The user transaction is unchanged, but because of the way it now executes
in the bridge environment, there are some restrictions on what it can do,
and some limitations on how it can use the bridge facility, because it is
not a real terminal.
- Abend information
- The bridge facility name is not used as the TERMID in any diagnostic
information produced as the result of an abend, except in a transaction dump.
- ASSIGN
- If the user transaction issues ASSIGN NETNAME, the value returned is
the NETNAME if there is one, or else the TERMID. The name is not visible outside
the user transaction, and may contain '}' characters.
You can only use
ASSIGN to request information about BMS attributes such as MAPCOLUMN, MAPHEIGHT,
MAPLINE, and MAPWIDTH if an ADS descriptor is present in the mapset. See The ADS descriptor (ADSD).
- BMS requests
- The Link3270 bridge supports the following BMS commands. If other
BMS functions that require a principal facility are used, they cause the user
transaction to abend ABR3.
- RECEIVE commands
-
- RECEIVE MAP TERMINAL
- RECEIVE MAP FROM
- RECEIVE MAP MAPPINGDEV
Note:
TERMINAL is implied if neither TERMINAL nor FROM is specified.
- SEND commands
-
- SEND MAP TERMINAL
- SEND TEXT TERMINAL
- SEND TEXT NOEDIT TERMINAL
- SEND TEXT MAPPED TERMINAL
- SEND CONTROL TERMINAL
- SEND MAP SET
- SEND TEXT SET
- SEND TEXT NOEDIT SET
- SEND TEXT MAPPED SET
Notes:
- TERMINAL is implied if none of TERMINAL, SET, or PAGING is specified.
- Routing
- Routing to real terminals from a transaction running on a bridge facility
is supported, but it is not possible to route to a bridge facility, nor to
specify a bridge facility as ERRTERM on ROUTE. If ERRTERM without a name is
specified on a ROUTE request issued in a bridge environment, the INVERRTERM
condition is raised.
PAGING is supported only under routing.
- Partitions
- Partition related commands and options are supported, but are treated
in the same way as they would be for a real terminal that does not support
partitions.
- SEND PARTNSET
- Supported, but the bridge exit is not invoked.
- RECEIVE PARTN
- Supported; the bridge exit is invoked with bridge exit area command
fields set up for a terminal control RECEIVE.
- INPARTN
- Accepted but ignored; not passed to the bridge exit.
- OUTPARTN
- Accepted but ignored; not passed to the bridge exit.
- ACTPARTN
- Accepted but ignored; not passed to the bridge exit.
- CICS-supplied transactions
- CEDF, CEDX, CSFE, and CSGM cannot run as user transactions.
- DB2® authorization check
- The RCT allows AUTHTYPE=TERMID or OPID which means that security checking
is done against the corresponding name. This fails in a bridge environment,
and AUTHTYPE=USERID must be used instead. This is the preferred method in
all environments.
- External security customization
- TERMID/OPID/TCTUA information is not passed in the DFHXSID parameter
list.
- Global User Exits
- The following global user exits (GLUEs) are not driven
because the bridge facility is not a real terminal.
- XBMIN
- to intercept a RECEIVE MAP request.
- XBMOUT
- to intercept a SEND MAP request.
- XTCATT
- before a task attach.
- XZCATT
- before a task attach (VTAM®).
- XZCIN
- after an input event (VTAM).
- XZCOUT
- before an output event (VTAM).
- XZCOUT1
- before a message is broken into RUs (VTAM).
The XALTENF and XICTENF exits can be driven if a request is made for
a bridge facility. The ‘terminal-not-found’ condition is raised because
the bridge facility is not a real terminal.
The standard user exit parameter
list field UEPTERM that points to the TERMID are not set for exits invoked
under a bridge task.
- ISSUE PASS
- ISSUE PASS is not supported and results in an INVREQ.
- ISSUE PRINT
- ISSUE PRINT is not supported and results in a no-op. A NORMAL condition
is returned.
- Monitoring
- A 3270 bridge transaction identifier is present in monitoring records.
- Remote DLI requests
- No security check of the PSB against the terminal is done for function-shipped
DLI requests.
- Security Processing
- When a bridge facility is created, it is signed on as a preset USERID
terminal, with the client's USERID. As with other preset terminals, the SIGNON
and SIGNOFF commands are not permitted, and INVREQ is raised.
The bridge
facility is signed off when it is discarded. It remains signed on in session
mode until a specific delete facility request is sent, or the keeptime interval
expires.
- START
- The user transaction can issue EXEC CICS START requests for its own
bridge facility. This allows existing menu-driven and pseudo-conversational
applications that use this interface to work in a bridge environment. See Pseudoconversational transactions for a description of START TERMID where TERMID specifies
the bridge facility.
The time delay options, (INTERVAL, TIME, AFTER, AT,
HOURS, MINUTES, SECONDS) are not normally used in the bridge environment,
but the bridge mechanism uses them to put the STARTs for a particular bridge
facility in time order, but the exact delays requested are not implemented.
TIME and AT specifications are ignored completely.
Other options on
the START command are partly supported :
- TERMID
- You can specify the name of your own bridge facility for this transaction,
or for any real terminal.
- USERID
- USERID and TERMID are mutually exclusive. The CICS translator rejects START requests with
both USERID and TERMID specified.
- TRANSID
- If the TRANSID cannot be defined as REMOTE, the TERMID will not be
found if the request is shipped to a remote system.
- SYSID
- Routing of START requests is not possible in a bridge environment.
This option is not supported, unless the value of the SYSID is the local SYSID.
If you specify any other value, the request will be shipped and the TERMID
will not be found on the remote system.
- NOCHECK
- This option only applies to shipped start requests and is ignored.
- PROTECT
- If you specify the PROTECT option on a START request for a bridge facility,
and the starting task abends before taking a syncpoint, the START request
is discarded. PROTECT normally delays the starting of the new task until a
SYNCPOINT has occurred. This happens automatically for a task issuing a START
for its own facility because the START cannot take effect until the starting
task has terminated and freed up its bridge facility.
- STARTed transactions
- Some menu applications use START to initiate subsequent transactions.
You can specify BRIHSC-START in the BRIH-STARTCODE field of a single transaction
mode request message, or in the first transaction of a session mode pseudoconversation,
to return the correct response to ASSIGN STARTCODE and INQUIRE TASK STARTCODE
commands issued by the user transaction.
User transactions that are
initiated by START may issue one or more RETRIEVEs to obtain data passed on
the START. When the bridge has passed all the data provided in the Link3270 request
message, ENDDATA is returned to the user transaction.
- Statistics
- You cannot use EXEC CICS COLLECT STATISTICS TERMINAL(xxxx) where xxxx
is a bridge facility.
- Storage violation counts
- No storage violation counts will be kept in a bridge facility.
- TCTUA
- The TCTUA is available to the user transaction using the EXEC CICS ADDRESS
command. You can modify the contents of the TCTUA using the XFAINTU global
user exit. See Initializing the TCTUA. Note that the TCTUA is NOT available
to any programs in other CICS regions that are linked to by the user transaction
using DPL.
- Transaction restart
- RESTART(NO) is forced for user transactions because CICS has no way
of restoring the initial input message.
- Transaction Routing
- Transaction Routing is not directly supported, see Transaction Routing considerations for
a technique you can use.. The Link3270 bridge supports work load balancing
with an affinity.
- TWA
- The TWA is available to the user transaction.