Subject Re: [firebird-support] Replication
Author David Johnson
GUID's use the MAC address ofthe NIC, the PC's time of day, a random number, and other factors. They do not require a network connection - you PC's serial number will work as well as the NIC's MAC address.

In DOS and UNIX, GUID's are generally created by a system call - I believe it was CreateGUID for the Windows world, and I forget entirely what it was for the UNIX world. Java users can obtain several versions of the algorithm from open source repositories.
----- Original Message -----
From: Alan McDonald
Sent: Tuesday, January 27, 2004 1:11 AM
Subject: RE: [firebird-support] Replication

> Where can I find info about this? How do GUIDs work? Do they need an
> internet connection? Are they based on the current time?
> If so, what is the time is not synchronized between the different
> machines?
> Thanks!
> Jonathan Neve.

GUIDs are spawned from a network card which is uniquely identified. It used
to be, I htink, that if there were no NIC, the GUID routines would object to
being asked to generate one but they do it anyway now. Not sure what the
spawn is in this instance. Not many PCs these days without NICs.
So no - time will not play a major role but time on the machine in question
will be used to create the tail of the GUID.
Get a GUID generator and generate a few on your PC - you'll see them


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