MOSIX is a proprietary distributed operating system . Although early versions were based on older UNIX systems, since 1999 it focuses on Linux clusters and grids . In a MOSIX cluster/grid there is no need to modify or to link applications with any library, to copy files or login to remote nodes, or even to assign processes to different nodes – it is all done automatically, like in an SMP .
50-415: MOSIX has been researched and developed since 1977 at The Hebrew University of Jerusalem by the research team of Prof. Amnon Barak. So far, ten major versions have been developed. The first version, called MOS, for Multicomputer OS , (1981–83) was based on Bell Lab's Seventh Edition Unix and ran on a cluster of PDP-11 computers. Later versions were based on Unix System V Release 2 (1987–89) and ran on
100-510: A Document type declaration (informally, a "doctype"). In browsers, the doctype helps to define the rendering mode—particularly whether to use quirks mode . The original purpose of the doctype was to enable the parsing and validation of HTML documents by SGML tools based on the Document type definition (DTD). The DTD to which the DOCTYPE refers contains a machine-readable grammar specifying
150-440: A URL that points to a directory structure instead of an actual web page within the directory structure, the web server will generally serve a default page, which is often referred to as a main or "index" page. A common filename for such a page is index. html , but most modern HTTP servers offer a configurable list of filenames that the server can use as an index. If a server is configured to support server-side scripting ,
200-708: A web server or from local storage and render the documents into multimedia web pages. HTML describes the structure of a web page semantically and originally included cues for its appearance. HTML elements are the building blocks of HTML pages. With HTML constructs, images and other objects such as interactive forms may be embedded into the rendered page. HTML provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links , quotes, and other items. HTML elements are delineated by tags , written using angle brackets . Tags such as < img > and < input > directly introduce content into
250-470: A 1 Gbit/s campus grid is nearly identical to that of a single cluster. It is particularly suitable for: A few examples: MOSIX4 was released in July 2014. As of version 4, MOSIX doesn't require kernel patching. After MOSIX became proprietary software in late 2001, Moshe Bar forked the last free version and started the openMosix project on February 10, 2002. On July 15, 2007, Bar decided to end
300-410: A cluster of VAX and NS32332 -based computers, followed by a BSD/OS -derived version (1991–93) for a cluster of 486/Pentium computers. Since 1999 MOSIX is tuned to Linux for x86 platforms. The second version of MOSIX, called MOSIX2, compatible with Linux-2.6 and 3.0 kernels. MOSIX2 is implemented as an OS virtualization layer that provides users and applications with a single system image with
350-407: A contractor at CERN , proposed and prototyped ENQUIRE , a system for CERN researchers to use and share documents. In 1989, Berners-Lee wrote a memo proposing an Internet -based hypertext system. Berners-Lee specified HTML and wrote the browser and server software in late 1990. That year, Berners-Lee and CERN data systems engineer Robert Cailliau collaborated on a joint request for funding, but
400-590: A given directory, the web server may be configured to provide an automatically generated listing of the files within the directory instead. With the Apache web server, for example, this behavior is provided by the mod_autoindex module and controlled by the Options +Indexes directive in the web server configuration files . These automated directory listings are sometimes a security risk because they enumerate sensitive files which may not be intended for public access, in
450-500: A grid allows owners of clusters to share their computational resources, while still preserving their autonomy over their own clusters and their ability to disconnect their nodes from the grid at any time, without disrupting already running programs. A MOSIX grid can extend indefinitely as long as there is trust between its cluster owners. This must include guarantees that guest applications will not be modified while running in remote clusters and that no hostile computers can be connected to
500-451: A pair is the start tag , and the second is the end tag (they are also called opening tags and closing tags ). Another important component is the HTML document type declaration , which triggers standards mode rendering. The following is an example of the classic "Hello, World!" program : The text between < html > and </ html > describes the web page, and
550-406: A process known as a directory indexing attack. Such a security misconfiguration may also assist in other attacks, such as a path or directory traversal attack . When accessing a directory, the various available index methods may also have a different impact on usage of OS resources ( RAM , CPU time , etc.) and thus on web server performances. Proceeding from fastest to slowest method, here
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#1732798386242600-425: A start tag) and do not use an end tag. Many tags, particularly the closing end tag for the very commonly used paragraph element < p > , are optional. An HTML browser or other agent can infer the closure for the end of an element from the context and the structural rules defined by the HTML standard. These rules are complex and not widely understood by most HTML authors. The general form of an HTML element
650-596: A user can give input/s like: Comments: Comments can help in the understanding of the markup and do not display in the webpage. There are several types of markup elements used in HTML: Most of the attributes of an element are name–value pairs , separated by = and written within the start tag of an element after the element's name. The value may be enclosed in single or double quotes, although values consisting of certain characters can be left unquoted in HTML (but not XHTML). Leaving attribute values unquoted
700-464: Is considered unsafe. In contrast with name-value pair attributes, there are some attributes that affect the element simply by their presence in the start tag of the element, like the ismap attribute for the img element. There are several common attributes that may appear in many elements : The abbreviation element, abbr , can be used to demonstrate some of these attributes: This example displays as HTML ; in most browsers, pointing
750-456: Is for HTML5. If a declaration is not included, various browsers will revert to " quirks mode " for rendering. HTML documents imply a structure of nested HTML elements . These are indicated in the document by HTML tags , enclosed in angle brackets thus: < p > . In the simple, general case, the extent of an element is indicated by a pair of tags: a "start tag" < p > and "end tag" </ p > . The text content of
800-432: Is most suitable for running compute intensive applications with low to moderate amount of input/output (I/O). Tests of MOSIX2 show that the performance of several such applications over a 1 Gbit/s campus grid is nearly identical to that of a single cluster. MOSIX is most suitable for running HPC applications with low to moderate amount of I/O. Tests of MOSIX show that the performance of several such applications over
850-409: Is the list: HTML Hypertext Markup Language ( HTML ) is the standard markup language for documents designed to be displayed in a web browser . It defines the content and structure of web content . It is often assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScript, a programming language. Web browsers receive HTML documents from
900-401: Is therefore: < tag attribute1 = "value1" attribute2 = "value2" > ''content'' </ tag > . Some HTML elements are defined as empty elements and take the form < tag attribute1 = "value1" attribute2 = "value2" > . Empty elements may enclose no content, for instance, the < br /> tag or
950-589: The Internet Engineering Task Force (IETF) with the mid-1993 publication of the first proposal for an HTML specification, the "Hypertext Markup Language (HTML)" Internet Draft by Berners-Lee and Dan Connolly , which included an SGML Document type definition to define the syntax. 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
1000-434: The de facto web standard for some time. HTML markup consists of several key components, including those called tags (and their attributes ), character-based data types , character references and entity references . HTML tags most commonly come in pairs like < h1 > and </ h1 > , although some represent empty elements and so are unpaired, for example < img > . The first tag in such
1050-456: The IETF's philosophy of basing standards on successful prototypes. Similarly, Dave Raggett 's competing Internet Draft, "HTML+ (Hypertext Markup Format)", 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. In 1995, this working group completed "HTML 2.0",
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#17327983862421100-480: The Linux run-time environment. It allows applications to run in remote nodes as if they run locally. Users run their regular (sequential and parallel) applications while MOSIX transparently and automatically seek resources and migrate processes among nodes to improve the overall performance. MOSIX2 can manage a cluster and a multicluster ( grid ) as well as workstations and other shared resources. Flexible management of
1150-546: The NCSA-originated index.html . Later web servers typically support this default file scheme in one form or another; this is usually configurable, with index.html being one of the default file names. In some cases, the home page of a website can be a menu of language options for large sites that use geotargeting . It is also possible to avoid this step, for example, by using content negotiation . In cases where no known index.* file exists within
1200-596: The XML syntax for HTML and is no longer being developed as a separate standard. On 28 May 2019, the W3C announced that WHATWG would be the sole publisher of the HTML and DOM standards. The W3C and WHATWG had been publishing competing standards since 2012. While the W3C standard was identical to the WHATWG in 2007 the standards have since progressively diverged due to different design decisions. The WHATWG "Living Standard" had been
1250-473: The attribute value itself. If document authors overlook the need to escape such characters, some browsers can be very forgiving and try to use context to guess their intent. The result is still invalid markup, which makes the document less accessible to other browsers and to other user agents that may try to parse the document for search and indexing purposes for example. Escaping also allows for characters that are not easily typed, or that are not available in
1300-574: The browser, and these characteristics can be altered or enhanced by the web page designer's additional use of CSS . Many of the text elements are mentioned in the 1988 ISO technical report TR 9537 Techniques for using SGML , which describes the features of early text formatting languages such as that used by the RUNOFF command developed in the early 1960s for the CTSS (Compatible Time-Sharing System) operating system. These formatting commands were derived from
1350-433: The characters < and & (when written as < and & , respectively) to be interpreted as character data, rather than markup. For example, a literal < normally indicates the start of a tag, and & normally indicates the start of a character entity reference or numeric character reference; writing it as & or & or & allows & to be included in
1400-441: The characters of the world's writing systems. HTML defines several data types for element content, such as script data and stylesheet data, and a plethora of types for attribute values, including IDs, names, URIs , numbers, units of length, languages, media descriptors, colors, character encodings, dates and times, and so on. All of these data types are specializations of character data. HTML documents are required to start with
1450-451: The commands used by typesetters to manually format documents. However, the SGML concept of generalized markup is based on elements (nested annotated ranges with attributes) rather than merely print effects, with separate structure and markup. HTML has been progressively moved in this direction with CSS. Berners-Lee considered HTML to be an application of SGML. It was formally defined as such by
1500-539: The content of an element or in the value of an attribute. The double-quote character ( " ), when not used to quote an attribute value, must also be escaped as " or " or " when it appears within the attribute value itself. Equivalently, the single-quote character ( ' ), when not used to quote an attribute value, must also be escaped as ' or ' (or as ' in HTML5 or XHTML documents ) when it appears within
1550-664: The cursor at the abbreviation should display the title text "Hypertext Markup Language." Most elements take the language-related attribute dir to specify text direction, such as with "rtl" for right-to-left text in, for example, Arabic , Persian or Hebrew . As of version 4.0, HTML defines a set of 252 character entity references and a set of 1,114,050 numeric character references , both of which allow individual characters to be written via simple markup, rather than literally. A literal character and its markup counterpart are considered equivalent and are rendered identically. The ability to " escape " characters in this way allows for
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1600-589: The document's character encoding , to be represented within the element and attribute content. For example, the acute-accented e ( é ), a character typically found only on Western European and South American keyboards, can be written in any HTML document as the entity reference é or as the numeric references é or é , using characters that are available on all keyboards and are supported in all character encodings. Unicode character encodings such as UTF-8 are compatible with all modern browsers and allow direct access to almost all
1650-445: The element, if any, is placed between these tags. Tags may also enclose further tag markup between the start and end, including a mixture of tags and text. This indicates further (nested) elements, as children of the parent element. The start tag may also include the element's attributes within the tag. These indicate other information, such as identifiers for sections within the document, identifiers used to bind style information to
1700-474: The files in the directory. Usually this option, often named autoindex , is also configurable. A scheme where web server serves a default file on per-subdirectory basis has been supported as early as NCSA HTTPd 0.3beta (22 April 1993), which defaults to serve index.html file in the directory. This scheme has been then adopted by CERN HTTPd since at least 2.17beta (5 April 1994), whose default supports Welcome.html and welcome.html in addition to
1750-517: 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 (W3C). In 2000, HTML became an international standard ( ISO / IEC 15445:2000). HTML 4.01
1800-412: The head, for example: HTML headings are defined with the < h1 > to < h6 > tags with H1 being the highest (or most important) level and H6 the least: The effects are: CSS can substantially change the rendering. Paragraphs: < br /> . The difference between < br /> and < p > is that < br /> breaks a line without altering
1850-425: The hyperlink tag, these were strongly influenced by SGMLguid , an in-house Standard Generalized Markup Language (SGML)-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, images, and other material into visible or audible web pages. Default characteristics for every item of HTML markup are defined in
1900-402: The inline < img > tag. The name of an HTML element is the name used in the tags. The end tag's name is preceded by a slash character, / , and that in empty elements the end tag is neither required nor allowed. If attributes are not mentioned, default values are used in each case. Header of the HTML document: < head > ... </ head > . The title is included in
1950-625: The list of filenames is controlled by the DirectoryIndex directive in the main server configuration file or in the configuration file for that directory . It is possible to not use file extensions at all, and be neutral to content delivery methods, and set the server to automatically pick the best file through content negotiation . If the server is unable to find a file with any of the names listed in its configuration, it may either return an error (usually 403 Index Listing Forbidden or 404 Not Found ) or generate its own index page listing
2000-427: The list will usually include entries allowing dynamic content to be used as the index page (e.g. index. cgi , index. pl , index. php , index. shtml , index. jsp , default. asp ) even though it may be more appropriate to still specify the HTML output ( index.html.php or index.html.aspx ), as this should not be taken for granted. An example is the popular open source web server Apache , where
2050-421: The local network. Nowadays these requirements are standard within clusters and organizational grids. MOSIX2 can run in native mode or in a virtual machine (VM). In native mode, performance is better, but it requires modifications to the base Linux kernel , whereas a VM can run on top of any unmodified operating system that supports virtualization, including Microsoft Windows , Linux and Mac OS X . MOSIX2
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2100-465: The look and layout of content. The World Wide Web Consortium (W3C), former maintainer of the HTML and current maintainer of the CSS standards, has encouraged the use of CSS over explicit presentational HTML since 1997. A form of HTML, known as HTML5 , is used to display video and audio, primarily using the < canvas > element, together with JavaScript. In 1980, physicist Tim Berners-Lee ,
2150-476: The openMosix project effective March 1, 2008, claiming that "the increasing power and availability of low cost multi-core processors is rapidly making single-system image (SSI) clustering less of a factor in computing". These plans were reconfirmed in March 2008. The LinuxPMI project is continuing development of the former openMosix code. index.php When an HTTP client (generally a web browser ) requests
2200-413: The page. Other tags such as < p > and </ p > surround and provide information about document text and may include sub-element tags. Browsers do not display the HTML tags but use them to interpret the content of the page. HTML can embed programs written in a scripting language such as JavaScript , which affects the behavior and content of web pages. The inclusion of CSS defines
2250-483: The permitted and prohibited content for a document conforming to such a DTD. Browsers, on the other hand, do not implement HTML as an application of SGML and as consequence do not read the DTD. HTML5 does not define a DTD; therefore, in HTML5 the doctype declaration is simpler and shorter: An example of an HTML 4 doctype This declaration references the DTD for the "strict" version of HTML 4.01. SGML-based validators read
2300-412: The presentation of the document, and for some tags such as the < img > used to embed images, the reference to the image resource in the format like this: < img src = "example.com/example.jpg" > Some elements, such as the line break < br /> do not permit any embedded content, either text or further tags. These require only a single empty tag (akin to
2350-491: The project was not formally adopted by CERN. In his personal notes of 1990, Berners-Lee listed "some of the many areas in which hypertext is used"; an encyclopedia is the first entry. The first publicly available description of HTML was a document called "HTML Tags", first mentioned on the Internet by Tim Berners-Lee in late 1991. It describes 18 elements comprising the initial, relatively simple design of HTML. Except for
2400-471: The semantic structure of the page, whereas < p > sections the page into paragraphs . The element < br /> is an empty element in that, although it may have attributes, it can take no content and it may not have an end tag. This is a link in HTML. To create a link the < a > tag is used. The href attribute holds the URL address of the link. There are many possible ways
2450-517: The text between < body > and </ body > is the visible page content. The markup text < title > This is a title </ title > defines the browser page title shown on browser tabs and window titles and the tag < div > defines a division of the page used for easy styling. Between < head > and </ head > , a < meta > element can be used to define webpage metadata. The Document Type Declaration <!DOCTYPE html>
2500-515: 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 (WHATWG), which became a joint deliverable with the W3C in 2008, and was completed and standardized on 28 October 2014. XHTML is a separate language that began as a reformulation of HTML 4.01 using XML 1.0. It is now referred to as
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