esky is an implementation of job freezing (checkpoint/resume) for Unix processes. It can save the state of a running process to disk then later resume it from the point it left off, possibly on a different machine. esky currently works on a limited but non-trivial range of processes. esky can cope with programs that open or mmap() files, including opening shared libraries with dlopen(). esky is implemented entirely in userspace - no kernel patches or modules are required. It works under Linux 2.2 and Solaris 2.6 and is written to be independent of CPU type.