What If We Actually Did It?!

Just a fun thought I had today: generate all the GUIDs!!!

Many people have pondered the uniqueness of various ID structures we have for computing (GUIDs, UUIDs, etc). In the end, any structure that must be represented by a finite number of bits has a finite number of combinations of those bits.

That said, for the .Net Guid class, Mr. Dee has a nice/funny thread about this inherent limit.

There are 122 random bits (128 - 2 for variant - 4 for version) so this calculates to 2¹²² or 5,316,911,983,139,663,491,615,228,241,121,400,000 possible combinations.

Perhaps a StackOverflow answer can help to put this in perspective:

And since there are about 7×10²² stars in the universe, and just under 2¹²⁸ GUIDs, then there are approximately 4.86×10¹⁵ — almost five quadrillion — GUIDs for every single star.

Knowing this, I’ve concluded that it’s our responsibility as computer scientists to generate every single GUID at some point in our collective lifetimes. To that end, I’ve started writing my unit tests so that they generate new GUIDs with each test. The more, the better! Whenever I need a random identifier, I use a GUID. Whenever I need a random string, I use a GUID.

With your help, I believe that we can achieve this goal.