Prior Art

§1.4.1 MS-DTYP #

The GUID and LUID types defined in this specification derive from the Microsoft Data Types specification (MS-DTYP), §2.3.4 (GUID) and §2.3.7 (LUID).

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.

The Peios LUID binary format diverges from MS-DTYP in one detail: HighPart is an unsigned 32-bit integer (uint32) rather than the signed 32-bit integer (LONG) used in MS-DTYP. The signed type in MS-DTYP is a Win32 API convention with no semantic purpose -- LUID values are never negative. Making the field unsigned simplifies comparison and eliminates a class of sign-extension bugs.

§1.4.2 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.

§1.4.3 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).