musl is a new implementation of the standard library for Linux-based systems. It is lightweight, fast, simple, free, and strives to be correct in the sense of standards-conformance and safety. It includes a wrapper for building programs against musl in place of the system standard library (e.g. glibc), making it possible to immediately evaluate the library and build compact statically linked binaries with it.
uClibc (µClibc) is a C library for developing embedded Linux systems. It is much smaller then the GNU C Library, but nearly all applications supported by glibc also work perfectly with uClibc. Porting applications from glibc to uClibc typically involves just recompiling the source code. uClibc even supports shared libraries and threading. It currently runs on standard Linux and MMU-less Linux (also known as µClinux) systems with support for ARM, i386, h8300, m68k, MIPS, mipsel, PowerPC, SH, SPARC, and v850 processors.
HelenOS is a microkernel-based multiserver operating system designed from scratch. By decomposing the operating system functionality into tens of isolated but intensively communicating userspace servers, it provides a computing environment that has several virtues such as flexibility, increased robustness, well defined explicit interfaces, and smaller complexity of individual components. HelenOS does not aim to be another clone of Unix or some other legacy system and is not POSIX-compliant (even though it may seem POSIX-similar at times). Instead, the goal has been to design it according to what is the most elegant and right thing to do. What makes HelenOS unique among the other multiserver operating systems is its multiplatform and multiprocessor microkernel. It will run on seven different processor architectures ranging from a 32-bit uniprocessor little-endian ARMv4 to a 64-bit multicore big-endian UltraSPARC T1.
Cobbler is a network installation and update server. It can be used to automatically set up PXE, install virtual guests, manage answer files, and reinstall existing Linux machines. Advanced features include importing distributions from DVDs and rsync mirrors, kickstart templating, integrated yum mirroring (integrated with the installer to make updates available at install time), creation of netboot ISOs, and built-in DHCP/DNS Management. Tools such as "cobbler triggers", a Python API, and an XMLRPC API allow integration with cobbler with the rest of your datacenter environment or other systems management applications. There is also a Web interface to simplify management of the install server. Cobbler supports RHEL 4+, Fedora, and derivative distributions, and is also able to install other popular distributions.
DirectFB is a thin library that provides developers with hardware graphics acceleration, input device handling and abstraction, an integrated windowing system with support for translucent windows and multiple display layers on top of the Linux framebuffer device. It is a complete hardware abstraction layer with software fallbacks for every graphics operation that is not supported by the underlying hardware.
ZThread is an advanced object-oriented threading and synchronization library, implemented in C++ for POSIX, MacOS, and Win32 systems. It provides an excellent and powerful abstraction from native threads. It includes interruptible thread objects and several other synchronization control objects.
Facter is a simple cross-platform library for determining basic facts about an operating system, like the operating system name, IP address, or MAC address. It supports multiple mechanisms for resolving a given fact, and these mechanisms can be restricted to only working on specified operating systems or operating system releases.
OSSP uuid is an API for ISO C, ISO C++, Perl and PHP and a corresponding CLI for the generation of DCE 1.1, ISO/IEC 11578:1996, and RFC4122 compliant Universally Unique Identifiers (UUIDs). It supports DCE 1.1 variant UUIDs of version 1 (time and node based), version 3 (name based, MD5), version 4 (random number based), and version 5 (name based, SHA-1). UUIDs are 128-bit numbers that are intended to have a high likelihood of uniqueness over space and time and are computationally difficult to guess. They are globally unique identifiers that can be locally generated without contacting a global registration authority.