Free implementation software for linux

pandoc is an implementation of markdown (and much more) in Haskell.
It can convert markdown-formatted text to HTML, LaTeX, rich text format, reStructuredText, or an S5 HTML slide show.
pandoc can also convert HTML, LaTeX, and reStructuredText to markdown.
Enhancements:
- This release fixes bugs in handling of ordered lists (in markdown) and raw HTML (in markdown and HTML).

ext2fuse is an implementation of the ext2 filesystem in user space, using the FUSE library. Uses might include as a base for filesystem projects, for FUSE or e2fsprogs testing, and for situations when a kernel mode filesystem is not appropriate.

NeEM is a library that provides an implementation of epidemic multicast (also called probabilistic or gossip-based) in wide-area networks by using multiple TCP/IP connections in a non-blocking fashion.
Epidemic multicast protocols achieve stable high throughput regardless of node and network faults and scale to very large numbers of participants. Implementation is based on Java 5 and takes advantage of NIO. The goal of this implementation is to be small, self-contained, and practical.
Enhancements:
- Introduces logging and the ability to bind to and advertise specific addresses.
- Some dead code removed in the network layer.
- UPnP based NAT traversal sample application added.

pyAwale is a pure Python implementation of the Ivory Coast rules for Awale. Awale is a game of great antiquity, and has been played around the world in various forms for millenia.

This project is a member of the mancala family of board games.

Heimdal is an implementation of Kerberos 5, largely written in Sweden (which was important when we started writing it, less so now). Heimdal project is freely available under a three clause BSD style license.
Other free implementations include the one from MIT, and Shishi.
Enhancements:
- Several bugs in iprop were fixed.
- Platforms without dlopen are now supported.
- RFC3526 modp group14 is now included by default.
- [kdc] database = { } entries are now handled without realm = stanzas.
- krb5_get_renewed_creds and kaserver preauth were fixed along with other bugs.

FreeNAS is a free implementation of a minimal FreeBSD distribution(for run it on a Compact Flash, CD-ROM or USB key) that provide NAS (Network-Attached Storage) services, supporting: CIFS, FTP, NFS protocols, with a Full WEB configuration interface.

The minimal FreeBSD distribution, Web interface,PHP scripts and documentations are based on M0n0wall.