Appendix 2.A Prior Art
2.A.1 MS-DTYP #
The GUID type defined in this document derives from the Microsoft Data Types specification (MS-DTYP), §2.3.4. The Peios GUID binary format is identical to the MS-DTYP GUID. The Peios GUID string format follows the same hyphenated hex convention but normalises to lowercase hex digits on output, where Microsoft implementations typically produce uppercase.
2.A.2 RFC 4122 #
RFC 4122 ("A Universally Unique IDentifier (UUID) URN Namespace") defines the UUID format and generation algorithms. The GUID binary layout used by Microsoft and adopted by Peios is the mixed-endian variant of the RFC 4122 UUID: the first three fields are little-endian integers and the last field is a raw byte array. This differs from the RFC 4122 network byte order representation where all fields are big-endian.
Peios generates version 4 (random) GUIDs as defined in RFC 4122 §4.4.
2.A.3 DCE RPC #
The GUID structure originates from the DCE 1.1 RPC specification,
which defined the uuid_t type with the same field layout. The
mixed-endian encoding reflects the DCE convention of encoding integer
fields in the sender's native byte order (little-endian on x86).