tag:blogger.com,1999:blog-5135517.post112402923218217497..comments2023-11-05T03:54:44.710-08:00Comments on Making it stick.: uuidPatrick Loganhttp://www.blogger.com/profile/02088461489050417591noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-5135517.post-1124827107297957302005-08-23T12:58:00.000-07:002005-08-23T12:58:00.000-07:00(Note: the original uuid generators use the networ...<I>(Note: the original uuid generators use the network card MAC address but the IP address is easier to get and just as good for this purpose.)</I><BR/><BR/>Not true.<BR/><BR/>If you have home users, for instance, behind NAT routers, odds are they all have 192.168.1.x as their IP address, for<BR/>some low value of x.<BR/><BR/>In corporate environments, internal networks often use the same 192.168.x.y subnet and then use NAT to "go legal" to talk to the outside world.<BR/><BR/>So this really might not be unique enough for your needs. <BR/><BR/>MAC IDs aren't all unique either, but they're a heck of a lot closer to it...<BR/><BR/>Of course, your uuid's will probably still be unique enough, because of the other fields. But don't delude yourself about the IP address being "just as good" as the MAC address.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5135517.post-1124052029155145842005-08-14T13:40:00.000-07:002005-08-14T13:40:00.000-07:00Calvin -- At least I did look at libuuid first. 8^...Calvin -- At least I did look at libuuid first. 8^(<BR/><BR/>The reason I wrote this is simple... Termite does not need a standard uuid and libuuid is not widely deployed. I am not interested in solving that problem per se, I just want Termite to be more accessible when it is released.<BR/><BR/>I do think a Termite application would want to use a standard uuid when communicating with the outside world. That could be done with libuuid and in particular a "uuidgen" server that is not necessarily installed in every node of Termite.<BR/><BR/>PJE -- I agree this should have a different name because it is not derived from, nor meant to be compatible with, any standard uuid.<BR/><BR/>Also PJE -- I'll look at that Python code. Thanks.Patrick Loganhttps://www.blogger.com/profile/02088461489050417591noreply@blogger.comtag:blogger.com,1999:blog-5135517.post-1124043079634452582005-08-14T11:11:00.000-07:002005-08-14T11:11:00.000-07:00By the way, here's a compliant implementation in P...By the way, here's a <A HREF="http://svn.eby-sarna.com/PEAK/src/peak/util/uuid.py?view=markup" REL="nofollow">compliant implementation in Python</A>.PJEhttps://www.blogger.com/profile/04688223805457202941noreply@blogger.comtag:blogger.com,1999:blog-5135517.post-1124042970193338522005-08-14T11:09:00.000-07:002005-08-14T11:09:00.000-07:00You might want to look at draft-leach-uuids-guids-...You might want to look at <A HREF="http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt" REL="nofollow">draft-leach-uuids-guids-01.txt</A>, which is sort of a defacto standard for GUID formats, as it documents all the various legacy GUID bit fields, as well as several variations of GUID generation methods, and the standard string format for them (which is *not* 4 32-bit fields, by the way). As it happens, GUIDs are not just arbitrary 128-bit numbers, they have a number of internal fields identifying their format and version. If you're just making up your own new unique ID system, it'd probably be better to call it something else and use an obviously different format, so that people don't think they can use your implementation with something that expects Leach-style UUIDs or GUIDs.PJEhttps://www.blogger.com/profile/04688223805457202941noreply@blogger.comtag:blogger.com,1999:blog-5135517.post-1124042930099418972005-08-14T11:08:00.000-07:002005-08-14T11:08:00.000-07:00The fact that we have so many non-conforming UUID ...The fact that we have <B>so many</B> non-conforming UUID generators, and all for little or no reason, is the cause of the real problem. Most people do what you just did, without even looking for libuuid first. If there really is any considerable lack of libuuid deployment (which I really doubt), then that is the only reason.Calvin Spealmanhttps://www.blogger.com/profile/07161631946662126734noreply@blogger.com