AMS: area message service for SLC

Abstract

The Area Message Service (AMS) is a TCP/IP based messaging service currently in use at SLAC. A number of projects under development here at SLAC require an application level interface to the 4.3BSD UNIX socket level communications functions using TCP/IP over ethernet. AMS provides connection management, solicited message transfer, unsolicited message transfer, and asynchronous notification of pending messages. AMS is written completely in ANSI 'C' and is currently portable over three hardware/operating system/network manager platforms, VAX/VMS/sup 1Multinet/sup 2/, PC/MS-DOS/sup 3Pathworks/sup 4/, VME 68K/pSOS/pNA/sup 5/. The basic architecture is a client-server connection where either end of the interface may be the server. This allows for connections and data flow to be initiated from either end of the interface. Included are details concerning the connection management, the handling of the multi-platform code, and the implementation process.<>