https://www.abebooks.com/9780387954011/Origin-Concurrent-Programming-Semaphores-Remote-0387954015/plp
One cannot build or understand a modern operating system unless one knows the principles of concurrent programming. This volume is a collection of 19 original...
the originconcurrent programmingsemaphoresremoteprocedure
https://github.com/Sam-Chug/newgrf-logic-semaphores
NewGRF for OpenTTD that turns semaphore signals into large pixels - Sam-Chug/newgrf-logic-semaphores
githubsamchuglogicsemaphores