|Operating system||Microsoft Windows|
|Type||Graphical user interface|
|License||Proprietary commercial software|
The Windows shell is the graphical user interface for the Microsoft Windows operating system. Its readily identifiable elements consists of the desktop, the taskbar, the Start menu, the task switcher and the AutoPlay feature. On some versions of Windows, it also includes Flip 3D and the charms. In Windows 10, the Windows Shell Experience Host interface drives visuals like the Start Menu, Action Center, Taskbar, and Task View/Timeline. However, the Windows shell also implements a shell namespace that enables computer programs running on Windows to access the computer's resources via the hierarchy of shell objects. "Desktop" is the top object of the hierarchy; below it there are a number of files and folders stored on the disk, as well as a number of special folders whose contents are either virtual or dynamically created. Recycle Bin, Libraries, Control Panel, This PC and Network are examples of such shell objects.
The Windows shell, as it is known today, is an evolution of what began with Windows 95, released in 1995. It is intimately identified with File Explorer, a Windows component that can browse the whole shell namespace.
Windows taskbar is a toolbar-like element that, by default, appears as a horizontal bar at the bottom of the desktop. It may be relocated to the top, left or right edges of the screen. Starting with Windows 98, its size can be changed. The taskbar can be configured to stay on top of all applications or to collapse and hide when it is not used. Depending on the version of operating system installed, the following elements may appear on the taskbar respectively from left to right:
Task switcher is a feature present in Windows 3.0 and all subsequent versions of Windows. It allows a user to cycle through existing application windows by holding down the key and tapping the key. Starting with Windows 95, as long as the key is pressed, a list of active windows is displayed, allowing the user to cycle through the list by tapping the key. An alternative to this form of switching is using the mouse to click on a visible portion of an inactive window. However, + may be used to switch out of a full screen window. This is particularly useful in video games that lock, restrict or alter mouse interactions for the purpose of the game. Starting with Windows Vista, Windows Desktop is included in the list and can be activated this way.
Windows 7 introduced Aero Flip (renamed Windows Flip in Windows 8). When the user holds down the key, Aero Flip causes only the contents of the selected window to be displayed. The remaining windows are replaced with transparent glass-like sheets that give an impression where the inactive window is located.
Windows 8 introduced Metro-style apps, which did not appear when + was pressed. (They have to be switched with their own dedicated task switcher, activated through the + combination.) Windows 8.1 extended + to manage the Metro-style apps as well.
Flip 3D is a supplemental task switcher. It was introduced with Windows Vista and removed in Windows 8. It is invoked by holding down the key and tapping the key. As long as the key remains pressed, Windows displays all application windows, including the Desktop, in an isometric view, diagonally across the screen from the top left corner to the bottom right corner. The active window at the time of pressing the key is placed in front of the others. This view is maintained while key is held down. and + cycle through the open windows, so that the user can preview them. When the key is released, the Flip 3D view is dismissed and the selected window comes to the front and into focus.
Windows 8 added a bar containing a set of five shortcuts known as the "charms", invoked by moving the mouse cursor into the top or bottom right-hand corners of the screen, or by swiping from the right edge of a compatible touchpad or touch screen. This feature was retained in 8.1.
Windows 10 removed the charms and moved the commands associated with them into the system menu of each application. For users with touch screens, swiping from the right of the touch screen now shows Action Center.
Starting with Windows 95, all versions of Windows feature a form of Start menu, usually by this very same name. Depending on the version of Windows, the menu features the following:
AutoPlay is a feature introduced in Windows XP that examines newly inserted removable media for content and displays a dialog containing options related to the type and content of that media. The possible choices are provided by installed software: it is thus not to be confused with the related AutoRun feature, configured by a file on the media itself, although AutoRun is selectable as an AutoPlay option when both are enabled.[verification needed]
File Explorer is a Windows component that can browse the shell namespace. In other words, it can browse disks, files and folder as a file manager would, but can also access Control Panel, dial-up network objects, and other elements introduced above. In addition, the
explorer.exe executable, which is responsible for launching File Explorer, is also responsible for launching the taskbar, the Start menu and part of the desktop. However, the task switcher, the charms, or AutoPlay operate even when all instances of the
explorer.exe process are closed, and other computer programs can still access the shell namespace without it. Initially called Windows Explorer, its name was changed to File Explorer beginning with Windows 8, although the program name remains
The first public demonstration of Windows, in 1983, had a simplistic shell called the Session Control Layer, which served as a constantly visible menu at the bottom of the screen. Clicking on Run would display a list of programs that one could launch, and clicking on Session Control would display a list of programs already running so one could switch between them.
Windows 1.0, shipped in November 1985, introduced MS-DOS Executive, a simple file manager that differentiated between files and folders by bold type. It lacked support for icons, although this made the program somewhat faster than the file manager that came with Windows 3.0. Programs could be launched by double-clicking on them. Files could be filtered for executable type, or by a user-selected wildcard, and the display mode could be toggled between full and compact descriptions. The file date column was not Y2K compliant.
Windows 2.0 made no significant change to MS-DOS Executive.
Windows 3.0, introduced in May 1990, shipped with a new shell called Program Manager. Based on Microsoft's work with OS/2 Desktop Manager, Program Manager sorted program shortcuts into groups. Unlike Desktop Manager, these groups were housed in a single window, in order to show off Microsoft's new Multiple Document Interface.
Program Manager in Windows 3.1 introduced wrappable icon titles, along with the new Startup group, which Program Manager would check on launch and start any programs contained within. Program Manager was also ported to Windows NT 3.1, and was retained through Windows NT 3.51.
Windows 95 introduced a new shell. The desktop became an interactive area that could contain files (including file shortcuts), folders, and special folders such as My Computer, Network Neighborhood and Recycle Bin. Windows Explorer, which replaced File Manager, opened both ordinary and special folders. The taskbar was introduced, which maintained buttons representing open windows, a digital clock, a notifications area for background processes and their notifications, and the Start button, which invoked the Start menu. The Start menu contains links to settings, recently used files and, like its predecessor Program Manager, shortcuts and program groups.
Program Manager is also included in Windows 95 for backward compatibility, in case the user disliked the new interface. This is included with all versions of Windows up to and including Windows XP Service Pack 1. In SP2 and SP3, PROGMAN.EXE is just an icon library, and it was completely removed from Windows Vista in 2006.
In early 1996, Netscape announced that the next release of its browser, codenamed "Constellation", would completely integrate with Windows and add a new shell, codenamed "HomePort", which would present the same files and shortcuts no matter which machine a user logged into. Microsoft started working on a similar Internet Explorer release, codenamed "Nashville". Internet Explorer 4.0 was redesigned and resulted in two products: the standalone Internet Explorer 4 and Windows Desktop Update, which updated the shell with features such as Active Desktop, Active Channels, Web folders, desktop toolbars such as the Quick Launch bars, ability to minimize windows by clicking their button on the taskbar, HTML-based folder customization, single click launching, image thumbnails, folder infotips, web view in folders, Back and Forward navigation buttons, larger toolbar buttons with text labels, favorites, file attributes in Details view, and an address bar in Windows Explorer, among other features. It also introduced the My Documents shell folder.
Future Windows releases, like Windows 95C (OSR 2.5) and Windows 98, included Internet Explorer 4 and the features of the Windows Desktop Update already built in. Improvements were made in Windows 2000 and Windows ME, such as personalized menus, ability to drag and sort menu items, sort by name function in menus, cascading Start menu special folders, customizable toolbars for Explorer, auto-complete in Windows Explorer address bar and Run box, displaying comments in file shortcuts as tooltips, advanced file type association features, extensible columns in Details view (IColumnProvider interface), icon overlays, places bar in common dialogs, high-color notification area icons and a search pane in Explorer.
Windows XP introduced a new Start Menu, with shortcuts to shell locations on the right and a list of most frequently used applications on the left. It also grouped taskbar buttons from the same program if the taskbar got too crowded, and hid notification icons if they had not been used for a while. For the first time, Windows XP hid most of the shell folders from the desktop by default, leaving only the Recycle Bin (although the user could get them back if they desired). Windows XP also introduced numerous other shell enhancements.
In the early days of the Longhorn project, an experimental sidebar, with plugins similar to taskbar plugins and a notifications history was built into the shell. However, when Longhorn was reset the integrated sidebar was discarded in favor of a separate executable file, sidebar.exe, which provided Web-enabled gadgets, thus replacing Active Desktop.
Windows Vista introduced a searchable Start menu and live taskbar previews to the Windows shell. It also introduced a redesigned Alt-Tab switcher which included live previews, and Flip 3D, an application switcher that would rotate through application windows in a fashion similar to a Rolodex when the user pressed the Win-Tab key combination. Windows 7 added 'pinned' shortcuts and 'jump lists' to the taskbar, and automatically grouped program windows into one icon (although this could be disabled).
Windows 8 removed Flip 3D in order to repurpose Win-Tab for displaying an application switcher sidebar containing live previews of active Windows Store apps for users without touchscreens.
Windows 10 added the possibility to have more than one virtual desktop, known as Task View, to group active program windows to their own virtual desktop. It is possible to navigate through these desktops using Ctrl+Win+Left or Right arrows, or by clicking on an icon in the taskbar, and creating them with Ctrl+Win+D. Win-Tab was repurposed to invoke an overview of all active windows and virtual desktops. Windows 10 also added Cortana to the Start menu, to provide interaction with the shell through vocal commands. Newer versions of Windows 10 include recent Microsoft Edge tabs in the Alt-Tab menu, which can be disabled to only show open programs, as is the behavior in prior versions of the operating system.
Windows supports the ability to replace the Windows shell with another program. A number of third party shells exist that can be used in place of the standard Windows shell.