iTS 1.0+)

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

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SCREEN COBOL Source Program

SCREEN COBOL programs handle processing operations which control display

terminals, communicate with external processes that control intelligent devices, and

communicate with other devices or processes in a Pathway environment.

You can use the SCREEN COBOL procedural language to:

•

Define the characteristics of terminal display screens

•

Control how data is to be displayed on and accepted from a terminal screen

•

Send messages to and receive replies from intelligent devices

•

Indicate how data is to be converted and how editing checks are to be applied to data

•

Specify and send messages to server processes to access or modify data in a

database

SCREEN COBOL is available for use with:

•

The 6510, 6520, 6530, 6540, and IBM 3270 terminals

•

Those devices operating as conversational mode terminals as recognized by the

Guardian file system

•

Intelligent devices such as personal computers, point-of-sale devices, automated

teller machines, communication lines, or Guardian processes, and the 6540 terminal

operating as a personal computer

A SCREEN COBOL program is always designed as if to control a single terminal or

device. The Terminal Control Process (TCP) that interprets the object code generated

by the SCREEN COBOL compiler can, however, perform simultaneous executions of

the same code for many terminals or devices under its control.

Program Operating Modes

Generally, a SCREEN COBOL program displays formatted information, receives data

entered from a terminal, and performs some action based on the data. SCREEN

COBOL enables you to write programs that perform these operations in:

•

Block mode (full-screen accept and display operations)

•

Conversational mode (line-by-line accept operations)

•

Intelligent mode (device-independent operations)

Some of the SCREEN COBOL statements and clauses act differently depending on the

mode.