Windows 8

Windows 8 is an operating system developed by Microsoft. It replaces Windows 7 and is replaced by Windows 8.1. It reached RTM on 2012-08-01 and was released to general availability on 2012-10-26. Windows 8 was one of the most short-lived releases, and its end of support was in 2016-01-12, as extended support was in favor of Windows 8.1.

Editions
It comes in four main editions: Core, RT, Pro, and Enterprise. All other editions are variations of those editions.
 * Windows 8 (Core) is the most basic edition available for purchase, and is intended for the average home user.
 * Windows RT (CoreARM) is Core for the ARM architecture. It can only launch Windows Store apps and signed Microsoft desktop applications, but apart from the addition of device encryption it has the same feature set as its base edition.
 * Windows 8 Single Language (CoreSingleLanguage) is Core sans the ability to install language packs.
 * Windows 8 China (CoreCountrySpecific), as the name implies is intended for the mainland Chinese market. It only allows the Simplified Chinese language pack to be installed.
 * Windows 8 Pro is meant for the enthusiast and business markets, and most notably supports running Hyper-V virtual machines, receiving RDP connections, and BitLocker.
 * Windows 8 Pro with Media Center is exactly what the name implies. It can be upgraded to from Core and Pro with Windows Anytime Upgrade.
 * Windows 8 Enterprise is designed for large organizations and can only be activated with a KMS server or MAK keys. It has the same feature set as Pro, but additionally allows creating Windows to Go portable workspaces. It doesn't have Windows Media Center and it cannot be added with any officially sanctioned methods.

New/improved features

 * Immersive User Interface (referred to as Modern UI, codenamed Metro)
 * Start screen which incorporates the Modern design language and replaces the Start menu of previous Windows versions, making it more touch-friendly.
 * Internet Explorer 10 was introduced, which was also the first version to have a 'Metro' mode for touch-friendly usage. Adobe Flash was also bundled with Internet Explorer.
 * Modern versions of Mail, Calendar, People and Reader were introduced, some replacing their Windows 7 desktop equivalents. A camera app was also introduced.
 * Windows Explorer was renamed as File Explorer and the interface was changed to one based on the Ribbon system.
 * New Desktop Window Manager features, such as support for software rendering, and performance improvements.
 * File History, which automatically creates backups of files located across the system, was introduced.
 * Reset and Refresh options were introduced(the former re-installs Windows, while the latter retains settings and removes desktop applications)
 * Windows Store, which is a place where users can purchase and download Metro-based apps, was introduced.
 * Windows to Go was introduced for the Enterprise edition, which allowed users to carry Windows in a flash drive or hard disk.
 * Task Manager was redesigned, now showing startup programs, average program use, and improved graphs.
 * File transfers were improved, now allowing users to pause a transfer. The file transfer would also be shown in a graph.
 * A new feature to improve boot times called Fast Boot was introduced, which did significantly cut down on booting times.
 * USB 3 is now fully natively supported.
 * Snap was introduced, allowing 2 Metro apps to be on one screen together.
 * Battery life was improved.
 * Online integration was introduced in the form of Microsoft Account, allowing users to use that account to login in Windows.
 * Improved support for cellular connectivity.
 * Windows Defender was upgraded to support full antivirus protection, effectively replacing Microsoft Security Essentials.
 * The lock screen was redesigned.
 * Hyper-V is now available on 64-bit versions of Windows 8 Pro and Enterprise.
 * The Windows Start orb was changed into a flatter trapezium based theme.
 * Taskbar and window border colours can now be selected automatically.
 * A new installer was introduced, which reduced restart times and significantly quickened the installation time.

Features removed/degraded

 * The Start Menu(and the button) was removed, which created a huge backlash and could well be the biggest reason for the eventual failure of Windows 8.
 * Windows 8 can no longer use unified search as was possible with Windows 7, instead you must search categorically.
 * DWM is now on permanently and cannot be turned off, effectively removing themes such as the Classic and Basic theme.
 * Translucency and blurring was lost in the windows as a flatter theme was introduced instead.
 * Metro apps require a minimum of 1024x768 and Snap required a minimum of 1366x768.
 * Windows 8 now requires NX, SSE2 and PAE extensions on the processor and needs it to be enabled.
 * Hyper-V requires SLAT for it to work on Windows 8.

Media Center
Unlike Windows Vista and Windows 7, Windows Media Center is not included by default in any Windows 8 edition. Customers with existing Windows 8 users can purchase Media Center with the Windows 8 Pro Pack, which includes Windows 8 Pro with Media Center. Customers with existing Windows 8 Pro licenses can purchase Media Center with the Windows 8 Pro Pack, which was free previously under a promotional offer (till 2013-01-31).