libsysconfcpus is an $LD_PRELOAD library that intercepts calls to sysconf() and adjusts the responses for _SC_NPROCESSORS_CONF and _SC_NPROCESSORS_ONLN, which are used to determine the number of processors available (either configured or online) at runtime in a system. Unfortunately, some closed-source software assumes that all of these processors may be used for computation, which is an assumption that is frequently not true on multiuser and HPC systems. libsysconfcpus provides a simple, non-intrusive way of adjusting the behavior of such software (when it is dynamically linked).
xlibtrace displays the interaction between X11 client programs and the X11 client shared library (libX11.so) by showing the Xlib calls that are made. Output is shown in a style similar to strace(1). It works by using the $LD_PRELOAD dynamic linker option to insert itself between the target X11 client program and libX11.so. This allows it to "intercept" all calls to X functions, whereupon it has the opportunity to print the name of the function being called, along with any arguments and return value. This can be particularly useful when analyzing the behavior of closed-source X11 programs.
GLD-fork is a fork of the GLD program by Salim Gasmi. The fork has been made because the original project has been dead for many years, and some new featured were needed. GLD-fork, as with the original GLD, adds greylisting functionality to the Postfix mail server. Greylisting is a fairly resource friendly anti-spam technique. GLD-fork can easily be combined with other (more resource consuming) tools to build anti-spam protection.
Diskus is a high-level hard drive diagnostic and limited repair tool. It checks the disk geometry by writing numbered IDs into the sectors of the hard drive. Later one can verify that these sector-IDs on the disk are still correct, thereby detecting data which was not correctly written. There is an option to "freshen" the data on your harddrive, which will read and rewrite the sectors. With modern drives this will re-map defective sectors.