Chicken does have support for fork(2), and some of the posix IPC stuff (pipes, sockets, maybe shm?) There's concurrent-native-callbacks, which allows you to ru

Chicken does have support for fork(2), and some of the posix IPC stuff (pipes, sockets, maybe shm?) There's concurrent-native-callbacks, which allows you to run Chicken callbacks inside other threads http://wiki.call-cc.org/eggref/4/concurrent-native-callbacks http://wiki.call-cc.org/eggref/4/concurrent-native-callbacks. Chicken also has MPI support, through http://wiki.call-cc.org/eggref/4/mpi http://wiki.call-cc.org/eggref/4/mpi, but I don't really know MPI well. Pthreads allows you to send C code (not scheme code) out to a pthread pool for execution. http://wiki.call-cc.org/eggref/4/pthreads http://wiki.call-cc.org/eggref/4/pthreads Mailbox allows for erlang-style threadsafe mailboxes (FIFO queues) http://wiki.call-cc.org/eggref/4/mailbox http://wiki.call-cc.org/eggref/4/mailbox, and mailbox-threads attaches a mailbox to each thread http://wiki.call-cc.org/eggref/4/mailbox-threads http://wiki.call-cc.org/eggref/4/mailbox-threads. Finally, remote-mailbox-threads allows for mailbox send/receives across threads through zmq http://wiki.call-cc.org/eggref/4/remote-mailbox-threads http://wiki.call-cc.org/eggref/4/remote-mailbox-threads. Not optimal, but it can all work.