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SNA 3270 Program Access

ND 210953

flowchart LR
    A(IBM host) --> B(ND-100 with PIOC)
    A --> C(ND-100)
    B --> D(SNA Gateway [SCL])
    C --> E(COSMOS Connection [DSA or WM-NU])
    D --> |LU type 2| F(ND SNA 3270<br>Program Access)
    D --> |LU type 1, 2, 3| G(ND SNA 3270<br>Term. Emulator)
    E --> |LU type 1| H(ND SNA RJE<br>Remote Job Entry)
    H --> |Job Output| I([Job Input (queue)])
      ND
Norsk Data

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SNA 3270 PROGRAM ACCESS

INTRODUCTION

The SNA 3270 Program Access enables an application on an ND computer to log on to an IBM mainframe application (IMS, CICS, TSO), and to read and update a central database.

The SNA gateway software runs in a separate processor (PIOC). This offloads much of the communication protocol handling from the ND-100 processor. Another advantage is that SNA 3270 Program Access works over the ND COSMOS network system. This cooperation with COSMOS allows distribution of SNA 3270 Program Access to several CPUs, while only one computer is connected to the IBM mainframe.

FEATURES

  • ND to IBM Program-to-Program communication
  • Starts a session with the host application as a 3270 Terminal
  • Separate communication processor (PIOC)
  • SNA Gateway to host (SDLC)
  • Connection to IBM 370, 30XX, 43XX, 8XXX computers
  • Simultaneous use of other ND SNA products on the same line to the host
  • Support through the COSMOS network to the ND SNA Gateway computer
  • Multiple Program-to-Program sessions simultaneously

PRODUCT DESCRIPTION

The ND SNA 3270 Program Access is a library of subroutines that can be used in local ND programs for communication with IBM programs. SNA 3270 Program Access is developed from the SNA 3270 Terminal Emulator, and many service routines are common to both programs.

The communication between the local ND program and the IBM program is logically divided into three phases:

  • Logging on
  • Dialogue
  • Logging off

A Script file is used when logging on and off. This file contains the interactions that are to be performed. The advantage with this facility is that it makes application programming easier and simplifies application maintenance.

In the dialogue sequence, the local application may call the subroutines supplied for sending and receiving host application data. In addition, there are routines for reading and writing data into the screen buffer. Each field may be addressed as a buffer with field number, or by line and column number.

It is also possible to use the Script file in the dialogue phase.

The nature of the product demands familiarity with the host application to be communicated with. Knowledge of the screen formats as well as their sequence is a necessity. ND therefore recommends that the ND SNA 3270 Terminal Emulator be used when the format of the Script file is defined.

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SNA 3270 Program Access

The ND SNA Gateway software and hardware are required, and contain the communication part (SDLC protocol emulation) and the interactive part. To offload the main computer, these parts run in a separate processor (PIOC).

ND SNA 3270 Program Access emulates IBM's PU type 2, and LU type 2.

Abbreviations

Abbreviation Meaning
CICS Customer Information Control System
IMS Information Management System
TSO Time Sharing Option
SNA System Network Architecture
SDLC Synchronous Data Link Control
PU Physical Unit
LU Logical Unit
PIOC Programmable Input Output Controller
XMSG X-Message
LAN Local Area Network.
WAN Wide Area Network.

Requirements

  • ND-100 Standard, ND-100/CX,
  • ND-110 Standard, or ND-110/CX
  • SINTRAN III VSE/VSX version i or later.
  • SNA Controller - Single line ND 108860
  • PIOC (with 512 Kb memory) ND 108670
  • SNA Gateway Software - Single line ND 210741 or
  • XMSG (SNA Program Access in Gateway computer) ND 210130 or
  • XMSG Inter System ND 210373

Documentation

SNA 3270 Program Access, Programmer Guide ........................... ND-60.104 EN
SNA Supervisor Installation and Operation Guide ..................... ND-30.054 EN