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From: Erik Mouw <erik@harddisk-recovery.com>
To: Linus Torvalds <torvalds@osdl.org>
Cc: linux@horizon.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
Date: Thu, 15 Dec 2005 17:52:55 +0100	[thread overview]
Message-ID: <20051215165255.GA5510@harddisk-recovery.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0512150752240.3292@g5.osdl.org>

On Thu, Dec 15, 2005 at 08:15:49AM -0800, Linus Torvalds wrote:
> First off, the data structure is called a "semaphore", and always has 
> been. It's _never_ been called a "mutex" in the first place, and the 
> operations have been called "down()" and "up()", because I thought calling 
> them P() and V() was just too damn traditional and confusing (I don't 
> speak dutch, and even if I did, I think shortening names to that degree is 
> just evil).

Just FYI, according to Dijkstra[1] V means "verhoog" which is dutch for
"increase". P means "prolaag" which isn't a dutch word, just something
Dijkstra invented. I guess he did that because "decrease" is "verlaag"
in dutch and that would give you the confusing V() and V()
operations...

Other explanations you see in dutch CS courses are "passeer" (pass),
"probeer" (try), "vrijgave" (unlock).

I do agree that Dijkstra should have used Prolaag() and Verhoog(), but
I guess those operations wouldn't have sticked in the english CS
literature.


Erik

[1] http://www.cs.utexas.edu/users/EWD/ewd00xx/EWD74.PDF

-- 
+-- Erik Mouw -- www.harddisk-recovery.com -- +31 70 370 12 90 --
| Lab address: Delftechpark 26, 2628 XH, Delft, The Netherlands

  reply	other threads:[~2005-12-15 16:53 UTC|newest]

Thread overview: 227+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-12-15 13:58 [PATCH 1/19] MUTEX: Introduce simple mutex implementation linux
2005-12-15 16:15 ` Linus Torvalds
2005-12-15 16:52   ` Erik Mouw [this message]
2005-12-15 17:23     ` Dick Streefland
2005-12-16 12:17     ` Erik Mouw
2005-12-17 10:59       ` Sander
2005-12-17 14:14         ` Douglas McNaught
2005-12-17 15:09           ` Sander
2005-12-19 10:44         ` Erik Mouw
2005-12-15 19:02   ` Nikita Danilov
2005-12-15 19:09   ` linux
2005-12-15 19:52     ` Linus Torvalds
2005-12-16  1:33       ` linux
2005-12-15 21:18     ` Steven Rostedt
2005-12-15 20:52   ` Steven Rostedt
  -- strict thread matches above, loose matches on Subject: below --
2005-12-16 12:49 linux
2005-12-16 15:24 ` David Howells
2005-12-16 18:03   ` linux
2005-12-15 17:45 Luck, Tony
2005-12-15 18:00 ` David Howells
2005-12-15 18:48 ` James Bottomley
2005-12-15 20:38 ` Jeff Dike
2005-12-15 23:45   ` Stephen Rothwell
2005-12-12 23:45 David Howells
2005-12-13  0:13 ` Nick Piggin
2005-12-13  0:19 ` Nick Piggin
2005-12-13  0:19 ` Andrew Morton
2005-12-13  7:54   ` Ingo Molnar
2005-12-13  7:58     ` Andi Kleen
2005-12-13  8:42       ` Andrew Morton
2005-12-13  8:49         ` Andi Kleen
2005-12-13  9:01           ` Andrew Morton
2005-12-13  9:02             ` Andrew Morton
2005-12-13 10:07               ` Jakub Jelinek
2005-12-13 10:11                 ` Andi Kleen
2005-12-13 10:15                   ` Jakub Jelinek
2005-12-13 10:25                   ` Andrew Morton
2005-12-14 10:46               ` Russell King
2005-12-13  9:05             ` Andi Kleen
2005-12-13  9:15               ` Andrew Morton
2005-12-13  9:24                 ` Andi Kleen
2005-12-13  9:44                   ` Andrew Morton
2005-12-13  9:49                     ` Andi Kleen
2005-12-13 10:28                   ` Andreas Schwab
2005-12-13 10:30                     ` Andi Kleen
2005-12-13 12:33                   ` Matthew Wilcox
2005-12-13 22:18               ` Adrian Bunk
2005-12-13 22:25                 ` Andi Kleen
2005-12-13 22:32                   ` Adrian Bunk
2005-12-13  9:11             ` Ingo Molnar
2005-12-13  9:04           ` Christoph Hellwig
2005-12-13  9:13             ` Ingo Molnar
2005-12-13 10:11             ` Jakub Jelinek
2005-12-13 10:19               ` Christoph Hellwig
2005-12-13 10:27                 ` Ingo Molnar
2005-12-15  4:53                 ` Miles Bader
2005-12-15  5:05                   ` Nick Piggin
2005-12-13  9:09           ` Ingo Molnar
2005-12-13  9:21             ` Andi Kleen
2005-12-13 16:16           ` Linus Torvalds
2005-12-13  9:03         ` Christoph Hellwig
2005-12-13  9:14           ` Andrew Morton
2005-12-13  9:21             ` Christoph Hellwig
2005-12-13  8:00     ` Arjan van de Ven
2005-12-13  9:03       ` Ingo Molnar
2005-12-13  9:09         ` Andi Kleen
2005-12-13  9:34           ` Ingo Molnar
2005-12-13 14:33             ` Mark Lord
2005-12-13 14:45               ` Arjan van de Ven
2005-12-13  9:37           ` Ingo Molnar
2005-12-13  9:19         ` Arjan van de Ven
2005-12-13  9:02     ` Christoph Hellwig
2005-12-13  9:39       ` Ingo Molnar
2005-12-13 10:00         ` Ingo Molnar
2005-12-13 17:40           ` Paul Jackson
2005-12-13 18:34           ` David Howells
2005-12-13 22:31             ` Paul Jackson
2005-12-14 11:02             ` David Howells
2005-12-14 11:12             ` David Howells
2005-12-14 11:18               ` Alan Cox
2005-12-14 12:35               ` David Howells
2005-12-14 13:58                 ` Thomas Gleixner
2005-12-14 23:40                   ` Mark Lord
2005-12-14 23:54                     ` Andrew Morton
2005-12-15 13:41                       ` Nikita Danilov
2005-12-15 14:56                         ` Alan Cox
2005-12-15 15:52                           ` Nikita Danilov
2005-12-15 16:50                             ` Christopher Friesen
2005-12-15 20:53                               ` Steven Rostedt
2005-12-15 15:55                           ` David Howells
2005-12-15 16:22                             ` linux-os (Dick Johnson)
2005-12-15 16:28                             ` Linus Torvalds
2005-12-15 17:04                               ` Thomas Gleixner
2005-12-15 17:09                               ` Paul Jackson
2005-12-15 17:17                               ` David Howells
2005-12-15 16:51                             ` David Howells
2005-12-15 16:56                             ` Paul Jackson
2005-12-15 17:28                             ` David Howells
2005-12-15 17:48                               ` Linus Torvalds
2005-12-15 18:20                                 ` Nikita Danilov
2005-12-15 20:58                                   ` Steven Rostedt
2005-12-15 19:21                                 ` Andrew Morton
2005-12-15 19:38                                   ` Linus Torvalds
2005-12-15 20:28                                   ` Steven Rostedt
2005-12-15 20:32                                     ` Geert Uytterhoeven
2005-12-16 21:41                                       ` Thomas Gleixner
2005-12-16 21:41                                         ` Linus Torvalds
2005-12-16 22:06                                           ` Thomas Gleixner
2005-12-16 22:19                                             ` Linus Torvalds
2005-12-16 22:32                                               ` Steven Rostedt
2005-12-16 22:42                                               ` Thomas Gleixner
2005-12-16 22:41                                                 ` Linus Torvalds
2005-12-16 22:49                                                   ` Steven Rostedt
2005-12-16 23:29                                                   ` Thomas Gleixner
2005-12-17  0:29                                                   ` Joe Korty
2005-12-17  1:00                                                     ` Linus Torvalds
2005-12-17  3:13                                                       ` Steven Rostedt
2005-12-17  7:34                                                         ` Linus Torvalds
2005-12-17 23:43                                                           ` Matthew Wilcox
2005-12-18  0:05                                                             ` Lee Revell
2005-12-18  0:21                                                               ` Matthew Wilcox
2005-12-18  1:25                                                                 ` Lee Revell
2005-12-22 12:27                                                             ` Bill Huey
2005-12-19 16:08                                                           ` Ingo Molnar
2005-12-22 12:40                                                           ` Bill Huey
2005-12-22 12:45                                                             ` Bill Huey
2005-12-19 23:46                                                       ` Keith Owens
2005-12-15 14:41                       ` Steven Rostedt
2005-12-14 23:57                     ` Thomas Gleixner
2005-12-14 23:57                       ` Mark Lord
2005-12-15  0:10                         ` Thomas Gleixner
2005-12-15  2:46                           ` Linus Torvalds
2005-12-15 15:53                           ` David Howells
2005-12-15 15:37                     ` David Howells
2005-12-15 19:28                       ` Andrew Morton
2005-12-15 20:18                         ` Andrew Morton
2005-12-15 21:28                           ` Steven Rostedt
2005-12-16 22:02                           ` Thomas Gleixner
2005-12-16 10:45                         ` David Howells
2005-12-13  9:55     ` Ingo Molnar
2005-12-13  0:30 ` Arnd Bergmann
2005-12-13  0:57 ` Daniel Walker
2005-12-13  3:23   ` Steven Rostedt
2005-12-13  2:57 ` Mark Lord
2005-12-13  3:17   ` Steven Rostedt
2005-12-13  9:06   ` Christoph Hellwig
2005-12-13  9:54 ` David Howells
2005-12-13 10:13   ` Ingo Molnar
2005-12-13 10:34     ` Ingo Molnar
2005-12-13 10:37       ` Ingo Molnar
2005-12-13 12:47       ` Oliver Neukum
2005-12-13 13:09         ` Alan Cox
2005-12-13 13:13           ` Matthew Wilcox
2005-12-13 14:04             ` Alan Cox
2005-12-13 13:24           ` Oliver Neukum
2005-12-14  1:00   ` Nick Piggin
2005-12-14 10:54   ` David Howells
2005-12-14 11:17     ` Nick Piggin
2005-12-14 11:46     ` David Howells
2005-12-14 21:23       ` Nick Piggin
2005-12-16 12:00       ` David Howells
2005-12-16 13:16         ` Nick Piggin
2005-12-16 15:53         ` David Howells
2005-12-16 23:41           ` Nick Piggin
2005-12-16 16:02         ` David Howells
2005-12-13 10:48 ` David Howells
2005-12-13 12:39   ` Matthew Wilcox
2005-12-13 10:54 ` Ingo Molnar
2005-12-13 11:23 ` David Howells
2005-12-13 11:24 ` David Howells
2005-12-13 13:45   ` Ingo Molnar
2005-12-13 11:34 ` David Howells
2005-12-13 13:05 ` Alan Cox
2005-12-13 13:15   ` Alan Cox
2005-12-13 23:21     ` Nikita Danilov
2005-12-13 13:32 ` David Howells
2005-12-13 14:00   ` Alan Cox
2005-12-13 14:35   ` Christopher Friesen
2005-12-13 14:44     ` Arjan van de Ven
2005-12-13 14:59       ` Christopher Friesen
2005-12-13 15:23   ` David Howells
2005-12-15  5:24     ` Miles Bader
2005-12-13 15:39   ` David Howells
2005-12-13 16:10     ` Alan Cox
2005-12-14 10:29       ` Arjan van de Ven
2005-12-14 11:03         ` Arjan van de Ven
2005-12-14 11:03         ` Alan Cox
2005-12-14 11:08           ` Arjan van de Ven
2005-12-14 11:24             ` Alan Cox
2005-12-14 11:35               ` Andrew Morton
2005-12-14 11:44                 ` Arjan van de Ven
2005-12-14 11:52                   ` Andi Kleen
2005-12-14 11:55                     ` Arjan van de Ven
2005-12-14 11:57                 ` David Howells
2005-12-14 12:19                   ` Jakub Jelinek
2005-12-16  1:54                   ` Nick Piggin
2005-12-16 11:02                   ` David Howells
2005-12-16 13:01                     ` Nick Piggin
2005-12-16 13:21                       ` Russell King
2005-12-16 13:41                         ` Nick Piggin
2005-12-16 13:46                         ` Linh Dang
2005-12-16 14:31                           ` Russell King
2005-12-16 15:24                             ` Linh Dang
2005-12-16 15:35                               ` Nick Piggin
2005-12-16 15:40                               ` Kyle Moffett
2005-12-16 15:49                             ` Linh Dang
2005-12-16 15:46                           ` David Howells
2005-12-16 15:58                             ` Russell King
2005-12-17 15:57                       ` Nikita Danilov
2005-12-16 16:28                     ` Linus Torvalds
2005-12-16 11:30                   ` David Howells
2005-12-16 16:33                     ` Linus Torvalds
2005-12-16 22:23                       ` David S. Miller
2005-12-16 22:38                         ` Linus Torvalds
2005-12-16 22:53                           ` David S. Miller
2005-12-17  0:41                             ` Jesse Barnes
2005-12-17  7:10                               ` David S. Miller
2005-12-17  7:40                                 ` Linus Torvalds
2005-12-17 17:22                                   ` Jesse Barnes
2005-12-17 17:19                                 ` Jesse Barnes
2005-12-17 22:38                             ` Richard Henderson
2005-12-17 23:05                               ` David S. Miller
2005-12-14 12:17                 ` Christoph Hellwig
2005-12-14 11:42               ` Arjan van de Ven
2005-12-14  8:31     ` Ingo Molnar
2005-12-13 20:04   ` Steven Rostedt
2005-12-13 21:03 ` David Howells

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