Check the Migration Guide and the VOS 15.0.0 SRB for updated information.
 

Preface

The Purpose of This Manual

VOS Communications Software: Synchronous Data Link Control (R043) documents the Stratus Synchronous Data Link Control (SDLC) protocol support.

Audience

This manual is intended for programmers using SDLC as the link-level communications protocol for their applications programs.

Before working with VOS Communications Software: Synchronous Data Link Control (R043), you should be familiar with the following Stratus manuals.

VOS Communications Software: Introduction 

VOS Subroutines Manuals

You can find specific information on SDLC in the following IBM documents.

IBM Synchronous Data Link Control General Information (GA27-3093)

Systems Network Architecture Technical Overview (GA30-3073)

Introduction to APPC (GG24-1584)

Revision Information

This is Revision 1 of VOS Communications Software: Synchronous Data Link Control (R043). It documents the SDLC software available with VOS Release 6.0.

This manual uses change bars at the left margin to indicate revisions.

  • A single bar indicates that information has been added or changed to describe new software or hardware functioning or to provide additional information about existing functioning.
  • Double bars indicate information that corrects an error that occurred in the preceding version of this manual.

If a revision is extensive, however, that revision is noted here in the manual's introduction and is not marked by change bars in the text.

In Chapter 1, a description of negotiable SDLC has been added.

In Chapter 3, the following opcodes have been added. 

toggle_xid_send_rcv_opcode (1413)
clear_xid_info_opcode (1414)
reconfig_addr_list_opcode (1415)

Also in Chapter 3, minor technical corrections and additions have been made to the following information structures. 

read_line_status_info
read_set_poll_list_info
set_xid_info
read_link_status_info

In addition, the following information has been added in appendixes.

  • complete declarations in C and PL/I (Appendixes B and F, respectively)
  • a description of error messages (Appendix G)
  • role negotiation examples (Appendix H)
  • examples of the output from the analyze_system requests dump_sdlc and monotor_sdlc (Appendix I)

Manual Organization

This manual contains five sections, nine appendixes and a glossary.

  • Chapter 1, "Overview of SDLC Programming Support," describes the VOS implementation of SDLC. It briefly describes the SDLC protocol, VOS support for SDLC, and programming considerations and configuration requirements for using SDLC under VOS.
  • Chapter 2, "Setup and Initialization Procedures," describes the procedures and VOS subroutines used to set up and initialize a VOS port for SDLC communications.
  • Chapter 3, "Control Operations," documents the control operations available to SDLC applications. It presents the s$control subroutine and the opcodes used with s$control to request control functions.
  • Chapter 4, "Input/Output Operations," describes the VOS I/O subroutines used to send and receive data on the SDLC line.
  • Chapter 5, "Clearing Procedures," presents the operations and VOS subroutines used to clear an SDLC channel and detach the VOS port from the application.
  • Appendixes A through F show the declarations of subroutines in VOS BASIC, VOS C, VOS COBOL, VOS FORTRAN, VOS Pascal, and VOS PL/I, respectively.
  • Appendix G lists the error messages that can be returned for each subroutine with a description of the cause, effect, and corrective action for each.
  • Appendix H presents some script examples of SDLC role negotiation.
  • Appendix I demonstrates the output of the analyze_system commands dump_sdlc and monitor_sdlc.

Notation

Stratus documentation uses computer font to represent text that would appear on your CRT screen or on a line printer. (Such text is referred to as literal text.) For example: 

call s$clear_device( port_id, error_code);

Slanted font is used to represent general terms that are to be replaced by literal values. In the following example, the term n shows that the user must supply an actual value for the length of buffer.

declare buffer char(n);

Italics are used for new terms when they are introduced and defined. For example:

SDLC data is transmitted in a special format called a frame.

Boldface is used to emphasize words within the text. For example:

Note: On a half-duplex communications line, the correct baud rate must be specified, even if a modem is supplying the clock.

Documentation Format for Subroutines

Stratus manuals use a standard format for documenting subroutines.

subroutine_name
The name of the subroutine is at the top of the first page of the subroutine description.

Purpose
Explains briefly what the subroutine does.

Usage
Shows how to declare the variables passed as arguments to the subroutine, declare the subroutine entry in a program, and call the subroutine.

Arguments
Describes the subroutine's arguments.

Explanation
Provides information about how to use the subroutine. (Not every subroutine description requires an Explanation section.)

Related Manuals

Refer to the following Stratus manuals for related documentation.

VOS Communications Software: Introduction 

VOS System Administrator's Guide (R012)

VOS Subroutines Manuals

VOS PL/I Subroutines Manual 

VOS BASIC Subroutines Manual (R018)

VOS COBOL Subroutines Manual 

VOS FORTRAN Subroutines Manual 

VOS Pascal Subroutines Manual 

VOS C Subroutines Manual 

A Note on the Contents of Stratus Manuals

Stratus manuals document all the subroutines and commands of the user interface. Any other commands and subroutines contained in VOS are intended solely for use by Stratus personnel and are subject to change without warning.

How to Comment on This Manual

You can comment on this manual by using the command comment_on_manual, described in the VOS System Administrator's Guide (R012). Type comment_on_manual, press , and then complete the form that appears on your screen. You must fill in this manual's part number, VOS System Administrator's Guide (R012). When you have completed the form, press . Your comments are sent to Stratus over the Remote Service Network. Note that VOS includes your name with your comments.

Stratus welcomes any corrections and suggestions for improving this manual.