From Drupal and Moodle, right through to a Git versioning system and Perl modules on CPAN, we contribute back to over 175 community open source projects. This list is in order of the number of projects contributed to.
linear probing hash table implementation written in pure C (c99)
a set implementation written in pure C (c99), uses linear probing for hash collisions
Linux for DaVinci™ Processors from Texas Instruments.
Linux Repository for digilent boards
This repository tracks the official stable and dev kernel branch and includes modules for using Hecatonchire in the kernel.
Linux Kernel (http://www.kernel.org/)
The Linux kernel is a Unix-like computer operating system kernel. It is used world-wide: the Linux operating system is based on it and deployed on both traditional computer systems such as personal computers and servers, usually in the form of Linux distributions, and on various embedded devices such as routers, wireless access points, PBXes, set-top boxes, FTA receivers, smart TVs, PVRs and NAS appliances. The Android operating system for tablet computers, smartphones and smartwatches is also based atop the Linux kernel. (from Wikipedia)
Linux NTFS file system support (https://www.tuxera.com/)
The goals of this project are: create a new Linux kernel driver for the NTFS file system (v1.2 and later 3.0), user space utilities (e.g. format, ntfs check, etc.) and a library to avoid code duplication and provide access to NTFS to other GPLed programs
Linux kernel for Texas Instruments OMAP series of processors
Linux source for Allwinner/Boxchip F20 (sun3i), A10 (sun4i) and A12/A13 (sun5i) SoCs.