An object is an entity which contains data or other objects. This is the basis of the hierarchical nature of HDS and is analogous to the concepts of file and directory . The primary way of identifying an HDS object is by its name , which must be unique within its own container object. The maximum length of an HDS name is 15 characters. Structure Primitive Structure objects contain other objects called components .
Primitive objects contain only numeric, character, or logical values.
Structures are analogous to the directories in a filing system and primitives are analogous to files. Different object names can be joined together to form a complete specification of a data object. This is done by appending a slice specification to the end of the object name. The slice specification is enclosed in parentheses and ranges of a given subscript are indicated by two integers separated by a colon. If no colons are present then a single cell or element of the object is refered to.