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44-490: The source code was released into the public domain on 30 April 1993. Some of the code still resides on Tim Berners-Lee 's NeXT Computer in the CERN museum and has not been recovered due to the computer's status as a historical artifact. To coincide with the 20th anniversary of the research center giving the web to the world, a project began in 2013 at CERN to preserve this original hardware and software associated with

88-441: 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

132-462: 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

176-430: 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

220-529: 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

264-444: 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

308-406: 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

352-405: 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

396-465: Is also a WYSIWYG editor. It allows the simultaneous editing and linking of many pages in different windows. The functions "Mark Selection", which creates an anchor, and "Link to Marked", which makes the selected text an anchor linking to the last marked anchor, allow the creation of links. Editing pages remotely is not possible, as the HTTP PUT method had not yet been implemented during the period of

440-442: 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

484-554: Is capable of displaying basic style sheets , downloading and opening any file type with a MIME type that is also supported by the NeXT system ( PostScript , movies, and sounds), browsing newsgroups , and spellchecking . In earlier versions, images are displayed in separate windows, until NeXTSTEP's Text class gained support for Image objects. WorldWideWeb is able to use different protocols: FTP , HTTP , NNTP , and local files . Later versions are able to display inline images. The browser

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528-452: 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

572-496: 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

616-470: 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

660-631: 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

704-602: Is the URI as understood by the Windows Shell API: Note that the drive letter followed by a colon and slash is part of the acceptable file URI. On Microsoft Windows systems, the normal colon (:) after a device letter has sometimes been replaced by a vertical bar (|) in file URLs. This reflected the original URL syntax, which made the colon a reserved character in a path part. Since Internet Explorer 4 , file URIs have been standardized on Windows, and should follow

748-477: 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

792-418: 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

836-499: Is valid, " file://simpen.txt " is not, although some interpreters manage to handle the latter). RFC 3986 includes additional information about the treatment of ".." and "." segments in URIs. There are two ways that Windows UNC filenames (such as \\server\folder\data.xml ) can be represented. These are both described in RFC 8089, Appendix E as "non-standard". The first way (called here

880-535: The WorldWideWeb browser in 1991 . When a new version was released in 1994, it was renamed Nexus Browser , in order to differentiate between the software ( WorldWideWeb ) and the World Wide Web . The team created so called "passive browsers" which do not have the ability to edit because it was hard to port this feature from the NeXT system to other operating systems . Porting to the X Window System

924-469: The "healthy" file://remotehost/share/dir/file.txt . File URLs are rarely used in Web pages on the public Internet, since they imply that a file exists on the designated host. The host specifier can be used to retrieve a file from an external source, although no specific file-retrieval protocol is specified; and using it should result in a message that informs the user that no mechanism to access that machine

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968-425: The 2-slash form; Java (for example, the method new URI(path) ) generally uses the 4-slash form. Either form allows the most common operations on URIs (resolving relative URIs, and dereferencing to obtain a connection to the remote file) to be used successfully. However, because these URIs are non-standard, some less common operations fail: an example is the normalize operation (defined in RFC 3986 and implemented in

1012-523: The 2-slash format) is to represent the server name using the Authority part of the URI, which then becomes file://server/folder/data.xml . The second way (called here the 4-slash format) is to represent the server name as part of the Path component, so the URI becomes file:////server/folder/data.xml . Both forms are actively used. Microsoft .NET (for example, the method new Uri(path) ) generally uses

1056-491: The Java java.net.URI.normalize() method) which reduces file:////server/folder/data.xml to the unusable form file:/server/folder/data.xml . Here are two Unix examples pointing to the same /etc/fstab file: The KDE environment uses URIs without an authority field: Here are some examples which may be accepted by some applications on Windows systems, referring to the same, local file c: \ WINDOWS \ clock.avi Here

1100-524: The Previous button would cause the browser to load the previous page linked in the table. This is useful for web pages which contain lists of links. Many still do, but the user interface link-chaining was not adopted by other contemporary browser writers, and it only gained popularity later. An equivalent functionality is nowadays provided by connecting web pages with explicit navigation buttons repeated on each webpage among those links, or with typed links in

1144-463: The application's active development. Files can be edited in a local file system which is in turn served onto the Web by an HTTP server. WorldWideWeb's navigation panel contains Next and Previous buttons that automatically navigate to the next or previous link on the last page visited, similar to Opera 's Rewind and Fast Forward buttons, or HyperCard ; i.e., if one navigated to a page from a table of links,

1188-400: The birth of the Web. Tim Berners-Lee wrote what would become known as WorldWideWeb on a NeXT Computer during the second half of 1990, while working for CERN , a European nuclear research agency. The first edition was completed "some time before" 25 December 1990, according to Berners-Lee, after two months of development. The browser was announced on the newsgroups and became available to

1232-520: The concept if any licensing issues were involved, he eventually opted to release it into the public domain . In 2021, Sotheby's held an auction for an NFT of the WorldWideWeb source code . Since WorldWideWeb was developed on and for the NeXTSTEP platform, the program uses many of NeXTSTEP's components – WorldWideWeb's layout engine was built around NeXTSTEP's Text class . WorldWideWeb

1276-426: 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

1320-600: The equivalent functions are not available) the above outline will help. To aid the installed base of legacy applications on Win32 PathCreateFromUrl recognizes certain URLs which do not meet these criteria, and treats them uniformly. These are called "legacy" file URLs as opposed to "healthy" file URLs. In the past, a variety of other applications have used other systems. Some added an additional two slashes. For example, UNC path \\remotehost\share\dir\file.txt would become file:////remotehost/share/dir/file.txt instead of

1364-406: 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

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1408-404: The following scheme. This applies to all applications which use URLMON or SHLWAPI for parsing, fetching or binding to URIs. To convert a path to a URL, use UrlCreateFromPath , and to convert a URL to a path, use PathCreateFromUrl . To access a file "the file.txt", the following might be used. For a network location: Or for a local file, the hostname is omitted, but the slash is not (note

1452-449: The format where host is the fully qualified domain name of the system on which the path is accessible, and path is a hierarchical directory path of the form directory / directory /.../ name . If host is omitted, it is taken to be " localhost ", the machine from which the URL is being interpreted. Note that when omitting host, the slash is not omitted (while " file:///piro.txt "

1496-624: The further development of the World Wide Web (e.g. HTML , and various communication protocols ). On 30 April 1993, the CERN directorate released the source code of WorldWideWeb into the public domain . Several versions of the software are still available on the web in various states. Berners-Lee initially considered releasing it under the GNU General Public License , but after hearing rumors that companies might balk at

1540-536: The general public in August 1991. By this time, several others, including Bernd Pollermann, Robert Cailliau , Jean-François Groff , and visiting undergraduate student Nicola Pellow – who later wrote the Line Mode Browser – were involved in the project. Berners-Lee considered different names for his new application, including The Mine of Information and The Information Mesh, before publicly launching

1584-541: The headers of the page. This places more of a burden on web site designers and developers, but allows them to control the presentation of the navigation links. WorldWideWeb does not have bookmarks as they exist in later browsers, but a similar feature was provided: to save a link for later use, users could link to it from their own home page (start page). Users could create multiple home pages, similar to folders in modern web browsers' bookmarks. Source code In computing , source code , or simply code or source ,

1628-475: 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

1672-507: The local system. For example file://./sharename/path/to/the%20file.txt will not work, because it will result in sharename being interpreted as part of the DOSDEVICES namespace, not as a network share. The following outline roughly describes the requirements. Use the provided functions if possible. If you must create a URL programmatically and cannot access SHLWAPI.dll (for example from script, or another programming environment where

1716-465: 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

1760-469: The same license, and nondiscrimination between different uses—including commercial use. The free reusability of open-source software can speed up development. File URI scheme In programming, a file uniform resource identifier (URI) scheme is a specific format of URI , used to specifically identify a file on a host computer. While URIs can be used to identify anything, there is specific syntax associated with identifying files. A file URI has

1804-414: 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

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1848-429: The third slash): This is not the same as providing the string "localhost" or the dot "." in place of the hostname. The string "localhost" will attempt to access the file as UNC path \\localhost\c:\path\to\the file.txt , which will not work since the colon is not allowed in a share name. The dot "." results in the string being passed as \\.\c:\path\to\the file.txt , which will work for local files, but not shares on

1892-498: Was not possible as nobody on the team had experience with the X Window System. Berners-Lee and Groff later adapted many of WorldWideWeb's components into a C programming language version, creating the libwww API . A number of early browsers appeared, notably ViolaWWW . They were all eclipsed by Mosaic in terms of popularity, which by 1993 had replaced the WorldWideWeb program. Those involved in its creation had moved on to other tasks, such as defining standards and guidelines for

1936-480: 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

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