Service-oriented architecture is a style of software design where services are provided to the other components by application components, through a communication protocol over a network. The basic principles of service-oriented architecture are independent of vendors and technologies. A service is a discrete unit of functionality that can be accessed remotely and acted upon and updated independently, such as retrieving a credit card statement online. A service has four properties according to one of many definitions of SOA: It logically represents a business activity with a specified outcome, it is self-contained. It is a black box for its consumers, it may consist of other underlying services. SOA was first termed Service-Based Architecture in 1998 by a team developing integrated foundational management services and business process-type services based upon units of work and using CORBA for inter-process communications. Different services can be used in conjunction to provide the functionality of a large software application, a principle SOA shares with modular programming.
Service-oriented architecture integrates distributed, separately-maintained and -deployed software components. It is enabled by technologies and standards that facilitate components' communication and cooperation over a network over an IP network. In SOA, services use protocols that describe how they pass and parse messages using description metadata; this metadata describes both the functional characteristics of the service and quality-of-service characteristics. Service-oriented architecture aims to allow users to combine large chunks of functionality to form applications which are built purely from existing services and combining them in an ad hoc manner. A service presents a simple interface to the requester that abstracts away the underlying complexity acting as a black box. Further users can access these independent services without any knowledge of their internal implementation; the related buzzword service-orientation promotes loose coupling between services. SOA separates functions into distinct units, or services, which developers make accessible over a network in order to allow users to combine and reuse them in the production of applications.
These services and their corresponding consumers communicate with each other by passing data in a well-defined, shared format, or by coordinating an activity between two or more services. A manifesto was published for service-oriented architecture in October, 2009; this came up with six core values which are listed as follows: Business value is given more importance than technical strategy. Strategic goals are given more importance than project-specific benefits. Intrinsic inter-operability is given more importance than custom integration. Shared services are given more importance than specific-purpose implementations. Flexibility is given more importance than optimization. Evolutionary refinement is given more importance than pursuit of initial perfection. SOA can be seen as part of the continuum which ranges from the older concept of distributed computing and modular programming, through SOA, on to current practices of mashups, SaaS, cloud computing. There are no industry standards relating to the exact composition of a service-oriented architecture, although many industry sources have published their own principles.
Some of these include the following: Standardized service contract Services adhere to a standard communications agreements, as defined collectively by one or more service-description documents within a given set of services. Service reference autonomy The relationship between services is minimized to the level that they are only aware of their existence. Service location transparency Services can be called from anywhere within the network that it is located no matter where it is present. Service longevity Services should be designed to be long lived. Where possible services should avoid forcing consumers to change if they do not require new features, if you call a service today you should be able to call the same service tomorrow. Service abstraction The services act as black boxes, their inner logic is hidden from the consumers. Service autonomy Services are independent and control the functionality they encapsulate, from a Design-time and a run-time perspective. Service statelessness Services are stateless, either return the requested value or give an exception hence minimizing resource use.
Service granularity A principle to ensure services have an adequate scope. The functionality provided by the service to the user must be relevant. Service normalization Services are consolidated to minimize redundancy. In some, this may not be done, These are the cases where performance optimization and aggregation are required. Service composability Services can be used to compose other services. Service discovery Services are supplemented with communicative meta data by which they can be discovered and interpreted. Service reusability Logic is divided into various services. Service encapsulation Many services which were not planned under SOA, may get encapsulated or become a part of SOA; each SOA building block can play any of the three roles: Service provider It creates a web service and provides its information to the service registry. Each provider debates upon a lot of hows and whys like which service to expose, which to give more importance: security or easy availability, what price to offer the service for and many more.
The provider has to decide what category the service should be listed in for a given broker service and what sort of trading partner agreements are required to use the service. Servi
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
Microsoft Azure is a cloud computing service created by Microsoft for building, testing and managing applications and services through Microsoft-managed data centers. It provides software as a service, platform as a service and infrastructure as a service and supports many different programming languages and frameworks, including both Microsoft-specific and third-party software and systems. Azure was announced in October 2008, started with codename "Project Red Dog", released on February 1, 2010, as "Windows Azure" before being renamed "Microsoft Azure" on March 25, 2014. Microsoft lists over 600 Azure services, of which some are covered below: Virtual machines, infrastructure as a service allowing users to launch general-purpose Microsoft Windows and Linux virtual machines, as well as preconfigured machine images for popular software packages. App services, platform as a service environment letting developers publish and manage websites. Websites, high density hosting of websites allows developers to build sites using ASP.
NET, PHP, Node.js, or Python and can be deployed using FTP, Mercurial, Team Foundation Server or uploaded through the user portal. This feature was announced in preview form in June 2012 at the Meet Microsoft Azure event. Customers can create websites in PHP, ASP. NET, Node.js, or Python, or select from several open source applications from a gallery to deploy. This comprises one aspect of the platform as a service offerings for the Microsoft Azure Platform, it was renamed to Web Apps in April 2015. WebJobs, applications that can be deployed to an App Service environment to implement background processing that can be invoked on a schedule, on demand, or run continuously; the Blob and Queue services can be used to communicate between WebApps and WebJobs and to provide state. Mobile Engagement collects real-time analytics, it provides push notifications to mobile devices. HockeyApp can be used to develop and beta-test mobile apps. Storage Services provides SDK APIs for storing and accessing data on the cloud.
Table Service lets programs store structured text in partitioned collections of entities that are accessed by partition key and primary key. It's a NoSQL non-relational database. Blob Service allows programs to store unstructured text and binary data as blobs that can be accessed by a HTTP path. Blob service provides security mechanisms to control access to data. Queue Service lets programs communicate asynchronously by message using queues. File Service allows access of data on the cloud using the REST APIs or the SMB protocol. Azure Search provides a subset of OData's structured filters using REST or SDK APIs. Cosmos DB is a NoSQL database service that implements a subset of the SQL SELECT statement on JSON documents. Redis Cache is a managed implementation of Redis. StorSimple manages storage tasks between cloud storage. SQL Database known as SQL Azure Database, works to create and extend applications into the cloud using Microsoft SQL Server technology, it integrates with Active Directory and Microsoft System Center and Hadoop.
SQL Data Warehouse is a data warehousing service designed to handle computational and data intensive queries on datasets exceeding 1TB. Azure Data Factory, is a data integration service that allows creation of data-driven workflows in the cloud for orchestrating and automating data movement and data transformation. Azure Data Lake is a scalable data storage and analytic service for big-data analytics workloads that require developers to run massively parallel queries. Azure HDInsight is a big data relevant service, that deploys Hortonworks Hadoop on Microsoft Azure, supports the creation of Hadoop clusters using Linux with Ubuntu. Azure Stream Analytics is a serverless scalable event processing engine that enables users to develop and run real-time analytics on multiple streams of data from sources such as devices, web sites, social media, other applications; the Microsoft Azure Service Bus allows applications running on Azure premises or off premises devices to communicate with Azure. This helps to build reliable applications in a service-oriented architecture.
The Azure service bus supports four different types of communication mechanisms: Event Hubs, which provide event and telemetry ingress to the cloud at massive scale, with low latency and high reliability. For example an event hub can be used to track data from cell phones such as a GPS location coordinate in real time. Queues, which allow one-directional communication. A sender application would send the message to the service bus queue, a receiver would read from the queue. Though there can be multiple readers for the queue only one would process a single message. Topics, which provide one-directional communication using a subscriber pattern, it is similar to a queue, however each subscriber will receive a copy of the message sent to a Topic. Optionally the subscriber can filter out messages based on specific criteria defined by the subscriber. Relays, which provide bi-directional communication. Unlike queues and topics, a relay doesn't store in-flight messages in its own memory. Instead, it just passes them on to the destination application.
A PaaS offering that can be used for content protection, streaming, or analytics. A global content delivery network for audio, applications and other static files, it can be used to cache static assets of websites geographically closer to users to increase performance. The network can be managed by a REST based HTTP API. Azure has 54 point of presence locations worldwide as of August 2018. Applic
The TOP500 project ranks and details the 500 most powerful non-distributed computer systems in the world. The project publishes an updated list of the supercomputers twice a year; the first of these updates always coincides with the International Supercomputing Conference in June, the second is presented at the ACM/IEEE Supercomputing Conference in November. The project aims to provide a reliable basis for tracking and detecting trends in high-performance computing and bases rankings on HPL, a portable implementation of the high-performance LINPACK benchmark written in Fortran for distributed-memory computers. China dominates the list with 229 supercomputers, leading the second place by a record margin of 121. Since June 2018, the American Summit is the world's most powerful supercomputer, reaching 143.5 petaFLOPS on the LINPACK benchmarks. The TOP500 list is compiled by Jack Dongarra of the University of Tennessee, Erich Strohmaier and Horst Simon of the National Energy Research Scientific Computing Center and Lawrence Berkeley National Laboratory, from 1993 until his death in 2014, Hans Meuer of the University of Mannheim, Germany.
In the early 1990s, a new definition of supercomputer was needed to produce meaningful statistics. After experimenting with metrics based on processor count in 1992, the idea arose at the University of Mannheim to use a detailed listing of installed systems as the basis. In early 1993, Jack Dongarra was persuaded to join the project with his LINPACK benchmarks. A first test version was produced in May 1993 based on data available on the Internet, including the following sources: "List of the World's Most Powerful Computing Sites" maintained by Gunter Ahrendt David Kahaner, the director of the Asian Technology Information Program; the information from those sources was used for the first two lists. Since June 1993, the TOP500 is produced bi-annually based on vendor submissions only. Since 1993, performance of the No. 1 ranked position has grown in accordance with Moore's law, doubling every 14 months. As of June 2018, Summit was fastest with an Rpeak of 187.6593 PFLOPS. For comparison, this is over 1,432,513 times faster than the Connection Machine CM-5/1024, the fastest system in November 1993 with an Rpeak of 131.0 GFLOPS.
As of November 2018, all supercomputers on TOP500 are 64-bit based on x86-64 CPUs, with few exceptions. Thirteen supercomputers are based on the Power ISA used by IBM POWER microprocessors and six on Fujitsu-designed SPARC64 chips (one of which – the K computer – was 1st in 2011 without any GPUs. A further two computers are based on related Chinese designs: ShenWei and Sunway SW26010 using Chinese co-processors. Further, a few computers use another non-US design, the PEZY-SC as an accelerator paired with Intel's Xeon. Two computers which first appeared on the list in 2018 are based on architectures never before seen on the Top500. One was a new x86-64 microarchitecture from Chinese vendor Sugon, using Hygon Dhyana CPUs and is ranked 38th, the other was the first ARM-based computer on the list – using Cavium ThunderX2 CPUs. Before the ascendancy of 32-bit x86 and 64-bit x86-64 in the early 2000s, a variety of RISC processor families made up most TOP500 supercomputers, including RISC architectures such as SPARC, MIPS, PA-RISC, Alpha.
In recent years heterogeneous computing using Nvidia's graphics processing units or Intel's x86-based Xeon Phi as coprocessors, has dominated the TOP500 because of better performance per watt ratios and higher absolute performance. All the fastest supercomputers in the decade since the Earth Simulator supercomputer have used operating systems based on Linux. Since November 2017, all the listed supercomputers use an operating system based on the Linux kernel. Since November 2015, no computer on the list runs Windows. In November 2014, Windows Azure cloud computer was no longer on the list of fastest supercomputers, leaving the Shanghai Supercomputer Center's Magic Cube as the only Windows-based supercomputer on the list, until it dropped off the list, it was ranked 436 in its last appearance on the list released in June 2015, while its best rank was 11 in 2008. It has been well over a decade since MIPS systems dropped off the list but the Gyoukou supercomputer that jumped to 4th place in November 2017 has MIPS as a small part of the coprocessors.
Use of 2,048-core coprocessors make the supercomputer much more energy efficient than the other top 10. At 19.86 million cores, it is by far the biggest system: double that of the best manycore system in the TOP500, the Chinese Sunway TaihuLight, ranked 3rd. Legend: Rank – Position within the TOP500 ranking. In the TOP500 list table, the computers are ordered first by their Rmax value. In the case of equal performances for different computers, the order is by Rpeak. For sites that have the same computer, the o
Windows Vista editions
Windows Vista—a major release of the Microsoft Windows operating system—was available in six different product editions: Starter. On September 5, 2006, Microsoft announced the USD pricing for editions available through retail channels. Microsoft made Windows Vista available for purchase and download from Windows Marketplace. Editions sold at retail were available in both Full and Upgrade versions and included Service Pack 1. Microsoft characterized the retail packaging for Windows Vista as "designed to be user-friendly, a small, plastic container designed to protect the software inside for life-long use." The packaging opens sideways to reveal the Windows Vista DVD suspended in a clear plastic case. The Windows Vista disc itself uses a holographic design similar to the discs that Microsoft has produced since Windows 98. With the exception of Windows Vista Starter, all editions support both 32-bit and 64-bit processor architectures. Microsoft ceased retail copies of Windows Vista in October 2010.
OEM distribution of Windows Vista ended in 2011 Windows Vista Starter Much like its predecessor, Windows XP Starter Edition, was available in "emerging markets", this edition of Windows Vista was sold in 139 developing countries in 70 languages. Microsoft did not make it available in developed technology markets such as the United States, the European Union, New Zealand, or other high income markets as defined by the World Bank. Windows Vista Starter can be installed from optical media for other editions of the operating system. Windows Vista Starter has significant limitations. Windows Vista Starter is licensed to run only on PCs with AMD's Athlon XP, Duron and Geode processors, Intel's Celeron, Pentium III processors, certain models of Pentium 4. Starter Edition comes with some locale-specific desktop wallpapers not found in other editions of the operating system. Windows Vista Home Basic Similar to Windows XP Home Edition, Home Basic targets budget-conscious users not requiring advanced media support for home use.
This edition lacks the Windows Aero graphical user interface with translucent glass effects. Home Basic supports one physical CPU, but with multiple cores, the 64-bit version supports up to 8 GB of RAM; this edition includes Windows Firewall, parental controls, Windows Photo Gallery, other features. Windows Movie Maker is included as well, but without support for working with high-definition video. Windows Vista Home Premium Containing all features from Home Basic and similar to Windows XP Media Center Edition, this edition supports additional features aimed for the home market segment, such as support for HDTV and DVD authoring and DVD burning, Windows Media Center with support for Extenders and the Xbox 360. Home Premium includes premium games, including Chess Titans, InkBall, Mahjong Titans, includes support for network projectors, auxiliary displays via Windows SideShow, the ability to schedule backups. Home Premium supports 10 simultaneous SMB peer-network connections; the version of Meeting Space included allows users to create meeting sessions.
Like Home Basic, Home Premium supports only one physical CPU, but supports multiple cores. The 64-bit version supports up to 16 GB of RAM. Windows Vista Business Comparable to Windows XP Professional and Windows XP Tablet PC Edition, Windows Vista Business Edition targets the business market, it includes all the features of Home Basic with the exception of parental controls and the Windows Vista Standard theme. This edition can participate in a Windows Server domain, it includes Internet Information Services, fax support, Rights Management Services client, Encrypting File System, system image backup and recovery, Offline Files, a single user Remote Desktop server, ad-hoc P2P collaboration capabilities, Shadow Copy support which provides access to previous versions of files, support for tablet PCs, other business-oriented management features. The Business edition of Windows Vista supports up to two physical CPUs, the 64-bit version supports 128 GB of RAM. Windows Vista Enterprise This edition targets the enterprise segment of the market: it comprises a superset of the Vista Business edition.
Additional features include support for Multilingual User Interface packages, BitLocker Drive Encryption, UNIX application-support. Not available through retail or OEM channels, this edition will get distributed through Microsoft Software Assurance. Since Vista Enterprise classes as a benefit of Microsoft Software Assurance, it includes several SA-only benefits, including a license allowing the running of up to four virtual machines running a mix of Vista editions and versions, access to Virtual PC Express, activation via VLK. Windows Vista Enterprise supports up to two physical CPUs, the 64-bit version supports up to 128 GB of RAM. Windows Vista Ultimate Windows Vista Ultimate combines all the features of the Home Premium and Business editions, includes "Ultimate Extras." The 64-bit version supports up to 128 GB of RAM. Microsoft released two notable variant upgrade versions of Windows Vista Ultimate: Windows Vista Ul
Microsoft Windows is a group of several graphical operating system families, all of which are developed and sold by Microsoft. Each family caters to a certain sector of the computing industry. Active Windows families include Windows Embedded. Defunct Windows families include Windows Mobile and Windows Phone. Microsoft introduced an operating environment named Windows on November 20, 1985, as a graphical operating system shell for MS-DOS in response to the growing interest in graphical user interfaces. Microsoft Windows came to dominate the world's personal computer market with over 90% market share, overtaking Mac OS, introduced in 1984. Apple came to see Windows as an unfair encroachment on their innovation in GUI development as implemented on products such as the Lisa and Macintosh. On PCs, Windows is still the most popular operating system. However, in 2014, Microsoft admitted losing the majority of the overall operating system market to Android, because of the massive growth in sales of Android smartphones.
In 2014, the number of Windows devices sold was less than 25 %. This comparison however may not be relevant, as the two operating systems traditionally target different platforms. Still, numbers for server use of Windows show one third market share, similar to that for end user use; as of October 2018, the most recent version of Windows for PCs, tablets and embedded devices is Windows 10. The most recent versions for server computers is Windows Server 2019. A specialized version of Windows runs on the Xbox One video game console. Microsoft, the developer of Windows, has registered several trademarks, each of which denote a family of Windows operating systems that target a specific sector of the computing industry; as of 2014, the following Windows families are being developed: Windows NT: Started as a family of operating systems with Windows NT 3.1, an operating system for server computers and workstations. It now consists of three operating system subfamilies that are released at the same time and share the same kernel: Windows: The operating system for mainstream personal computers and smartphones.
The latest version is Windows 10. The main competitor of this family is macOS by Apple for personal computers and Android for mobile devices. Windows Server: The operating system for server computers; the latest version is Windows Server 2019. Unlike its client sibling, it has adopted a strong naming scheme; the main competitor of this family is Linux. Windows PE: A lightweight version of its Windows sibling, meant to operate as a live operating system, used for installing Windows on bare-metal computers, recovery or troubleshooting purposes; the latest version is Windows PE 10. Windows IoT: Initially, Microsoft developed Windows CE as a general-purpose operating system for every device, too resource-limited to be called a full-fledged computer. However, Windows CE was renamed Windows Embedded Compact and was folded under Windows Compact trademark which consists of Windows Embedded Industry, Windows Embedded Professional, Windows Embedded Standard, Windows Embedded Handheld and Windows Embedded Automotive.
The following Windows families are no longer being developed: Windows 9x: An operating system that targeted consumers market. Discontinued because of suboptimal performance. Microsoft now caters to the consumer market with Windows NT. Windows Mobile: The predecessor to Windows Phone, it was a mobile phone operating system; the first version was called Pocket PC 2000. The last version is Windows Mobile 6.5. Windows Phone: An operating system sold only to manufacturers of smartphones; the first version was Windows Phone 7, followed by Windows Phone 8, the last version Windows Phone 8.1. It was succeeded by Windows 10 Mobile; the term Windows collectively describes any or all of several generations of Microsoft operating system products. These products are categorized as follows: The history of Windows dates back to 1981, when Microsoft started work on a program called "Interface Manager", it was announced in November 1983 under the name "Windows", but Windows 1.0 was not released until November 1985.
Windows 1.0 was to achieved little popularity. Windows 1.0 is not a complete operating system. The shell of Windows 1.0 is a program known as the MS-DOS Executive. Components included Calculator, Cardfile, Clipboard viewer, Control Panel, Paint, Reversi and Write. Windows 1.0 does not allow overlapping windows. Instead all windows are tiled. Only modal dialog boxes may appear over other windows. Microsoft sold as included Windows Development libraries with the C development environment, which included numerous windows samples. Windows 2.0 was released in December 1987, was more popular than its predecessor. It features several improvements to the user memory management. Windows 2.03 changed the OS from tiled windows to overlapping windows. The result of this change led to Apple Computer filing a suit against Microsoft alleging infringement on Apple's copyrights. Windows 2.0
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