When ASSIGNing a COBOL-internal file name to an external file (aka: DDname), the external name is prefixed with certain strings to establish the type (class) of device and record organization. The external name is also called the system name of a file, while somefile is the COBOL-internal name.
SELECT SOMEFILE ASSIGN TO CLASS-ORGANIZATION NAME.
The device classes are:
Code Class DA Direct Access (mass storage) UR Unit Record (card reader/punch and printers) UT UTility (generally tape or PS disk)
The organisation could have the following values:
Code Organization type Valid for Classes S standard sequential DA, UR, UT D direct access DA R relative access DA I ISAM (Indexed Sequential Access Method) DA
- Cobol Select and Assign, Turnkey-MVS Group archive