Microsoft Corporation is an American multinational technology company with headquarters in Redmond, Washington. It develops, licenses and sells computer software, consumer electronics, personal computers, related services, its best known software products are the Microsoft Windows line of operating systems, the Microsoft Office suite, the Internet Explorer and Edge web browsers. Its flagship hardware products are the Xbox video game consoles and the Microsoft Surface lineup of touchscreen personal computers; as of 2016, it is the world's largest software maker by revenue, one of the world's most valuable companies. The word "Microsoft" is a portmanteau of "microcomputer" and "software". Microsoft is ranked No. 30 in the 2018 Fortune 500 rankings of the largest United States corporations by total revenue. Microsoft was founded by Bill Gates and Paul Allen on April 4, 1975, to develop and sell BASIC interpreters for the Altair 8800, it rose to dominate the personal computer operating system market with MS-DOS in the mid-1980s, followed by Microsoft Windows.
The company's 1986 initial public offering, subsequent rise in its share price, created three billionaires and an estimated 12,000 millionaires among Microsoft employees. Since the 1990s, it has diversified from the operating system market and has made a number of corporate acquisitions, their largest being the acquisition of LinkedIn for $26.2 billion in December 2016, followed by their acquisition of Skype Technologies for $8.5 billion in May 2011. As of 2015, Microsoft is market-dominant in the IBM PC-compatible operating system market and the office software suite market, although it has lost the majority of the overall operating system market to Android; the company produces a wide range of other consumer and enterprise software for desktops and servers, including Internet search, the digital services market, mixed reality, cloud computing and software development. Steve Ballmer replaced Gates as CEO in 2000, envisioned a "devices and services" strategy; this began with the acquisition of Danger Inc. in 2008, entering the personal computer production market for the first time in June 2012 with the launch of the Microsoft Surface line of tablet computers.
Since Satya Nadella took over as CEO in 2014, the company has scaled back on hardware and has instead focused on cloud computing, a move that helped the company's shares reach its highest value since December 1999. In 2018, Microsoft surpassed Apple as the most valuable publicly traded company in the world after being dethroned by the tech giant in 2010. Childhood friends Bill Gates and Paul Allen sought to make a business utilizing their shared skills in computer programming. In 1972 they founded their first company, named Traf-O-Data, which sold a rudimentary computer to track and analyze automobile traffic data. While Gates enrolled at Harvard, Allen pursued a degree in computer science at Washington State University, though he dropped out of school to work at Honeywell; the January 1975 issue of Popular Electronics featured Micro Instrumentation and Telemetry Systems's Altair 8800 microcomputer, which inspired Allen to suggest that they could program a BASIC interpreter for the device. After a call from Gates claiming to have a working interpreter, MITS requested a demonstration.
Since they didn't yet have one, Allen worked on a simulator for the Altair while Gates developed the interpreter. Although they developed the interpreter on a simulator and not the actual device, it worked flawlessly when they demonstrated the interpreter to MITS in Albuquerque, New Mexico. MITS agreed to distribute it, marketing it as Altair BASIC. Gates and Allen established Microsoft on April 4, 1975, with Gates as the CEO; the original name of "Micro-Soft" was suggested by Allen. In August 1977 the company formed an agreement with ASCII Magazine in Japan, resulting in its first international office, "ASCII Microsoft". Microsoft moved to a new home in Bellevue, Washington in January 1979. Microsoft entered the operating system business in 1980 with its own version of Unix, called Xenix. However, it was MS-DOS. After negotiations with Digital Research failed, IBM awarded a contract to Microsoft in November 1980 to provide a version of the CP/M OS, set to be used in the upcoming IBM Personal Computer.
For this deal, Microsoft purchased a CP/M clone called 86-DOS from Seattle Computer Products, which it branded as MS-DOS, though IBM rebranded it to PC DOS. Following the release of the IBM PC in August 1981, Microsoft retained ownership of MS-DOS. Since IBM had copyrighted the IBM PC BIOS, other companies had to reverse engineer it in order for non-IBM hardware to run as IBM PC compatibles, but no such restriction applied to the operating systems. Due to various factors, such as MS-DOS's available software selection, Microsoft became the leading PC operating systems vendor; the company expanded into new markets with the release of the Microsoft Mouse in 1983, as well as with a publishing division named Microsoft Press. Paul Allen resigned from Microsoft in 1983 after developing Hodgkin's disease. Allen claimed that Gates wanted to dilute his share in the company when he was diagnosed with Hodgkin's disease because he didn't think he was working hard enough. After leaving Microsoft, Allen lost billions of dollars on ill-conceived or mistimed technology investments.
He invested in low-tech sectors, sports teams, commercial real estate. Despite having begun jointly developing a new operating system, OS/2, with IBM in
PacketFence is an open-source network access control system which provides the following features: registration, detection of abnormal network activities, proactive vulnerability scans, isolation of problematic devices, remediation through a captive portal, 802.1X, wireless integration and User-Agent / DHCP fingerprinting. Marcotte, Ludovic. "PacketFence". Linux Journal. Retrieved 2009-03-11. Wallen, Jack. "SolutionBase: Use PacketFence to stop unwanted network traffic". Techrepublic. Retrieved 2015-11-25. Wallen, Jack. "SolutionBase: Installing and configuring Network Access Control with PacketFence". Techrepublic. Retrieved 2015-11-25. Wallen, Jack. "SolutionBase: Administer PacketFence with ease via Web interface". Techrepublic. Retrieved 2015-11-25. Balzard, Regis. "PacketFence Revisited". Linux Journal. Retrieved 2009-03-11. Gehl, Dominik. "PacketFence 1.7 offers client-free open-source NAC". LinuxWorld.com. Retrieved 2009-03-11. Buford, Cory. "Securing your network with PacketFence". Linux.com. Retrieved 2009-03-11.
Bilodeau, Olivier. "PacketFence: Because NAC doesn't have to be hard!". Insecure Magazine. Retrieved 2012-02-23. PacketFence website PacketFence on Sourceforge FLOSS Weekly 155: PacketFence, at the FLOSS Weekly podcast, March 2, 2011, retrieved March 3, 2011
In the fields of physical security and information security, access control is the selective restriction of access to a place or other resource. The act of accessing may mean entering, or using. Permission to access a resource is called authorization. Locks and login credentials are two analogous mechanisms of access control. Geographical access control may be enforced with a device such as a turnstile. There may be fences to avoid circumventing this access control. An alternative of access control in the strict sense is a system of checking authorized presence, see e.g. Ticket controller. A variant is e.g. of a shop or a country. The term access control refers to the practice of restricting entrance to a property, a building, or a room to authorized persons. Physical access control can be achieved by a human, through mechanical means such as locks and keys, or through technological means such as access control systems like the mantrap. Within these environments, physical key management may be employed as a means of further managing and monitoring access to mechanically keyed areas or access to certain small assets.
Physical access control is a matter of who and when. An access control system determines, allowed to enter or exit, where they are allowed to exit or enter, when they are allowed to enter or exit; this was accomplished through keys and locks. When a door is locked, only someone with a key can enter through the door, depending on how the lock is configured. Mechanical locks and keys do not allow restriction of the key holder to specific dates. Mechanical locks and keys do not provide records of the key used on any specific door, the keys can be copied or transferred to an unauthorized person; when a mechanical key is lost or the key holder is no longer authorized to use the protected area, the locks must be re-keyed. Electronic access control uses computers to solve the limitations of mechanical keys. A wide range of credentials can be used to replace mechanical keys; the electronic access control system grants access based on the credential presented. When access is granted, the door is unlocked for a predetermined time and the transaction is recorded.
When access is refused, the door remains locked and the attempted access is recorded. The system will monitor the door and alarm if the door is forced open or held open too long after being unlocked; when a credential is presented to a reader, the reader sends the credential's information a number, to a control panel, a reliable processor. The control panel compares the credential's number to an access control list, grants or denies the presented request, sends a transaction log to a database; when access is denied based on the access control list, the door remains locked. If there is a match between the credential and the access control list, the control panel operates a relay that in turn unlocks the door; the control panel ignores a door open signal to prevent an alarm. The reader provides feedback, such as a flashing red LED for an access denied and a flashing green LED for an access granted; the above description illustrates a single factor transaction. Credentials can be passed around. For example, Alice has access rights to the server room.
Alice either gives Bob her credential. To prevent this, two-factor authentication can be used. In a two factor transaction, the presented credential and a second factor are needed for access to be granted. There are three types of authenticating information: something the user knows, e.g. a password, pass-phrase or PIN something the user has, such as smart card or a key fob something the user is, such as fingerprint, verified by biometric measurementPasswords are a common means of verifying a user's identity before access is given to information systems. In addition, a fourth factor of authentication is now recognized: someone you know, whereby another person who knows you can provide a human element of authentication in situations where systems have been set up to allow for such scenarios. For example, a user have forgotten their smart card. In such a scenario, if the user is known to designated cohorts, the cohorts may provide their smart card and password, in combination with the extant factor of the user in question, thus provide two factors for the user with the missing credential, giving three factors overall to allow access.
A credential is a physical/tangible object, a piece of knowledge, or a facet of a person's physical being that enables an individual access to a given physical facility or computer-based information system. Credentials can be something a person knows, something they have, something they are, or some combination of these items; this is known as multi-factor authentication. The typical credential is an access card or key-fob, newer software can turn users' smartphones into access devices. There are many card technologies including magnetic stripe, bar code, Wiegand, 125 kHz proximity, 26-bit card-swipe, contact smart cards, contactless smart cards. Available are key-fobs, which are more compact than ID cards, attach to a key ring. Biometric technologies include fingerprint, facial recognition, iris recognition, retinal scan and hand geometry; the built-in biometric technologies found o
Antivirus software, or anti-virus software known as anti-malware, is a computer program used to prevent and remove malware. Antivirus software was developed to detect and remove computer viruses, hence the name. However, with the proliferation of other kinds of malware, antivirus software started to provide protection from other computer threats. In particular, modern antivirus software can protect users from: malicious browser helper objects, browser hijackers, keyloggers, rootkits, trojan horses, malicious LSPs, fraudtools and spyware; some products include protection from other computer threats, such as infected and malicious URLs, spam and phishing attacks, online identity, online banking attacks, social engineering techniques, advanced persistent threat and botnet DDoS attacks. Although the roots of the computer virus date back as early as 1949, when the Hungarian scientist John von Neumann published the "Theory of self-reproducing automata", the first known computer virus appeared in 1971 and was dubbed the "Creeper virus".
This computer virus infected Digital Equipment Corporation's PDP-10 mainframe computers running the TENEX operating system. The Creeper virus was deleted by a program created by Ray Tomlinson and known as "The Reaper"; some people consider "The Reaper" the first antivirus software written – it may be the case, but it is important to note that the Reaper was a virus itself designed to remove the Creeper virus. The Creeper virus was followed by several other viruses; the first known that appeared "in the wild" was "Elk Cloner", in 1981, which infected Apple II computers. In 1983, the term "computer virus" was coined by Fred Cohen in one of the first published academic papers on computer viruses. Cohen used the term "computer virus" to describe a program that: "affect other computer programs by modifying them in such a way as to include a copy of itself." The first IBM PC compatible "in the wild" computer virus, one of the first real widespread infections, was "Brain" in 1986. From the number of viruses has grown exponentially.
Most of the computer viruses written in the early and mid-1980s were limited to self-reproduction and had no specific damage routine built into the code. That changed when more and more programmers became acquainted with computer virus programming and created viruses that manipulated or destroyed data on infected computers. Before internet connectivity was widespread, computer viruses were spread by infected floppy disks. Antivirus software came into use, but was updated infrequently. During this time, virus checkers had to check executable files and the boot sectors of floppy disks and hard disks. However, as internet usage became common, viruses began to spread online. There are competing claims for the innovator of the first antivirus product; the first publicly documented removal of an "in the wild" computer virus was performed by Bernd Fix in 1987. In 1987, Andreas Lüning and Kai Figge, who founded G Data Software in 1985, released their first antivirus product for the Atari ST platform. In 1987, the Ultimate Virus Killer was released.
This was the de facto industry standard virus killer for the Atari ST and Atari Falcon, the last version of, released in April 2004. In 1987, in the United States, John McAfee founded the McAfee company and, at the end of that year, he released the first version of VirusScan. In 1987, Peter Paško, Rudolf Hrubý, Miroslav Trnka created the first version of NOD antivirus. In 1987, Fred Cohen wrote that there is no algorithm that can detect all possible computer viruses. At the end of 1987, the first two heuristic antivirus utilities were released: Flushot Plus by Ross Greenberg and Anti4us by Erwin Lanting. In his O'Reilly book, Malicious Mobile Code: Virus Protection for Windows, Roger Grimes described Flushot Plus as "the first holistic program to fight malicious mobile code."However, the kind of heuristic used by early AV engines was different from those used today. The first product with a heuristic engine resembling modern ones was F-PROT in 1991. Early heuristic engines were based on dividing the binary in different sections: data section, code section.
Indeed, the initial viruses re-organized the layout of the sections, or overrode the initial portion of section in order to jump to the end of the file where malicious code was located—only going back to resume execution of the original code. This was a specific pattern, not used at the time by any legitimate software, which represented an elegant heuristic to catch suspicious code. Other kinds of more advanced heuristics were added, such as suspicious section names, incorrect header size, regular expressions, partial pattern in-memory matching. In 1988, the growth of antivirus companies continued. In Germany, Tjark Auerbach released the first version of AntiVir. In Bulgaria, Dr. Vesselin Bontchev released his first freeware antivirus program. Frans Veldman released the first version of ThunderByte Antivirus known as TBAV. In Czechoslovakia, Pavel Baudiš and Eduard Kučera started avast! (at th
Windows 8 is a personal computer operating system, produced by Microsoft as part of the Windows NT family of operating systems. The operating system was released to manufacturing on August 1, 2012, with general availability on October 26, 2012. Windows 8 introduced major changes to the operating system's platform and user interface to improve its user experience on tablets, where Windows was now competing with mobile operating systems, including Android and iOS. In particular, these changes included a touch-optimized Windows shell based on Microsoft's "Metro" design language, the Start screen, a new platform for developing "apps" with an emphasis on touchscreen input, integration with online services, Windows Store, an online store for downloading and purchasing new software. Windows 8 added support for USB 3.0, Advanced Format hard drives, near field communications, cloud computing. Additional security features were introduced, such as built-in antivirus software, integration with Microsoft SmartScreen phishing filtering service and support for UEFI Secure Boot on supported devices with UEFI firmware, to prevent malware from infecting the boot process.
Windows 8 was released to a mixed critical reception. Although reaction towards its performance improvements, security enhancements, improved support for touchscreen devices was positive, the new user interface of the operating system was criticized for being confusing and difficult to learn when used with a keyboard and mouse instead of a touchscreen. Despite these shortcomings, 60 million Windows 8 licenses were sold through January 2013, a number that included both upgrades and sales to OEMs for new PCs. On October 17, 2013, Microsoft released Windows 8.1. It addressed some aspects of Windows 8 that were criticized by reviewers and early adopters and incorporated additional improvements to various aspects of the operating system. Windows 8 was succeeded by Windows 10 in July 2015. Microsoft stopped providing support and updates for Windows 8 RTM on January 12, 2016, per Microsoft lifecycle policies regarding service packs, Windows 8.1 must be installed to maintain support and receive further updates.
Windows 8 development started before Windows 7 had shipped in 2009. At the Consumer Electronics Show in January 2011, it was announced that the next version of Windows would add support for ARM system-on-chips alongside the existing x86 processors produced by vendors AMD and Intel. Windows division president Steven Sinofsky demonstrated an early build of the port on prototype devices, while Microsoft CEO Steve Ballmer announced the company's goal for Windows to be "everywhere on every kind of device without compromise." Details began to surface about a new application framework for Windows 8 codenamed "Jupiter", which would be used to make "immersive" applications using XAML that could be distributed via a new packaging system and a rumored application store. Three milestone releases of Windows 8 leaked to the general public. Milestone 1, Build 7850, was leaked on April 12, 2011, it was the first build where the text of a window was written centered instead of aligned to the left. It was probably the first appearance of the Metro-style font, its wallpaper had the text shhh... let's not leak our hard work.
However, its detailed build number reveals that the build was created on September 22, 2010. The leaked copy was Enterprise edition; the OS still reads as "Windows 7". Milestone 2, Build 7955, was leaked on April 25, 2011; the traditional Blue Screen of Death was replaced by a new black screen, although this was scrapped. This build introduced a new ribbon in Windows Explorer. Build 7959, with minor changes but the first 64-bit version was leaked on May 1, 2011; the "Windows 7" logo was temporarily replaced with text displaying "Microsoft Confidential". On June 17, 2011, build 7989 64-bit edition was leaked, it introduced a new boot screen featuring the same fish as the default Windows 7 Beta wallpaper, scrapped, the circling dots as featured in the final. It had the text Welcome below them, although this was scrapped. On June 1, 2011, Microsoft unveiled Windows 8's new user interface, as well as additional features at both Computex Taipei and the D9: All Things Digital conference in California; the "Building Windows 8" blog launched on August 15, 2011, featuring details surrounding Windows 8's features and its development process.
Microsoft unveiled more Windows 8 features and improvements on the first day of the Build conference on September 13, 2011. Microsoft released the first public beta build of Windows Developer Preview at the event. A Samsung tablet running the build was distributed to conference attendees; the build was released for download in the day in standard 32-bit and 64-bit versions, plus a special 64-bit version which included SDKs and developer tools for developing Metro-style apps. The Windows Store was not available in this build. According to Microsoft, there were about 535,000 downloads of the developer preview within the first 12 hours of its release. Set to expire on March 11, 2012, in February 2012 the Developer Preview's expiry date was changed to January 15, 2013. On February 19, 2012, Microsoft unveiled a new logo to be adopted for Windows 8. Designed by Pentagram partner Paula Scher, the Windows logo was changed to resemble a set of four window panes. Additionally, the entire logo is now rend
Linux is a family of free and open-source software operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is packaged in a Linux distribution. Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy. Popular Linux distributions include Debian and Ubuntu. Commercial distributions include SUSE Linux Enterprise Server. Desktop Linux distributions include a windowing system such as X11 or Wayland, a desktop environment such as GNOME or KDE Plasma. Distributions intended for servers may omit graphics altogether, include a solution stack such as LAMP; because Linux is redistributable, anyone may create a distribution for any purpose. Linux was developed for personal computers based on the Intel x86 architecture, but has since been ported to more platforms than any other operating system.
Linux is the leading operating system on servers and other big iron systems such as mainframe computers, the only OS used on TOP500 supercomputers. It is used by around 2.3 percent of desktop computers. The Chromebook, which runs the Linux kernel-based Chrome OS, dominates the US K–12 education market and represents nearly 20 percent of sub-$300 notebook sales in the US. Linux runs on embedded systems, i.e. devices whose operating system is built into the firmware and is tailored to the system. This includes routers, automation controls, digital video recorders, video game consoles, smartwatches. Many smartphones and tablet computers run other Linux derivatives; because of the dominance of Android on smartphones, Linux has the largest installed base of all general-purpose operating systems. Linux is one of the most prominent examples of open-source software collaboration; the source code may be used and distributed—commercially or non-commercially—by anyone under the terms of its respective licenses, such as the GNU General Public License.
The Unix operating system was conceived and implemented in 1969, at AT&T's Bell Laboratories in the United States by Ken Thompson, Dennis Ritchie, Douglas McIlroy, Joe Ossanna. First released in 1971, Unix was written in assembly language, as was common practice at the time. In a key pioneering approach in 1973, it was rewritten in the C programming language by Dennis Ritchie; the availability of a high-level language implementation of Unix made its porting to different computer platforms easier. Due to an earlier antitrust case forbidding it from entering the computer business, AT&T was required to license the operating system's source code to anyone who asked; as a result, Unix grew and became adopted by academic institutions and businesses. In 1984, AT&T divested itself of Bell Labs; the GNU Project, started in 1983 by Richard Stallman, had the goal of creating a "complete Unix-compatible software system" composed of free software. Work began in 1984. In 1985, Stallman started the Free Software Foundation and wrote the GNU General Public License in 1989.
By the early 1990s, many of the programs required in an operating system were completed, although low-level elements such as device drivers and the kernel, called GNU/Hurd, were stalled and incomplete. Linus Torvalds has stated that if the GNU kernel had been available at the time, he would not have decided to write his own. Although not released until 1992, due to legal complications, development of 386BSD, from which NetBSD, OpenBSD and FreeBSD descended, predated that of Linux. Torvalds has stated that if 386BSD had been available at the time, he would not have created Linux. MINIX was created by Andrew S. Tanenbaum, a computer science professor, released in 1987 as a minimal Unix-like operating system targeted at students and others who wanted to learn the operating system principles. Although the complete source code of MINIX was available, the licensing terms prevented it from being free software until the licensing changed in April 2000. In 1991, while attending the University of Helsinki, Torvalds became curious about operating systems.
Frustrated by the licensing of MINIX, which at the time limited it to educational use only, he began to work on his own operating system kernel, which became the Linux kernel. Torvalds began the development of the Linux kernel on MINIX and applications written for MINIX were used on Linux. Linux matured and further Linux kernel development took place on Linux systems. GNU applications replaced all MINIX components, because it was advantageous to use the available code from the GNU Project with the fledgling operating system. Torvalds initiated a switch from his original license, which prohibited commercial redistribution, to the GNU GPL. Developers worked to integrate GNU components with the Linux kernel, making a functional and free operating system. Linus Torvalds had wanted to call his invention "Freax", a portmant
Windows XP is a personal computer operating system produced by Microsoft as part of the Windows NT family of operating systems. It was released to manufacturing on August 24, 2001, broadly released for retail sale on October 25, 2001. Development of Windows XP began in the late 1990s as "Neptune", an operating system built on the Windows NT kernel, intended for mainstream consumer use. An updated version of Windows 2000 was originally planned for the business market; as such, Windows XP was the first consumer edition of Windows not to be based on MS-DOS. Upon its release, Windows XP received positive reviews, with critics noting increased performance and stability, a more intuitive user interface, improved hardware support, expanded multimedia capabilities. However, some industry reviewers were concerned by the new licensing model and product activation system. Extended support for Windows XP ended on April 8, 2014, after which the operating system ceased receiving further support or security updates to most users.
As of March 2019, 1.75% of Windows PCs run Windows XP, the OS is still most popular in some countries with up to 38% of the Windows share. In the late 1990s, initial development of what would become Windows XP was focused on two individual products. However, the projects proved to be too ambitious. In January 2000, shortly prior to the official release of Windows 2000, technology writer Paul Thurrott reported that Microsoft had shelved both Neptune and Odyssey in favor of a new product codenamed "Whistler", after Whistler, British Columbia, as many Microsoft employees skied at the Whistler-Blackcomb ski resort; the goal of Whistler was to unify both the consumer and business-oriented Windows lines under a single, Windows NT platform: Thurrott stated that Neptune had become "a black hole when all the features that were cut from were re-tagged as Neptune features. And since Neptune and Odyssey would be based on the same code-base anyway, it made sense to combine them into a single project". At PDC on July 13, 2000, Microsoft announced that Whistler would be released during the second half of 2001, unveiled the first preview build, 2250.
The build notably introduced an early version of Windows XP's visual styles system. Microsoft released the first beta build of Whistler, build 2296, on October 31, 2000. Subsequent builds introduced features that users of the release version of Windows XP would recognise, such as Internet Explorer 6.0, the Microsoft Product Activation system and the Bliss desktop background. On February 5, 2001, Microsoft announced that Whistler would be known as Windows XP, where XP stands for "eXPerience". In June 2001, Microsoft indicated that it was planning to, in conjunction with Intel and other PC makers, spend at least 1 billion US dollars on marketing and promoting Windows XP; the theme of the campaign, "Yes You Can", was designed to emphasize the platform's overall capabilities. Microsoft had planned to use the slogan "Prepare to Fly", but it was replaced due to sensitivity issues in the wake of the September 11 attacks. On August 24, 2001, Windows XP build. During a ceremonial media event at Microsoft Redmond Campus, copies of the RTM build were given to representatives of several major PC manufacturers in briefcases, who flew off on decorated helicopters.
While PC manufacturers would be able to release devices running XP beginning on September 24, 2001, XP was expected to reach general, retail availability on October 25, 2001. On the same day, Microsoft announced the final retail pricing of XP's two main editions, "Home" and "Professional". While retaining some similarities to previous versions, Windows XP's interface was overhauled with a new visual appearance, with an increased use of alpha compositing effects, drop shadows, "visual styles", which changed the appearance of the operating system; the number of effects enabled are determined by the operating system based on the computer's processing power, can be enabled or disabled on a case-by-case basis. XP added ClearType, a new subpixel rendering system designed to improve the appearance of fonts on liquid-crystal displays. A new set of system icons was introduced; the default wallpaper, Bliss, is a photo of a landscape in the Napa Valley outside Napa, with rolling green hills and a blue sky with stratocumulus and cirrus clouds.
The Start menu received its first major overhaul in XP, switching to a two-column layout with the ability to list and display used applications opened documents, the traditional cascading "All Programs" menu. The taskbar can now group windows opened by a single application into one taskbar button, with a popup menu listing the individual windows; the notification area hides "inactive" icons by default. A "common tasks" list was added, Windows Explorer's sidebar was updated to use a new task-based design with lists of common actions. Fast user switching allows additional users to log into a Windows XP machine without existing users having to close their programs and loggin