Autoplay

AutoPlay, a feature introduced in Windows 98, examines newly discovered removable media and devices and, based on content such as pictures, music or video files, launches an appropriate application to play or display the content. It is closely related to the AutoRun operating system feature. AutoPlay was created in order to simplify the use of peripheral devices – MP3 players, memory cards, USB storage devices and others – by automatically starting the software needed to access and view the content on these devices. AutoPlay can be enhanced by AutoPlay-compatible software and hardware. It can be configured by the user to associate favourite applications with AutoPlay events and actions.

When a user inserts a CD-ROM into a drive or attaches a USB camera, Windows detects the arrival and starts a process of examining the device or searching the medium. It is looking for properties of the device or content on the medium so that AutoPlay can present a set of meaningful options to the user. When the user makes a particular choice, they also have the option to make that selection automatic the next time Windows sees that content or device.

The dialog shows the result of a user placing a DVD into a DVD reader, in this case the D: drive. AutoPlay has determined that content is most likely a DVD movie and presents a set of actions to the user based on that decision. These actions are called Handlers and there are sets of Handlers associated with various types of content. The user can now make their decision and click OK to proceed. However, if they also tick the "Always do the selected action" tick box at this point, they will not be prompted the next time that particular content type is seen on that particular drive; the selected application will automatically start.

If a user regrets that decision or wishes to make automatic AutoPlay selections for any particular content type, the AutoPlay properties for any drive are accessible through the My Computer desktop icon. Selecting a drive and then "File/Properties" from the Windows Explorer menu, followed by the selecting the AutoPlay tab, gives a dialog similar to that shown. The content types can be selected with the drop down box. Here the dialog shows the Handlers available if AutoPlay ever determines the content type on drive D: to be "Pictures". Selecting an action to perform makes that action automatic for that user. Selecting "Prompt me each time to choose an action" deletes any association; AutoPlay will prompt the next time.

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Wikipedia