Subject:
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RE: Brainstorms
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Newsgroups:
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lugnet.robotics
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Date:
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Mon, 12 Aug 2002 01:30:14 GMT
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Original-From:
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Russell C. Brown [RR-1] <RCBROWN@AUSTINstopspam.RR.COM>
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Reply-To:
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<rcbrown@austinNOSPAM.rr.com>
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Viewed:
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852 times
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This may be totally off-base--I'm not as techy as you guys--but the software
biz has the idea of a universally unique ID (UUID, a.k.a. GUID for globally
unique ID).
It's a way of generating a unique number without any centralized management.
Windows relies on GUIDs extensively (look up CoCreateGUID), as do CORBA and
DCE. W3C provides a Java UUID generator in org.w3c.util.UUID. There are some
circumstances where duplicate numbers could be generated, but those
circumstances are preventable and the odds of a collision are vanishingly
small anyway. The generation technique is more likely to be unique than
random numbers and is not as sensitive to the quality of the pseudorandom
number generator.
Could you just generate a new UUID for each brick you manufacture and
hardwire it, put it in an EPROM, or something like that?
Here's some more information from http://www.webopedia.com/TERM/G/GUID.html:
GUID: Short for Globally Unique Identifier, a unique 128-bit number that is
produced by the Windows OS or by some Windows applications to identify a
particular component, application, file, database entry, and/or user. For
instance, a Web site may generate a GUID and assign it to a user's browser
to record and track the session. A GUID is also used in a Windows registry
to identify COM DLLs. Knowing where to look in the registry and having the
correct GUID yields a lot information about a COM object (i.e., information
in the type library, its physical location, etc.). Windows also identifies
user accounts by a username (computer/domain and username) and assigns it a
GUID. Some database administrators even will use GUIDs as primary key values
in databases.
GUIDs can be created in a number of ways, but usually they are a combination
of a few unique settings based on specific point in time (e.g., an IP
address, network MAC address, clock date/time, etc.).
Hope that's helpful or at least not annoying. :)
--Russ
> -----Original Message-----
> From: news-gateway@lugnet.com
> [mailto:news-gateway@lugnet.com]On Behalf
> Of Ralph Hempel
> Sent: Saturday, August 10, 2002 11:59 AM
> To: lego-robotics@crynwr.com
> Subject: RE: Brainstorms
>
>
> Wayne,
>
> In the spec you indicate that each brick gets its own 128
> bit random number. This is like a serial number that is
> initially use to uniquely identify each brick with a shorter
> BrickID.
>
> This is a common technique in fire alarm systems where
> each device is assigned a short ID from a larger serial number.
>
> Why the random numbers?
>
> Never mind, I just figured it out. You're allowing individuals
> to build their own bricks so you have no control of how the
> numbers get assigned.
>
> I guess the probability of collisions is so low that you'd
> never see a collision anyways....
>
>
> Cheers, Ralph
>
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Message has 1 Reply:
 | | RE: Brainstorms GUID
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| Quoting "Russell C. Brown [RR-1]" <rcbrown@austin.rr.com>: (...) Well, one easy answer is to use a Dallas serial number chip. They are way less than a dollar in quantity. Actually each 1Wire device has a guaranteed unique ID. Some have EE memory for (...) (22 years ago, 12-Aug-02, to lugnet.robotics)
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Message is in Reply To:
| | RE: Brainstorms
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| Wayne, In the spec you indicate that each brick gets its own 128 bit random number. This is like a serial number that is initially use to uniquely identify each brick with a shorter BrickID. This is a common technique in fire alarm systems where (...) (22 years ago, 10-Aug-02, to lugnet.robotics)
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