CONNECTIVITY Cut the cord. Right now. Unfortunately, simply buying wireless data devices is the least of the problems, especially on packet networks. Actually getting applications to execute over wireless communications links leads to dozens of developmental barriers. Hardware, software even airtime service providers deliver some application assistance with their products, but the range of offerings, while clearly related, is far from uniform and is never enough. .urther, the terminology is often blurred. One company s toolkit is another s middleware or operating environment or platform. Packet systems are the least uniform and most complex | The Wireless Data Haadbaak Fourth Edition. James F. DeRose Copyright 1999 John Wiley Sons Inc. ISBNs 0-471-31651-2 Hardback 0-471-22458-8 Electronic 17 CONNECTIVITY INTRODUCTION Cut the cord. Right now. Unfortunately simply buying wireless data devices is the least of the problems especially on packet networks. Actually getting applications to execute over wireless communications links leads to dozens of developmental barriers. Hardware software even airtime service providers deliver some application assistance with their products but the range of offerings while clearly related is far from uniform and is never enough. Further the terminology is often blurred. One company s toolkit is another s middleware or operating environment or platform. Packet systems are the least uniform and most complex. Examples of the enormous range of products follow in increasing degrees of complexity beginning with the client modem and working through servers and gateways to the host application. DEFINING THE PROBLEM Origins In 1982 IBM began to convert its existing field service application programs to operate over its private DCS system. The software changes were deep and insidious. At the host system programmers were forced to stay one level behind the current virtual telecommunications access method VTAM release. The addressing structure for 32 000 mobile devices the initial design was unlike anything that had yet been 279 280 CONNECTIVITY seen a variation of IBM s System Network Architecture s SNA s LU-0 was used. This was nonstandard and very primitive. New error alert conditions had to be accommodated. Notification codes for base station problems had to be developed and inserted in the network management software. When repair personnel were dispatched to a base station site sometimes on a mountain top the system had to respond to the cabinet doors being opened a sign that the repair person had likely arrived. Application development in both client device and .
