An interactive conversation facility on CMS

Away to effect interactive communications using CMS is by means of the MSG and TELL commands. Both require, as a parameter, the address of the user to be contacted, whilst any other input character represents the text of the message. The command must be repeated for every other line of text to be sent. MSG communicates with users on the same VM/ESA system, TELL with systems on a SNA network. The communication facility realised allows an interactive "Conversation" between two users on the same VM/ESA system. This facility, based on APPC, makes use of the new functionality API (Application Programming Interfaces) of VM/ESA. As programming interfaces towards APPC/M routines, CPI-C has been used, and the code has been written in REXX.