UUID = Universally Unique IDentifier, aka GUID (= Globally Unique IDentifier).
Representation
llllllll-mmmm-Mhhh-Nsss-nnnnnnnnnnnn.
Each letter encodes 4 bits.
l - time low: the low 32 bits of the time.
m - time mid: the middle 16 bits of the time.
h - time high: the high 12 bits of the time
s - (plus 1 to 3 bits of N): Clock sequence
M - indicates UUID version, the one to three most significant bits of N the UUD variant.
n - the 48 bits of the node.
Microsoft Windows
Apparently,
Microsoft chose to represent GUIDs with curly braces:
{llllllll-mmmm-Mhhh-Nsss-nnnnnnnnnnnn}, for example in the
registry.
Also, they apparently used
mixed endianness : the first three parts are little-endian and the last two parts are little-endian. The byte array
00,
11,
22, …
ff would be represented as:
33221100-5544-7766-8899-aabbccddeeff
Windows uses GUIDs heavily in the realm of
COM, for example to identify COM obects (in which case the GUID is called
CLSID).