Pathway/iTS TCP and Terminal Programming Guide

Compaq NonStop™ Pathway/iTS TCP and Terminal Programming Guide—426751-001
5-1
5
Managing Transactions With the TMF
Subsystem
This section provides information about the Compaq Transaction Management Facility
(TMF) subsystem for SCREEN COBOL programmers. It also briefly discusses
PATHCOM and SPI parameter options for Pathway applications that use SCREEN
COBOL requesters and the TMF subsystem.
The general environment for Pathway applications that use SCREEN COBOL
requesters and the TMF subsystem is a requester/server environment where SCREEN
COBOL programs accept input from terminal operators and transform the input into
requests to servers for database services. The servers, in turn, satisfy the requests by
reading, locking, and changing (or adding or deleting) records in audited database files.
Servers can be written in C, C++, COBOL85, pTAL, TAL, FORTRAN, or Pascal, and
they must follow the record-locking rules imposed by the TMF subsystem.
To write application requesters that use the TMF subsystem, you should be familiar with
the following information, which is provided in this section:
•
The recommended structure for applications that use the TMF subsystem
•
How to use the SCREEN COBOL statements that support the TMF subsystem
For information about writing servers that use the TMF subsystem, you should refer to
the NonStop™ TS/MP Pathsend and Server Programming Manual.
In addition, you should refer to the NonStop™ TM/MP Application Programmer's
Guide for discussions of the following topics related to the TMF subsystem:
•
How to access audited database files
•
General guidelines for coding servers
•
Locking rules that must be followed by processes that change records in audited
database files
•
How to cope with transaction deadlock
•
Anomalies that can occur during transaction backout
Task Overview
Figure 5-1 illustrates the basic tasks involved in programming Pathway applications that
use SCREEN COBOL requesters and the TMF subsystem.