HP UX 11i v1 I/O Cards manual Physical Terminal Tables

ZCOM Tables and Data Structures

Physical Terminal Tables

PTTXLX - Pointer to next PTT on the express list linkage

This linkage (containing the physical terminal table address) is used to link together physical terminals on the Mux which have messages queued on the express transmit queue. This field is NULL if the terminal is not on the list. It is initialized to NULL by TTGEN and is maintained by the LDM and DAM.

PTTXQX - Express transmit buffer queue

This queue contains the express transmit requests waiting to be sent. It also contains the terminal configuration (zcntl) requests. When a message has been transferred to the card, the buffers are moved to the unacknowledged transmit buffer queue. Once the buffer has been acknowledged as sent or flushed by the card it is removed from the unacknowledged queue and returned to the sending program (if requested by the program).

The express transmit queue is designed for passing critical control (protocol dependent) data to the terminal. In general, none of the normal queue limit mechanisms apply to requests on this queue. Normal user data should NEVER be placed on this queue. An example of appropriate requests would be an X.25 Reset request or X.25 Expedited data. Requests on this queue are always processed first, regardless of any transmit limits that may have been reached.

PTTXLA - Pointer to next PTT on the high priority list linkage

This linkage (containing the physical terminal table address) is used to link together physical terminals on the Mux which have messages queued on their high priority transmit queue. This field is NULL if the terminal is not on the list. It is initialized to NULL by TTGEN and is maintained by the LDM and DAM.

PTTXQA - High priority transmit buffer queue

This queue contains the high priority transmit requests waiting to be sent. It also contains the terminal configuration (zcntl) requests. The data on this queue is processed only after all express transmit data has been processed. When a message has been transferred to the card, the buffers are moved to the unacknowledged transmit buffer queue. Once the buffer has been acknowledged as sent or flushed by the card it is removed from the unacknowledged queue and returned to the sending program (if requested by the program). Note that requests on this queue are subject to the unacknowledged and port transmit limits.

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