When an inbound APPC/MVS transaction program is scheduled by the
APPC/MVS transaction scheduler, it is distinguished from other MVS
work as follows:
- Initialization
- In response to an inbound allocate request from its partner,
a transaction program is initiated through a program controlled interface,
namely the allocate callable service. If the allocate service follows
the LU 6.2 protocol, it can be issued from a program on the local
MVS and from a program in a different operating system or even in
a different network. For information about the Allocate call and other
callable services used in APPC, see z/OS MVS Programming: Writing Transaction Programs for APPC/MVS.
- Definition
- Each inbound APPC/MVS transaction program is defined by a TP
profile that is created by the installation and stored in a VSAM key
sequenced data set. The TP profile contains scheduling parameters
and a subset of JCL to define resource requirements. For information
about TP profiles, see Controlling the Execution of Transaction Programs. For information about
the subset of JCL to use, see Specific Scheduler JCL Information for TP Profiles
- Output
- APPC/MVS-scheduled TPs can use the same JES SYSOUT functions
available to other MVS applications, with the exception that SYSOUT
data sets allocated by TPs are treated as spin data sets. To guarantee
that spin data sets are processed before initiator cleanup, IBM® recommends that all SYSOUT specifications,
for both standard and multi-trans TPs, include the FREE=CLOSE parameter.
For more information about SYSOUT processing, see Specific Scheduler JCL Information for TP Profiles.
If
the installation changes the default subsystem for APPC work with
the SUBSYS parameter in an ASCHPMxx parmlib member, then JES services
may be unavailable to APPC/MVS-scheduled TPs.
- Performance
- Transaction initiators are managed based on response time goals
set for classes. Classes are defined in an ASCHPMxx parmlib member,
and a TP is assigned to a class in its TP profile. More information
about classes appears later in this chapter and in Defining Scheduling Characteristics with ASCHPMxx.
Information about how to set a response time goal appears in Defining Classes and Response Time Goals.
For information about APPC performance, see APPC/MVS Measurement and Tuning.
- Management
- System management facilities (SMF) provides records to support
transaction programs running on an z/OS system, and the Resource
Measurement Facility (RMF) reports on this work. For more information
about the support SMF provides, see Using SMF to Audit APPC Work.
- Security
- Authority to use a transaction program can be controlled by
a security product. Transaction programs can be made available as
a public resource, or can be limited to particular users or groups
of users. For more information, see Setting up Network Security.
- Problem Determination
- Transaction program processing is logged differently from work
scheduled by a job entry subsystem. Runtime execution messages are
written to a TP message log, the name of which is specified in the
TP profile. For more information about logging, see Logging Transaction Program Processing.
When APPC/MVS finds errors during
processing of inbound requests, APPC/MVS can send error log information
to a partner system or program. Error log information describes errors
that APPC/MVS finds when it tries to schedule a TP, such as problems
with logical unit (LU) definitions or problems with processing allocate
requests. Alternate transaction schedulers can also send error log
information when processing their inbound requests.
For information
about how an alternate scheduler can send error log information and
the format of the variable that is used to send that information,
see the description of the Cleanup_TP service in z/OS MVS System Messages, Vol 3 (ASB-BPX).