Question

The function in COM to create a GUID (CoCreateGUID) uses a “Decentralized Uniqueness Algorithm”, but my question is, what is it?

Can anybody explain?

Answer 1

A method to generate an ID that has some guarantee to be unique without relying on any kind of coordination through a central “ID provider” (which requires a network connection and can be hard to organize). There are basically two methods for this, neither actually providing an absolute guarantee:

1. Use a reasonably unique ID for the local machine (typically its MAC address) and add a locally unique ID (e.g. timestamp + process number + autoincrementing counter).
2. Use a good random number generator with a good seed to generate the ID and make it long enough that collisions are too unlikely to matter.