OKL4 Microkernels are a family of second-generation microkernels based on the original designs and implementations by Jochen Liedtke. Originally implemented in highly tuned i386-specific assembly language code, the API has seen extensive development in a number of directions, both in achieving a higher grade of platform independence and also in improving security, isolation, and robustness. There have been various re-implementations of the original binary kernel interface and its higher level successors, including L4Ka::Pistachio, L4/MIPS, and Fiasco. For this reason, the name L4 now applies to the whole microkernel family including the L4 kernel interface and its different versions.
Rocks is a complete "cluster on a CD" solution for x86 and IA64 Red Hat Linux COTS clusters. Building a Rocks cluster does not require any experience in clustering, yet a cluster architect will find a flexible and programmatic way to redesign the entire software stack just below the surface (appropriately hidden from the majority of users). Although Rocks includes the tools expected from any clustering software stack (PBS, Maui, GM support, Ganglia, etc), it is unique in its simplicity of installation.
The stmpclean utility removes old files (and old empty directories) from the specified directory. It is meant to be used to clean directories such as "/tmp" where old files tend to accumulate. stmpclean never removes files or directories owned by root, which is a feature, not a bug. Great care is taken while descending into the directory, and the operation is secure. Anything that's not a directory, regular file, or symbolic link is also left alone (because programs like screen(1) create sockets and FIFOs under /tmp and expect them to be long-lived). Unlike other programs that do the same task, stmpclean never forks and consumes limited amount of memory. If stmpclean determines a race condition it will log the situation and exit with a failure.