Fast Path output messages (SLU P)

When defined with the system definition TERMINAL macro option statement FPACK or an ETO logon descriptor, Fast Path output messages are sent requesting an exception DR2 response when certain events occur.

Fast Path output messages request an exception DR2 response when any of the following occurs:
  • Queued output messages are available to be sent to a component defined for the workstation as PROGRAM1.
  • The system definition TERMINAL macro option BID or an ETO logon descriptor option BID is defined, and queued output is available to be sent to a component defined for the workstation as PROGRAM2.
  • The system definition TERMINAL macro option NOBID or an ETO logon descriptor option NOBID is defined, and queued output messages are available to be sent to a program. This component is not output protected due to a previous output or this Fast Path message. (That is, multiple components might be protected or reset selectively as defined in this topic.)

Unlike non-Fast Path output, the output message remains outstanding (not dequeued) and the terminal remains in response mode until the terminal sends data, a ready-to-receive (RTR) command, or the DR2 response to cause the message to be dequeued. The RTR command should be considered when no input is to be generated for an abnormally long time (for example, when the terminal operator plans to leave the terminal). The input message from the terminal, the RTR command, or the DR2 response acknowledges that the preceding output has been received and is recoverable; therefore, IMS might dequeue the output message, process any input message, or send any available output.

The system definition TERMINAL macro option NFPACK or an ETO logon descriptor indicates that the Fast Path output exception DR2 and next input acknowledgment protocol should not be used. In this case, Fast Path output messages are always sent requesting standard recoverable output message response protocols (DR2 response).

When the DR2 response is received, IMS dequeues the output message, removes the terminal from response mode, and sends any available queued output for PROGRAM1 components or non-output protected PROGRAM2 components defined for the workstation. Output protection is set at the component level during output for PROGRAM2 components and can be selectively reset for one or more components based on subsequent input.

Also use the NFPACK option for all 4730 terminals. This allows any asynchronous output messages to be sent immediately following the acknowledgment of the Fast Path output reply.