An operating system is system software that manages computer hardware and software resources and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may include accounting software for cost allocation of processor time, mass storage and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is executed directly by the hardware and makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer – from cellular phones and video game consoles to web servers and supercomputers; the dominant desktop operating system is Microsoft Windows with a market share of around 82.74%. MacOS by Apple Inc. is in second place, the varieties of Linux are collectively in third place. In the mobile sector, use in 2017 is up to 70% of Google's Android and according to third quarter 2016 data, Android on smartphones is dominant with 87.5 percent and a growth rate 10.3 percent per year, followed by Apple's iOS with 12.1 percent and a per year decrease in market share of 5.2 percent, while other operating systems amount to just 0.3 percent.
Linux distributions are dominant in supercomputing sectors. Other specialized classes of operating systems, such as embedded and real-time systems, exist for many applications. A single-tasking system can only run one program at a time, while a multi-tasking operating system allows more than one program to be running in concurrency; this is achieved by time-sharing, where the available processor time is divided between multiple processes. These processes are each interrupted in time slices by a task-scheduling subsystem of the operating system. Multi-tasking may be characterized in co-operative types. In preemptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, such as Solaris and Linux—as well as non-Unix-like, such as AmigaOS—support preemptive multitasking. Cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking.
32-bit versions of both Windows NT and Win9x, used preemptive multi-tasking. Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem. A multi-user operating system extends the basic concept of multi-tasking with facilities that identify processes and resources, such as disk space, belonging to multiple users, the system permits multiple users to interact with the system at the same time. Time-sharing operating systems schedule tasks for efficient use of the system and may include accounting software for cost allocation of processor time, mass storage and other resources to multiple users. A distributed operating system manages a group of distinct computers and makes them appear to be a single computer; the development of networked computers that could be linked and communicate with each other gave rise to distributed computing. Distributed computations are carried out on more than one machine; when computers in a group work in cooperation, they form a distributed system.
In an OS, distributed and cloud computing context, templating refers to creating a single virtual machine image as a guest operating system saving it as a tool for multiple running virtual machines. The technique is used both in virtualization and cloud computing management, is common in large server warehouses. Embedded operating systems are designed to be used in embedded computer systems, they are designed to operate on small machines like PDAs with less autonomy. They are able to operate with a limited number of resources, they are compact and efficient by design. Windows CE and Minix 3 are some examples of embedded operating systems. A real-time operating system is an operating system that guarantees to process events or data by a specific moment in time. A real-time operating system may be single- or multi-tasking, but when multitasking, it uses specialized scheduling algorithms so that a deterministic nature of behavior is achieved. An event-driven system switches between tasks based on their priorities or external events while time-sharing operating systems switch tasks based on clock interrupts.
A library operating system is one in which the services that a typical operating system provides, such as networking, are provided in the form of libraries and composed with the application and configuration code to construct a unikernel: a specialized, single address space, machine image that can be deployed to cloud or embedded environments. Early computers were built to perform a series of single tasks, like a calculator. Basic operating system features were developed in the 1950s, such as resident monitor functions that could automatically run different programs in succession to speed up processing. Operating systems did not exist in their more complex forms until the early 1960s. Hardware features were added, that enabled use of runtime libraries and parallel processing; when personal computers became popular in the 1980s, operating systems were made for them similar in concept to those used on larger computers. In the 1940s, the earliest electronic digital systems had no operating systems.
Electronic systems of this time were programmed on rows of mechanical switches or by jumper wires on plug boards. These were special-purpose systems that, for example, generated ballistics tables for the military or controlled the pri
AOLpress is a discontinued HTML editor, available from America Online. It was developed as NaviPress by the company NaviSoft before being bought by AOL, it was discontinued in 2000. However, the last version may still be found on some Web sites for downloading. AOLpress was rather strict about enforcing legal HTML: when saving edited pages that were created outside AOLpress, code that did not conform to the HTML 3.2 standard and specifications may have been changed to do so. Today, the HTML code used is outdated and may not display more recent Web sites correctly, it does not support PNG images, this limits its support on many sites where the newer PNG format has been adopted. In February 1994, NaviSoft Inc. released NaviPress, a Web browser with an integrated HTML editor. NaviPress was similar to the first Web browser, WorldWideWeb, created by TIm Berners-Lee, for the classic Mac OS and Microsoft Windows. According to Berners-Lee, "NaviPress was a true browser and editor, which produced clean HTML."In late 1995, AOL acquired NaviSoft, the package was renamed "GNNPress" later "AOLpress", made available for downloading on AOL's Global Network Navigator site.
In Weaving the Web, Berners-Lee attributes the death of AOLpress to the release of Netscape Navigator 2.0 in 1996. AOL's Steve Case reached an agreement with Bill Gates so that AOL users could use a version of the Explorer browser, which did not have HTML editing functionality; this agreement led to the decline of AOLpress. According to Berners-Lee, AOLpress was, at the time, "one of the few commercial browsers that provided simple online editing."In 1998, AOLpress made PC Magazine's "Best Products of the Year" issue. The editors describe it as "the only program that combines WYSIWYG Web page editing, HTML source code editing, Web site management, Web browsing in a single interface." The article goes on to say that AOLpress "isn't an editor that looks like a browser. It is a browser." AOLpress 2.0 requires 8 megabytes of RAM, with more recommended, a display capable of at least 256 colors, an Intel 80386 CPU, 8 megabytes of free disk space, either Windows NT or Windows 95 operating system. While the installer is 16-bit and will not work under 64-bit Windows to install the software, AOLpress is capable of launching under Windows 8, though it crashes within a short time after starting.
Although the program is not accepted by Windows 7, it will run in compatibility mode in Windows 10. AOLpress website AOLpress at the Wayback Machine AOLPress on the Evolt Browsers Archive
It describes 18 elements comprising the initial simple design of HTML. Except for the hyperlink tag, these were influenced by SGMLguid, an in-house Standard Generalized Markup Language -based documentation format at CERN. Eleven of these elements still exist in HTML 4. HTML is a markup language that web browsers use to interpret and compose text and other material into visual or audible web pages. Default characteristics for every item of HTML markup are defined in the browser, these characteristics can be altered or enhanced by the web page designer's additional use of CSS. Many of the text elements are found in the 1988 ISO technical report TR 9537 Techniques for using SGML, which in turn covers the features of early text formatting languages such as that used by the RUNOFF command developed in the early 1960s for the CTSS operating system: these formatting commands were derived from the commands used by typesetters to manually format documents. However, the SGML concept of generalized markup is based on elements rather than print effects, with the separation of structure and markup.
Berners-Lee considered HTML to be an application of SGML. It was formally defined as such by the Internet Engineering Task Force with the mid-1993 publication of the first proposal for an HTML specification, the "Hypertext Markup Language" Internet Draft by Berners-Lee and Dan Connolly, which included an SGML Document type definition to define the grammar; the draft expired after six months, but was notable for its acknowledgment of the NCSA Mosaic browser's custom tag for embedding in-line images, reflecting the IETF's philosophy of basing standards on successful prototypes. Dave Raggett's competing Internet-Draft, "HTML+", from late 1993, suggested standardizing already-implemented features like tables and fill-out forms. After the HTML and HTML+ drafts expired in early 1994, the IETF created an HTML Working Group, which in 1995 completed "HTML 2.0", the first HTML specification intended to be treated as a standard against which future implementations should be based. Further development under the auspices of the IETF was stalled by competing interests.
Since 1996, the HTML specifications have been maintained, with input from commercial software vendors, by the World Wide Web Consortium. However, in 2000, HTML became an international standard. HTML 4.01 was published in late 1999, with further errata published through 2001. In 2004, development began on HTML5 in the Web Hypertext Application Technology Working Group, which became a joint deliverable with the W3C in 2008, completed and standardized on 28 October 2014. November 24, 1995 HTML 2.0 was published as RFC 1866. Supplemental RFCs added capabilities: November 25, 1995: RFC 1867 May 1996: RFC 1942 August 1996: RFC 1980 January 1997: RFC 2070 January 14, 1997 HTML 3.2 was published as a W3C Recommendation. It was the first version developed and standardized by the W3C, as the IETF had closed its HTML Working Group on September 12, 1996. Code-named "Wilbur", HTML 3.2 dropped math formulas reconciled overlap among various proprietary extensions and adopted most of Netscape's visual markup tags.
Netscape's blink element and Microsoft's marquee element were omitted due to a mutual agreement between the two companies. A markup for mathematical formu
Russia the Russian Federation, is a transcontinental country in Eastern Europe and North Asia. At 17,125,200 square kilometres, Russia is by far or by a considerable margin the largest country in the world by area, covering more than one-eighth of the Earth's inhabited land area, the ninth most populous, with about 146.77 million people as of 2019, including Crimea. About 77 % of the population live in the European part of the country. Russia's capital, Moscow, is one of the largest cities in the world and the second largest city in Europe. Extending across the entirety of Northern Asia and much of Eastern Europe, Russia spans eleven time zones and incorporates a wide range of environments and landforms. From northwest to southeast, Russia shares land borders with Norway, Estonia, Latvia and Poland, Ukraine, Azerbaijan, China and North Korea, it shares maritime borders with Japan by the Sea of Okhotsk and the U. S. state of Alaska across the Bering Strait. However, Russia recognises two more countries that border it, Abkhazia and South Ossetia, both of which are internationally recognized as parts of Georgia.
The East Slavs emerged as a recognizable group in Europe between the 3rd and 8th centuries AD. Founded and ruled by a Varangian warrior elite and their descendants, the medieval state of Rus arose in the 9th century. In 988 it adopted Orthodox Christianity from the Byzantine Empire, beginning the synthesis of Byzantine and Slavic cultures that defined Russian culture for the next millennium. Rus' disintegrated into a number of smaller states; the Grand Duchy of Moscow reunified the surrounding Russian principalities and achieved independence from the Golden Horde. By the 18th century, the nation had expanded through conquest and exploration to become the Russian Empire, the third largest empire in history, stretching from Poland on the west to Alaska on the east. Following the Russian Revolution, the Russian Soviet Federative Socialist Republic became the largest and leading constituent of the Union of Soviet Socialist Republics, the world's first constitutionally socialist state; the Soviet Union played a decisive role in the Allied victory in World War II, emerged as a recognized superpower and rival to the United States during the Cold War.
The Soviet era saw some of the most significant technological achievements of the 20th century, including the world's first human-made satellite and the launching of the first humans in space. By the end of 1990, the Soviet Union had the world's second largest economy, largest standing military in the world and the largest stockpile of weapons of mass destruction. Following the dissolution of the Soviet Union in 1991, twelve independent republics emerged from the USSR: Russia, Belarus, Uzbekistan, Azerbaijan, Kyrgyzstan, Tajikistan and the Baltic states regained independence: Estonia, Lithuania, it is governed as a federal semi-presidential republic. Russia's economy ranks as the twelfth largest by nominal GDP and sixth largest by purchasing power parity in 2018. Russia's extensive mineral and energy resources are the largest such reserves in the world, making it one of the leading producers of oil and natural gas globally; the country is one of the five recognized nuclear weapons states and possesses the largest stockpile of weapons of mass destruction.
Russia is a great power as well as a regional power and has been characterised as a potential superpower. It is a permanent member of the United Nations Security Council and an active global partner of ASEAN, as well as a member of the Shanghai Cooperation Organisation, the G20, the Council of Europe, the Asia-Pacific Economic Cooperation, the Organization for Security and Co-operation in Europe, the World Trade Organization, as well as being the leading member of the Commonwealth of Independent States, the Collective Security Treaty Organization and one of the five members of the Eurasian Economic Union, along with Armenia, Belarus and Kyrgyzstan; the name Russia is derived from Rus', a medieval state populated by the East Slavs. However, this proper name became more prominent in the history, the country was called by its inhabitants "Русская Земля", which can be translated as "Russian Land" or "Land of Rus'". In order to distinguish this state from other states derived from it, it is denoted as Kievan Rus' by modern historiography.
The name Rus itself comes from the early medieval Rus' people, Swedish merchants and warriors who relocated from across the Baltic Sea and founded a state centered on Novgorod that became Kievan Rus. An old Latin version of the name Rus' was Ruthenia applied to the western and southern regions of Rus' that were adjacent to Catholic Europe; the current name of the country, Россия, comes from the Byzantine Greek designation of the Rus', Ρωσσία Rossía—spelled Ρωσία in Modern Greek. The standard way to refer to citizens of Russia is rossiyane in Russian. There are two Russian words which are commonly
Electronic mail is a method of exchanging messages between people using electronic devices. Invented by Ray Tomlinson, email first entered limited use in the 1960s and by the mid-1970s had taken the form now recognized as email. Email operates across computer networks, which today is the Internet; some early email systems required the author and the recipient to both be online at the same time, in common with instant messaging. Today's email systems are based on a store-and-forward model. Email servers accept, forward and store messages. Neither the users nor their computers are required to be online simultaneously. An ASCII text-only communications medium, Internet email was extended by Multipurpose Internet Mail Extensions to carry text in other character sets and multimedia content attachments. International email, with internationalized email addresses using UTF-8, has been standardized, but as of 2017 it has not been adopted; the history of modern Internet email services reaches back to the early ARPANET, with standards for encoding email messages published as early as 1973.
An email message sent in the early 1970s looks similar to a basic email sent today. Email had an important role in creating the Internet, the conversion from ARPANET to the Internet in the early 1980s produced the core of the current services; the term electronic mail was used generically for any electronic document transmission. For example, several writers in the early 1970s used the term to describe fax document transmission; as a result, it is difficult to find the first citation for the use of the term with the more specific meaning it has today. Electronic mail has been most called email or e-mail since around 1993, but variations of the spelling have been used: email is the most common form used online, is required by IETF Requests for Comments and working groups and by style guides; this spelling appears in most dictionaries. E-mail is the format that sometimes appears in edited, published American English and British English writing as reflected in the Corpus of Contemporary American English data, but is falling out of favor in some style guides.
Mail was the form used in the original protocol standard, RFC 524. The service is referred to as mail, a single piece of electronic mail is called a message. EMail is a traditional form, used in RFCs for the "Author's Address" and is expressly required "for historical reasons". E-mail is sometimes used, capitalizing the initial E as in similar abbreviations like E-piano, E-guitar, A-bomb, H-bomb. An Internet e-mail consists of an content. Computer-based mail and messaging became possible with the advent of time-sharing computers in the early 1960s, informal methods of using shared files to pass messages were soon expanded into the first mail systems. Most developers of early mainframes and minicomputers developed similar, but incompatible, mail applications. Over time, a complex web of gateways and routing systems linked many of them. Many US universities were part of the ARPANET, which aimed at software portability between its systems; that portability helped make the Simple Mail Transfer Protocol influential.
For a time in the late 1980s and early 1990s, it seemed that either a proprietary commercial system or the X.400 email system, part of the Government Open Systems Interconnection Profile, would predominate. However, once the final restrictions on carrying commercial traffic over the Internet ended in 1995, a combination of factors made the current Internet suite of SMTP, POP3 and IMAP email protocols the standard; the diagram to the right shows a typical sequence of events that takes place when sender Alice transmits a message using a mail user agent addressed to the email address of the recipient. The MUA formats the message in email format and uses the submission protocol, a profile of the Simple Mail Transfer Protocol, to send the message content to the local mail submission agent, in this case smtp.a.org. The MSA determines the destination address provided in the SMTP protocol, in this case email@example.com, a qualified domain address. The part before the @ sign is the local part of the address the username of the recipient, the part after the @ sign is a domain name.
The MSA resolves a domain name to determine the qualified domain name of the mail server in the Domain Name System. The DNS server for the domain b.org responds with any MX records listing the mail exchange servers for that domain, in this case mx.b.org, a message transfer agent server run by the recipient's ISP. smtp.a.org sends the message to mx.b.org using SMTP. This server may need to forward the message to other MTAs before the message reaches the final message delivery agent; the MDA delivers it to the mailbox of user bob. Bob's MUA picks up the message using either the Post Office Protocol or the Internet Message Access Protocol. In addition to this example and complications exist in the email system: Alice or Bob may use a client connected to a corporate email system, such as IBM Lotus Notes or Microsoft Exchange; these systems have their own internal email format and their clients communicate with the email server using a vendor-specific, proprietary protocol. The server sends or receives email via the Internet through the product's Internet mail gateway which does any necessary reformatt
GNU Emacs is the most popular and most ported Emacs text editor. It was created by GNU Project founder Richard Stallman. In common with other varieties of Emacs, GNU Emacs is extensible using a Turing complete programming language. GNU Emacs has been called "the most powerful text editor available today". With proper support from the underlying system, GNU Emacs is able to display files in multiple character sets, has been able to display most human languages since at least 1999. Throughout its history, GNU Emacs has been a central component of the GNU project, a flagship of the free software movement. GNU Emacs is sometimes abbreviated as GNUMACS to differentiate it from other EMACS variants; the tag line for GNU Emacs is "the extensible self-documenting text editor". In 1976, Stallman wrote the first Emacs, in 1984, began work on GNU Emacs, to produce a free software alternative to the proprietary Gosling Emacs. GNU Emacs was based on Gosling Emacs, but Stallman's replacement of its Mocklisp interpreter with a true Lisp interpreter required that nearly all of its code be rewritten.
This became the first program released by the nascent GNU Project. GNU Emacs is written in C and provides Emacs Lisp implemented in C, as an extension language. Version 13, the first public release, was made on March 20, 1985; the first distributed version of GNU Emacs was version 15.34, released in 1985. Early versions of GNU Emacs were numbered as "1.x.x," with the initial digit denoting the version of the C core. The "1" was dropped after version 1.12 as it was thought that the major number would never change, thus the major version skipped from "1" to "13". A new third version number was added to represent changes made by user sites. In the current numbering scheme, a number with two components signifies a release version, with development versions having three components. GNU Emacs was ported to Unix, it offered more features than Gosling Emacs, in particular a full-featured Lisp as its extension language, soon replaced Gosling Emacs as the de facto Unix Emacs editor. Markus Hess exploited a security flaw in GNU Emacs' email subsystem in his 1986 cracking spree, in which he gained superuser access to Unix computers.
Although users submitted patches and Elisp code to the net.emacs newsgroup, participation in GNU Emacs development was restricted until 1999, was used as an example of the "Cathedral" development style in The Cathedral and the Bazaar. The project has since adopted anonymous CVS access. Development took place in a single CVS trunk until 2008, today uses the Git DVCS. Richard Stallman has remained the principal maintainer of GNU Emacs, but he has stepped back from the role at times. Stefan Monnier and Chong Yidong have overseen maintenance since 2008. On September 21, 2015 Monnier announced that he would be stepping down as maintainer effective with the feature freeze of Emacs 25. Longtime contributor John Wiegley was announced as the new maintainer on November 5, 2015; the terms of the GNU General Public License state that the Emacs source code, including both the C and Emacs Lisp components, are available for examination and redistribution. Older versions of the GNU Emacs documentation appeared under an ad-hoc license that required the inclusion of certain text in any modified copy.
In the GNU Emacs user's manual, for example, this included instructions for obtaining GNU Emacs and Richard Stallman's essay The GNU Manifesto. The XEmacs manuals, which were inherited from older GNU Emacs manuals when the fork occurred, have the same license. Newer versions of the documentation use the GNU Free Documentation License with "invariant sections" that require the inclusion of the same documents and that the manuals proclaim themselves as GNU Manuals. For GNU Emacs, like many other GNU packages, it remains policy to accept significant code contributions only if the copyright holder executes a suitable disclaimer or assignment of their copyright interest to the Free Software Foundation. Bug fixes and minor code contributions of fewer than 10 lines are exempt; this policy is in place so that the FSF can defend the software in court if its copyleft license is violated. In 2011, it was noticed that GNU Emacs had been accidentally releasing some binaries without corresponding source code for two years, in opposition to the intended spirit of the GPL, resulting in a copyright violation.
Richard Stallman described this incident as "a bad mistake", promptly fixed. The FSF didn't sue any downstream redistributors who unknowingly violated the GPL by distributing these binaries. In its normal editing mode, GNU Emacs behaves like other text editors and allows the user to insert characters with the corresponding keys and to move the editing point with the arrow keys. Escape key sequences or pressing the control key and/or the meta key, alt key or super keys in conjunction with a regular key produces modified keystrokes that invoke functions from the Emacs Lisp environment. Commands such as save-buffer and save-buffers-kill-emacs combine multiple modified keystrokes; some GNU Emacs commands work by invoking an external program, such as ispell for spell-checking or GNU Compiler Collection for program compilation, parsing the program's output, displaying the result in GNU Emacs. Emacs supports "inferior processes"—long-lived processes that interact with an Emacs buffer; this is used to implement shell-mode, running a Unix shell as inferior process, as well as read–eval–print loop modes for various programming languages.
Emacs' support for external processes makes it an attractive environment for interactive programming along the lines of Interlisp or Smalltalk. Users who prefer
The Graphics Interchange Format, is a bitmap image format, developed by a team at the online services provider CompuServe led by American computer scientist Steve Wilhite on June 15, 1987. It has since come into widespread usage on the World Wide Web due to its wide support and portability between many applications and operating systems; the format supports up to 8 bits per pixel for each image, allowing a single image to reference its own palette of up to 256 different colors chosen from the 24-bit RGB color space. It supports animations and allows a separate palette of up to 256 colors for each frame; these palette limitations make GIF less suitable for reproducing color photographs and other images with color gradients, but it is well-suited for simpler images such as graphics or logos with solid areas of color. GIF images are compressed using the Lempel–Ziv–Welch lossless data compression technique to reduce the file size without degrading the visual quality; this compression technique was patented in 1985.
Controversy over the licensing agreement between the software patent holder and CompuServe in 1994 spurred the development of the Portable Network Graphics standard. By 2004 all the relevant patents had expired. CompuServe introduced GIF on June 15, 1987 to provide a color image format for their file downloading areas, replacing their earlier run-length encoding format, black and white only. GIF became popular because it used LZW data compression, more efficient than the run-length encoding that formats such as those used by PCX and MacPaint, large images could therefore be downloaded in a reasonably short time with slow modems; the original version of GIF was called 87a. In 1989, CompuServe released an enhanced version, called 89a, which added support for animation delays, transparent background colors, storage of application-specific metadata; the 89a specification supports incorporating text labels as text, but as there is little control over display fonts, this feature is not used. The two versions can be distinguished by looking at the first six bytes of the file, when interpreted as ASCII, read "GIF87a" and "GIF89a", respectively.
CompuServe encouraged the adoption of GIF by providing downloadable conversion utilities for many computers. By December 1987, for example, an Apple IIGS user could view pictures created on an Atari ST or Commodore 64. GIF was one of the first two image formats used on Web sites, the other being the black-and-white XBM. In September 1995 Netscape Navigator 2.0 added the ability for animated GIFs to loop. The feature of storing multiple images in one file, accompanied by control data, is used extensively on the Web to produce simple animations; the optional interlacing feature, which stores image scan lines out of order in such a fashion that a downloaded image was somewhat recognizable helped GIF's popularity, as a user could abort the download if it was not what was required. In May 2015 Facebook added support for GIF; as a noun, the word GIF is found in the newer editions of many dictionaries. In 2012, the American wing of the Oxford University Press recognized GIF as a verb as well, meaning "to create a GIF file", as in "GIFing was perfect medium for sharing scenes from the Summer Olympics".
The press's lexicographers voted it their word of the year, saying that GIFs have evolved into "a tool with serious applications including research and journalism". The creators of the format pronounced the word as "jif" with a soft "G" as in "gin". Steve Wilhite says that the intended pronunciation deliberately echoes the American peanut butter brand Jif, CompuServe employees would say "Choosy developers choose GIF", spoofing this brand's television commercials; the word is now widely pronounced with a hard "G" as in "gift". In 2017, an informal poll on programming website Stack Overflow showed some numerical preference for hard-"G" pronunciation among respondents in eastern Europe, though both soft-"G" and enunciating each letter individually were found to be popular in Asia and emerging countries; the American Heritage Dictionary cites both, indicating "jif" as the primary pronunciation, while Cambridge Dictionary of American English offers only the hard-"G" pronunciation. Merriam-Webster's Collegiate Dictionary and the OED cite both pronunciations, but place "gif" in the default position.
The New Oxford American Dictionary gave only "jif" in its 2nd edition but updated it to "jif, gif" in its 3rd edition. The disagreement over the pronunciation led to heated Internet debate. On the occasion of receiving a lifetime achievement award at the 2013 Webby Award ceremony, Wilhite rejected the hard-"G" pronunciation, his speech led to 17,000 posts on Twitter and 50 news articles; the White House and TV program Jeopardy! entered the debate during 2013. GIFs are suitable for sharp-edged line art with a limited number of colors; this takes advantage of the format's lossless compression, which favors flat areas of uniform color with well defined edges. GIFs may be used to store low-color sprite data for games. GIFs can be used for low-resolution video clips. Conceptually, a GIF file describes a fixed-sized graphical area populated with zero or more "images". Many GIF files have a single image. Others divide the logical screen into separate sub-images; the images may function as animation frames in an animated GIF file, but again these need not fill the entire logical screen.
GIF files start with a fixed-length header ("GIF87a" o