iTS 1.0+)

Introduction to SCREEN COBOL

Compaq NonStop™ Pathway/iTS SCREEN COBOL Reference Manual—426750-001

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Pathway Environment Overview

To give you an overview of the Pathway transaction processing environment, the

various components of this environment are described below, including how each

component affects SCREEN COBOL programs.

Pathway System Components

The primary components of the Pathway environment are:

•

The Pathway monitor (PATHMON) process—the central controlling process for

operations in the Pathway environment

•

PATHCOM—the command interface to the PATHMON process

•

SCREEN COBOL—the high-level language used to code requester programs that

act as intermediaries between display terminals (or external processes that control

intelligent devices) and Pathway servers

•

Terminal control process (TCP)—the process that interprets SCREEN COBOL

object code and controls the terminals running transaction processing applications

•

Requesters—programs that usually provide presentation services for terminal

devices and communicate with server processes. Requesters may be tasks executing

SCREEN COBOL code within a (multithreaded) terminal control process, or they

may be Pathsend processes written in TAL, C, COBOL85, or Pascal.

•

Servers—processes that perform database operations in response to messages

received from requesters and reply to those messages

•

Compaq NonStop™ Transaction Management Facility (TMF)—the data

management product that is available for use with Pathway/iTS to maintain the

consistency of the database and provide the tools for database recovery

•

Compaq Inspect—the interactive, symbolic program debugging tool that you can

use to examine and modify SCREEN COBOL programs

Figure 1-1. Operations Performed by SCREEN COBOL Programs

001CDT .CDD

DISPLAY forms

ACCEPT data

SEND message to server

Receive reply

DISPLAY data