SNAX/HLS Application Programming Manual

Life Cycle of a Session
Sessions
3–10 104707 Tandem Computers Incorporated
To use the character maps, specify the name of the charactermap file to SNAX/HLS at
startup using the CHARMAPFILE configuration parameter (which defaults to
$SYSTEM.SYSTEM.ZCHARMAP). ZCHARMAP is the charactermap file name for
NLS–MAPS). A default character map for the SNAX/HLS process can be specified
with the CHARMAPNAME configuration parameter, which supports the standard
ASCII–to–EBCDIC translation as its default value. You can change CHARMAPNAME
and CHARMAPFILE parameters by using the HLSCOM ALTER command (refer to
the SNAX/HLS Configuration and Control Manual for more information on SPI).
To specify translation on a session, set the TRANSLATE PROFILE attribute. You can
also specify a character map in the PROFILE using the CHARMAP attribute to
override the process default. If you do not specify the CHARMAP PROFILE attribute,
the session continues to use the current default character map for the process. (For
more information on PROFILE attributes, refer to the SNAX/HLS Configuration and
Control Manual.)
Note Characterset conversion is not available between charactersets other than Tandem standard ASCII and
EBCDIC characterset conversion. If it is performed in SNAX/HLS, do not select characterset conversion
in the Tandem SNA access method (for example, SNAX/XF). For more information, refer to t he
SNAX/XF and SNAX/CDF Device Access Methods Programming Manual.
Pipelining A session is pipelined if it can be accessed by more than one requester. To allow this,
the PROFILE attribute PIPELINE–LU–IND must be set. (For more information on
PROFILE attributes, refer to the SNAX/HLS Configuration and Control Manual.) Any
subsequent HLS–ALLOCATE or OPEN–SESSION verbs issued specifying such a
PROFILE must specify YES in the PIPELINE–LU–IND field. Failure to do so causes
the verb to be rejected with an error.
Even though pipelined sessions can be accessed by more than one requester, there is
still only one read work queue and one receive data queue for the session. These
queues are shared by the requesters. As data arrives from the session partner, or as an
event occurs that causes a data element to be queued to the receive data queue, the
data is delivered in a reply to the oldest outstanding receive type verb. Therefore, the
requesters must be equivalent and context free. Because they must be context free,
you should not use the LARGE-MESSAGE-OPTION because there is no guarantee that
the same requester will receive all the elements in the chain. It also means that you
should not use notification because there is no guarantee that the sender of the chain
will be the recipient of the RC–REQUEST–REJECT or
RC–NOTIFICATION message.