Bernd Kreimeier

Bernd Kreimeier is a programmer and professional author. He approached id Software in 1997 with a proposal to publicly release the Doom source code alongside a book he would write detailing its internal workings and explaining how to modify and extend the code. Before he could finish the book project, however, his prospective publisher canceled the deal, feeling that Doom as a subject had become too dated for the book to turn a profit. As a result, Bernd went ahead and released a cleaned-up, slightly modified version of the code later that year with John Carmack's blessing. This release, considered the Linux Doom source code, formed the basis of the majority of the unofficial community source ports which followed, with the first release, DOSDoom v0.1, following within a day's time.

In 2005, Bernd created Terminal DOOM, a Doom 3 mod and unique source port of Doom designed to run inside the id Tech 4 game engine's UI terminal subsystem using a render to texture approach.