Dutch Computer Science: Dijkstra, semaphores, P and V

@ 2012-06-21 by João Paulo Pizani Flor

Last week my only computer (a laptop I bought in 2008) started to refuse to boot, it died! In fact, it’s hard drive died… And, as I’m now within an extreme budget (saving for my trip to the Netherlands), I decided to remain without any personal computer :O

To make the situation even more bizarre, my headphones also died recently - which turned my my daily commute with the bus into a very, how should I put it, “introspective” period. In one of those “day dreams”, I somehow managed to combine my weak knowledge of Computer Science with my even weaker knowledge of the dutch language and arrived then at a ridiculously simple conclusion, but one that immediately made me smile :)

Do you perhaps happen to know semaphores, those little things used to synchronize threads? So, the concept of “semaphore” as a synchronization mechanism was invented by a dutch computer scientist, a very famous one, by the way: Edsger Wybe Dijkstra. Meneer Dijkstra is best known for - besides having invented semaphores - conceiving the “Dining Philosophers” problem and for having invented a very nice algorithm to calculate the shortest path between two vertices in a graph.

But then, back to my day dream: Do you remember that semaphores have two fundamental operations, called P and V? So, mind you, in that moment of mental quasi-emptiness I finally realized - all by myself - that P means Proberen (“to try”, in Dutch), and that V means Vrijen (which is “to free”, in Dutch)…

Nice, huh?

EDIT: Now, according to Wikipedia, V really stands for Verhogen (which is “to increase”, in Dutch). But then, again, I think that Vrijen sounds much nicer, so screw Wikipedia :)

EDIT 2: Okay, so “vrijen” has a much more interesting meaning than I naïvely tought… See it for yourself: Vrijen