a direct machine-to-machine basis. Data synchronization in general can use other approaches to share files, such as distributed filesystems, version control, or mirrors. Files were first exchanged on removable media. Computers were able to access remote files using filesystem mounting, bulletin board systems, FTP servers. Internet Relay Chat and Hotline enabled users to communicate remotely through chat and to exchange files; the mp3 encoding, standardized in 1991 and reduced the size of audio files, grew to widespread use in the late 1990s. In 1998, MP3.com and Audiogalaxy were established, the Digital Millennium Copyright Act was unanimously passed, the first mp3 player devices were launched. In June 1999, Napster was released as an unstructured centralized peer-to-peer system, requiring a central server for indexing and peer discovery, it is credited as being the first peer-to-peer file sharing system. Gnutella, eDonkey2000, Freenet were released in 2000, as MP3.com and Napster were facing litigation.
Gnutella, released in March, was the first decentralized file sharing network. In the gnutella network, all connecting software was considered equal, therefore the network had no central point of failure. In July, Freenet became the first anonymity network. In September the eDonkey2000 client and server software was released. In 2001, Kazaa and Poisoned for the Mac was released, its FastTrack network was distributed, though unlike gnutella, it assigned more traffic to'supernodes' to increase routing efficiency. The network was proprietary and encrypted, the Kazaa team made substantial efforts to keep other clients such as Morpheus off of the FastTrack network. In July 2001, Napster was sued by several recording companies and lost in A&M Records, Inc. v. Napster, Inc.. In the case of Napster, it has been ruled that an online service provider could not use the "transitory network transmission" safe harbor in the DMCA if they had control of the network with a server. Shortly after its loss in court, Napster was shut down to comply with a court order.
This drove users to other P2P applications and file sharing continued its growth. The Audiogalaxy Satellite client grew in popularity, the LimeWire client and BitTorrent protocol were released; until its decline in 2004, Kazaa was the most popular file sharing program despite bundled malware and legal battles in the Netherlands and the United States. In 2002, a Tokyo district court ruling shut down File Rogue, the Recording Industry Association of America filed a lawsuit that shut down Audiogalaxy. From 2002 through 2003, a number of BitTorrent services were established, including Suprnova.org, isoHunt, TorrentSpy, The Pirate Bay. In 2002, the RIAA was filing lawsuits against Kazaa users; as a result of such lawsuits, many universities added file sharing regulations in their school administrative codes. With the shutdown of eDonkey in 2005, eMule became the dominant client of the eDonkey network. In 2006, police raids took down the Razorback2 eDonkey server and temporarily took down The Pirate Bay.“The File Sharing Act was launched by Chairman Towns in 2009, this act prohibited the use of applications that allowed individuals to share federal information amongst one another.
On the other hand, only specific file sharing application were made available to federal computers”. In 2009, the Pirate Bay trial ended in a guilty verdict for the primary founders of the tracker; the decision was appealed, leading to a second guilty verdict in November 2010. In October 2010, Limewire was forced to shut down following a court order in Arista Records LLC v. Lime Group LLC but the gnutella network remains active through open source clients like Frostwire and gtk-gnutella. Furthermore, multi-protocol file sharing software such as MLDonkey and Shareaza adapted in order to support all the major file sharing protocols, so users no longer had to install and configure multiple file sharing programs. On January 19, 2012, the United States Department of Justice shut down the popular domain of Megaupload; the file sharing site has claimed to have over 50,000,000 people a day. Kim Dotcom was arrested with three associates in New Zealand on January 20, 2012 and is awaiting extradition; the case involving the downfall of the world's largest and most popular file sharing site was not well received, with hac
Many-to-many (data model)
In systems analysis, a many-to-many relationship is a type of cardinality that refers to the relationship between two entities A and B in which A may contain a parent instance for which there are many children in B and vice versa. For example, think of A as Authors, B as Books. An Author can write several Books, a Book can be written by several Authors. In a relational database management system, such relationships are implemented by means of an associative table, say, AB with two one-to-many relationships A -> AB and B -> AB. In this case the logical primary key for AB is formed from the two foreign keys. In web application frameworks such as CakePHP and Ruby on Rails, a many-to-many relationship between entity types represented by logical model database tables is sometimes referred to as a HasAndBelongsToMany relationship. Associative Entities One-to-one One-to-many
Communication is the act of conveying meanings from one entity or group to another through the use of mutually understood signs and semiotic rules. The main steps inherent to all communication are: The formation of communicative motivation or reason. Message composition. Message encoding. Transmission of the encoded message as a sequence of signals using a specific channel or medium. Noise sources such as natural forces and in some cases human activity begin influencing the quality of signals propagating from the sender to one or more receivers. Reception of signals and reassembling of the encoded message from a sequence of received signals. Decoding of the reassembled encoded message. Interpretation and making sense of the presumed original message; the scientific study of communication can be divided into: Information theory which studies the quantification and communication of information in general. The channel of communication can be visual, auditory and haptic, electromagnetic, or biochemical.
Human communication is unique for its extensive use of abstract language. Development of civilization has been linked with progress in telecommunication. Nonverbal communication describes the processes of conveying a type of information in the form of non-linguistic representations. Examples of nonverbal communication include haptic communication, chronemic communication, body language, facial expressions, eye contact, how one dresses. Nonverbal communication relates to the intent of a message. Examples of intent are voluntary, intentional movements like shaking a hand or winking, as well as involuntary, such as sweating. Speech contains nonverbal elements known as paralanguage, e.g. rhythm, intonation and stress. It establishes trust. Written texts include nonverbal elements such as handwriting style, the spatial arrangement of words and the use of emoticons to convey emotion. Nonverbal communication demonstrates one of Paul Wazlawick's laws: you cannot not communicate. Once proximity has formed awareness, living creatures begin interpreting.
Some of the functions of nonverbal communication in humans are to complement and illustrate, to reinforce and emphasize, to replace and substitute, to control and regulate, to contradict the denovative message. Nonverbal cues are relied on to express communication and to interpret others' communication and can replace or substitute verbal messages. However, non-verbal communication is ambiguous; when verbal messages contradict non-verbal messages, observation of non-verbal behaviour is relied on to judge another's attitudes and feelings, rather than assuming the truth of the verbal message alone. There are several reasons as to why non-verbal communication plays a vital role in communication: "Non-verbal communication is omnipresent." They are included in every single communication act. To have total communication, all non-verbal channels such as the body, voice, touch, distance and other environmental forces must be engaged during face-to-face interaction. Written communication can have non-verbal attributes.
E-mails and web chats allow an individual's the option to change text font colours, stationary and capitalization in order to capture non-verbal cues into a verbal medium. "Non-verbal behaviours are multifunctional." Many different non-verbal channels are engaged at the same time in communication acts and allow the chance for simultaneous messages to be sent and received. "Non-verbal behaviours may form a universal language system." Smiling, pointing and glaring are non-verbal behaviours that are used and understood by people regardless of nationality. Such non-verbal signals allow the most basic form of communication when verbal communication is not effective due to language barriers. Verbal communication is the written conveyance of a message. Human language can be defined as a system of symbols and the grammars by which the symbols are manipulated; the word "language" refers to common properties of languages. Language learning occurs most intensively during human childhood. Most of the thousands of human languages use patterns of sound or gesture for symbols which enable communication with others around them.
Languages tend to share certain properties. There is no defined line between a dialect. Constructed languages such as Esperanto, programming languages, various mathematical formalism is not restricted to the properties shared by human languages; as mentioned, language can be characterized as symbolic. Charles Ogden and I. A Richards developed The Triangle of Meaning model to explain the symbol, the referent, the meaning; the properties of language are governed by rules. Language follows phonological rules, syntactic rules, semantic rules, pragmatic rules; the meanings that are attached to words can be otherwise known as denotative.
The Internet is the global system of interconnected computer networks that use the Internet protocol suite to link devices worldwide. It is a network of networks that consists of private, academic and government networks of local to global scope, linked by a broad array of electronic and optical networking technologies; the Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents and applications of the World Wide Web, electronic mail and file sharing. Some publications no longer capitalize "internet"; the origins of the Internet date back to research commissioned by the federal government of the United States in the 1960s to build robust, fault-tolerant communication with computer networks. The primary precursor network, the ARPANET served as a backbone for interconnection of regional academic and military networks in the 1980s; the funding of the National Science Foundation Network as a new backbone in the 1980s, as well as private funding for other commercial extensions, led to worldwide participation in the development of new networking technologies, the merger of many networks.
The linking of commercial networks and enterprises by the early 1990s marked the beginning of the transition to the modern Internet, generated a sustained exponential growth as generations of institutional and mobile computers were connected to the network. Although the Internet was used by academia since the 1980s, commercialization incorporated its services and technologies into every aspect of modern life. Most traditional communication media, including telephony, television, paper mail and newspapers are reshaped, redefined, or bypassed by the Internet, giving birth to new services such as email, Internet telephony, Internet television, online music, digital newspapers, video streaming websites. Newspaper and other print publishing are adapting to website technology, or are reshaped into blogging, web feeds and online news aggregators; the Internet has enabled and accelerated new forms of personal interactions through instant messaging, Internet forums, social networking. Online shopping has grown exponentially both for major retailers and small businesses and entrepreneurs, as it enables firms to extend their "brick and mortar" presence to serve a larger market or sell goods and services online.
Business-to-business and financial services on the Internet affect supply chains across entire industries. The Internet has no single centralized governance in either technological implementation or policies for access and usage; the overreaching definitions of the two principal name spaces in the Internet, the Internet Protocol address space and the Domain Name System, are directed by a maintainer organization, the Internet Corporation for Assigned Names and Numbers. The technical underpinning and standardization of the core protocols is an activity of the Internet Engineering Task Force, a non-profit organization of loosely affiliated international participants that anyone may associate with by contributing technical expertise. In November 2006, the Internet was included on USA Today's list of New Seven Wonders; when the term Internet is used to refer to the specific global system of interconnected Internet Protocol networks, the word is a proper noun that should be written with an initial capital letter.
In common use and the media, it is erroneously not capitalized, viz. the internet. Some guides specify that the word should be capitalized when used as a noun, but not capitalized when used as an adjective; the Internet is often referred to as the Net, as a short form of network. As early as 1849, the word internetted was used uncapitalized as an adjective, meaning interconnected or interwoven; the designers of early computer networks used internet both as a noun and as a verb in shorthand form of internetwork or internetworking, meaning interconnecting computer networks. The terms Internet and World Wide Web are used interchangeably in everyday speech. However, the World Wide Web or the Web is only one of a large number of Internet services; the Web is a collection of interconnected documents and other web resources, linked by hyperlinks and URLs. As another point of comparison, Hypertext Transfer Protocol, or HTTP, is the language used on the Web for information transfer, yet it is just one of many languages or protocols that can be used for communication on the Internet.
The term Interweb is a portmanteau of Internet and World Wide Web used sarcastically to parody a technically unsavvy user. Research into packet switching, one of the fundamental Internet technologies, started in the early 1960s in the work of Paul Baran and Donald Davies. Packet-switched networks such as the NPL network, ARPANET, the Merit Network, CYCLADES, Telenet were developed in the late 1960s and early 1970s; the ARPANET project led to the development of protocols for internetworking, by which multiple separate networks could be joined into a network of networks. ARPANET development began with two network nodes which were interconnected between the Network Measurement Center at the University of California, Los Angeles Henry Samueli School of Engineering and Applied Science directed by Leonard Kleinrock, the NLS system at SRI International by Douglas Engelbart in Menlo Park, California, on 29 October 1969; the third site was the Culler-Fried Interactive Mathematics Center at the University of California, Santa Barbara, followed by the University of
A blog is a discussion or informational website published on the World Wide Web consisting of discrete informal diary-style text entries. Posts are displayed in reverse chronological order, so that the most recent post appears first, at the top of the web page; until 2009, blogs were the work of a single individual of a small group, covered a single subject or topic. In the 2010s, "multi-author blogs" emerged, featuring the writing of multiple authors and sometimes professionally edited. MABs from newspapers, other media outlets, think tanks, advocacy groups, similar institutions account for an increasing quantity of blog traffic; the rise of Twitter and other "microblogging" systems helps integrate MABs and single-author blogs into the news media. Blog can be used as a verb, meaning to maintain or add content to a blog; the emergence and growth of blogs in the late 1990s coincided with the advent of web publishing tools that facilitated the posting of content by non-technical users who did not have much experience with HTML or computer programming.
A knowledge of such technologies as HTML and File Transfer Protocol had been required to publish content on the Web, early Web users therefore tended to be hackers and computer enthusiasts. In the 2010s, the majority are interactive Web 2.0 websites, allowing visitors to leave online comments, it is this interactivity that distinguishes them from other static websites. In that sense, blogging can be seen as a form of social networking service. Indeed, bloggers do not only produce content to post on their blogs, but often build social relations with their readers and other bloggers. However, there are high-readership blogs. Many blogs provide commentary on topic, ranging from politics to sports. Others function as more personal online diaries, others function more as online brand advertising of a particular individual or company. A typical blog combines text, digital images, links to other blogs, web pages, other media related to its topic; the ability of readers to leave publicly viewable comments, interact with other commenters, is an important contribution to the popularity of many blogs.
However, blog owners or authors moderate and filter online comments to remove hate speech or other offensive content. Most blogs are textual, although some focus on art, videos and audio. In education, blogs can be used as instructional resources; these blogs are referred to as edublogs. Microblogging is another type of blogging, featuring short posts. On 16 February 2011, there were over 156 million public blogs in existence. On 20 February 2014, there were around 172 million Tumblr and 75.8 million WordPress blogs in existence worldwide. According to critics and other bloggers, Blogger is the most popular blogging service used today. However, Blogger does not offer public statistics. Technorati lists 1.3 million blogs as of February 22, 2014. The term "weblog" was coined by Jorn Barger on 17 December 1997; the short form, "blog", was coined by Peter Merholz, who jokingly broke the word weblog into the phrase we blog in the sidebar of his blog Peterme.com in April or May 1999. Shortly thereafter, Evan Williams at Pyra Labs used "blog" as both a noun and verb and devised the term "blogger" in connection with Pyra Labs' Blogger product, leading to the popularization of the terms.
Before blogging became popular, digital communities took many forms including Usenet, commercial online services such as GEnie, Byte Information Exchange and the early CompuServe, e-mail lists, Bulletin Board Systems. In the 1990s, Internet forum software created running conversations with "threads". Threads are topical connections between messages on a virtual "corkboard". From 14 June 1993, Mosaic Communications Corporation maintained their "What’s New" list of new websites, updated daily and archived monthly; the page was accessible by a special ``. The earliest instance of a commercial blog was on the first business to consumer Web site created in 1995 by Ty, Inc. which featured a blog in a section called "Online Diary". The entries were maintained by featured Beanie Babies that were voted for monthly by Web site visitors; the modern blog evolved from the online diary where people would keep a running account of the events in their personal lives. Most such writers journalers. Justin Hall, who began personal blogging in 1994 while a student at Swarthmore College, is recognized as one of the earlier bloggers, as is Jerry Pournelle.
Dave Winer's Scripting News is credited with being one of the older and longer running weblogs. The Australian Netguide magazine maintained the Daily Net News on their web site from 1996. Daily Net News ran links and daily reviews of new websites in Australia. Another early blog was Wearable Wireless Webcam, an online shared diary of a person's personal life combining text, digital video, digital pictures transmitted live from a wearable computer and EyeTap device to a web site in 1994; this practice of semi-automated blogging with live video together with text was referred to as sousveillance, such journals were used as evidence in legal matters. Some early bloggers, such as The Misanthropic Bitch, who began in 1997 referred to their online presence as a zine, before the term blog entered common usage. Early blogs were manually updated components of common Websites. In 1995, the "Online Diary" on
Peer-to-peer computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are privileged, equipotent participants in the application, they are said to form a peer-to-peer network of nodes. Peers make a portion of their resources, such as processing power, disk storage or network bandwidth, directly available to other network participants, without the need for central coordination by servers or stable hosts. Peers are both suppliers and consumers of resources, in contrast to the traditional client-server model in which the consumption and supply of resources is divided. Emerging collaborative P2P systems are going beyond the era of peers doing similar things while sharing resources, are looking for diverse peers that can bring in unique resources and capabilities to a virtual community thereby empowering it to engage in greater tasks beyond those that can be accomplished by individual peers, yet that are beneficial to all the peers.
While P2P systems had been used in many application domains, the architecture was popularized by the file sharing system Napster released in 1999. The concept has inspired new philosophies in many areas of human interaction. In such social contexts, peer-to-peer as a meme refers to the egalitarian social networking that has emerged throughout society, enabled by Internet technologies in general. While P2P systems had been used in many application domains, the concept was popularized by file sharing systems such as the music-sharing application Napster; the peer-to-peer movement allowed millions of Internet users to connect "directly, forming groups and collaborating to become user-created search engines, virtual supercomputers, filesystems." The basic concept of peer-to-peer computing was envisioned in earlier software systems and networking discussions, reaching back to principles stated in the first Request for Comments, RFC 1. Tim Berners-Lee's vision for the World Wide Web was close to a P2P network in that it assumed each user of the web would be an active editor and contributor and linking content to form an interlinked "web" of links.
The early Internet was more open than present day, where two machines connected to the Internet could send packets to each other without firewalls and other security measures. This contrasts to the broadcasting-like structure of the web; as a precursor to the Internet, ARPANET was a successful client-server network where "every participating node could request and serve content." However, ARPANET was not self-organized, it lacked the ability to "provide any means for context or content-based routing beyond'simple' address-based routing."Therefore, USENET, a distributed messaging system, described as an early peer-to-peer architecture, was established. It was developed in 1979 as a system; the basic model is a client-server model from the user or client perspective that offers a self-organizing approach to newsgroup servers. However, news servers communicate with one another as peers to propagate Usenet news articles over the entire group of network servers; the same consideration applies to SMTP email in the sense that the core email-relaying network of mail transfer agents has a peer-to-peer character, while the periphery of e-mail clients and their direct connections is a client-server relationship.
In May 1999, with millions more people on the Internet, Shawn Fanning introduced the music and file-sharing application called Napster. Napster was the beginning of peer-to-peer networks, as we know them today, where "participating users establish a virtual network independent from the physical network, without having to obey any administrative authorities or restrictions." A peer-to-peer network is designed around the notion of equal peer nodes functioning as both "clients" and "servers" to the other nodes on the network. This model of network arrangement differs from the client–server model where communication is to and from a central server. A typical example of a file transfer that uses the client-server model is the File Transfer Protocol service in which the client and server programs are distinct: the clients initiate the transfer, the servers satisfy these requests. Peer-to-peer networks implement some form of virtual overlay network on top of the physical network topology, where the nodes in the overlay form a subset of the nodes in the physical network.
Data is still exchanged directly over the underlying TCP/IP network, but at the application layer peers are able to communicate with each other directly, via the logical overlay links. Overlays are used for indexing and peer discovery, make the P2P system independent from the physical network topology. Based on how the nodes are linked to each other within the overlay network, how resources are indexed and located, we can classify networks as unstructured or structured. Unstructured peer-to-peer networks do not impose a particular structure on the overlay network by design, but rather are formed by nodes that randomly form connections to each other.. Because there is no structure globally imposed upon them, unstructured networks are easy to build and allow for localized optimizations to different regions of the overlay; because the role of all peers in the network is the same, unstructured networks are robust in the face of high rates of "churn"—that is, when large numbers of peers are joining and leaving the network.
Modern history, the modern period or the modern era, is the linear, historiographical approach to the time frame after post-classical history. Modern history can be further broken down into periods: The early modern period began in the early 16th century; the late modern period began in the mid-18th century. It took all of human history up to 1804 for the world's population to reach 1 billion. Contemporary history is the span of historic events from 1945 that are relevant to the present time; this article covers the 1800–1950 time period with a brief summary of 1500–1800. For a more in depth article on modern times before 1800, see Early Modern period. In the pre-modern era, many people's sense of self and purpose was expressed via a faith in some form of deity, be it that in a single God or in many gods. Pre-modern cultures have not been thought of creating a sense of distinct individuality, though. Religious officials, who held positions of power, were the spiritual intermediaries to the common person.
It was only through these intermediaries. Tradition was sacred to ancient cultures and was unchanging and the social order of ceremony and morals in a culture could be enforced; the term modern was coined in the 16th century to indicate recent times. The European Renaissance, which marked the transition between the Late Middle Ages and Early Modern times, started in Italy and was spurred in part by the rediscovery of classical art and literature, as well as the new perspectives gained from the Age of Discovery and the invention of the telescope and microscope, expanding the borders of thought and knowledge. In contrast to the pre-modern era, Western civilization made a gradual transition from pre-modernity to modernity when scientific methods were developed which led many to believe that the use of science would lead to all knowledge, thus throwing back the shroud of myth under which pre-modern peoples lived. New information about the world was discovered via empirical observation, versus the historic use of reason and innate knowledge.
The term Early Modern was introduced in the English language in the 1930s to distinguish the time between what has been called the Middle Ages and time of the late Enlightenment. It is important to note. In usage in other parts of the world, such as in Asia, in Muslim countries, the terms are applied in a different way, but in the context with their contact with European culture in the Age of Discovery. In the Contemporary era, there were various socio-technological trends. Regarding the 21st century and the late modern world, the Information Age and computers were forefront in use, not ubiquitous but present in everyday life; the development of Eastern powers was with China and India becoming more powerful. In the Eurasian theater, the European Union and Russian Federation were two forces developed. A concern for Western world, if not the whole world, was the late modern form of terrorism and the warfare that has resulted from the contemporary terrorist acts; the modern period has been a period of significant development in the fields of science, politics and technology.
It has been an age of discovery and globalization. During this time, the European powers and their colonies, began a political and cultural colonization of the rest of the world. By the late 19th and 20th centuries, modernist art, politics and culture has come to dominate not only Western Europe and North America, but every civilized area on the globe, including movements thought of as opposed to the west and globalization; the modern era is associated with the development of individualism, urbanization and a belief in the possibilities of technological and political progress. Wars and other perceived problems of this era, many of which come from the effects of rapid change, the connected loss of strength of traditional religious and ethical norms, have led to many reactions against modern development. Optimism and belief in constant progress has been most criticized by postmodernism while the dominance of Western Europe and Anglo-America over other continents has been criticized by postcolonial theory.
One common conception of modernity is the condition of Western history since the mid-15th century, or the European development of movable type and the printing press. In this context the "modern" society is said to develop over many periods, to be influenced by important events that represent breaks in the continuity; the modern era includes the early period, called the early modern period, which lasted from c. 1500 to around c. 1800. Particular facets of early modernity include: The Renaissance in Italy The Reformation and Counter Reformation The Age of Discovery The Columbian Exchange and Colonization of the Americas The rise of mercantilism and capitalism The Golden Age of PiracyImportant events in the early modern period include: The spread of the printing press The Thirty Years' War and the Peace of Westphalia in Europe The English Civil War, the Glorious Revolution, the union