autorun automagically recognizes all available CDROMs in the system, mounts them upon insertion of a media and executes a possible autorun executable on the CD. The user can remove the media; autorun will call unmount after that.
The operating system facility and associated files that automatically open an application or document when a CD is inserted in a CD-ROM drive.
Autorun or autoplay (sometimes spelled in Camel Case as AutoRun or AutoPlay) is the ability of many modern computer operating systems to automatically take some action upon the inserting of removable media such as a CD-ROM, DVD-ROM, or flash media.