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The autoinstall control program for APPC connections
The purpose of the autoinstall control program is to provide CICS with any extra
information it needs to complete an autoinstall request. For APPC connections, the
control program selects the template to be used, and provides a name for the new
connection.
If autoinstall is enabled, when CICS receives an APPC BIND request for an
SNASVCMG session (or for the only session of a single-session connection), if
there is no matching CONNECTION definition, CICS passes the partner’s VTAM
NETNAME to the autoinstall control program. The control program uses information
from the BIND, which is passed in the communications area, to select the most
appropriate template on which to base a new connection.
The control program needs to know the NETNAME or SYSID of all the templates, in
order to return the name of the most suitable one. If it attempts to use an unsuitable
template, message DFHZC6922 is issued, explaining why the template is unusable.
If the template is usable, CICS makes a copy of the definitions within it and
attempts to install the new CONNECTION definition. If the installation is not
successful, message DFHZC6903 is issued.
Recovery and restart
Autoinstalled connections are not cataloged by CICS, so they are not recovered at
an emergency restart or a warm restart.
The autoinstall control program at INSTALL
The autoinstall control program is invoked at INSTALL for:
v Local VTAM terminals
v MVS consoles
v Local APPC single-session connections initiated by a CINIT
v Local APPC parallel-session connections initiated by a BIND
v Local APPC single-session connections initiated by a BIND
v Shipped terminals and connections
v Client virtual terminals.
On each invocation, CICS passes a parameter list to the control program by means
of a communication area addressed by DFHEICAP. The parameter list passed at
INSTALL of local terminals and APPC single-session connections initiated by CINIT
is described in “The communication area at INSTALL for terminals” on page 518.
The parameter list passed at INSTALL of MVS consoles is described in “The
autoinstall control program at INSTALL” on page 536. The parameter list passed at
INSTALL of shipped terminals and connections is described in “The communications
area at INSTALL for shipped terminals” on page 562. The parameter list passed at
INSTALL of Client virtual terminals is described in “The communications area at
INSTALL for Client virtual terminals” on page 571. This section describes only
INSTALL of local APPC connections initiated by BIND requests.
The communication area at INSTALL for APPC connections
The communications area is mapped by the DSECT for the assembler version of
DFHZATDY, which is supplied in CICSTS32.CICS.SDFHMAC.
Chapter 12. Writing a program to control autoinstall of APPC connections 545