1.
BBC Research & Development
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BBC Research & Development is the national technical research department of the BBC. BBC R&D is part of the wider BBC Digital, and is led by Andy Conroy, in 2011 the North Lab moved into Salford MediaCityUK along with several other departments of the BBC, whilst the South Lab remained in White City in London. The department as it today was formed in 1993 from the merger of the BBC Designs Department. From 2006 to 2008 it was known as Research and Innovation but has reverted to its original name. It has also involved in many well known consumer technologies such as teletext, DAB, NICAM. It was at the forefront of development of FM radio, stereo FM and these innovations have led to Queens Awards for Innovation in 1969,1974,1983,1987,1992,1998,2001 and 2011. In the 1970s, its engineers designed the famous LS3/5A studio monitor for use in outside broadcasting units, licensed to manufacturers, the loudspeaker sold 100,000 pairs in its 20+ years life. BBC R&D engineers and researchers are active on approximately 50 projects. These include R&D projects built around BBC Redux—the proof of concept for the cross-platform, a-weighting CEEFAX Dirac Equal-loudness contour ITU-R468 noise weighting NICAM Peak programme meter Sound-in-Syncs VERA videotape format Kamaelia Backstage. bbc. co
2.
BBC
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The British Broadcasting Corporation is a British public service broadcaster. It is headquartered at Broadcasting House in London, the BBC is the worlds oldest national broadcasting organisation and the largest broadcaster in the world by number of employees. It employs over 20,950 staff in total,16,672 of whom are in public sector broadcasting, the total number of staff is 35,402 when part-time, flexible, and fixed contract staff are included. The BBC is established under a Royal Charter and operates under its Agreement with the Secretary of State for Culture, Media and Sport. The fee is set by the British Government, agreed by Parliament, and used to fund the BBCs radio, TV, britains first live public broadcast from the Marconi factory in Chelmsford took place in June 1920. It was sponsored by the Daily Mails Lord Northcliffe and featured the famous Australian Soprano Dame Nellie Melba, the Melba broadcast caught the peoples imagination and marked a turning point in the British publics attitude to radio. However, this public enthusiasm was not shared in official circles where such broadcasts were held to interfere with important military and civil communications. By late 1920, pressure from these quarters and uneasiness among the staff of the licensing authority, the General Post Office, was sufficient to lead to a ban on further Chelmsford broadcasts. But by 1922, the GPO had received nearly 100 broadcast licence requests, John Reith, a Scottish Calvinist, was appointed its General Manager in December 1922 a few weeks after the company made its first official broadcast. The company was to be financed by a royalty on the sale of BBC wireless receiving sets from approved manufacturers, to this day, the BBC aims to follow the Reithian directive to inform, educate and entertain. The financial arrangements soon proved inadequate, set sales were disappointing as amateurs made their own receivers and listeners bought rival unlicensed sets. By mid-1923, discussions between the GPO and the BBC had become deadlocked and the Postmaster-General commissioned a review of broadcasting by the Sykes Committee and this was to be followed by a simple 10 shillings licence fee with no royalty once the wireless manufactures protection expired. The BBCs broadcasting monopoly was made explicit for the duration of its current broadcast licence, the BBC was also banned from presenting news bulletins before 19.00, and required to source all news from external wire services. Mid-1925 found the future of broadcasting under further consideration, this time by the Crawford committee, by now the BBC under Reiths leadership had forged a consensus favouring a continuation of the unified broadcasting service, but more money was still required to finance rapid expansion. Wireless manufacturers were anxious to exit the loss making consortium with Reith keen that the BBC be seen as a service rather than a commercial enterprise. The recommendations of the Crawford Committee were published in March the following year and were still under consideration by the GPO when the 1926 general strike broke out in May. The strike temporarily interrupted newspaper production and with restrictions on news bulletins waived the BBC suddenly became the source of news for the duration of the crisis. The crisis placed the BBC in a delicate position, the Government was divided on how to handle the BBC but ended up trusting Reith, whose opposition to the strike mirrored the PMs own
3.
Proof of concept
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A proof of concept is usually small and may or may not be complete. The appearance of the terms in news archives suggests it might have been in use as long ago as 1967. In 1969 Committee on Science and Astronautics, the column also provided definitions for the related but distinct terms breadboard, prototype, engineering prototype, and brassboard. Sky Captain and the World of Tomorrow,300, and Sin City were all shot in front of a greenscreen with almost all backgrounds, all three used proof-of-concept short films. In the case of Sin City, the film became the prologue of the final film. Pixar sometimes creates short animated films use a difficult or untested technique. Their short film Geris Game used techniques for animation of cloth, in engineering and technology, a rough prototype of a new idea is often constructed as a proof of concept. For example, a concept of an electrical device may be constructed using a breadboard. A patent application often requires a demonstration of functionality prior to being filed, some universities have proof of concept centers to fill the funding gap for seed-stage investing and accelerate the commercialization of university innovations. Proof of concept centers provide seed funding to novel, early stage research that most often would not be funded by any other conventional source, in the field of business development and sales, a vendor may allow a prospect customer to trial a product. In these cases, the proof of concept may mean the use of specialized sales engineers to ensure that the vendor makes a best-possible effort. Winzapper was a proof of concept which possessed the bare minimum of capabilities needed to remove an item from the Windows Security Log. Once a vendor is satisfied, a prototype is developed which is used to seek funding or to demonstrate to prospective customers. A steel thread is technical proof of concept that all of the technologies in a solution. By contrast, a proof of technology aims to determine the solution to some problem or to demonstrate that a given configuration can achieve a certain throughput. No business users need be involved in a proof of technology, a pilot project refers to an initial roll-out of a system into production, targeting a limited scope of the intended final solution. The scope may be limited by the number of users who can access the system, the business processes affected, the purpose of a pilot project is to test, often in a production environment. Although not suggested by natural language, and in contrast to usage in other areas, Proof of Principle, a third term, Proof of Mechanism, is closely related and is also described here
4.
Flash Video
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Flash Video is a container file format used to deliver digital video content over the Internet using Adobe Flash Player version 6 and newer. Flash Video content may also be embedded within SWF files, there are two different video file formats known as Flash Video, FLV and F4V. The audio and video data within FLV files are encoded in the manner as they are within SWF files. The F4V file format is based on the ISO base media file format and is starting with Flash Player 9 update 3, both formats are supported in Adobe Flash Player and developed by Adobe Systems. FLV was originally developed by Macromedia, in the early 2000s, Flash Video used to be the de facto standard for web-based streaming video. Notable users of it include Hulu, VEVO, Yahoo, Video, metacafe, Reuters. com, and many other news providers. Flash Video FLV files usually contain material encoded with codecs following the Sorenson Spark or VP6 video compression formats, the most recent public releases of Flash Player also support H.264 video and HE-AAC audio. All of these formats are restricted by patents. Flash Video is viewable on most operating systems via the Adobe Flash Player, apples iOS devices, along with almost all other mobile devices, do not support the Flash Player plugin and so require other delivery methods such as provided by the Adobe Flash Media Server. Support for video in SWF file format was added in Flash Player 6, in 2003, Flash Player 7 added direct support for FLV file format. Because of restrictions in the FLV file format, Adobe Systems has created in 2007 new file formats listed below, Flash Player does not check the extension of the file, but rather looks inside the file to detect which format it is. The new file formats are completely different from the older FLV file format, for example, F4V does not support Screen video, Sorenson Spark, VP6 video compression formats and ADPCM, Nellymoser audio compression formats. Authors of Flash Player strongly encourage everyone to embrace the new file format F4V. There are functional limits with the FLV structure when streaming H.264 or AAC which could not be overcome without a redesign of the file format and this is one reason why Adobe Systems is moving away from the traditional FLV file structure. Initial format since 2002 is Flash Video, file suffix is. flv with a MIME derived Internet media type of video/x-flv. SWF files published for Flash Player 6 and later versions are able to exchange audio, video, one way to feed data to Flash Media Server is from files in the FLV file format. Starting with SWF files created for Flash Player 7, Flash Player can play FLV file format directly, starting with SWF files created for Flash Player 9 Update 3, Flash Player can also play the new F4V file format. Use of the H.264 and AAC compression formats in the FLV file format has some limitations, commonly, Flash Video FLV files contain video bit streams which are a proprietary variant of the H.263 video standard, under the name of Sorenson Spark
5.
BBC iPlayer
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BBC iPlayer is an internet streaming catchup television and radio service in the United Kingdom. The service is available on a range of devices, including mobile phones and tablets, personal computers. Neither the iPlayer services nor the individual TV programmes display any commercial advertising, the terms BBC iPlayer, iPlayer, and BBC Media Player all refer to the same services. BBC Redux was developed as a proof of concept for a cross-platform, BBC iPlayer left beta and went live on 25 December 2007. On 25 June 2008, a new-look iPlayer was launched, originally as a beta-test version alongside the earlier version, the site tagline was Catch up on the last 7 days of BBC TV & Radio, reflecting that programmes were unavailable on iPlayer after this time. The BBC state on their website that this is due to copyright reasons, the marketing slogan was later changed to Making the unmissable, unmissable. In May 2010 the site was updated again, to include a recommendations feature, the feature was added to the search function and the channels function. When users click on a programme by another broadcaster, they are redirected to the relevant broadcasters catch up service, in April 2014, BBC iPlayer was once again relaunched with a new look and a different user interface. From October 2014, the BBC extended the availability for programmes on iPlayer from 7 days to 30 days. However, due to legal reasons, most news bulletins are available for 24 hours after initial broadcast. Some archive programming is availabily for the term, such as Timewatch. Specific applications for mobile platforms were launched in February 2011 and these were initially for iOS and Android devices, where the launch would have the biggest impact. In 2015, the BBC reported that it was moving towards playing audio, the original iPlayer service was launched in October 2005, undergoing a five-month trial by five thousand broadband users until 28 February 2006. The iPlayer was heavily criticised for delay in its launch, rebranding, a new, improved iPlayer service then had another very limited user trial which began on 15 November 2006. At various times during its development, iPlayer was known as the Integrated Media Player, Interactive Media Player and this was done reportedly to allow British ISPs and the BBC to gauge the effect of the iPlayer traffic on the Internet within the UK. However, it was only to users of Windows XP. This was a decision by the BBC, which led to a petition against the decision being posted on 10 Downing Streets e-petition website. The petition reached 16,082 signatures on 20 August 2007, the response from the Government was
6.
Video on demand
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IPTV technology is often used to bring video on demand to televisions and personal computers. Internet television, using the Internet, is a popular form of video on demand. VOD can also be accessed via desktop client applications such as the Apple iTunes online content store, some airlines offer VOD as in-flight entertainment to passengers through individually controlled video screens embedded in seatbacks or armrests or offered via portable media players. Some video on demand services such as Netflix use a model that requires users to pay a monthly fee to access a bundled set of content. Other services use a model, where access is free for Internet users. Downloading and streaming video on demand systems provide the user all of the features of Portable media players. Some VOD systems that store and stream programs from hard drives use a memory buffer to allow the user to fast forward. It is possible to put video servers on local area networks, streaming video servers can also serve a wider community via a WAN, in which case the responsiveness may be reduced. Download VOD services are practical to homes equipped with cable modems or DSL connections, servers for traditional cable and telco VOD services are usually placed at the cable head-end serving a particular market as well as cable hubs in larger markets. In the telco world, they are placed in either the central office, the first Video on Demand systems used tapes as the realtime source of video streams. GTE started as a trial in 1990 with AT&T providing all components, by 1992 VOD servers were supplying previously encoded digital video from disks and DRAM. In the US the 1982 anti-trust break-up of AT&T resulted in a number of telephone companies called Baby Bells. Following this the Cable Communications Policy Act of 1984 prohibited telephone companies from providing services within their operating regions. All of these companies and others began holding trials to setup systems for supplying Video on Demand over telephone, in November 1992 Bell Atlantic announced a VOD trial. The IBM was developing video server code-named Tiger Shark, concurrently Digital Equipment was developing a scalable video server. Bell Atlantic selected IBM and April 1993 the system became the first VOD over ADSL to be deployed outside the lab, in 1994-5 US West went on to file for VOD at several cities. 330,000 subscribers in Denver,290,000 in Minneapolis, many VOD trials were held with various combinations of server, network and set-top. Of these the primary players in the US were the companies, using DEC, Microsoft, Oracle, IBM, Hewlett-Packard, USA Video, nCube, SGI
7.
Digital video recorder
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A digital video recorder is an electronic device that records video in a digital format to a disk drive, USB flash drive, SD memory card, SSD or other local or networked mass storage device. The term includes set-top boxes with direct to disk recording, portable media players and TV gateways with recording capability, and digital camcorders. Personal computers are connected to video capture devices and used as DVRs. Many DVRs are classified as electronic devices, such devices are sometimes referred to as personal video recorders. Consumer digital video recorders ReplayTV and TiVo were launched at the 1999 Consumer Electronics Show in Las Vegas, Microsoft also demonstrated a unit with DVR capability, but this did not become available until the end of 1999 for full DVR features in Dish Networks DISHplayer receivers. TiVo shipped their first units on March 31,1999, ReplayTV won the Best of Show award in the video category with Netscape co-founder Marc Andreessen as an early investor and board member, but TiVo was more successful commercially. Many DVRs use the MPEG format for compressing the digital video, video recording capabilities have become an essential part of the modern set-top box, as TV viewers have wanted to take control of their viewing experiences. Digital video recorders tied to a video service At the 1999 CES, which also included WebTV Networks internet TV. By the end of 1999 the Dishplayer had full DVR capabilities and within a year, in the UK, digital video recorders are often referred to as plus boxes. Freeview+ have been around in the UK since the late 2000s, british Sky Broadcasting markets a popular combined receiver and DVR as Sky+. TiVo launched a UK model in 2000, and is no longer supported, except for third party services, south African based Africa Satellite TV beamer Multichoice recently launched their DVR which is available on their DStv platform. Astro introduced their DVR system, called Astro MAX, which was the first PVR in Malaysia but was phased out two years after its introduction. In the case of television, there is no encoding necessary in the DVR since the signal is already a digitally encoded MPEG stream. The digital video recorder simply stores the digital stream directly to disk and it can, however, also force the manufacturer to implement non-skippable advertisements and automatically expiring recordings. The overall net effect on video recorders and related technology is unlikely to be substantial as standalone DVRs are currently readily available on the open market. In 2003 many Satellite and Cable providers introduced dual-tuner digital video recorders, in the UK, BSkyB introduced their first PVR Sky+ with dual tuner support in 2001. These machines have two independent tuners within the same receiver, kogan. com introduced a dual-tuner PVR in the Australian market allowing free-to-air television to be recorded on a removable hard drive. Some dual-tuner DVRs also have the ability to output to two television sets at the same time
8.
README
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A README file contains information about other files in a directory or archive of computer software. A form of documentation, it is usually a plain text file called READ. ME, README. TXT, README. md. The files name is always written in upper case. However, the popularity of GitHub has contributed towards README files still being used in open-source software. On GitHub, if a Git repository has a README file in its directory, it is automatically converted into formatted HTML. Various different file extensions can be used, and conversion to HTML takes account of the extension of the file – for example. The expression readme file is also used generically, for files with a similar purpose. Check your Readme files to avoid common Windows problems and this article is based in part on the Jargon File, which is in the public domain
9.
GitHub
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GitHub is a web-based Git or version control repository and Internet hosting service. It offers all of the version control and source code management functionality of Git as well as adding its own features. It provides access control and several features such as bug tracking, feature requests, task management. GitHub offers both plans for private and free repositories on the account which are commonly used to host open-source software projects. As of April 2016, GitHub reports having more than 14 million users and more than 85.5 million repositories, the trademark mascot of GitHub is Octocat, an anthropomorphized cat with cephalopod limbs. Development of the GitHub platform began on 1 October 2007, the site was launched in April 2008 by Tom Preston-Werner, Chris Wanstrath, and PJ Hyett after it had been made available for a few months prior as a beta release. Projects on GitHub can be accessed and manipulated using the standard Git command-line interface, GitHub also allows registered and non-registered users to browse public repositories on the site. Multiple desktop clients and Git plugins have also created by GitHub. The site provides social networking-like functions such as feeds, followers, wikis, a user must create an account in order to contribute content to the site, but public repositories can be browsed and downloaded by anyone. With a registered account, users are able to discuss, manage, create repositories, submit contributions to others repositories. The software that runs GitHub was written using Ruby on Rails and Erlang by GitHub, Inc. developers Chris Wanstrath, PJ Hyett, GitHub is mostly used for code. Emojis GitHub Pages, small websites can be hosted from public repositories on GitHub, nested task-lists within files Visualization of geospatial data 3D render files that can be previewed using a new integrated STL file viewer that displays the files on a 3D canvas. The viewer is powered by WebGL and Three. js, photoshops native PSD format can be previewed and compared to previous versions of the same file. GitHubs Terms of Service do not require public software projects hosted on GitHub to meet the Open Source Definition. For that reason, it is advisable for users and developers intending to use a piece of software found on GitHub to read the license in the repository to determine if it meets their needs. The Terms of Service state, By setting your repositories to be viewed publicly, you agree to allow others to view, GitHub also operates other services, a pastebin-style site called Gist that is for hosting code snippets, and a slide hosting service called Speaker Deck. Tom Preston-Werner presented the then-new Gist feature at a punk rock Ruby conference in 2008, Gist builds on the traditional simple concept of a pastebin by adding version control for code snippets, easy forking, and SSL encryption for private pastes. Because each gist has its own Git repository, multiple code snippets can be contained in a single paste, further, forked code can be pushed back to the original author in the form of a patch, so gists can become more like mini-projects
10.
BBC One
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BBC One is the flagship television channel of the British Broadcasting Corporation in the United Kingdom, Isle of Man and Channel Islands. It was launched on 2 November 1936 as the BBC Television Service and it was renamed BBC TV in 1960, using this name until the launch of sister channel BBC2 in 1964, whereupon the BBC TV channel became known as BBC1, with the current spelling adopted in 1997. The channels annual budget for 2012–13 is £1.14 billion, the channel is funded by the television licence fee together with the BBCs other domestic television stations, and therefore shows uninterrupted programming without commercial advertising. It is currently the most watched channel in the United Kingdom, ahead of its traditional rival for ratings leadership. As of June 2013 the channel controller for BBC One is Charlotte Moore, the BBC began its own regular television programming from the basement of Broadcasting House, London, on 22 August 1932. BBC Television returned on 7 June 1946 at 15,00, Jasmine Bligh, one of the original announcers, made the first announcement, saying, Good afternoon everybody. Do you remember me, Jasmine Bligh, the Mickey Mouse cartoon of 1939 was repeated twenty minutes later. The competition quickly forced the channel to change its identity and priorities following a reduction in its audience. The 1962 Pilkington Report on the future of broadcasting noticed this, and it therefore decided that Britains third television station should be awarded to the BBC. The station, renamed BBC TV in 1960, became BBC1 when BBC2 was launched on 20 April 1964 transmitting an incompatible 625-line image on UHF. The only way to all channels was to use a complex dual-standard 405- and 625-line, VHF and UHF, receiver. Old 405-line-only sets became obsolete in 1985, when transmission in the standard ended, although standards converters have become available for enthusiasts who collect, BBC1 was based at the purpose-built BBC Television Centre at White City, London between 1960 and 2013. In the weeks leading up to 15 November 1969, BBC1 unofficially transmitted the occasional programme in its new colour system, to test it. At midnight on 15 November, simultaneously with ITV and two years after BBC2, BBC1 officially began 625-line PAL colour programming on UHF with a broadcast of a concert by Petula Clark, colour transmissions could be received on monochrome 625-line sets until the end of analogue broadcasting. In terms of share, the most successful period for BBC1 was under Bryan Cowgill between 1973 and 1977, when the channel achieved an average audience share of 45%. On 30 December 1980, the BBC announced their intention to introduce a new breakfast television service to compete with TV-am. On 17 January 1983, the first edition of Breakfast Time was shown on BBC One, becoming the first UK wide breakfast television service and continued to lead in the rating until 1984. The first major overhaul was to axe the deeply unpopular Sixty Minutes current affairs programme and its replacement was the BBC Six OClock News, a straight new programme in a bid to shore up its failing early evening slot
11.
DVB-T
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This system transmits compressed digital audio, digital video and other data in an MPEG transport stream, using coded orthogonal frequency-division multiplexing modulation. It is also the format widely used worldwide for Electronic News Gathering for transmission of video, in the case of DVB-T, there are two choices for the number of carriers known as 2K-mode or 8K-mode. These are actually 1,705 or 6,817 sub-carriers that are approximately 4 kHz or 1 kHz apart, DVB-T offers three different modulation schemes. The DVB-T Standard is published as EN300744, Framing structure, channel coding, many countries that have adopted DVB-T have published standards for their implementation. These include the D-book in the UK, the Italian DGTVi, DVB-T has been further developed into newer standards such as DVB-H, which was a commercial failure and is no longer in operation, and DVB-T2, which was initially finalised in August 2011. DVB-T as a digital transmission delivers data in a series of blocks at the symbol rate. DVB-T is a COFDM transmission technique which includes the use of a Guard Interval and it allows the receiver to cope with strong multipath situations. Within a geographical area, DVB-T also allows single-frequency network operation, in such cases the signals from each transmitter in the SFN needs to be accurately time-aligned, which is done by sync information in the stream and timing at each transmitter referenced to GPS. The length of the Guard Interval can be chosen and it is a trade-off between data rate and SFN capability. The longer the interval the larger is the potential SFN area without creating intersymbol interference. It is possible to operate SFNs which do not fulfill the guard interval condition if the self-interference is properly planned and monitored, with reference to the figure, a short description of the signal processing blocks follows. Source coding and MPEG-2 multiplexing Compressed video, compressed audio, one or more MPEG-PSs are joined together into an MPEG transport stream, this is the basic digital stream which is being transmitted and received by TV sets or home Set Top Boxes. Allowed bitrates for the transported data depend on a number of coding and modulation parameters, splitter Two different MPEG-TSs can be transmitted at the same time, using a technique called Hierarchical Transmission. It may be used to transmit, for example a standard definition SDTV signal, generally, the SDTV signal is more robust than the HDTV one. At the receiver, depending on the quality of the received signal, MUX adaptation and energy dispersal The MPEG-TS is identified as a sequence of data packets, of fixed length. With a technique called energy dispersal, the sequence is decorrelated. External interleaver Convolutional interleaving is used to rearrange the transmitted data sequence, Internal encoder A second level of error correction is given by a punctured convolutional code, which is often denoted in STBs menus as FEC. There are five valid coding rates, 1/2, 2/3, 3/4, 5/6, Internal interleaver Data sequence is rearranged again, aiming to reduce the influence of burst errors
12.
TV tuner card
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A TV tuner card is a kind of television tuner that allows television signals to be received by a computer. Most TV tuners also function as video cards, allowing them to record television programs onto a hard disk much like the digital video recorder does. The interfaces for TV tuner cards are most commonly either PCI bus expansion card or the newer PCI Express bus for many modern cards, in addition, some video cards double as TV tuners, notably the ATI All-In-Wonder series. The card contains a tuner and an analog-to-digital converter along with demodulation, some lower-end cards lack an onboard processor and, like a Winmodem, rely on the systems CPU for demodulation. More advanced TV tuners encode the signal to Motion JPEG or MPEG, some cards also have analog input and many also provide a radio tuner. A hybrid tuner has one tuner that can be configured to act as an analog tuner or a digital tuner, switching between the systems is fairly easy, but cannot be done immediately. The card operates as a digital tuner or an analog tuner until reconfigured and this is similar to a hybrid tuner, except there are two separate tuners on the card. One can watch analog while recording digital, or vice versa, the card operates as an analog tuner and a digital tuner simultaneously. The advantages over two separate cards are cost and utilization of expansion slots in the computer, as many regions around the world convert from analog to digital broadcasts, these tuners are gaining popularity. Like the analog cards, the Hybrid and Combo tuners can have specialized chips on the card to perform the encoding. The tuner cards with this hardware encoding are generally thought of as being higher quality, small USB tuner sticks have become more popular in 2006 and 2007 and are expected to increase in popularity. These small tuners generally do not have hardware encoding due to size, many TV tuners can function as FM radios, this is because there are similarities between broadcast television and FM radio. The FM radio spectrum is close to that used by VHF terrestrial TV broadcasts, and many broadcast television systems around the world use FM audio. So listening to an FM radio station is simply a case of configuring existing hardware. S, there is also a converter for watching DVB-H in Europe and elsewhere via WiFi streaming video. Video capture cards are a class of video capture devices designed to directly into expansion slots in personal computers and servers. Models from many manufacturers are available, all comply with one of the popular host bus standards including PCI and these cards typically include one or more software drivers to expose the cards features, via various operating systems, to software applications that further process the video for specific purposes. As a class, the cards are used to capture baseband analog composite video, S-Video, some specialized cards support digital video via digital video delivery standards including Serial Digital Interface and, more recently, the emerging HDMI standard. These models often support both standard definition and high definition variants, while most PCI and PCI-Express capture devices are dedicated to that purpose, AGP capture devices are usually included with the graphics adapted on the board as an all-in-one package
13.
Freesat
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Freesat is a free-to-air digital satellite television joint venture between the BBC and ITV plc, serving the United Kingdom. The service was formed as a memorandum in 2007 and has been marketed since 6 May 2008, Freesats main competitors are Freeview and Freesat from Sky. On digital terrestrial, the channels have always been available free-to-air with the appropriate equipment, in 2007 Freeview was available to only 73% of the population. After analogue TV services were replaced in the digital switchover, this increased to 98. 5% for the public service channels, to provide more widespread coverage and a larger number of channels, a digital satellite alternative was felt necessary. The use of encryption meant that anyone wishing to view the channels had to purchase equipment from Sky, similarly, to use the Videoguard encryption, the broadcasters needed to pay a fee to NDS Group. In May 2003 the BBC moved most of its channels from the Astra 2A satellite to Astra 2D and this move allowed the BBC to stop encrypting its broadcasts while continuing to meet its rights obligations. It dropped the two months later. Two months later, ITV, whose channels had already been located on the Astra 2D satellite since launching on the Sky platform some years earlier, also made their channels free-to-air. On 18 November 2008, Channel 5 commenced broadcasting a single channel via Freesat, eventually adding its ancillary services 5USA, viva moved from free-to-view to free-to-air on satellite on 19 March 2013, before launching on Freesat on 2 April 2013. On 2 April 2013, all seven of Box Televisions channels left Skys subscription package, with six becoming free-to-air on satellite, on 15 April four of the channels – The Box, TV, Kiss TV and Smash Hits – were added to the Freesat EPG. This was followed by Heat and Magic on 29 April, the Freesat project aims to provide a managed service with an Electronic Programme Guide and interactive features similar to the Freeview service launched three years earlier. Unlike Freeview, however, these features are available on approved receivers manufactured under licence from Freesat. The initial plan was to launch the service in early 2006 and this was postponed to Autumn 2007 as approval from the BBC Trust was only received in April 2007. However, the service was delayed and was officially launched on 6 May 2008. The service launched officially on 6 May 2008, from the launch, Freesat advertised all national television channels from the BBC and ITV as being available on the platform, as well as all national BBC radio networks. Channel 4 also managed to make most of its channels free-to-air in preparation for the launch. In addition some channels from other such as Chello Zone, CSC Media Group, Al Jazeera English, Zee Live, Zee News RIA Novosti. BBC HD was the only channel available on Freesat from launch day
14.
Freeview (UK)
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Freeview is the United Kingdoms digital terrestrial television platform. It is operated by DTV Services Ltd, a joint venture between the BBC, ITV, Channel 4, Sky and transmitter operator Arqiva, the service provides consumer access via an aerial to the six DTT multiplexes covering the United Kingdom. In April 2014 it had some 60 DVB-T TV channels,26 digital radio channels,10 HD channels, six services,11 streamed channels. A number of new HD channels launched in 2014, from a new group of multiplexes awarded to Arqiva, the new HD channels were launched in selected areas on 10 December 2013 with a further roll-out during 2014. DTV Services delivery of television and radio is labelled Freeview. Reception of Freeview requires a Freeview tuner, either in a separate box or built into the TV set. Since 2008 all new TV sets sold in the United Kingdom have a built-in Freeview tuner, Freeview HD requires a HDTV-capable tuner. Digital video recorders with a built-in Freeview tuner are labelled Freeview+, depending on model, DVRs and HDTV sets with a Freeview tuner may offer standard Freeview or Freeview HD. DMOL, a company owned by the operators of the six DTT multiplexes is responsible for platform management and policy, including the electronic programme guide. The founding members of DTV Services, who trade as Freeview, were the BBC, Crown Castle UK, on 11 October 2006, ITV plc and Channel 4 became equal shareholders. Since then, the Freeview model has been copied in Australia, with the launch of Freeview other channels were broadcast free-to-air, such as, Sky Travel, UK History, Sky News, Sky Sports News, The Hits and TMF were available from the start. BBC Four and the interactive BBC streams were moved to multiplex B, under the initial plans, the two multiplexes operated by Crown Castle would carry eight channels altogether. The seventh stream became shared by UK Bright Ideas and Ftn which launched in February 2003, the eighth stream was left unused until April 2004 when the shopping channel Ideal World launched on Freeview. There are now 14 streams carried by the two multiplexes, with Multiplex C carrying 6 streams, and Multiplex D carrying 8 and it has recently been announced that more streams are now available on the multiplexes, and that bidding is under way. The Freeview service underwent an upgrade on 30 September 2009. The changes, meant to ensure reception of Channel 5. The Freeview website crashed and the centre was inundated as a result of the problems. The change involved an update to the NIT, which some receivers could not accommodate, many thousands of people could not receive some channels
15.
MPEG transport stream
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MPEG transport stream is a standard digital container format for transmission and storage of audio, video, and Program and System Information Protocol data. It is used in broadcast systems such as Digital Video Broadcasting, ATSC, further, a transport stream may carry multiple programs. Transport stream is specified in MPEG-2 Part 1, Systems, formally known as ISO/IEC standard 13818-1 or ITU-T Rec, many unrelated streams are often mixed together, such as several different television channels, or multiple angles of a movie. This is particularly important for videoconferencing, where one large frame may introduce unacceptable audio delay. A packet is the unit of data in a transport stream. Each packet starts with a byte and a header, that may be followed with optional additional headers. All header fields are read as big-endian, the 188-byte packet size was originally chosen for compatibility with ATM systems. Each table or elementary stream in a stream is identified by a 13-bit packet identifier. A demultiplexer extracts elementary streams from the stream in part by looking for packets identified by the same PID. In most applications, time-division multiplexing will be used to decide how often a particular PID appears in the transport stream, Transport stream has a concept of programs. Every single program is described by a Program Map Table which has a unique PID, for instance, a transport stream used in digital television might contain three programs, to represent three television channels. Suppose each channel consists of one stream, one or two audio streams, and any necessary metadata. A receiver wishing to decode a particular channel merely has to decode the payloads of each PID associated with its program and it can discard the contents of all other PIDs. A transport stream with more than one program is referred to as MPTS - Multi Program Transport Stream, a single program transport stream is referred to as SPTS - Single Program Transport Stream. There are 4 PSI tables, Program Association, Program Map, Conditional Access, the MPEG-2 specification does not specify the format of the CAT and NIT. PAT stands for Program Association Table and it lists all programs available in the transport stream. Each of the programs is identified by a 16-bit value called program_number. Each of the programs listed in PAT has a value of PID for its Program Map Table
16.
Television program
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It may be a single production, or more commonly, a series of related productions. A limited number of episodes of a show may be called a miniseries or a serial or limited series. Television series are without a fixed length and are divided into seasons or series. While there is no defined length, U. S. industry practice has traditionally favored longer television seasons than those of other countries, a one-time broadcast may be called a special, or particularly in the UK a special episode. A television film is a film that is initially broadcast on television rather than released in theaters or direct-to-video, a program can be either recorded, as on video tape, other various electronic media forms, played with an on-demand player or viewed on live television. Television programs may be fictional, or non-fictional and it may be topical, or historical. They could be primarily instructional or educational, or entertaining as is the case in situation comedy, a drama program usually features a set of actors playing characters in a historical or contemporary setting. The program follows their lives and adventures, except for soap opera-type serials, many shows especially before the 1980s, remained static without story arcs, and the main characters and premise changed little. If some change happened to the characters lives during the episode, because of this, the episodes could be broadcast in any order. Since the 1980s, there are series that feature progressive change to the plot. For instance, Hill Street Blues and St. Elsewhere were two of the first American prime time television series to have this kind of dramatic structure. While the later series, Babylon 5 is an example of such production that had a predetermined story running over its intended five-season run. In 2012, it was reported that television was growing into a component of major media companies revenues than film. Some also noted the increase in quality of television programs. When a person or company decides to create a new series, they develop the elements, consisting of the concept, the characters, the crew. Then they offer it to the networks in an attempt to find one interested enough to order a prototype first episode of the series. They want very much to get the word out on what types of shows they’re looking for, to create the pilot, the structure and team of the whole series must be put together. If the network likes the pilot, they pick up the show to air it the next season, sometimes they save it for mid-season, or request rewrites and further review
17.
MPEG-2
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MPEG-2 is a standard for the generic coding of moving pictures and associated audio information. MPEG-2 is widely used as the format of television signals that are broadcast by terrestrial, cable. It also specifies the format of movies and other programs that are distributed on DVD, TV stations, TV receivers, DVD players, and other equipment are often designed to this standard. MPEG-2 was the second of several developed by the Moving Pictures Expert Group and is an international standard. Parts 1 and 2 of MPEG-2 were developed in a collaboration with ITU-T, while MPEG-2 is the core of most digital television and DVD formats, it does not completely specify them. Regional institutions can adapt it to their needs by restricting and augmenting aspects of the standard, MPEG-2 includes a Systems section, part 1, that defines two distinct, but related, container formats. Program stream exceptions are M2TS, which is used on Blu-ray discs, AVCHD on re-writable DVDs, while VOB on DVDs and Enhanced VOB on the short lived HD DVD do not waste storage space and just use the program stream. MPEG-2 Systems is formally known as ISO/IEC 13818-1 and as ITU-T Rec, ISO authorized the SMPTE Registration Authority, LLC as the registration authority for MPEG-2 format identifiers. This provision will permit the MPEG-2 transport standard to all types of data while providing for a method of unambiguous identification of the characteristics of the underlying private data. The Video section, part 2 of MPEG-2, is similar to the previous MPEG-1 standard, but also support for interlaced video. MPEG-2 video is not optimized for low bit-rates, especially less than 1 Mbit/s at standard definition resolutions, all standards-compliant MPEG-2 Video decoders are fully capable of playing back MPEG-1 Video streams conforming to the Constrained Parameters Bitstream syntax. MPEG-2/Video is formally known as ISO/IEC 13818-2 and as ITU-T Rec, with some enhancements, MPEG-2 Video and Systems are also used in some HDTV transmission systems, and is the standard format for over-the-air ATSC digital television.1 multichannel. This method is backwards-compatible, allowing MPEG-1 audio decoders to decode the two main components of the presentation. MPEG-2 part 3 also defined additional bit rates and sample rates for MPEG-1 Audio Layer I, MPEG-2 BC low bitrate encoding with halved sampling rate multichannel encoding with up to 5.1 channels, a. k. a. MPEG Multichannel Part 7 of the MPEG-2 standard specifies a rather different, Part 7 is referred to as MPEG-2 AAC. AAC is more efficient than the previous MPEG audio standards, and is in some ways less complicated than its predecessor, MPEG-1 Audio, Layer 3, in that it does not have the hybrid filter bank. It supports from 1 to 48 channels at sampling rates of 8 to 96 kHz, with multichannel, multilingual, advanced Audio is also defined in Part 3 of the MPEG-4 standard. MPEG-2 NBC MPEG-2 AAC multichannel encoding with up to 48 channels MPEG-2 standards are published as parts of ISO/IEC13818, each part covers a certain aspect of the whole specification
18.
Sun Fire
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Sun Fire is a series of server computers introduced in 2001 by Sun Microsystems. The Sun Fire branding coincided with the introduction of the UltraSPARC III processor, in 2003, Sun broadened the Sun Fire brand, introducing Sun Fire servers using the Intel Xeon processor. In 2004, these early Intel Xeon models were superseded by models powered by AMD Opteron processors, also in 2004, Sun introduced Sun Fire servers powered by the UltraSPARC IV dual-core processor. In 2007, Sun again introduced Intel Xeon Sun Fire servers, sPARC-based Sun Fire systems were produced until 2010, while x86-64 based machines were marketed until mid-2012. In mid-2012, Oracle Corporation ceased to use the Sun Fire brand for new server models, ultraSPARC-based Sun Fire models are licensed to run the Solaris operating system versions 8,9, and 10. Although not officially supported, some Linux versions are available from third parties. The z suffix was used previously to differentiate the V880z Visualization Server variant of the V880 server. Suns first-generation blade server platform, the Sun Fire B1600 chassis, later Sun blade systems were sold under the Sun Blade brand. In 2007, Sun, Fujitsu and Fujitsu Siemens introduced the common SPARC Enterprise brand for server products, the first SPARC Enterprise models were the Fujitsu-developed successors to the midrange and high-end Sun Fire E-series. Later T-series servers have also been badged SPARC Enterprise rather than Sun Fire, some servers were produced in two versions, the original version and a later RoHS version. As of 2012, the x86 server range continued under the Sun Server or Oracle Server names, fireplane Sun System Handbook, Version 2.1
19.
X86-64
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X86-64 is the 64-bit version of the x86 instruction set. It supports vastly larger amounts of memory and physical memory than is possible on its 32-bit predecessors. X86-64 also provides 64-bit general-purpose registers and numerous other enhancements and it is fully backward compatible with 16-bit and 32-bit x86 code. The original specification, created by AMD and released in 2000, has been implemented by AMD, Intel, the AMD K8 processor was the first to implement the architecture, this was the first significant addition to the x86 architecture designed by a company other than Intel. Intel was forced to suit and introduced a modified NetBurst family which was fully software-compatible with AMDs design. VIA Technologies introduced x86-64 in their VIA Isaiah architecture, with the VIA Nano, the x86-64 specification is distinct from the Intel Itanium architecture, which is not compatible on the native instruction set level with the x86 architecture. AMD64 was created as an alternative to the radically different IA-64 architecture, the first AMD64-based processor, the Opteron, was released in April 2003. AMDs processors implementing the AMD64 architecture include Opteron, Athlon 64, Athlon 64 X2, Athlon 64 FX, Athlon II, Turion 64, Turion 64 X2, Sempron, Phenom, Phenom II, FX, Fusion and Ryzen. The primary defining characteristic of AMD64 is the availability of 64-bit general-purpose processor registers, 64-bit integer arithmetic and logical operations, the designers took the opportunity to make other improvements as well. Some of the most significant changes are described below, pushes and pops on the stack default to 8-byte strides, and pointers are 8 bytes wide. Additional registers In addition to increasing the size of the general-purpose registers, AMD64 still has fewer registers than many common RISC instruction sets or VLIW-like machines such as the IA-64. However, an AMD64 implementation may have far more internal registers than the number of architectural registers exposed by the instruction set, additional XMM registers Similarly, the number of 128-bit XMM registers is also increased from 8 to 16. Larger virtual address space The AMD64 architecture defines a 64-bit virtual address format and this allows up to 256 TB of virtual address space. The architecture definition allows this limit to be raised in future implementations to the full 64 bits and this is compared to just 4 GB for the x86. This means that very large files can be operated on by mapping the entire file into the address space, rather than having to map regions of the file into. Larger physical address space The original implementation of the AMD64 architecture implemented 40-bit physical addresses, current implementations of the AMD64 architecture extend this to 48-bit physical addresses and therefore can address up to 256 TB of RAM. The architecture permits extending this to 52 bits in the future, for comparison, 32-bit x86 processors are limited to 64 GB of RAM in Physical Address Extension mode, or 4 GB of RAM without PAE mode. Any implementation therefore allows the physical address limit as under long mode
20.
10 Gigabit Ethernet
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10 Gigabit Ethernet is a group of computer networking technologies for transmitting Ethernet frames at a rate of 10 gigabits per second. It was first defined by the IEEE802. 3ae-2002 standard, half duplex operation and repeater hubs do not exist in 10GbE. Like previous versions of Ethernet, 10GbE can use either copper or fiber cabling, however, because of its bandwidth requirements, higher-grade copper cables are required, category 6a or Class F/Category 7 cables for lengths up to 100 meters. The 10 Gigabit Ethernet standard encompasses a number of different physical layer standards, a networking device, such as a switch or a network interface controller may have different PHY types through pluggable PHY modules, such as those based on SFP+. At the time that the 10 Gigabit Ethernet standard was developed, the WAN PHY encapsulates Ethernet packets in SONET OC-192c frames and operates at a slightly slower data-rate than the local area network PHY. Over the years the Institute of Electrical and Electronics Engineers 802.3 working group has published several standards relating to 10GbE, to implement different 10GbE physical layer standards, many interfaces consist of a standard socket into which different PHY modules may be plugged. Physical layer modules are not specified in a standards body. Relevant MSAs for 10GbE include XENPAK, XFP and SFP+, when choosing a PHY module, a designer considers cost, reach, media type, power consumption, and size. A single point-to-point link can have different MSA pluggable formats on either end as long as the 10GbE optical or copper port type inside the pluggable is identical, XENPAK was the first MSA for 10GE and had the largest form factor. X2 and XPAK were later competing standards with smaller form factors, X2 and XPAK have not been as successful in the market as XENPAK. XFP came after X2 and XPAK and it is also smaller, the newest module standard is the enhanced small form-factor pluggable transceiver, generally called SFP+. Based on the small form-factor pluggable transceiver and developed by the ANSI T11 fibre channel group, it is smaller still, SFP+ has become the most popular socket on 10GE systems. SFP+ modules do only optical to electrical conversion, no clock and data recovery, SFP+ modules share a common physical form factor with legacy SFP modules, allowing higher port density than XFP and the re-use of existing designs for 24 or 48 ports in a 19 rack width blade. Optical modules are connected to a host by either a XAUI, XENPAK, X2, and XPAK modules use XAUI to connect to their hosts. XAUI uses a data channel and is specified in IEEE802.3 Clause 48. XFP modules use a XFI interface and SFP+ modules use an SFI interface, XFI and SFI use a single lane data channel and the 64b/66b encoding specified in IEEE802.3 Clause 49. SFP+ modules can further be grouped into two types of host interfaces, linear or limiting, limiting modules are preferred except when using old fiber infrastructure which requires the use of the linear interface provided by 10GBASE-LRM modules. There are two classifications for optical fiber, single-mode and multi-mode, in SMF light follows a single path through the fiber while in MMF it takes multiple paths resulting in differential mode delay
21.
Serial Attached SCSI
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Serial Attached SCSI is a point-to-point serial protocol that moves data to and from computer storage devices such as hard drives and tape drives. SAS replaces the older Parallel SCSI bus technology that first appeared in the mid-1980s, SAS, like its predecessor, uses the standard SCSI command set. SAS offers optional compatibility with SATA, versions 2 and later and this allows for SATA drives to be connected to most SAS backplanes or controllers. The reverse, connecting SAS drives to SATA backplanes, is not possible, the T10 technical committee of the International Committee for Information Technology Standards develops and maintains the SAS protocol, the SCSI Trade Association promotes the technology. Initiators may be provided as a component on the motherboard or as an add-on host bus adapter. A target, a device containing logical units and target ports that receives device service and task management requests for processing, a target device could be a hard disk or a disk array system. A service delivery subsystem, the part of an I/O system that transmits information between an initiator and a target, typically cables connecting an initiator and target with or without expanders and backplanes constitute a service delivery subsystem. Expanders, devices that form part of a delivery subsystem. Expanders facilitate the connection of multiple SAS End devices to a single initiator port, sAS-1,3.0 Gbit/s, introduced in 2004 SAS-2,6.0 Gbit/s, available since February 2009 SAS-3,12.0 Gbit/s, available since March 2013 SAS-4,22. Each SAS port in a SAS domain has a SCSI port identifier that identifies the port uniquely within the SAS domain and it is assigned by the device manufacturer, like an Ethernet devices MAC address, and is typically worldwide unique as well. SAS devices use these port identifiers to address communications to each other, in addition, every SAS device has a SCSI device name, which identifies the SAS device uniquely in the world. One doesnt often see these names because the port identifiers tend to identify the device sufficiently. For comparison, in parallel SCSI, the SCSI ID is the port identifier, in Fibre Channel, the port identifier is a WWPN and the device name is a WWNN. In SAS, both SCSI port identifiers and SCSI device names take the form of a SAS address, which is a 64 bit value, people sometimes refer to a SCSI port identifier as the SAS address of a device, out of confusion. People sometimes call a SAS address a World Wide Name or WWN, for a SAS expander device, the SCSI port identifier and SCSI device name are the same SAS address. The SAS bus operates point-to-point while the SCSI bus is multidrop, each SAS device is connected by a dedicated link to the initiator, unless an expander is used. If one initiator is connected to one target, there is no opportunity for contention, with parallel SCSI, SAS has no termination issues and does not require terminator packs like parallel SCSI. SAS allows up to 65,535 devices through the use of expanders, SAS allows a higher transfer speed than most parallel SCSI standards
22.
RAID
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RAID is a data storage virtualization technology that combines multiple physical disk drive components into a single logical unit for the purposes of data redundancy, performance improvement, or both. Data is distributed across the drives in one of several ways, referred to as RAID levels, depending on the level of redundancy. The different schemes, or data distribution layouts, are named by the word RAID followed by a number, each schema, or RAID level, provides a different balance among the key goals, reliability, availability, performance, and capacity. RAID levels greater than RAID0 provide protection against unrecoverable sector read errors, the underlying concept of RAID was first spoken of by the co-founders of Geac Computer Corporation, Gus German and Ted Grunau, who referred to it as MF-100. The term RAID was invented by David Patterson, Garth A. Gibson, although failures would rise in proportion to the number of drives, by configuring for redundancy, the reliability of an array could far exceed that of any large single drive. Around 1983, DEC began shipping subsystem mirrored RA8X disk drives as part of its HSC50 subsystem, in 1986, Clark et al. at IBM filed a patent disclosing what was subsequently named RAID5. Around 1988, the Thinking Machines DataVault used error correction codes in an array of disk drives, a similar approach was used in the early 1960s on the IBM353. Industry RAID manufacturers later tended to interpret the acronym as standing for redundant array of independent disks, many RAID levels employ an error protection scheme called parity, a widely used method in information technology to provide fault tolerance in a given set of data. Most use simple XOR, but RAID6 uses two separate parities based respectively on addition and multiplication in a particular Galois field or Reed–Solomon error correction, RAID can also provide data security with solid-state drives without the expense of an all-SSD system. For example, a fast SSD can be mirrored with a mechanical drive, for this configuration to provide a significant speed advantage an appropriate controller is needed that uses the fast SSD for all read operations. A number of schemes have evolved. Originally, there were five RAID levels, but many variations have evolved, notably several nested levels, the capacity of a RAID0 volume is the sum of the capacities of the disks in the set, the same as with a spanned volume. There is no added redundancy for handling disk failures, just as with a spanned volume, thus, failure of one disk causes the loss of the entire RAID0 volume, with reduced possibilities of data recovery when compared with a broken spanned volume. The concurrent operations make the throughput of most read and write operations equal to the throughput of one multiplied by the number of disks. Increased throughput is the big benefit of RAID0 versus spanned volume, RAID1 RAID1 consists of data mirroring, without parity or striping. Data is written identically to two drives, thereby producing a set of drives. Thus, any read request can be serviced by any drive in the set, if a request is broadcast to every drive in the set, it can be serviced by the drive that accesses the data first, improving performance. Sustained read throughput, if the controller or software is optimized for it, approaches the sum of throughputs of every drive in the set, actual read throughput of most RAID1 implementations is slower than the fastest drive
23.
Serial ATA
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Serial ATA is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. Although, a number of hot plug PATA offering were first invented and marketed by Core International beginning in the late 1980s for the Micro Channel architecture bus controllers, prior to SATAs introduction in 2003, the PATA was simply known as ATA. The AT Attachment name originated after the 1984 release of the IBM Personal Computer AT, the IBM AT was the first mass-produced computer where the hard disk was key to the systems performance. The IBM AT’s controller interface became a de facto industry interface for the inclusion of hard disks, SATA host adapters and devices communicate via a high-speed serial cable over two pairs of conductors. In contrast, parallel ATA uses a 16-bit wide data bus with many support and control signals. To ensure backward compatibility with legacy ATA software and applications, SATA uses the same basic ATA, SATA has replaced parallel ATA in consumer desktop and laptop computers, SATAs market share in the desktop PC market was 99% in 2008. A2008 standard, CFast to replace CompactFlash is based on SATA, Serial ATA industry compatibility specifications originate from the Serial ATA International Organization. The SATA-IO group collaboratively creates, reviews, ratifies, and publishes the interoperability specifications, the remainder of this article will try to use the terminology and specifications of SATA-IO. The term Hot Plug was a registered trademark issued by the USPTO and it was invented for computer components including PATA in the late 1980s by Hal Prewitt, founder of Core International. First patent details were disclosed in 1987 in USA and Europe related to development of the technology to connect host bus adapters to mass storage device however the filings were not completed. Core created and in 1990 marketed the worlds first disk controller, host adapter, disk drives, disk arrays, initial implementations were on the IBM PS/2 series and Micro Channel architecture bus controllers. The Serial ATA Spec includes logic for SATA device hotplugging, Devices and motherboards that meet the interoperability specification are capable of hot plugging. Unlike PATA, both SATA and eSATA support hot swapping by design, however, this feature requires proper support at the host, device, and operating-system levels. In general, all SATA devices support hot swapping, also most SATA host adapters support this command, advanced Host Controller Interface is an open host controller interface published and used by Intel, which has become a de facto standard. It allows the use of advanced features of SATA such as hotplug, if AHCI is not enabled by the motherboard and chipset, SATA controllers typically operate in IDE emulation mode, which does not allow access to device features not supported by the ATA standard. Even in those instances, a driver may have been created for a specific chipset. SATA revisions are often designated with a dash followed by roman numerals, e. g. SATA-III, to avoid confusion with the speed, revision 1. 0a was released on January 7,2003. First-generation SATA interfaces, now known as SATA1.5 Gbit/s, communicate at a rate of 1.5 Gbit/s, taking 8b/10b encoding overhead into account, they have an actual uncoded transfer rate of 1.2 Gbit/s
24.
Hard disk drive
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The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a manner, meaning that individual blocks of data can be stored or retrieved in any order. HDDs are a type of storage, retaining stored data even when powered off. Introduced by IBM in 1956, HDDs became the dominant secondary storage device for computers by the early 1960s. Continuously improved, HDDs have maintained this position into the era of servers. More than 200 companies have produced HDDs historically, though after extensive industry consolidation most current units are manufactured by Seagate, Toshiba, as of 2016, HDD production is growing, although unit shipments and sales revenues are declining. While SSDs have higher cost per bit, SSDs are replacing HDDs where speed, power consumption, small size, the primary characteristics of an HDD are its capacity and performance. Capacity is specified in unit prefixes corresponding to powers of 1000, the two most common form factors for modern HDDs are 3. 5-inch, for desktop computers, and 2. 5-inch, primarily for laptops. HDDs are connected to systems by standard interface cables such as PATA, SATA, Hard disk drives were introduced in 1956, as data storage for an IBM real-time transaction processing computer and were developed for use with general-purpose mainframe and minicomputers. The first IBM drive, the 350 RAMAC in 1956, was approximately the size of two medium-sized refrigerators and stored five million six-bit characters on a stack of 50 disks. In 1962 the IBM350 RAMAC disk storage unit was superseded by the IBM1301 disk storage unit, cylinder-mode read/write operations were supported, and the heads flew about 250 micro-inches above the platter surface. Motion of the head array depended upon a binary system of hydraulic actuators which assured repeatable positioning. The 1301 cabinet was about the size of three home refrigerators placed side by side, storing the equivalent of about 21 million eight-bit bytes, access time was about a quarter of a second. Also in 1962, IBM introduced the model 1311 disk drive, users could buy additional packs and interchange them as needed, much like reels of magnetic tape. Later models of removable pack drives, from IBM and others, became the norm in most computer installations, non-removable HDDs were called fixed disk drives. Some high-performance HDDs were manufactured with one head per track so that no time was lost physically moving the heads to a track, known as fixed-head or head-per-track disk drives they were very expensive and are no longer in production. In 1973, IBM introduced a new type of HDD code-named Winchester and its primary distinguishing feature was that the disk heads were not withdrawn completely from the stack of disk platters when the drive was powered down. Instead, the heads were allowed to land on an area of the disk surface upon spin-down
25.
Fsck
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The system utility fsck is a tool for checking the consistency of a file system in Unix and Unix-like operating systems, such as Linux and OS X. A similar command, CHKDSK exists in Microsoft Windows and it can be pronounced F-S-C-K, F-S-check, fizz-check, F-sack, fisk, fizik, F-sick, F-sock, fuck, fucked, F-suck, F-sek, the sibilant fsk, farsk or fusk. Generally, fsck is run either automatically at boot time, or manually by the system administrator, the command works directly on data structures stored on disk, which are internal and specific to the particular file system in use - so a matching fsck command tailored is generally required. The exact behaviors of various fsck implementations vary, but they follow a common order of internal operations. Partially recovered files where the file name cannot be reconstructed are typically recovered to a lost+found directory that is stored at the root of the file system. A system administrator can also run fsck manually if they there is a problem with the file system. The file system is normally checked while unmounted, mounted read-only, modern journaling file systems are designed such that tools such as fsck do not need to be run after unclean shutdown. The UFS2 Filesystem in FreeBSD has a background fsck, so it is not necessary to wait for fsck to finish before accessing the disk. Full copy-on-write file systems such as ZFS and Btrfs are designed to avoid most causes of corruption and have no traditional fsck repair tool, both have a scrub utility which examines and repairs any problems, in the background and on a mounted filesystem. The equivalent programs on Microsoft Windows and MS-DOS are CHKDSK and SCANDISK, the severity of file system corruption, led to the terms fsck and fscked becoming used among Unix system administrators as a minced oath for fuck and fucked
26.
File system
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In computing, a file system or filesystem is used to control how data is stored and retrieved. Without a file system, information placed in a storage medium would be one large body of data with no way to tell where one piece of information stops, by separating the data into pieces and giving each piece a name, the information is easily isolated and identified. Taking its name from the way paper-based information systems are named, the structure and logic rules used to manage the groups of information and their names is called a file system. There are many different kinds of file systems, each one has different structure and logic, properties of speed, flexibility, security, size and more. Some file systems have been designed to be used for specific applications, for example, the ISO9660 file system is designed specifically for optical discs. File systems can be used on different types of storage devices that use different kinds of media. The most common device in use today is a hard disk drive. Other kinds of media that are used include flash memory, magnetic tapes, in some cases, such as with tmpfs, the computers main memory is used to create a temporary file system for short-term use. Some file systems are used on local storage devices, others provide file access via a network protocol. Some file systems are virtual, meaning that the files are computed on request or are merely a mapping into a different file system used as a backing store. The file system access to both the content of files and the metadata about those files. It is responsible for arranging storage space, reliability, efficiency, before the advent of computers the term file system was used to describe a method of storing and retrieving paper documents. By 1961 the term was being applied to computerized filing alongside the original meaning, by 1964 it was in general use. A file system consists of two or three layers, sometimes the layers are explicitly separated, and sometimes the functions are combined. The logical file system is responsible for interaction with the user application and it provides the application program interface for file operations — OPEN, CLOSE, READ, etc. and passes the requested operation to the layer below it for processing. The logical file system manage open file table entries and per-process file descriptors and this layer provides file access, directory operations, security and protection. The second optional layer is the file system. This interface allows support for multiple concurrent instances of physical file systems, the third layer is the physical file system
27.
Sun Microsystems
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Sun contributed significantly to the evolution of several key computing technologies, among them Unix, RISC processors, thin client computing, and virtualized computing. Sun was founded on February 24,1982, at its height, the Sun headquarters were in Santa Clara, California, on the former west campus of the Agnews Developmental Center. On January 27,2010, Oracle Corporation acquired Sun by for US$7.4 billion, other technologies include the Java platform, MySQL, and NFS. Sun was a proponent of open systems in general and Unix in particular, the initial design for what became Suns first Unix workstation, the Sun-1, was conceived by Andy Bechtolsheim when he was a graduate student at Stanford University in Palo Alto, California. Bechtolsheim originally designed the SUN workstation for the Stanford University Network communications project as a personal CAD workstation and it was designed around the Motorola 68000 processor with an advanced memory management unit to support the Unix operating system with virtual memory support. He built the first ones from spare parts obtained from Stanfords Department of Computer Science, on February 24,1982, Vinod Khosla, Andy Bechtolsheim, and Scott McNealy, all Stanford graduate students, founded Sun Microsystems. Bill Joy of Berkeley, a developer of the Berkeley Software Distribution. The Sun name is derived from the initials of the Stanford University Network, Sun was profitable from its first quarter in July 1982. By 1983 Sun was known for producing 68000-based systems with high-quality graphics that were the only computers other than DECs VAX to run 4. 2BSD and it licensed the computer design to other manufacturers, which typically used it to build Multibus-based systems running Unix from UniSoft. Suns initial public offering was in 1986 under the stock symbol SUNW, the symbol was changed in 2007 to JAVA, Sun stated that the brand awareness associated with its Java platform better represented the companys current strategy. Suns logo, which features four interleaved copies of the sun in the form of a rotationally symmetric ambigram, was designed by professor Vaughan Pratt. The initial version of the logo was orange and had the sides oriented horizontally and vertically, but it was rotated to stand on one corner and re-colored purple. In the dot-com bubble, Sun began making more money. It also began spending more, hiring workers and building itself out. Some of this was because of demand, but much was from web start-up companies anticipating business that would never happen. Sales in Suns important hardware division went into free-fall as customers closed shop, several quarters of steep losses led to executive departures, rounds of layoffs, and other cost cutting. In December 2001, the fell to the 1998, pre-bubble level of about $100. But it kept falling, faster than many other tech companies, a year later it had dipped below $10 but bounced back to $20
28.
Open-source model
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Open-source software may be developed in a collaborative public manner. According to scientists who studied it, open-source software is a prominent example of open collaboration, a 2008 report by the Standish Group states that adoption of open-source software models has resulted in savings of about $60 billion per year to consumers. In the early days of computing, programmers and developers shared software in order to learn from each other, eventually the open source notion moved to the way side of commercialization of software in the years 1970-1980. In 1997, Eric Raymond published The Cathedral and the Bazaar and this source code subsequently became the basis behind SeaMonkey, Mozilla Firefox, Thunderbird and KompoZer. Netscapes act prompted Raymond and others to look into how to bring the Free Software Foundations free software ideas, the new term they chose was open source, which was soon adopted by Bruce Perens, publisher Tim OReilly, Linus Torvalds, and others. The Open Source Initiative was founded in February 1998 to encourage use of the new term, a Microsoft executive publicly stated in 2001 that open source is an intellectual property destroyer. I cant imagine something that could be worse than this for the software business, IBM, Oracle, Google and State Farm are just a few of the companies with a serious public stake in todays competitive open-source market. There has been a significant shift in the corporate philosophy concerning the development of FOSS, the free software movement was launched in 1983. In 1998, a group of individuals advocated that the free software should be replaced by open-source software as an expression which is less ambiguous. Software developers may want to publish their software with an open-source license, the Open Source Definition, notably, presents an open-source philosophy, and further defines the terms of usage, modification and redistribution of open-source software. Software licenses grant rights to users which would otherwise be reserved by law to the copyright holder. Several open-source software licenses have qualified within the boundaries of the Open Source Definition, the open source label came out of a strategy session held on April 7,1998 in Palo Alto in reaction to Netscapes January 1998 announcement of a source code release for Navigator. They used the opportunity before the release of Navigators source code to clarify a potential confusion caused by the ambiguity of the free in English. Many people claimed that the birth of the Internet, since 1969, started the open source movement, the Free Software Foundation, started in 1985, intended the word free to mean freedom to distribute and not freedom from cost. Since a great deal of free software already was free of charge, such software became associated with zero cost. The Open Source Initiative was formed in February 1998 by Eric Raymond and they sought to bring a higher profile to the practical benefits of freely available source code, and they wanted to bring major software businesses and other high-tech industries into open source. Perens attempted to open source as a service mark for the OSI. The Open Source Initiatives definition is recognized by governments internationally as the standard or de facto definition, OSI uses The Open Source Definition to determine whether it considers a software license open source
29.
C (programming language)
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C was originally developed by Dennis Ritchie between 1969 and 1973 at Bell Labs, and used to re-implement the Unix operating system. C has been standardized by the American National Standards Institute since 1989, C is an imperative procedural language. Therefore, C was useful for applications that had formerly been coded in assembly language. Despite its low-level capabilities, the language was designed to encourage cross-platform programming, a standards-compliant and portably written C program can be compiled for a very wide variety of computer platforms and operating systems with few changes to its source code. The language has become available on a wide range of platforms. In C, all code is contained within subroutines, which are called functions. Function parameters are passed by value. Pass-by-reference is simulated in C by explicitly passing pointer values, C program source text is free-format, using the semicolon as a statement terminator and curly braces for grouping blocks of statements. The C language also exhibits the characteristics, There is a small, fixed number of keywords, including a full set of flow of control primitives, for, if/else, while, switch. User-defined names are not distinguished from keywords by any kind of sigil, There are a large number of arithmetical and logical operators, such as +, +=, ++, &, ~, etc. More than one assignment may be performed in a single statement, function return values can be ignored when not needed. Typing is static, but weakly enforced, all data has a type, C has no define keyword, instead, a statement beginning with the name of a type is taken as a declaration. There is no function keyword, instead, a function is indicated by the parentheses of an argument list, user-defined and compound types are possible. Heterogeneous aggregate data types allow related data elements to be accessed and assigned as a unit, array indexing is a secondary notation, defined in terms of pointer arithmetic. Unlike structs, arrays are not first-class objects, they cannot be assigned or compared using single built-in operators, There is no array keyword, in use or definition, instead, square brackets indicate arrays syntactically, for example month. Enumerated types are possible with the enum keyword and they are not tagged, and are freely interconvertible with integers. Strings are not a data type, but are conventionally implemented as null-terminated arrays of characters. Low-level access to memory is possible by converting machine addresses to typed pointers
30.
OpenSolaris
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OpenSolaris is a discontinued, open source computer operating system based on Solaris created by Sun Microsystems. It was also the name of the project initiated by Sun to build a developer and user community around the software, prior to Oracles moving of core development behind closed doors, a group of former OpenSolaris developers decided to fork the core software under the name OpenIndiana. The OpenIndiana project, a part of the illumos Foundation, aims to continue the development, since then many more illumos distributions are available for use, continuing development in open or offering support. OpenSolaris is a descendant of the UNIX System V Release 4 code base developed by Sun and it is the only version of the System V variant of UNIX available as open source. OpenSolaris was developed as a combination of several software consolidations that were open sourced subsequent to Solaris 10 and it includes a variety of free software, including popular desktop and server software. OpenSolaris was based on Solaris, which was released by Sun in 1991. Solaris is a version of UNIX System V Release 4, jointly developed by Sun and it was licensed by Sun from Novell to replace SunOS. Planning for OpenSolaris started in early 2004, a pilot program was formed in September 2004 with 18 non-Sun community members and ran for 9 months growing to 145 external participants. Sun submitted the CDDL to the OSI, which approved it on January 14,2005. The first part of the Solaris code base to be open sourced was the Solaris Dynamic Tracing facility, a tool that aids in the analysis, debugging, dTrace was released under the CDDL on January 25,2005 on the newly launched opensolaris. org website. The bulk of the Solaris system code was released on June 14,2005, there remains some system code that is not open sourced, and is available only as pre-compiled binary files. The members were Roy Fielding, Al Hopper, Rich Teer, Casper Dik, on February 10,2006 Sun approved The OpenSolaris Charter, which reestablished this body as the independent OpenSolaris Governing Board. The task of creating a document or constitution for this organization was given to the OGB. While under Sun Microsystems control, there were snapshots of Solaris Nevada. The stable releases of OpenSolaris are based on these Nevada builds, initially, Suns Solaris Express program provided a distribution based on the OpenSolaris code in combination with software found only in Solaris releases. The first independent distribution was released on June 17,2005, the new distribution was planned to refresh the user experience, and would become the successor to Solaris Express as the basis for future releases of Solaris. On May 5,2008, OpenSolaris 2008.05 was released in a format that could be booted as a Live CD or installed directly and it uses the GNOME desktop environment as the primary user interface. The later OpenSolaris 2008.11 release included a GUI for ZFS snapshotting capabilities, known as Time Slider, in December 2008, Sun Microsystems and Toshiba America Information Systems announced plans to distribute Toshiba laptops pre-installed with OpenSolaris
31.
Lolcat
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A lolcat is an image macro of one or more cats. The images text is often idiosyncratic and grammatically incorrect, and is known as lolspeak, Lolcat is a compound word of the acronymic abbreviation for LOL and the word cat. A synonym for lolcat is cat macro, since the images are a type of image macro, lolcats are commonly designed for photo sharing imageboards and other Internet forums. British portrait photographer Harry Pointer created a carte de visite series featuring cats posed in various situations in the early 1870s, to these he usually added amusing text intended to further enhance their appeal. Other notable early figures include Harry Whittier Frees and Walter Potter, the first recorded use of the term lolcat is from the anonymous imageboard 4chan. The word Lolcat was in use as early as June 2006, and their popularity was spread through usage on forums such as Something Awful. The News Journal states that some trace the lolcats back to the site 4chan, ikenburg adds that the images have been slinking around the Internet for years under various labels, but they did not become a sensation until early 2007 with the advent of I Can Has Cheezburger. The first image on I CAN HAZ CHEEZBURGER. was posted on January 11,2007, the domain name caturday. com was registered on April 30,2005. Entertainment Weekly put them on its end-of-the-decade, best-of list, saying and we can neber haz enuf of deez capshioned pics of cuddlie kittehs. Lolcat was also a runner-up under the Most Creative category under the American Dialect Society Word of the Year Awards, in December 2014, the word lolcat entered the Oxford English Dictionary, appearing in its online version. Lolcat is a composite of two words, lol and cat, lol stands for Laugh out Loud or Laughing out Loud, hence, lolcats are intended to be funny and to include jokes. Lolcats images comprise a photo of a cat with a large caption characteristically set in a sans serif font such as Impact or Arial Black. The image is, on occasion, digitally edited for effect, the caption generally acts as a speech balloon encompassing a comment from the cat, or as a description of the depicted scene. The text parodies the grammar-poor patois stereotypically attributed to Internet slang, frequently, lolcat captions take the form of phrasal templates. Some phrases have a source, usually a well-known Internet meme, such as All your base are belong to us or Do not want. The language of lolcats has also likened to baby talk, however it draws on a variety of linguistic resources. Common themes include jokes of the form Im in ur, -ing ur, many lolcat images capture cats performing characteristically human actions or appearing to use modern technology, such as computers. There are several well-known lolcat images and single-word captions that have spawned many variations and imitations, others include Fail and I Can Has Cheezburger
32.
HTTP 404
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In the code 404, the first digit indicates a client error, such as a mistyped Uniform Resource Locator. The following two digits indicate the specific error encountered, hTTPs use of three-digit codes is similar to the use of such codes in earlier protocols such as FTP and NNTP. At the HTTP level, a 404 response code is followed by a human-readable reason phrase, the HTTP specification suggests the phrase Not Found and many web servers by default issue an HTML page that includes both the 404 code and the Not Found phrase. A404 error is often returned when pages have been moved or deleted, because these two options require special server configuration, most websites do not make use of them. 404 errors should not be confused with DNS errors, which appear when the given URL refers to a name that does not exist. A404 error indicates that the server itself was found, the protocol level phrase, which is hidden from the user, is rarely customized. Internet Explorer, however, will not display custom pages unless they are larger than 512 bytes, Google Chrome includes similar functionality, where the 404 is replaced with alternative suggestions generated by Google algorithms, if the page is under 512 bytes in size. Another problem is that if the page does not provide a favicon, Many organizations use 404 error pages as an opportunity to inject humor into what may otherwise be a serious website. For example, Metro UK shows a bear on a skateboard. While many websites send additional information in a 404 error message—such as a link to the homepage of a website or a search box—some also endeavor to find the correct web page the user wanted, extensions are available for some popular content management systems to do this. A number of tools exist that crawl through a website to find pages that return 404 status codes and these tools can be helpful in finding links that exist within a particular website. The limitation of these tools is that they only find links within one particular website, as a result, these tools miss out on 83% of the 404s on websites. One way around this is to find 404 errors by analyzing external links, another common method is tracking traffic to 404 pages using log file analysis. This can be useful to understand more about what 404s users reached on the site, another method of tracking traffic to 404 pages is using JavaScript-based traffic tracking tools. Some websites report a not found error by returning a web page with a 200 OK response code, falsely reporting that the page loaded properly. Soft 404s are problematic for automated methods of discovering whether a link is broken, some search engines, like Yahoo, use automated processes to detect soft 404s. This can also be done on purpose to some browsers to display a customized 404 error message rather than replacing what is served with a browser-specific friendly error message. This can confuse programs that expect and act on specific responses, other ISPs return a HTTP403 forbidden error in the same circumstances
