GUID (Globally Unique Identifier) is a 128-bit binary number generated by an algorithm. It is primarily used in networks or systems with multiple nodes and computers. Ideally, no two computers or computer clusters should produce the same GUID. The total number of GUIDs is 2^128 (3.4×10^38), making the probability of generating two identical GUIDs randomly extremely low but not zero. The term "GUID" can also refer specifically to Microsoft's implementation of the