A Brief History of the UUID
I can actually fill in some of the details about the history of UUID&#x27;s.  Paul Leach was an architect who worked at Apollo, OSF, and later Microsoft.  I met Paul in the mid-90&#x27;s when he was an architect at OSF, and I was the tech load for Kerberos v5 development at MIT.  OSF DCE was going to use Kerberos for authentication, and was going to use Apollo RFC as its RPC layer.<p>It was from talking to Paul that I learned about UUID&#x27;s, and I added libuuid into e2fsprogs 1.05, released September 7, 1996.  UUID&#x27;s were used in Linux in the ext2 superblock, and later on, GNOME picked it up and used it extensively, which meant among other things that if you wanted to run GNOME on FreeBSD or NetBSD or Solaris, you had to compile e2fsprogs to get libuuid.  :-)<p>Later on Paul went on to Microsoft, and I&#x27;m fairly certain that it was due to Paul that Microsoft adopted the OSF DCE RPC layer for its internal use, and UUID&#x27;s started being used extensively inside Microsoft.  UUID&#x27;s also got used in Intel&#x27;s EFI specification for the GPT partition table, although somewhere along the way they got renamed &quot;Globally Unique ID&#x27;s&quot; --- it&#x27;s the same spec, though.<p>While Paul was at Microsoft, the specs for UUID&#x27;s finally got standardized by the IETF as RFC 4122, so you no longer needed to get find dated copies of the OSF DCE specification (or download e2fsprogs since I had an early version of the UUID Internet Draft in the sources long before it finally squirted out the other end of the RFC publication pipeline).<p>As far as uuidd is concerned, the reason why it exists is because a certain very large Enterprise Resource Planning system was using libuuid to generate uuid&#x27;s for its objects, and it needed to create them very, very quickly so they can initalize the customer&#x27;s ERP database in finite time.  They were also using the time-based UUID&#x27;s, with the UUID stored in the database with the bytes cleverly rearranged so the time bits would be stored in the LSB, and the Ethernet MAC address would be in the MSB, so that a database using a B-tree (plus prefix key compression) for its indexing would be able to very efficiently index the UUID&#x27;s.  This is similar to k-ordering trick that Flake was using, but this very large enterprise planning company was doing in 2007, five years before team at Boundary came up with Flake, and they were doing it using standard UUID&#x27;s, but simply storing the Time-based UUID bytes in a different order.  (I believe they were also simply storing the ID in binary form, instead of base-62 encoding, since if you&#x27;re going to have jillions of objects in your ERP database, you want them to be as efficient as possible.)<p>Anyway, a certain Linux distribution company contacted me on behalf of this very large Enterprise Resource Planning company, and we came up with a scheme where the uuidd daemon could issue blocks of time-based UUID&#x27;s to clients, so we could amortize the UUID generation over blocks of 50 or 100 UUID&#x27;s at a time.  (This ERP was generating a <i></i><i>huge</i><i></i> number of UUID&#x27;s.)  I did it as a freebie, because I was tickled pick that libuuid was such a critical part of a large ERP system, and it wasn&#x27;t that hard to implement the uuidd extension to libuuid.