AutoRun enabled application CD-ROMs to automatically launch a program which could then guide the user through the installation process.
By placing settings in an autorun.inf file, manufacturers could decide what actions were taken when their CD-ROM was inserted.
Extra settings have been added in successive versions of Windows to support AutoPlay and other new features.
The structure is that of a classic Windows .ini file, containing information and commands as "key=value" pairs, grouped into sections.
How an inf file is handled depends on the version of Windows in use, the volume drive type and certain Registry settings.
The first icon stored within setup.exe itself will represent the drive in Explorer: Following are the sections and keys allowed in a valid autorun.inf.
[9] There also exist architecture specific section types for systems such as Windows NT 4 running on RISC.