ATTACH and SCHEDULER parameters with ISC edit

The following series of figures illustrate the use of the ATTACH parameters when using ISC edit for IMS input and output messages.

ISC edit is used for normal transactions, commands, and message switches between LTERMs when one of the following occurs:
  • An ATTACH FM header is received while in a between-brackets state that does not specify a destination process name (DPN).
  • The DPN names IMS ISC edit as defined during IMS system definition.
  • No ATTACH FM header is received either when the attach manager is in the between-brackets reset state or when the active process is ISC edit.
  • The DPN=ISCEDT.
Figure 1. Example of message switch from another subsystem terminal to IMS terminal
A non-IMS subsystem uses ATTACH parameters DPN=ISCEDT, RDPN= , PRN=T2, RPRN=, and data=..., sending a message to IMS, where the ISC edit process uses data=(T2)... to output to IMS terminal.
Note: The IMS LTERM name for terminal T2 can be supplied either as the input primary resource name (PRN) or as the first field in the data.
Figure 2. Example of another subsystem accessing an IMS application program with a reply back to the subsystem terminal
Other subsystem uses DPN=ISCEDT, RDPN= , PRN=T2, RPRN= , data=... for message from Process P1 to IMS ISC edit process and TRAN1. IMS replies to Process 1 with DPN=P1, RDPN= , PRN=T1, RPRN= , and data...
Note: The IMS transaction code can be supplied either as the input PRN or within the data. The input RDPN and RPRN parameters become the DPN and PRN parameters respectively for any resulting reply from the application program when not processed by MFS.

In the following figure, messages are routed from IMS Terminal 1 to the ISC edit process through either a message switch or an MPP or Fast Path message routing application. The ISC edit process uses SCHEDULER parameters to send the message to a transaction on another subsystem. The other subsystem then sends the message back to IMS and the ISC edit process using similar SCHEDULER parameters. The ISC edit process directs the message back to Terminal 1.

Figure 3. Example of message routing with ISC edit
IMS ISC edit process uses the SCHEDULER parameters DPN=SCHEDULER, SCDDPN= , SCDRDPN=ISCEDT, SCDRPRN=T1, data=... Other subsystem uses DPN=SCHEDULER, SCDDPN=ISCEDT, SCDPRN=T1, data=...
Note: The IMS LTERM name can be supplied either as the input SCDPRN or the first data field.