Accessing programs that do not use MFS

The two input edit choices for existing application programs that do not use MFS are ISC edit and basic edit.

ISC Edit is the default edit process for ISC input to IMS. An existing application program expects the transaction code to be at the start of the input message and to be followed by a blank. When this is true, the sending subsystem should ensure that the transaction code is placed at the start of the data stream, followed by a blank. Password security is for statically defined terminals only and can only be invoked by placing the password after the transaction code in the data stream and ensuring that the SNA-defined PRN in the FM header is not present. When ISC Edit is used, the input data stream sent to IMS should match the application program's I/O area exactly.

Basic edit for ISC input provides standard editing as if the input comes from a terminal. It is used to edit device and operator control characters. The sending subsystem could simply pass through to IMS a data stream from a device that would normally use basic edit if it were attached directly to IMS. In this situation, IMS's ISC basic edit support eliminates application-provided editing in the sending subsystem. Basic edit is selected by the sending subsystem when it places the characters 'BASICEDT' in the DPN field of the FM header.