Comment by dmlittle

1 year ago

It depend on the UUID version you're using. Version 4 (Random) will always have that value be 4 as per RFC 9562. So 99999999-9999-9999-9999-999999999999 is a valid UUID but not a valid UUID v4. If you wanted to be pedantic the website should have been named https://everyuuidv4.com/

https://datatracker.ietf.org/doc/html/rfc9562

The last line of https://xkcd.com/566/, except it's UUID formats.

  • Are you suggesting we should never have made the random one, and stuck with mac address plus timestamp forever?

    • I think object identifiers would be better, althoug they should add another arc that does not require registration, based on: (fixed prefix).(type of identifier).(number of days past epoch).(parts according to type of identifier).(optional extra parts). (I had partially written my proposal, and I would want ITU and/or ISO (preferably ITU) to approve it and then manage it.) For example, type 0 could mean international telephone numbers, type 1 could mean version 4 IP address, type 2 could mean domain names (encoding each part as bijective base 37, from right to left), 3 could mean a combination of geographic coordinates with radio frequencies, 4 could mean telephone numbers with auto-delegated telephone extensions, etc. (I had also considered such things as automatic delegation, clock drift, etc; it is more carefully considered than UUID and some other types of identifiers.)

      1 reply →