SNAX/HLS Configuration and Control Manual

The Application Interface
Product Overview
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Verb Names SNAX/HLS makes every attempt to use verb and modifier names that are easy to
understand. Application programmers can thus avoid SNA jargon such as brackets
(uninterruptible units of work), chains (logical messages), and request shutdown
sequences (orderly termination of communication).
Table 1-1 shows SNA and SNAX/HLS terms that are similar in meaning. Each SNA
term is followed by the equivalent SNAX/HLS term and a brief definition.
Table 1-1. Correspondence Between SNA and SNAX/HLS Terms
SNA Term SNAX/HLS Term Meaning
Brackets Transactions Uninterrupted units of work.
Chains Messages Complete messages.
Request shutdown
sequences
Prepare-to-close A sequence that provides orderly termination of
traffic to prepare for session termination.
Send CDI Prepare-to-receive Declaration that sender has stopped sending text
and will now await text.
End chain End-of-message Signals the end of a message; used when
application handles message blocking.
Quiesce protocol Flow control of
messages
A way to stop sending new messages.
Self-Configuring
Characteristics
SNAX/HLS is a generic, self-configuring process that applies to a wide range of SNA
environments. SNAX/HLS examines the SNA BIND message (used to specify a
session). The BIND contains a variety of option fields that detail the specifics of a
given logical communication channel between two session partners. If the BIND is
within the range of values acceptable to SNAX/HLS, internal control blocks are
customized automatically to fit the specifics of the current session.
In providing a PROFILE, the designer exerts control over the application interface. For
example, one PROFILE option directs SNAX/HLS either to generate responses
automatically or to allow the application to do so. This and other PROFILE options
can be used to hide details by allowing SNAX/HLS to act on behalf of the application.
They can also be used to hide new features introduced in subsequent versions of
SNAX/HLS and thus ensure program compatibility.