Linux Today
Today Linux is used in numerous domains, from embedded systems to supercomputers, and has secured a place in server installations with the popular LAMP application stack. Linux has also become popular with the newly founded netbook market, with many devices such as the ASUS Eee PC and Acer Aspire One shipping with Linux distributions pre-installed. Torvalds continues to direct the development of the kernel. Stallman heads the Free Software Foundation, which in turn supports the GNU components. Finally, individuals and corporations develop third-party non-GNU components. These third-party components comprise a vast body of work and may include both kernel modules and user applications and libraries. Linux vendors and communities combine and distribute the kernel, GNU components, and non-GNU components, with additional package management software in the form of Linux distributions.
Windows Vista
Windows Vista (pronounced /ˈvɪstə/) is a line of operating systems developed by Microsoft for use on personal computers, including home and business desktops, laptops, Tablet PCs, and media center PCs. Prior to its announcement on July 22, 2005, Windows Vista was known by its codename Longhorn. Development was completed on November 8, 2006; over the following three months it was released in stages to computer hardware and software manufacturers, business customers, and retail channels. On January 30, 2007, it was released worldwide, and was made available for purchase and download from Microsoft's website. The release of Windows Vista came more than five years after the introduction of its predecessor, Windows XP, the longest time span between successive releases of Microsoft Windows.
Windows Vista contains many changes and new features, including an updated graphical user interface and visual style dubbed Windows Aero, improved searching features, new multimedia creation tools such as Windows DVD Maker, and redesigned networking, audio, print, and display sub-systems. Vista also aims to increase the level of communication between machines on a home network, using peer-to-peer technology to simplify sharing files and digital media between computers and devices. Windows Vista includes version 3.0 of the .NET Framework, which aims to make it significantly easier for software developers to write applications than with the traditional Windows API.
For graphics, Vista introduces a new Windows Display Driver Model and a major revision to Direct3D. The new driver model facilitates the new Desktop Window Manager, which provides the tearing-free desktop and special effects that are the cornerstones of Windows Aero. Direct3D 10, developed in conjunction with major display driver manufacturers, is a new architecture with more advanced shader support, and allows the graphics processing unit to render more complex scenes without assistance from the CPU. It features improved load balancing between CPU and GPU and also optimizes data transfer between them.
At the core of the operating system, many improvements have been made to the memory manager, process scheduler and I/O scheduler. The Heap Manager implements additional features such as integrity checking in order to improve robustness and defend against buffer overflow security exploits, although this comes at the price of breaking backward compatibility with some legacy applications. A Kernel Transaction Manager has been implemented that enables applications to work with the file system and Registry using atomic transaction operations.
Windows Vista contains many changes and new features, including an updated graphical user interface and visual style dubbed Windows Aero, improved searching features, new multimedia creation tools such as Windows DVD Maker, and redesigned networking, audio, print, and display sub-systems. Vista also aims to increase the level of communication between machines on a home network, using peer-to-peer technology to simplify sharing files and digital media between computers and devices. Windows Vista includes version 3.0 of the .NET Framework, which aims to make it significantly easier for software developers to write applications than with the traditional Windows API.
For graphics, Vista introduces a new Windows Display Driver Model and a major revision to Direct3D. The new driver model facilitates the new Desktop Window Manager, which provides the tearing-free desktop and special effects that are the cornerstones of Windows Aero. Direct3D 10, developed in conjunction with major display driver manufacturers, is a new architecture with more advanced shader support, and allows the graphics processing unit to render more complex scenes without assistance from the CPU. It features improved load balancing between CPU and GPU and also optimizes data transfer between them.
At the core of the operating system, many improvements have been made to the memory manager, process scheduler and I/O scheduler. The Heap Manager implements additional features such as integrity checking in order to improve robustness and defend against buffer overflow security exploits, although this comes at the price of breaking backward compatibility with some legacy applications. A Kernel Transaction Manager has been implemented that enables applications to work with the file system and Registry using atomic transaction operations.
Ubuntu
Ubuntu (IPA: [uːˈbuːntuː] in English, [ùɓúntú] in Zulu) is a free computer operating system based on the Linux kernel. Its name comes from the Zulu word ubuntu, loosely translated as "humanity". Ubuntu's goals include providing an up-to-date, stable operating system for the average user, with a strong focus on usability and ease of installation. Ubuntu has been rated as the most popular Linux distribution, claiming approximately 30% of desktop Linux installations in a survey.
Ubuntu is free and open source, meaning that not only is it distributed without charge, but it may also be freely improved upon. Ubuntu is sponsored by Canonical Ltd, which is owned by South African entrepreneur Mark Shuttleworth. Instead of selling Ubuntu itself, Canonical makes money by selling paid support for Ubuntu. By keeping Ubuntu free and open Canonical is able to leverage the talents of outside developers willing to contribute rather than having to do all development within the company itself.
Kubuntu and Xubuntu are official subprojects of the Ubuntu project, aiming to bring the KDE and Xfce desktop environments, respectively, to the Ubuntu core (by default Ubuntu uses GNOME for its desktop environment). Edubuntu is an official subproject designed for school environments and should be equally suitable for children to use at home. Gobuntu is an official subproject that is aimed at adhering strictly to the Free Software Foundation's Four Freedoms. Ubuntu JeOS (pronounced "Juice") is the newest official subproject. JeOS is a concept for what an operating system should look like in the context of a virtual appliance.
Ubuntu releases new versions every six months, and supports those releases for 18 months with daily security fixes and patches to critical bugs. LTS (Long Term Support) releases, which occur every two years, are supported for three years for desktops and five years for servers. The most recent version, Ubuntu 8.04 LTS (Hardy Heron), was released on April 24, 2008, although an update, Ubuntu 8.04.1 has been released. The next version will be 8.10 (Intrepid Ibex) and is scheduled for release in October 2008.
Ubuntu is free and open source, meaning that not only is it distributed without charge, but it may also be freely improved upon. Ubuntu is sponsored by Canonical Ltd, which is owned by South African entrepreneur Mark Shuttleworth. Instead of selling Ubuntu itself, Canonical makes money by selling paid support for Ubuntu. By keeping Ubuntu free and open Canonical is able to leverage the talents of outside developers willing to contribute rather than having to do all development within the company itself.
Kubuntu and Xubuntu are official subprojects of the Ubuntu project, aiming to bring the KDE and Xfce desktop environments, respectively, to the Ubuntu core (by default Ubuntu uses GNOME for its desktop environment). Edubuntu is an official subproject designed for school environments and should be equally suitable for children to use at home. Gobuntu is an official subproject that is aimed at adhering strictly to the Free Software Foundation's Four Freedoms. Ubuntu JeOS (pronounced "Juice") is the newest official subproject. JeOS is a concept for what an operating system should look like in the context of a virtual appliance.
Ubuntu releases new versions every six months, and supports those releases for 18 months with daily security fixes and patches to critical bugs. LTS (Long Term Support) releases, which occur every two years, are supported for three years for desktops and five years for servers. The most recent version, Ubuntu 8.04 LTS (Hardy Heron), was released on April 24, 2008, although an update, Ubuntu 8.04.1 has been released. The next version will be 8.10 (Intrepid Ibex) and is scheduled for release in October 2008.
Ajax
Ajax (asynchronous JavaScript and XML), or AJAX, is a group of interrelated web development techniques used for creating interactive web applications or rich Internet applications. With Ajax, web applications can retrieve data from the server asynchronously in the background without interfering with the display and behavior of the existing page. Data is retrieved using the XMLHttpRequest object or through the use of Remote Scripting in browsers that do not support it. Despite the name, the use of JavaScript, XML, or its asynchronous use is not required.
While the term Ajax was coined in 2005, techniques for the asynchronous loading of content date back to 1996, when Internet Explorer introduced the IFrame element. Microsoft's Remote Scripting, introduced in 1998, acted as a more elegant replacement for these techniques, with data being pulled in by a Java applet with which the client side could communicate using JavaScript. In 1999, Microsoft created the XMLHttpRequest object as an ActiveX control in Internet Explorer 5, and developers of Mozilla and Safari followed soon after with native versions of the object. On April 5, 2006 the World Wide Web Consortium (W3C) released the first draft specification for the object in an attempt to create an official web standard.
The term Ajax has come to represent a broad group of web technologies that can be used to implement a web application that communicates with a server in the background, without interfering with the current state of the page. In the article that coined the term Ajax, Jesse James Garrett explained that it refers specifically to these technologies:
XHTML and CSS for presentation
the Document Object Model for dynamic display of and interaction with data
XML and XSLT for the interchange and manipulation of data, respectively
the XMLHttpRequest object for asynchronous communication
JavaScript to bring these technologies together
Since then, however, there have been a number of developments in the technologies used in an Ajax application, and the definition of the term Ajax. In particular, it has been noted that:
JavaScript is not the only client-side scripting language that can be used for implementing an Ajax application. Other languages such as VBScript are also capable of the required functionality.
the XMLHttpRequest object is not necessary for asynchronous communication. It has been noted that IFrames are capable of the same effect.
XML is not required for data interchange and therefore XSLT is not required for the manipulation of data. JavaScript Object Notation (JSON) is often used as an alternative format for data interchange, although other formats such as preformatted HTML or plain text can also be used.
While the term Ajax was coined in 2005, techniques for the asynchronous loading of content date back to 1996, when Internet Explorer introduced the IFrame element. Microsoft's Remote Scripting, introduced in 1998, acted as a more elegant replacement for these techniques, with data being pulled in by a Java applet with which the client side could communicate using JavaScript. In 1999, Microsoft created the XMLHttpRequest object as an ActiveX control in Internet Explorer 5, and developers of Mozilla and Safari followed soon after with native versions of the object. On April 5, 2006 the World Wide Web Consortium (W3C) released the first draft specification for the object in an attempt to create an official web standard.
The term Ajax has come to represent a broad group of web technologies that can be used to implement a web application that communicates with a server in the background, without interfering with the current state of the page. In the article that coined the term Ajax, Jesse James Garrett explained that it refers specifically to these technologies:
XHTML and CSS for presentation
the Document Object Model for dynamic display of and interaction with data
XML and XSLT for the interchange and manipulation of data, respectively
the XMLHttpRequest object for asynchronous communication
JavaScript to bring these technologies together
Since then, however, there have been a number of developments in the technologies used in an Ajax application, and the definition of the term Ajax. In particular, it has been noted that:
JavaScript is not the only client-side scripting language that can be used for implementing an Ajax application. Other languages such as VBScript are also capable of the required functionality.
the XMLHttpRequest object is not necessary for asynchronous communication. It has been noted that IFrames are capable of the same effect.
XML is not required for data interchange and therefore XSLT is not required for the manipulation of data. JavaScript Object Notation (JSON) is often used as an alternative format for data interchange, although other formats such as preformatted HTML or plain text can also be used.
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