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From: "H. Peter Anvin" <hpa@zytor.com>
To: davids@webmaster.com
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Time-based RFC 4122 UUID generator
Date: Mon, 19 Nov 2007 22:44:47 -0800	[thread overview]
Message-ID: <4742825F.9000109@zytor.com> (raw)
In-Reply-To: <MDEHLPKNGKAHNMBLJOLKCECCIFAC.davids@webmaster.com>

David Schwartz wrote:
> 
> Any UUID generator that can produce duplicate UUIDs with probability
> significantly less than purely random UUIDs is so badly broken that it
> should not ever be used. Anyone who finds such a UUID generator should
> immediately either fix it or throw it on the junk heap. Anyone who knowingly
> uses such a UUID generator should be publically shamed.
> 
> Rather than (or at the very least, in addition to) adding a new UUID
> generator, let's fix the one(s) we have.
> 

I presume you mean "significantly higher."

Realistically speaking, a random UUID is probably the best you're going 
to ever get.  I highly suspect that any time- and MAC-address-based 
solution is going to suffer from mis-set clocks and misprogrammed MAC 
addresses more often than you will have collisions in a 122-bit random 
number.

	-hpa

  parent reply	other threads:[~2007-11-20  6:46 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-18 19:38 [PATCH] Time-based RFC 4122 UUID generator Helge Deller
2007-11-18 21:05 ` Andrew Morton
2007-11-18 21:34   ` Sam Ravnborg
2007-11-18 21:43     ` Helge Deller
2007-11-19 21:56       ` David Schwartz
2007-11-19 22:58         ` Alan Cox
2007-11-20  6:44         ` H. Peter Anvin [this message]
2007-11-20 22:58         ` Helge Deller
2007-11-21  0:20           ` Alan Cox
2007-11-18 21:40   ` Helge Deller
2007-11-20  6:31     ` Matt Mackall
2007-11-20 21:59       ` Helge Deller
2007-11-20 22:55         ` Matt Mackall
2007-11-20 23:11           ` Helge Deller
2007-11-20 23:34             ` Matt Mackall
2007-11-20 23:00         ` Theodore Tso
2007-11-20 23:30           ` Helge Deller
2007-12-10  5:36           ` [e2fsprogs PATCH] Userspace solution to time-based UUID without duplicates Theodore Tso
2007-12-16 21:53             ` Helge Deller
2007-12-17  0:07               ` Theodore Tso
2007-11-20  6:15 ` [PATCH] Time-based RFC 4122 UUID generator Andrew Morton
2007-11-20 22:40   ` Helge Deller

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