gtpd2m1wData Communications Services Reference

Description

Purpose

The purpose of the mapping support package is to construct and format application to application, application to terminal, and terminal to application data streams. Input messages originating with field oriented terminals (e.g., 3277 display station) consist of device dependent control characters and text. This package deletes the former and arranges the latter in a symbolically addressable manner for the requesting user program. Similarly, output data streams created by user application programs are comprised solely of text. This package inserts into this data stream the appropriate special device control characters required to display the information on field oriented terminals (e.g., 3270 CRTs) or to print the formatted information on hard copy devices (1980-24, 3284, 3286, 3287, 1977).

Functions

Component Programs

Map File Create And Load Program
This program, utilizing user created formats and field definitions, generates the Terminal Map Record files in an offline mode. These files, which consist of references to records that are to be deleted, replaced, and added, are then processed for loading onto the online files.

Input/Output Mapping Program
This program, which is activated by user request, maps or formats application to application, terminal to application, and application to terminal data streams. When mapping terminal to application or application to application data streams, this program deletes device dependent control characters from the input and places the remaining data in a formatted message block corresponding to a DSECT which has been assembled into the user program. To perform this function, this program references information contained in the Terminal Map Record. The mapping of input data streams is available to field oriented terminals; currently this includes the 3277 Display Stations, Models 1 and 2.

When mapping application to terminal and application to application data streams, 03-ASF inserts device dependent special control characters into the user created text. The Terminal Map Record which defines the format of the message and field position and characteristics, is referenced to provide the necessary information to create the updated data stream. The output mapping facility is available for formatting 3270 display stations and printers, and the 1977, 1980-21, and 1980-24 hard copy terminals.

Multiple Screen Control Program
The first function of this program is to segment long messages that are to be displayed on a 3270 CRT into screen size elements or pages. The information defining the start of each page (AMSG file address and displacement) is stored in a Page/Scroll Control Record (AS5MB). Upon terminal operator request, this program determines the specific line number or page to be displayed from the definition in the MSS Record and constructs the appropriate screen size display for the terminal.

The second function of this program is to assemble input message blocks containing fields which have been modified by terminal operator action; these fields are components of a multiple page display at a CRT terminal. As the terminal operator completes data entry for each page or panel, 03-ASC files the input message and stores the prime file address in the MSS. When the terminal operator has completed multiple screen input activity, this program will assemble the chain of input blocks for mapping.

Associated Programs

Other Components of This Package

The generation of physical map records on file and symbolic reference modules (DSECTS) in assembled programs is dependent upon an input source of parameterized macro statements. The user defines and names fields and the characteristics associated with each format. These source statements are then catalogued under unique format or map names in a Map Source Statement Library; this library provides the input to the offline element of the Map File Create And Load Program (03-ASL) and the MVS Assembler.

DPANL
Terminal Panel Display Macro

This macro provides the capability for the user to identify various displays or reports by assigning unique map names and map sequence numbers to each of the formats. In addition, the user defines overall characteristics (terminal type, message block size, mode, upper case conversion for input data, etc.) for each of the formats.

DDATA
Terminal Data Field Display Macro

This macro provides the capability for the user to assign symbolic names to individual fields and define those fields with various characteristics (length, 3270 attributes, constant text). The former allows the user program to symbolically address individual fields in a DSECT; the latter allows the user to vary the delineation of fields within a format.