... On Solaris 2.5 we use SUN PThreads (the native thread support in 2.4 and earlier versions are not good enough) and on Linux we use LinuxThreads by Xavier Leroy, Xavier.Leroy@inria.fr . The hard part of porting to a new Unix variant without good native thread support is probably to port MIT-pthreads. ... The MySQL distribution includes a patched version of Provenzano's Pthreads from MIT (see MIT Pthreads web page ). This can be used for some operating systems that do not have POSIX threads. ...