SURL | Storage URL | An SURL is a locator for a physical file, where the scheme specific part is understood by a Storage Resource Manager (SRM). It is a URL where the scheme is `srm' and the host is a valid SRM host. |
UUID | Universally Unique IDentifier | A UUID is a 128 bits long number, and is either guaranteed to be different from all other UUIDs generated until 3400 A.D. or extremely likely to be different (depending on the mechanism chosen to generate it). |
GUID | Grid Unique IDentifier | A UUID generated by the Replica Management System for an SURL. It is created at the SURL registration time. A GUID is immutable. |
LFN | Logical File Name | A Logical File Name is a user defined alias to a GUID. Unlike GUIDs, aliases are mutable but they still should be globally unique. Since the Replica Management System has no control over the creation of LFNs, this global uniqueness is only weakly enforced. |
TURL | Transport URL | A Transport URL is returned by a SRM in response to a request for a way to access a SURL. It includes the actual protocol you can access the SURL by. For instance, `gsiftp' for GridFTP, or `http' for HTTP access. |