jozwiak@uicsrd.csrd.uiuc.edu (09/10/88)
I was just wondering if anyone knew what Dijkstra's semaphore functions P and V stood for in Dutch? john
siebren@cwi.nl (Siebren van der Zee) (09/12/88)
In article <45000017@uicsrd.csrd.uiuc.edu> jozwiak@uicsrd.csrd.uiuc.edu writes: > I was just wondering if anyone knew what Dijkstra's >semaphore functions P and V stood for in Dutch? > john It is related to the train-world - of zoiets - where trains might have to wait if there is another one on the traject (is this proper English?). 'P' stands for "passeren"; and 'V' stands for "vrijgeven". Hope this helps, Siebren van der Zee. siebren@cwi.nl In case you're interested in the meaning: passeren = pass, vrijgeven = free, empty.
hulsebos@philmds.UUCP (Rob Hulsebos) (09/13/88)
In article <45000017@uicsrd.csrd.uiuc.edu> jozwiak@uicsrd.csrd.uiuc.edu writes: >I was just wondering if anyone knew what Dijkstra's >semaphore functions P and V stood for in Dutch? I know of two tales, don't know whether they're true or not. [1] Since Dijkstra seems to have invented the P and V operations while lecturing at Eindhoven's university, and Eindhoven hosts a soccer club named PSV, whose stadium was visible from the main building of the university.... need I say more :-) BTW, PSV is short for "Philips Sport Vereniging" (Philips Sporting Club) so if you use a P don't forget to pay royalties :-) [2] A process executing P can either 'P'ass or be halted. When it then executes the V, it increases the semaphore's counter (to increase == 'V'erhogen in Dutch ). Thus, P and V are just the first letters of the Dutch words describing what these operations do. Dijkstra is, to my knowledge, still alive and currently lecturing in Texas. You may want to ask it himself. ------------------------------------------------------------------------------ R.A. Hulsebos, Philips I&E Automation Modules ...!mcvax!philmds!hulsebos Building TQ-III-1 room 11 phone: +31-40-785723 Eindhoven, The Netherlands
jv@mhres.mh.nl (Johan Vromans) (09/13/88)
From article <7640@boring.cwi.nl>, by siebren@cwi.nl (Siebren van der Zee): > In article <45000017@uicsrd.csrd.uiuc.edu> jozwiak@uicsrd.csrd.uiuc.edu writes: >> I was just wondering if anyone knew what Dijkstra's >>semaphore functions P and V stood for in Dutch? >> john I remember from long ago ... P = Pakken (meaning: take, reserve) V = Vrijgeven (meaning: free) -- Johan
friedl@vsi.UUCP (Stephen J. Friedl) (09/15/88)
In article <45000017@uicsrd.csrd.uiuc.edu> jozwiak@uicsrd.csrd.uiuc.edu writes: >I was just wondering if anyone knew what Dijkstra's >semaphore functions P and V stood for in Dutch? In article <801@philmds.UUCP>, hulsebos@philmds.UUCP (Rob Hulsebos) writes: >[good tale] > > Dijkstra is, to my knowledge, still alive and currently lecturing > in Texas. You may want to ask it himself. He's at University of Texas at Austin, don't know his address. I think he got an endowed chair or something. -- Steve Friedl V-Systems, Inc. +1 714 545 6442 3B2-kind-of-guy friedl@vsi.com {backbones}!vsi.com!friedl attmail!vsi!friedl ------------Nancy Reagan on conductance: "Just say mho"------------
tom@nlgvax.UUCP (Tom van Peer) (09/20/88)
P stands for "passeer": pass by a signal and enter a block.
V stands for "verlaat": leave a block, clear the signal.
As I remember it , this stems from train business, where tracks are
divided into blocks and only one train can be in a block at any given
time. Nice analogy, isn't it ? In Dutch a semaphore is a synonym for a
signal post, but I've never heard anyone working with the railways talk
about semaphores...
--
Tom van Peer
Nederlands Philips Bedrijven, Dependance Nat. Lab. Building XP
Willem Alexanderlaan 7B, 5664 AN Geldrop - The Netherlands. Tel: +31-40-892334
E-mail: mcvax!philmds!nlgvax!tom or tom@pcg.philips.nl