FluffOS
FluffOS is Discworld's fork of the MudOS driver. Features added in FluffOS that are not present in MudOS include available MXP output, UTF-8 capability, support for running on 64-bit architectures, IPv6 support, and (optionally) stricter type checking of variables in LPC code. Recent versions of the Discworld mudlib only run on the FluffOS server. It is open source under the MudOS license.
The Dead Souls Mudlib is another FluffOS mudlib. Like the Discworld mudlib, it was originally written for MudOS, but current versions require FluffOS.
Read more about this topic: Discworld Mudlib