Early research and development:
61-592: Merging the networks and creating the Internet: Commercialization, privatization, broader access leads to the modern Internet: Examples of Internet services: NCSA Mosaic was among the first widely available web browsers , instrumental in popularizing the World Wide Web and the general Internet by integrating multimedia such as text and graphics. Mosaic was the first browser to display images inline with text (instead of
122-441: A compiler or an assembler . The resulting executable is machine code ready for the computer. Alternatively, source code can be executed without conversion via an interpreter . An interpreter loads the source code into memory. It simultaneously translates and executes each statement . A method that combines compilation and interpretation is to first produce bytecode . Bytecode is an intermediate representation of source code that
183-462: A source-code editor that can alert the programmer to common errors. Modification often includes code refactoring (improving the structure without changing functionality) and restructuring (improving structure and functionality at the same time). Nearly every change to code will introduce new bugs or unexpected ripple effects , which require another round of fixes. Code reviews by other developers are often used to scrutinize new code added to
244-430: A trade secret . Proprietary, secret source code and algorithms are widely used for sensitive government applications such as criminal justice , which results in black box behavior with a lack of transparency into the algorithm's methodology. The result is avoidance of public scrutiny of issues such as bias. Access to the source code (not just the object code) is essential to modifying it. Understanding existing code
305-528: A What's New page, and about one new link was being added per day. This was a time when access to the Internet was expanding rapidly outside its previous domain of academia and large industrial research institutions. Yet it was the availability of Mosaic and Mosaic-derived graphical browsers themselves that drove the explosive growth of the Web to over 10,000 sites by August 1995 and millions by 1998. Metcalfe expressed
366-529: A bottleneck. This led to the introduction of high-level programming languages such as Fortran in the mid-1950s. These languages abstracted away the details of the hardware, instead being designed to express algorithms that could be understood more easily by humans. As instructions distinct from the underlying computer hardware , software is therefore relatively recent, dating to these early high-level programming languages such as Fortran , Lisp , and Cobol . The invention of high-level programming languages
427-444: A project. The purpose of this phase is often to verify that the code meets style and maintainability standards and that it is a correct implementation of the software design . According to some estimates, code review dramatically reduce the number of bugs persisting after software testing is complete. Along with software testing that works by executing the code, static program analysis uses automated tools to detect problems with
488-531: A section in the menu for deleting cookies. Finer-grained management of cookies usually requires a browser extension . The first web browser, called WorldWideWeb , was created in 1990 by Sir Tim Berners-Lee . He then recruited Nicola Pellow to write the Line Mode Browser , which displayed web pages on dumb terminals . The Mosaic web browser was released in April 1993, and was later credited as
549-510: A separate browser began to decrease after the 1994 release of Netscape Navigator , the relevance of which was noted in The HTML Sourcebook: The Complete Guide to HTML : "Netscape Communications has designed an all-new WWW browser Netscape, that has significant enhancements over the original Mosaic program." In 1994, SCO released Global Access, a modified version of SCO's Open Desktop Unix , which became
610-417: A separate window). Named for supporting multiple Internet protocols , including Hypertext Transfer Protocol , File Transfer Protocol , Network News Transfer Protocol , and Gopher , its intuitive interface, reliability, personal computer support, and simple installation all contributed to Mosaic's initial popularity. Mistakenly described as the first graphical web browser, it was preceded by WorldWideWeb ,
671-572: A server. Mosaic led to the Internet boom of the 1990s. Other browsers existed during this period, such as Erwise , ViolaWWW , MidasWWW , and tkWWW , but did not have the same effect as Mosaic on public use of the Internet. In the October 1994 issue of Wired magazine, Gary Wolfe notes in the article titled "The (Second Phase of the) Revolution Has Begun: Don't look now, but Prodigy , AOL , and CompuServe are all suddenly obsolete – and Mosaic
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#1732772167205732-406: A specific platform, source code can be ported to a different machine and recompiled there. For the same source code, object code can vary significantly—not only based on the machine for which it is compiled, but also based on performance optimization from the compiler. Most programs do not contain all the resources needed to run them and rely on external libraries . Part of the compiler's function
793-839: A sync service and web accessibility features. Common user interface (UI) features: While mobile browsers have similar UI features as desktop versions, the limitations of touch screens require mobile UIs to be simpler. The difference is significant for users accustomed to keyboard shortcuts . The most popular desktop browsers also have sophisticated web development tools . Web browsers are popular targets for hackers , who exploit security holes to steal information, destroy files , and other malicious activities. Browser vendors regularly patch these security holes, so users are strongly encouraged to keep their browser software updated. Other protection measures are antivirus software and being aware of scams . Source code In computing , source code , or simply code or source ,
854-864: A version specifically targeting OpenVMS operating system, is one of the longest-lived efforts to maintain Mosaic. Using the VMS support already built-in in original version (Bjorn S. Nilsson ported Mosaic 1.2 to VMS in the summer of 1993), developers incorporated a substantial part of the HTML engine from mMosaic, another defunct flavor of the browser. As of the most recent version (4.2), released in 2007, VMS Mosaic supported HTML 4.0, OpenSSL , cookies , and various image formats including GIF , JPEG , PNG , BMP , TGA , TIFF and JPEG 2000 image formats. The browser works on VAX , Alpha , and Itanium platforms. Another long-lived version, Mosaic-CK , developed by Cameron Kaiser,
915-495: A web browser is to fetch content and display it on the user's device. This process begins when the user inputs a Uniform Resource Locator (URL), such as https://en.wikipedia.org/ , into the browser. Virtually all URLs on the Web start with either http: or https: which means they are retrieved with the Hypertext Transfer Protocol (HTTP). For secure mode (HTTPS), the connection between
976-465: Is Google Chrome , with a 67% global market share on all devices, followed by Safari with 18%. A web browser is not the same thing as a search engine , though the two are often confused. A search engine is a website that provides links to other websites. However, to connect to a website's server and display its web pages, a user must have a web browser installed. In some technical contexts, browsers are referred to as user agents . The purpose of
1037-405: Is a plain text computer program written in a programming language . A programmer writes the human readable source code to control the behavior of a computer . Since a computer, at base, only understands machine code , source code must be translated before a computer can execute it. The translation process can be implemented three ways. Source code can be converted into machine code by
1098-401: Is an application for accessing websites . When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen. Browsers are used on a range of devices, including desktops , laptops , tablets , and smartphones . By 2020, an estimated 4.9 billion people had used a browser. The most-used browser
1159-442: Is an overarching term that can refer to a code's correct and efficient behavior, its reusability and portability , or the ease of modification. It is usually more cost-effective to build quality into the product from the beginning rather than try to add it later in the development process. Higher quality code will reduce lifetime cost to both suppliers and customers as it is more reliable and easier to maintain . Maintainability
1220-460: Is based on Mozilla 's code. Both of these codebases are open-source, so a number of small niche browsers are also made from them. The most popular browsers share many features in common. They automatically log users' browsing history , unless the users turn off their browsing history or use the non-logging private mode . They also allow users to set bookmarks , customize the browser with extensions , and can manage user passwords . Some provide
1281-452: Is frequently cited as a contributing factor to the maturation of their programming skills. Some people consider source code an expressive artistic medium . Source code often contains comments —blocks of text marked for the compiler to ignore. This content is not part of the program logic, but is instead intended to help readers understand the program. Companies often keep the source code confidential in order to hide algorithms considered
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#17327721672051342-496: Is necessary to understand how it works and before modifying it. The rate of understanding depends both on the code base as well as the skill of the programmer. Experienced programmers have an easier time understanding what the code does at a high level. Software visualization is sometimes used to speed up this process. Many software programmers use an integrated development environment (IDE) to improve their productivity. IDEs typically have several features built in, including
1403-481: Is not the first web browser for Microsoft Windows; this is Thomas R. Bruce 's little-known Cello . The Unix version of Mosaic was already famous before the Microsoft Windows, Amiga, and Mac versions were released. Other than displaying images embedded in the text (rather than in a separate window), Mosaic's original feature set is similar to the browsers on which it was modeled, such as ViolaWWW. But Mosaic
1464-470: Is quickly interpreted. The first programmable computers, which appeared at the end of the 1940s, were programmed in machine language (simple instructions that could be directly executed by the processor). Machine language was difficult to debug and was not portable between different computer systems. Initially, hardware resources were scarce and expensive, while human resources were cheaper. As programs grew more complex, programmer productivity became
1525-631: Is that many software engineering courses do not emphasize it. Development engineers who know that they will not be responsible for maintaining the software do not have an incentive to build in maintainability. The situation varies worldwide, but in the United States before 1974, software and its source code was not copyrightable and therefore always public domain software . In 1974, the US Commission on New Technological Uses of Copyrighted Works (CONTU) decided that "computer programs, to
1586-477: Is the quality of software enabling it to be easily modified without breaking existing functionality. Following coding conventions such as using clear function and variable names that correspond to their purpose makes maintenance easier. Use of conditional loop statements only if the code could execute more than once, and eliminating code that will never execute can also increase understandability. Many software development organizations neglect maintainability during
1647-418: Is to link these files in such a way that the program can be executed by the hardware. Software developers often use configuration management to track changes to source code files ( version control ). The configuration management system also keeps track of which object code file corresponds to which version of the source code file. The number of lines of source code is often used as a metric when evaluating
1708-437: Is well on its way to becoming the world's standard interface": When it comes to smashing a paradigm, pleasure is not the most important thing. It is the only thing. If this sounds wrong, consider Mosaic. Mosaic is the celebrated graphical "browser" that allows users to travel through the world of electronic information using a point-and-click interface. Mosaic's charming appearance encourages users to load their own documents onto
1769-408: The most popular browser. Microsoft debuted Internet Explorer in 1995, leading to a browser war with Netscape. Within a few years, Microsoft gained a dominant position in the browser market for two reasons: it bundled Internet Explorer with its popular Windows operating system and did so as freeware with no restrictions on usage. The market share of Internet Explorer peaked at over 95% in
1830-579: The About box. Internet Explorer 7 was audited by Microsoft to ensure that it contained no Spyglass Mosaic code, and thus no longer credits Spyglass or Mosaic. After NCSA stopped work on Mosaic, development of the NCSA Mosaic for the X Window System source code was continued by several independent groups. These independent development efforts include mMosaic (multicast Mosaic) which ceased development in early 2004, and Mosaic-CK and VMS Mosaic. VMS Mosaic ,
1891-488: The NCSA Mosaic source code. Microsoft licensed Spyglass Mosaic in 1995 for US$ 2 million, modified it, and renamed it Internet Explorer . After a later auditing dispute, Microsoft paid Spyglass $ 8 million. The 1995 user guide The HTML Sourcebook: The Complete Guide to HTML , specifically states, in a section called Coming Attractions , that Internet Explorer "will be based on the Mosaic program". Versions of Internet Explorer before version 7 stated "Based on NCSA Mosaic" in
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1952-450: The Net, including color photos, sound bites, video clips, and hypertext "links" to other documents. By following the links – click, and the linked document appears – you can travel through the online world along paths of whim and intuition. Mosaic is not the most direct way to find online information. Nor is it the most powerful. It is merely the most pleasurable way, and in the 18 months since it
2013-458: The Web might be better than sex. In the third generation, Andreessen and Bina left NCSA to found Netscape... Netscape Navigator was later developed by Netscape , which employed many of the original Mosaic authors; however, it intentionally shared no code with Mosaic. Netscape Navigator's code descendant is Mozilla Firefox . Spyglass, Inc. licensed the technology and trademarks from NCSA for producing its own web browser but never used any of
2074-513: The basis for many other browsers, including Microsoft Edge , currently in third place with about a 5% share, as well as Samsung Internet and Opera in fifth and sixth places respectively with over 2% market share each. The other two browsers in the top four are made from different codebases . Safari , based on Apple 's WebKit code, is the second most popular web browser and is dominant on Apple devices, resulting in an 18% global share. Firefox , in fourth place, with about 3% market share,
2135-494: The browser and web server is encrypted , providing a secure and private data transfer. Web pages usually contain hyperlinks to other pages and resources. Each link contains a URL, and when it is clicked or tapped , the browser navigates to the new resource. Most browsers use an internal cache of web page resources to improve loading times for subsequent visits to the same page. The cache can store many items, such as large images, so they do not need to be downloaded from
2196-691: The creation of the first dynamic web pages . From 1994 to 1997, the National Science Foundation supported the further development of Mosaic. Marc Andreessen, the leader of the team that developed Mosaic, left NCSA and, with James H. Clark , one of the founders of Silicon Graphics, Inc. (SGI), and four other former students and staff of the University of Illinois , started Mosaic Communications Corporation. Mosaic Communications eventually became Netscape Communications Corporation , producing Netscape Navigator . Mosaic's popularity as
2257-426: The development phase, even though it will increase long-term costs. Technical debt is incurred when programmers, often out of laziness or urgency to meet a deadline, choose quick and dirty solutions rather than build maintainability into their code. A common cause is underestimates in software development effort estimation , leading to insufficient resources allocated to development. A challenge with maintainability
2318-659: The early 2000s. In 1998, Netscape launched what would become the Mozilla Foundation to create a new browser using the open-source software model. This work evolved into the Firefox browser, first released by Mozilla in 2004. Firefox's market share peaked at 32% in 2010. Apple released its Safari browser in 2003; it remains the dominant browser on Apple devices, though it did not become popular elsewhere. Google debuted its Chrome browser in 2008, which steadily took market share from Internet Explorer and became
2379-406: The extent that they embody an author's original creation, are proper subject matter of copyright". Proprietary software is rarely distributed as source code. Although the term open-source software literally refers to public access to the source code , open-source software has additional requirements: free redistribution, permission to modify the source code and release derivative works under
2440-440: The first commercial product to incorporate Mosaic. However, by 1998, the Mosaic user base had almost completely evaporated as users moved to other web browsers. The licensing terms for NCSA Mosaic were generous for a proprietary software program. In general, non-commercial use was free of charge for all versions (with certain limitations). Additionally, the X Window System/Unix version publicly provided source code (source code for
2501-594: The first web browser to find mainstream popularity. Its innovative graphical user interface made the World Wide Web easy to navigate and thus more accessible to the average person. This, in turn, sparked the Internet boom of the 1990s, when the Web grew at a very rapid rate. The lead developers of Mosaic then founded the Netscape corporation, which released the Mosaic-influenced Netscape Navigator in 1994. Navigator quickly became
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2562-475: The instructions can be carried out. After being compiled, the program can be saved as an object file and the loader (part of the operating system) can take this saved file and execute it as a process on the computer hardware. Some programming languages use an interpreter instead of a compiler. An interpreter converts the program into machine code at run time , which makes them 10 to 100 times slower than compiled programming languages. Software quality
2623-529: The lesser-known Erwise , and ViolaWWW . Mosaic was developed at the National Center for Supercomputing Applications (NCSA) at the University of Illinois at Urbana–Champaign beginning in late 1992, released in January 1993, with official development and support until January 1997. Mosaic lost market share to Netscape Navigator in late 1994, and had only a tiny fraction of users left by 1997, when
2684-513: The most popular browser in 2012. Chrome has remained dominant ever since. By 2015, Microsoft replaced Internet Explorer with Edge for the Windows 10 release. Since the early 2000s, browsers have greatly expanded their HTML , CSS , JavaScript , and multimedia capabilities. One reason has been to enable more sophisticated websites, such as web apps . Another factor is the significant increase of broadband connectivity in many parts of
2745-418: The other versions was available after agreements were signed). Despite persistent rumors to the contrary, however, Mosaic was never released as open source software during its brief reign as a major browser; there were always constraints on permissible uses without payment. As of 1993, license holders included these: Robert Reid notes that Andreessen's team hoped: ... to rectify many of the shortcomings of
2806-588: The pivotal role of Mosaic this way: In the Web's first generation, Tim Berners-Lee launched the Uniform Resource Locator (URL), Hypertext Transfer Protocol (HTTP), and HTML standards with prototype Unix-based servers and browsers. A few people noticed that the Web might be better than Gopher. In the second generation, Marc Andreessen and Eric Bina developed NCSA Mosaic at the University of Illinois. Several million then suddenly noticed that
2867-465: The productivity of computer programmers, the economic value of a code base, effort estimation for projects in development, and the ongoing cost of software maintenance after release. Source code is also used to communicate algorithms between people – e.g., code snippets online or in books. Computer programmers may find it helpful to review existing source code to learn about programming techniques. The sharing of source code between developers
2928-809: The project was discontinued. Microsoft licensed one of the derivative commercial products, Spyglass Mosaic, to create Internet Explorer in 1995. In December 1991, the High Performance Computing Act of 1991 was passed, which provided funding for new projects at the NCSA, where after trying ViolaWWW , David Thompson demonstrated it to the NCSA software design group. This inspired Marc Andreessen and Eric Bina – two programmers working at NCSA – to create Mosaic. Andreessen and Bina began developing Mosaic in December 1992 for Unix's X Window System , calling it xmosaic . Marc Andreessen announced
2989-514: The project's first release, the "alpha/beta version 0.5," on January 23, 1993. Version 1.0 was released on April 21, 1993. Ports to Microsoft Windows and Macintosh were released in September. A port of Mosaic to the Amiga was available by October 1993. NCSA Mosaic for Unix (X Window System) version 2.0 was released on November 10, 1993 and was notable for adding support for forms , thus enabling
3050-474: The scene. Starting with next to nothing, the rates of the web growth (quoted in the press) hovering around tens of thousands of percent over ridiculously short periods of time were no real surprise. Ultimately, web browsers such as Mosaic became the killer applications of the 1990s. Web browsers were the first to bring a graphical interface to search tools the Internet's burgeoning wealth of distributed information services. A mid-1994 guide lists Mosaic alongside
3111-401: The server again. Cached items are usually only stored for as long as the web server stipulates in its HTTP response messages. During the course of browsing, cookies received from various websites are stored by the browser. Some of them contain login credentials or site preferences. However, others are used for tracking user behavior over long periods of time, so browsers typically provide
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#17327721672053172-457: The software from so-called Unix computers that are popular only in technical and academic circles, to the [Microsoft] Windows operating system, which is used on more than 80 percent of the computers in the world, especially personal and commercial computers. Mosaic is based on the libwww library and thus supported a wide variety of Internet protocols included in the library: Archie , FTP , gopher , HTTP , NNTP , telnet , WAIS . Mosaic
3233-414: The source code. Many IDEs support code analysis tools, which might provide metrics on the clarity and maintainability of the code. Debuggers are tools that often enable programmers to step through execution while keeping track of which source code corresponds to each change of state. Source code files in a high-level programming language must go through a stage of preprocessing into machine code before
3294-439: The traditional, text-oriented information search tools of the time, Archie and Veronica , Gopher , and WAIS but Mosaic quickly subsumed and displaced them all. Joseph Hardin, the director of the NCSA group within which Mosaic was developed, said downloads were up to 50,000 a month in mid-1994. In November 1992, there were twenty-six websites in the world and each one attracted attention. In its release year of 1993, Mosaic had
3355-421: The very primitive prototypes then floating around the Internet. Most significantly, their work transformed the appeal of the Web from niche uses in the technical area to mass-market appeal. In particular, these University of Illinois students made two key changes to the Web browser, which hyper-boosted its appeal: they added graphics to what was otherwise boring text-based software, and, most importantly, they ported
3416-416: The work of Berners-Lee and the hypertext theorists before him, is generally recognized as the beginning of the web as it is now known. Mosaic, the first web browser to win over the Net masses, was released in 1993 and made freely accessible to the public. The adjective phenomenal, so often overused in this industry, is genuinely applicable to the... 'explosion' in the growth of the web after Mosaic appeared on
3477-405: The world, enabling people to access data-intensive content, such as streaming HD video on YouTube , that was not possible during the era of dial-up modems . Google Chrome has been the dominant browser since the mid-2010s and currently has a 67% global market share on all devices. The vast majority of its source code comes from Google's open-source Chromium project; this code is also
3538-487: Was last released (version 2.7ck9) on July 11, 2010; a maintenance release with minor compatibility fixes (version 2.7ck10) was released on January 9, 2015, followed by another one (2.7ck11) in October 2015. The stated goal of the project is " Lynx with graphics" and runs on Mac OS X, Power MachTen , Linux and other compatible Unix-like OSs . The X, Windows, and Mac versions of Mosaic all had separate development teams and code bases. Web browser A web browser
3599-404: Was released, Mosaic has incited a rush of excitement and commercial energy unprecedented in the history of the Net. Reid also refers to Matthew K. Gray's website, Internet Statistics: Growth and Usage of the Web and the Internet , which indicates a dramatic leap in web use around the time of Mosaic's introduction. David Hudson concurs with Reid: Marc Andreessen's realization of Mosaic, based on
3660-480: Was simultaneous with the compilers needed to translate the source code automatically into machine code that can be directly executed on the computer hardware . Source code is the form of code that is modified directly by humans, typically in a high-level programming language. Object code can be directly executed by the machine and is generated automatically from the source code, often via an intermediate step, assembly language . While object code will only work on
3721-445: Was the first browser written and supported by a team of full-time programmers, was reliable and easy enough for novices to install, and the inline graphics proved immensely appealing. Mosaic is said to have made the Internet accessible to the ordinary person. Mosaic was the first browser to explore the concept of collaborative annotation in 1993 but never passed the test state. Mosaic was the first browser that could submit forms to
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