Pathway/iTS TCP and Terminal Programming Guide

Managing Transactions With the TMF Subsystem
Compaq NonStop™ Pathway/iTS TCP and Terminal Programming Guide—426751-001
5-11
Timeouts on SEND Operations to Servers
In a PATHMON environment that normally runs with the TMF subsystem, do not use
the following commands to turn off TMF subsystem operations temporarily:
SET SERVER TMF ON
SET TERM TMF OFF
SET PROGRAM TMF OFF
The condition resulting from these commands appears to allow normal operation
because the BEGIN-TRANSACTION statement that would have failed if the TMF
subsystem were stopped now appears to work; the TCP allows a SEND operation to a
server that can access and update only nonaudited files. Files updated by servers are not
protected by the TMF subsystem, and the TCP does not perform checkpoints before or
after SEND statements.
Timeouts on SEND Operations to Servers
Although the syntax of the SCREEN COBOL SEND statement does not include a
TIMEOUT clause, you can effectively supply one with the PATHCOM SET SERVER
command. When you include a TIMEOUT clause in the SET SERVER command, all
SENDs to that server class are timed by the TCP. If the specified number of seconds
elapses after a SEND operation is initiated and before a reply is received, the TCP issues
a Guardian CANCEL procedure call against the outstanding I/O to the server. If the
SEND operation was performed while the requester program was in transaction mode,
SET SERVER
SET TERM
SET PROGRAM
TMF OFF
TMF ON
TMF ON
SEND error 13
3
SEND statement executes
5
SET SERVER
SET TERM
SET PROGRAM
TMF OFF
TMF OFF
TMF OFF
SEND error 13
3
SEND statement executes
5
LEGEND
Transaction Mode. The SEND statement is executed after the SCREEN COBOL program has issued a
BEGIN-TRANSACTION statement, but before the program has issued an END-TRANSACTION or an
ABORT-TRANSACTION statement. Note that a program is considered to be in transaction mode if it
executes a BEGIN-TRANSACTION statement even if the TMF parameter is set to OFF for the terminal or
program.
Note 1. These are PATHCOM command parameter settings for normal TMF and Pathway operations; SET
SERVER TMF ON must be set within PATHCOM or SPI.
Note 2. Although no transaction identifier was present, Pathway/iTS has allowed the SEND operation. If the
server attempts a file lock or update operation on an audited file, Guardian file-system error 75 is returned to
the server. How this information is returned by the server to the SCREEN COBOL requester is application
dependent.
Note 3. TMF mode violation: the error is returned in the SCREEN COBOL TERMINATION-STATUS special
register.
Note 4. These are PATHCOM command parameter settings for special program testing. These settings provide
a convenient way to partially test or debug a SCREEN COBOL program on a system that does not yet have
the TMF subsystem configured. The program will execute, but all SEND requests to audited files will
receive Guardian file-system error 75 replies.
Note 5. These are PATHCOM command parameter settings for normal Pathway operations without the TMF
subsystem.
Table 5-1. SEND Operations With the TMF Subsystem (page 2 of 2)
PATHCOM Commands Audited Files