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
Mozilla Firefox is a free and open-source web browser developed by The Mozilla Foundation and its subsidiary, Mozilla Corporation. Firefox is available for Microsoft Windows, macOS, Linux, BSD, illumos and Solaris operating systems, its sibling, Firefox for Android, is available. Firefox uses the Gecko layout engine to render web pages, which implements current and anticipated web standards. In 2017, Firefox began incorporating new technology under the code name Quantum to promote parallelism and a more intuitive user interface. An additional version, Firefox for iOS, was released on November 12, 2015. Due to platform restrictions, it uses the WebKit layout engine instead of Gecko, as with all other iOS web browsers. Firefox was created in 2002 under the codename "Phoenix" by the Mozilla community members who desired a standalone browser, rather than the Mozilla Application Suite bundle. During its beta phase, Firefox proved to be popular with its testers and was praised for its speed and add-ons compared to Microsoft's then-dominant Internet Explorer 6.
Firefox was released on November 9, 2004, challenged Internet Explorer's dominance with 60 million downloads within nine months. Firefox is the spiritual successor of Netscape Navigator, as the Mozilla community was created by Netscape in 1998 before their acquisition by AOL. Firefox usage grew to a peak of 32% at the end of 2009, with version 3.5 overtaking Internet Explorer 7, although not Internet Explorer as a whole. Usage declined in competition with Google Chrome; as of January 2019, Firefox has 9.5% usage share as a "desktop" browser, according to StatCounter, making it the second-most popular such web browser. Firefox is still the most popular desktop browser in a few countries including Cuba and Eritrea with 72.26% and 83.28% of the market share, respectively. According to Mozilla, in December 2014, there were half a billion Firefox users around the world; the project began as an experimental branch of the Mozilla project by Dave Hyatt, Joe Hewitt, Blake Ross. They believed the commercial requirements of Netscape's sponsorship and developer-driven feature creep compromised the utility of the Mozilla browser.
To combat what they saw as the Mozilla Suite's software bloat, they created a stand-alone browser, with which they intended to replace the Mozilla Suite. On April 3, 2003, the Mozilla Organization announced that they planned to change their focus from the Mozilla Suite to Firefox and Thunderbird; the community-driven SeaMonkey was formed and replaced the Mozilla Application Suite in 2005. The Firefox project has undergone several name changes, it was titled Phoenix, which carried the implication of the mythical firebird that rose triumphantly from the ashes of its dead predecessor, in this case from the "ashes" of Netscape Navigator after it had been killed off by Microsoft Internet Explorer in the "First Browser War". Phoenix was renamed due to trademark issues with Phoenix Technologies. In response, the Mozilla Foundation stated that the browser would always bear the name Mozilla Firebird to avoid confusion. After further pressure, on February 9, 2004, Mozilla Firebird became Mozilla Firefox.
The name Firefox was said to be derived from a nickname of the red panda, which became the mascot for the newly named project. For the abbreviation of Firefox, Mozilla prefers Fx or fx, though it is abbreviated as FF; the Firefox project went through many versions before version 1.0 was released on November 9, 2004. In 2016, Mozilla announced a project known as Quantum, which sought to improve Firefox's Gecko engine and other components to improve Firefox's performance, modernize its architecture, transition the browser to a multi-process model; these improvements came in the wake of decreasing market share to Google Chrome, as well as concerns that its performance was lapsing in comparison. Despite its improvements, these changes required existing add-ons for Firefox to be made incompatible with newer versions, in favor of a new extension system, designed to be similar to Chrome and other recent browsers. Firefox 57, released in November 2017, was the first version to contain enhancements from Quantum, has thus been named Firefox Quantum.
Firefox supported add-ons using the XUL and XPCOM APIs, which allowed them to directly access and manipulate much of the browser's internal functionality. As they are not compatible with its m
SeaMonkey is a free and open-source Internet suite. It is the continuation of the former Mozilla Application Suite, based on the same source code, which itself grew out of Netscape Communicator and formed the base of Netscape 6 and Netscape 7. SeaMonkey was created in 2005 after the Mozilla Foundation decided to focus on standalone projects such as Firefox and Thunderbird; the development of SeaMonkey is community-driven, in contrast to the Mozilla Application Suite, which until its last released version was governed by the Mozilla Foundation. The new project-leading group is called the SeaMonkey Council. Compared to Firefox, the SeaMonkey web browser keeps the more traditional-looking interface of Netscape and the Mozilla Suite. Many XUL-based Firefox and Thunderbird add-ons can be modified for compatibility with SeaMonkey, although add-ons built with the WebExtensions architecture used by newer Firefox versions are not yet compatible. SeaMonkey consists of a web browser, a descendant of the Netscape family, an e-mail and news client program, an HTML editor ).
The software suite supports skins. It comes with two skins in the default installation and Classic. Recent versions do not include the IRC client. SeaMonkey Mail is a traditional e-mail client that includes support for multiple accounts, junk mail detection, message filters, HTML message support, address books, among other features, it shares code with Mozilla Thunderbird. SeaMonkey Composer is a WYSIWYG HTML editor, its main user interface features four tabs: Normal, HTML tags, HTML code, browser preview. The generated code is HTML 4.01 Transitional. SeaMonkey Composer is no longer maintained, but the underlying editor code is shared with the Mail component; the SeaMonkey project releases official builds for Linux, macOS, Windows. It releases “unofficial” x86-64 builds for Linux. To avoid confusing organizations that still want to use the original Mozilla Suite, the new product needed a new name. After initial speculation by members of the community, a July 2, 2005 announcement confirmed that SeaMonkey would become the name of the Internet suite superseding the Mozilla Suite.
"Seamonkey" refers to brine shrimp and had been used by Netscape and the Mozilla Foundation as a code name for the never-released "Netscape Communicator 5" and the Mozilla Suite itself. The name "Seamonkey" was derived by Netscape management to replace "Buttmonkey", which their developers had chosen following an internal contest for the codename.. The SeaMonkey Council has now trademarked the name with help from the Mozilla Foundation; the project uses a separate numbering scheme, with the first release being called SeaMonkey 1.0. Despite having a different name and version number, SeaMonkey 1.0 is based on the same code as Mozilla Suite 1.7. For trademark and copyright reasons, Debian rebranded SeaMonkey and distributed it as Iceape until 2013. On March 10, 2005, the Mozilla Foundation announced that it would not release any official versions of Mozilla Application Suite beyond 1.7.x, since it had now focused on the standalone applications Firefox and Thunderbird. However, the Foundation emphasized that it would still provide infrastructure for community members who wished to continue development.
In effect, this meant that the suite would still continue to be developed, but now by the SeaMonkey Council instead of the Mozilla Foundation. SeaMonkey was first released on September 15, 2005. SeaMonkey 1 was released on January 30, 2006. Core Mozilla project source code was licensed under a disjunctive tri-license that gave the choice of one of the three following sets of licensing terms: Mozilla Public License, version 1.1 or GNU General Public License, version 2.0 or GNU Lesser General Public License, version 2.1 or later. The SeaMonkey Council, the team responsible for project and release management consists of Philip Chee, Karsten Düsterloh, Jens Hatlak, Robert Kaiser, Ian Neal, Neil Rashbrook and Justin Wood. Parts of this table are based on the roadmap and the meeting notes. Old release Current release Current test release The SeaMonkey Project SeaMonkey Wiki
The user interface, in the industrial design field of human–computer interaction, is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine from the human end, whilst the machine feeds back information that aids the operators' decision-making process. Examples of this broad concept of user interfaces include the interactive aspects of computer operating systems, hand tools, heavy machinery operator controls, process controls; the design considerations applicable when creating user interfaces are related to or involve such disciplines as ergonomics and psychology. The goal of user interface design is to produce a user interface which makes it easy and enjoyable to operate a machine in the way which produces the desired result; this means that the operator needs to provide minimal input to achieve the desired output, that the machine minimizes undesired outputs to the human. User interfaces are composed of one or more layers including a human-machine interface interfaces machines with physical input hardware such a keyboards, game pads and output hardware such as computer monitors and printers.
A device that implements a HMI is called a human interface device. Other terms for human-machine interfaces are man–machine interface and when the machine in question is a computer human–computer interface. Additional UI layers may interact with one or more human sense, including: tactile UI, visual UI, auditory UI, olfactory UI, equilibrial UI, gustatory UI. Composite user interfaces are UIs that interact with two or more senses; the most common CUI is a graphical user interface, composed of a tactile UI and a visual UI capable of displaying graphics. When sound is added to a GUI it becomes a multimedia user interface. There are three broad categories of CUI: standard and augmented. Standard composite user interfaces use standard human interface devices like keyboards and computer monitors; when the CUI blocks out the real world to create a virtual reality, the CUI is virtual and uses a virtual reality interface. When the CUI does not block out the real world and creates augmented reality, the CUI is augmented and uses an augmented reality interface.
When a UI interacts with all human senses, it is called a qualia interface, named after the theory of qualia. CUI may be classified by how many senses they interact with as either an X-sense virtual reality interface or X-sense augmented reality interface, where X is the number of senses interfaced with. For example, a Smell-O-Vision is a 3-sense Standard CUI with visual display and smells; the user interface or human–machine interface is the part of the machine that handles the human–machine interaction. Membrane switches, rubber keypads and touchscreens are examples of the physical part of the Human Machine Interface which we can see and touch. In complex systems, the human–machine interface is computerized; the term human–computer interface refers to this kind of system. In the context of computing, the term extends as well to the software dedicated to control the physical elements used for human-computer interaction; the engineering of the human–machine interfaces is enhanced by considering ergonomics.
The corresponding disciplines are human factors engineering and usability engineering, part of systems engineering. Tools used for incorporating human factors in the interface design are developed based on knowledge of computer science, such as computer graphics, operating systems, programming languages. Nowadays, we use the expression graphical user interface for human–machine interface on computers, as nearly all of them are now using graphics. There is a difference between a user interface and an operator interface or a human–machine interface; the term "user interface" is used in the context of computer systems and electronic devices Where a network of equipment or computers are interlinked through an MES -or Host to display information. A human-machine interface is local to one machine or piece of equipment, is the interface method between the human and the equipment/machine. An operator interface is the interface method by which multiple equipment that are linked by a host control system is accessed or controlled.
The system may expose several user interfaces to serve different kinds of users. For example, a computerized library database might provide two user interfaces, one for library patrons and the other for library personnel; the user interface of a mechanical system, a vehicle or an industrial installation is sometimes referred to as the human–machine interface. HMI is a modification of the original term MMI. In practice, the abbreviation MMI is still used although some may claim that MMI stands for something different now. Another abbreviation is HCI, but is more used for human–computer interaction. Other terms used are operator interface terminal; however it is abbreviated, the terms refer to the'layer' that separates a human, operating a machine from the machine itself. Without a clean and usable interface, humans would not be able to
Open-source software is a type of computer software in which source code is released under a license in which the copyright holder grants users the rights to study and distribute the software to anyone and for any purpose. Open-source software may be developed in a collaborative public manner. Open-source software is a prominent example of open collaboration. Open-source software development generates an more diverse scope of design perspective than any company is capable of developing and sustaining long term. A 2008 report by the Standish Group stated that adoption of open-source software models have resulted in savings of about $60 billion per year for consumers. In the early days of computing and developers shared software in order to learn from each other and evolve the field of computing; the open-source notion moved to the way side of commercialization of software in the years 1970-1980. However, academics still developed software collaboratively. For example Donald Knuth in 1979 with the TeX typesetting system or Richard Stallman in 1983 with the GNU operating system.
In 1997, Eric Raymond published The Cathedral and the Bazaar, a reflective analysis of the hacker community and free-software principles. The paper received significant attention in early 1998, was one factor in motivating Netscape Communications Corporation to release their popular Netscape Communicator Internet suite as free software; this source code subsequently became the basis behind SeaMonkey, Mozilla Firefox and KompoZer. Netscape's act prompted Raymond and others to look into how to bring the Free Software Foundation's free software ideas and perceived benefits to the commercial software industry, they concluded that FSF's social activism was not appealing to companies like Netscape, looked for a way to rebrand the free software movement to emphasize the business potential of sharing and collaborating on software source code. The new term they chose was "open source", soon adopted by Bruce Perens, publisher Tim O'Reilly, Linus Torvalds, others; the Open Source Initiative was founded in February 1998 to encourage use of the new term and evangelize open-source principles.
While the Open Source Initiative sought to encourage the use of the new term and evangelize the principles it adhered to, commercial software vendors found themselves threatened by the concept of distributed software and universal access to an application's source code. A Microsoft executive publicly stated in 2001 that "open source is an intellectual property destroyer. I can't imagine something that could be worse than this for the software business and the intellectual-property business." However, while Free and open-source software has played a role outside of the mainstream of private software development, companies as large as Microsoft have begun to develop official open-source presences on the Internet. IBM, Oracle and State Farm are just a few of the companies with a serious public stake in today's 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 term free software should be replaced by open-source software as an expression, less ambiguous and more comfortable for the corporate world.
Software licenses grant rights to users which would otherwise be reserved by copyright law to the copyright holder. Several open-source software licenses have qualified within the boundaries of the Open Source Definition; the most prominent and popular example is the GNU General Public License, which "allows free distribution under the condition that further developments and applications are put under the same licence", thus free. The open source label came out of a strategy session held on April 7, 1998 in Palo Alto in reaction to Netscape's January 1998 announcement of a source code release for Navigator. A group of individuals at the session included Tim O'Reilly, Linus Torvalds, Tom Paquin, Jamie Zawinski, Larry Wall, Brian Behlendorf, Sameer Parekh, Eric Allman, Greg Olson, Paul Vixie, John Ousterhout, Guido van Rossum, Philip Zimmermann, John Gilmore and Eric S. Raymond, they used the opportunity before the release of Navigator's source code to clarify a potential confusion caused by the ambiguity of the word "free" in English.
Many people claimed that the birth of the Internet, since 1969, started the open-source movement, while others do not distinguish between open-source and free software movements. The Free Software Foun
In interface design, a tabbed document interface or Tab is a graphical control element that allows multiple documents or panels to be contained within a single window, using tabs as a navigational widget for switching between sets of documents. It is an interface style most associated with web browsers, web applications, text editors, preference panes, with window managers tiling window managers, being lesser known examples. GUI tabs are modeled after traditional card tabs inserted in paper files or card indexes; the WordVision DOS word processor for the IBM PC in 1982 was the first commercially available product with a tabbed interface. PC Magazine in 1994 wrote that it "has served as a free R&D department for the software business—its bones picked over for a decade by programmers looking for so-called new ideas"; the NeWS version of UniPress's Gosling Emacs text editor was another early product, with multiple tabbed windows in 1988. It was used to develop an authoring tool for the Ben Shneiderman's HyperTIES browser, in 1988.
HyperTIES supported pie menus for managing windows and browsing hypermedia documents with PostScript applets. Don Hopkins developed and released several versions of tabbed window frames for the NeWS window system as free software, which the window manager applied to all NeWS applications, enabled users to drag the tabs around to any edge of the window. HyperTIES was a "hypermedia" browser, a term first used by Ted Nelson in 1965; the first "web" browser came out in 1990, the term "World Wide Web" was not invented until 1990. In 1992 Borland's Quattro Pro popularized tabs for spreadsheets. In 1994, BookLink Technologies featured tabbed windows in its InternetWorks browser; that same year, the text editor UltraEdit appeared with a modern multi-row tabbed interface. The tabbed interface approach was followed by the Internet Explorer shell NetCaptor in 1997; these were followed by a number of others like IBrowse in 1999, Opera in 2000, MultiViews October 2000, which changed its name into MultiZilla on 1 April 2001, Galeon in early 2001, Mozilla 0.9.5 in October 2001, Phoenix 0.1 in October 2002, Konqueror 3.1 in January 2003, Safari in 2003.
With the release of Internet Explorer 7 in 2006, all major web browsers featured a tabbed interface. Users have adopted the use of tabs in web browsing and web search. A study of tabbed browsing behavior in June 2009 found that users switched tabs in 57% of tab sessions, 36% of users used new tabs to open search engine results at least once during that period. Numerous special functions in association with browser tabs have emerged since then. One example is visual tabbed browsing in OmniWeb version 5, which displays preview images of pages in a drawer to the left or right of the main browser window. Another feature is the ability to re-order tabs and to bookmark all of the webpages opened in tab panes in a given window in a group or bookmark folder. Links can most be opened in several modes, using different user interface options and commands: in a new main window in the same main window and tab panel in the same main window and a new tab panel, activated in the same main window and a new tab panel, which remains in the background until the user switches to it.
There are minor usability issues such as whether a new tab opens in the end of the tab list or next to its "parent". For example, Internet Explorer marks tab families with different colours; the name TDI implies similarity to the Microsoft Windows standards for multiple document interfaces and single document interfaces, but TDI does not form part of the Microsoft Windows User Interface Guidelines. There is some debate about. In many ways the Workbook window management model most resembles TDI; however this is a recent addition to the Windows User Interface Guidelines, most developers still prefer to view SDI or MDI as the primary document models for MS Windows. Because the tabbed document interface holds many different documents logically under one window, it keeps the primary operating system interface free of the clutter that would be created by a large number of small child windows. Another advantage is. Tabbed web browsers allow users to save their browsing session and return to it later.
Although the tabbed document interface does allow for multiple views under one window, there are problems with this interface. One such problem is dealing with many tabs at once; when a window is tabbed to a certain number that exceeds the available display area, the tabs clutter up. Multi-row tabs are a second issue; some prefer to have many tabs open, some programs help making these compact yet identifiable, while dealing with multiple rows of tabs in one window is seen to have two disadvantages: It creates excess window clutter, unless it is limited to about 3 rows that can be scrolled by the mouse wheel. It complicates what should be an easy-to-read dialog, at the same time makes it easier to see the titles of many tabs at once. Finding a specific tab in a 3 or 4 level tabular interface can be difficult for some people. Part of the issue with this difficul
A favicon known as a shortcut icon, website icon, tab icon, URL icon, or bookmark icon, is a file containing one or more small icons, associated with a particular website or web page. A web designer can create such an icon and upload it to a website by several means, graphical web browsers will make use of it. Browsers that provide favicon support display a page's favicon in the browser's address bar and next to the page's name in a list of bookmarks. Browsers that support a tabbed document interface show a page's favicon next to the page's title on the tab, site-specific browsers use the favicon as a desktop icon. Favicons can be used to have a textless favorite site, saving space. In March 1999, Microsoft released Internet Explorer 5; the favicon was a file called favicon.ico placed in the root directory of a website. It was used in Internet Explorer's favorites and next to the URL in the address bar if the page was bookmarked. A side effect was that the number of visitors who had bookmarked the page could be estimated by the requests of the favicon.
This side effect no longer works, as all modern browsers load the favicon file to display in their web address bar, regardless of whether the site is bookmarked. The favicon was standardized by the World Wide Web Consortium in the HTML 4.01 recommendation, released in December 1999, in the XHTML 1.0 recommendation, released in January 2000. The standard implementation uses a link element with a rel attribute in the <head> section of the document to specify the file format and file name and location. Unlike in the prior scheme, the file can be in any Web site directory and have any image file format. In 2003, the.ico format was registered by a third party with the Internet Assigned Numbers Authority under the MIME type image/vnd.microsoft.icon. However, when using the.ico format to display as images, Internet Explorer cannot display files served with this standardized MIME type. A workaround for Internet Explorer is to associate.ico with the non-standard image/x-icon MIME type in Web servers.
RFC 5988 established an IANA link relation registry, rel="icon" was registered in 2010 based on the HTML5 specification. The popular <link rel="shortcut icon" type="image/png" href="image/favicon.png"> theoretically identifies two relations, "shortcut" and "icon", but "shortcut" is not registered and is redundant. In 2011 the HTML living standard specified that for historical reasons "shortcut" is allowed before "icon". Internet Explorer 5–10 supports only the ICO file format. Netscape 7 and Internet Explorer versions 5 and 6 display the favicon only when the page is bookmarked, not when the pages are visited as in browsers; the following tables illustrate support of various features with major web browsers. Unless noted, the version numbers indicate the starting version number of a supported feature; the following table illustrates the image file format support for the favicon. Additionally, such icon files can be 16×16, 32×32, 48×48, or 64×64 pixels in size, 8-bit, 24-bit, or 32-bit in color depth.
The ICO file format article explains the details for icons with more than 256 colors on various Microsoft Windows platforms. This table illustrates the different areas of the browser. Opera Software added the ability to change the favicon in the Speed Dial in Opera 10; this table illustrates the different ways. The standard implementation uses a link element with a rel attribute in the <head> section of the document to specify the file format and file name and location. If links for both PNG and ICO favicons are present, PNG-favicon-compatible browsers select which format and size to use as follows. Firefox and Safari will use the favicon. Chrome for Mac will use. Chrome for Windows will use the favicon that comes first if it is 16×16, otherwise the ICO. If none of the aforementioned options are available, both Chromes will use whichever favicon comes first the opposite of Firefox and Safari. Indeed, Chrome for Mac will ignore the 16×16 favicon and use the 32×32 version, only to scale it back down to 16×16 on non-retina devices.
Opera will choose from any of the available icons at random. Only SeaMonkey doesn’t fetch favicon.ico files in the website’s root by default. For Apple devices with the iOS operating system version 1.1.3 or as well as some Android devices, it is possible to provide a custom icon that users can display on their home screens by using theAdd to Home Screen button within the share sheet in Safari. This feature is enabled by supplying a <link rel="apple-touch-icon"...> in the <head> section of documents served by the website. If the custom icon is not provided, a thumbnail of the web page will be put on the home screen instead; the recommended basic size for this icon is 152×152 pixels. For the iPad, the basic size is 180x180 pixels. Android tablets prefer a 192x192 PNG icon; the icon file referenced by apple-touch-icon is modified to add rounded corners. On the iOS versions prior to iOS 7, a drop shadow, reflective shine would be added, apple-touch-icon-precomposed icon may be provided to instruct devices not to apply reflective shine on the image.
With rounded corners, added by iOS<link rel="apple-touch-icon" href="https://example.com/image.png"> No HTML is required by browsers or mobile devices to retrieve these icons, either. The website's root is the default location for the file apple-touch-icon.png