gtps2m1aACF/SNA Data Communications Reference

TPF/APPC Work Blocks

TPF/APPC also uses the following work blocks:

TPF/APPC Work Block

The TPF/APPC work block is a working storage block attached to data level 15 (DF) of an ECB that issued a TPF/APPC verb request. If there is a block attached to a data level required by the TPF/APPC support code, the system detaches the block from the ECB with the DETAC macro and then reattaches it with the ATTAC macro when the data level is no longer needed by the support code.

The work block is used to:

The work block is created by the TPF/APPC support programs and released before returning control to the verb requester.

TPF/APPC Change Number of Sessions Work Block

The TPF/APPC change number of sessions (CNOS) work block is a working storage block attached to data level 5 of an ECB that issued a CNOS verb request.

The CNOS work block is used to:

The CNOS work block is created by the CNOS support programs and released before returning control to the verb requester.

TPF/APPC Partner Work Block

The TPF/APPC partner work block is a working storage block used for the TPF/APPC mapped conversation support. The partner work block is used to store information from the side information table between the time a conversation is initialized and actually allocated. (See Mapped Conversations for a definition and explanation of the side information table.) Once the conversation is allocated, the block is released and the conversation gets the information from the LU. The information that is stored in the partner work block includes:

TPF/APPC Half-Session to Presentation Services Record

The TPF/APPC half-session to presentation services records (HPR) are 4K short-term file pool records used to buffer input messages. The TPF/APPC support package receives incoming messages from the communications source program in AM0SG format. These messages are then put on an inbound queue in HPR records. For more information about queuing, see Inbound Message Queuing.