Access types

The starting point for designing the JRIO interfaces is an abstract view of the type and manner of data access (of the sort that is also taken as a basis in the IBM implementation) which is independent of file systems and access methods.

From the viewpoint of the application, the type and manner of data access can then be classified in the following access types:

• Sequential access

  Read access to records/pages takes place sequentially. Write access extends the file at the end.

• Random access

  In a file processed using this access type any individual records be positioned to before reading or writing.

• Keyed access

  In a file processed using this access type, individual records can be selected for reading and/or writing by specifying keys.