About This File
Original file: http://www.doomworld.com/classicdoom/info/shareware.php
This is the shareware version of Doom. It is the latest version available.
The shareware come with the first episode "Knee-Deep in the Dead".
Note that this version was designed to work with DOS. To run it under modern systems, DOSBox or a source port is required.
Details (and a download link of the shareware IWAD file) can be found on the Doom wiki page.