Pathmaker Programming Guide

Modifying a Server Skeleton or Service Skeleton
Advanced Pathmaker Programming Topics
9–38 067868 Tandem Computers Incorporated
Changing the Maximum
Number of Requesting
Processes
In Pathmaker applications, the system file named $RECEIVE is the communication
mechanism between a requester process and a server process. Both the COBOL server
skeleton and the C server include code to define two tables used by $RECEIVE to list
the requesting processes and the replies sent to the requesting processes. In a COBOL
server, a RECEIVE-CONTROL paragraph defines two tables for this purpose; the
Receive-Control table and the Reply table. In the C server, an equivalent declaration is
provided.
Receive-Control table Records the requesting processes that open a server process.
(MAXREQUESTERS)
Reply table Records the replies sent to the requesting process; the Reply
table is not used when the Transaction Monitoring Facility
(TMF) is used by the server class.
Within Pathmaker applications, the default sizes of these two tables depend on
whether any of the services in the server are using TMF.
If any service in the server uses TMF to protect its transaction, the Pathmaker product
generates code to allocate a Receive-Control table that occurs 50 times. If any service
uses TMF, the Pathmaker product sets TMF ON in the generated Pathway
configuration for a service class that contains any service with TMF ON. The
corresponding server does not need a reply table because the TCP will not perform
checkpoint operations on it. Refer to the Pathway System Management Guide for more
information.
The Pathmaker product sets TMF OFF in the generated Pathway configuration for a
service class that contains no services with TMF ON. In this case, the corresponding
server needs a Reply table, because the TCP will be running in normal checkpointing
mode. The Pathmaker product generates code to allocate a smaller Receive control
table, one that occurs 5 times, and generates code to allocate a Reply table.
The most important effect these two default table sizes have is upon the MAXLINKS
parameter in the Pathway configuration of this application. The MAXLINKS
parameter in the SET SERVER command is the maximum number of concurrent links
permitted between all requesters and a server in this server class. MAXLINKS must be
less than or equal to the size of the Receive-Control table as follows:
If TMF is used for any service in the server, MAXLINKS must be less than or equal
to 50.
If TMF is not used for any service in the server, MAXLINKS must be less than or
equal to 5.
Note You will probably never have to change the default values that the Pathmaker product establishes for
these two tables.