DECnet-DOS Programmers Reference Manual Apr86

This "DECnet-DOS Programmer's Reference Manual," published in April 1986, is intended for application developers creating programs for Digital Equipment Corporation's DECnet networking software running on MS-DOS and PC DOS systems (versions 2.10, 2.11, and 3.10), including the DECnet-Rainbow V1.1 and DECnet-DOS V1.1 software versions.

The manual details the design considerations and specific programming calls necessary to develop DECnet-DOS applications, enabling personal computers (IBM PC/XT, AT, and Rainbow 100) to function as DECnet Phase IV end nodes within a network.

It outlines two main forms of task-to-task communication:

1. Transparent Communication: This simpler method allows programs to use standard MS-DOS I/O system calls (such as open, read, write, and close) for basic network operations, including remote file access and inter-task data exchange.
2. Nontransparent Communication: This provides a more comprehensive interface for advanced network programming, allowing access to features like optional user data and out-of-band messages. It is supported through:
   • C Language Socket Interface Calls: A set of functions for client and server tasks to establish logical links, send, and receive data. These calls aim for compatibility with DECnet-ULTRIX systems.
   • Assembly Language Network Process Interface Calls: A lower-level interface that directly interacts with the DECnet network process using I/O Control Blocks (IOCBs).

The document also covers key concepts such as client and server tasks, sockets (addressable communication endpoints), and blocking/nonblocking I/O operations. It describes utility functions for accessing network node databases, handling errors, and provides programming examples to illustrate the use of the various interfaces.