The 5800 system stores two types of data: arbitrary object data and structured metadata records. Every metadata record is associated with exactly one data object. Every data object has at least one metadata record. A unique object identifier (OID) is returned when a metadata record is stored. The OID can later be used to retrieve the metadata record or its object data. In addition, metadata records can be retrieved by a query:
OID ↔ Metadata Record -> Object Data
The two types of metadata are system metadata and user metadata. The names and types of system metadata are predefined and cannot be overridden by the user.