DECnet-20 Users Guide Dec82

This document, the DECnet-20 User's Guide (AA-J679A-TM), published in December 1982, provides comprehensive information for using and programming DECnet-20 (version 3) in conjunction with the TOPS-20 operating system on DECSYSTEM-2040S/2060 computers. Its primary purpose is to outline how DECSYSTEM-20 computers can interface with DIGITAL's corporate network, DECnet.

The manual is structured into three main parts, catering to different user types:

1. Part I: Introduction provides an overview of DECnet-20's structure, capabilities, and fundamental network concepts. This includes explanations of physical and logical links, network job file numbers (JFNs), task and node identification, and the various network facilities available.
2. Part II: Programmer's Guide details how MACRO programmers can interface with DECnet-20. It covers the essential programming facilities for:
   • Establishing Network Connections: Obtaining and opening network JFNs for target and source tasks.
   • Managing Network Interrupts: Enabling software interrupt channels for various network events.
   • Retrieving Link Information: Accessing data from the link data base, such as link status, host name, task name, user identification, password, account strings, optional data, object type, object-descriptor, and segment size.
   • Accepting or Rejecting Connections: Programmatically controlling network connection requests.
   • Transferring Information: Sending and receiving data (in logical message or byte stream formats) and high-priority interrupt messages over network links.
   • Closing Network Connections: Procedures for normal and aborted disconnections.
3. Part III: Terminal User's Guide describes network utilities and EXEC commands available to non-privileged terminal users. This includes:
   • TOPS-20 DECnet-20 EXEC Commands: Information commands to list accessible DECnet nodes and job status, and commands to set output locations and use destination-node switches.
   • Network File Transfer (NFT): A utility for accessing, deleting, copying, listing directories, printing, submitting, taking, and typing files on remote DECnet hosts, with detailed explanations of file access information and processing modes.
   • SETHOST (Remote Login Capability): Information and examples on logging into remote TOPS-20 hosts in a DECnet network, including controlling scrolling and handling disconnections.

The document also includes appendices listing disconnect/reject codes, DECnet object types, and a comprehensive glossary of terms. It emphasizes that application programmers and system managers/programmers should read the entire manual, while terminal users can focus on Part III.