TS/MP Pathsend and Server Programming Manual (G06.24+, H06.03+)

Introduction to Pathway Application Programming
NonStop TS/MP Pathsend and Server Programming Manual–132500
1-7
Pathway Applications
Scalability
Your organization must be able to expand its transaction processing system as its
operations evolve and its technical requirements change. Tandem NonStop systems are
expressly designed to support incremental, modular expansion, allowing you to increase
the size and processing power of your transaction processing system by:
•
Adding hardware and application resources to your existing system
•
Linking individual Pathway applications into a single network or adding more
Pathway applications to an existing network
•
Supporting an open systems architecture in which standards-based networks as well
as devices and systems from other vendors can be connected to your Tandem system
Distributed Processing
Data communications technology allows organizations to extend their online operations
over long distances to form global networks and to support distributed processing. The
Pathway environment, in conjunction with the Tandem NonStop Kernel operating
system, allows you to distribute application processes within a single system.
Additionally, NonStop TS/MP and NonStop TM/MP, in conjunction with the Expand
networking software, allow you to spread processes, data, and transactions across a
network of Tandem NonStop systems. The coordination of transactions among
application servers residing within an Expand network and possibly accessing different
resource managers (NonStop SQL/MP and Enscribe) is known as distributed transaction
processing (DTP).
Pathway Applications
Pathway applications consist of two types of programs: requester programs and server
programs. This design allows application logic to be distributed near the resources it
manages. For example, presentation services are located near terminal devices or
workstations; database logic resides in server programs near that database. Requesters
and servers communicate by using the Guardian file system or the message system that
is part of the Tandem NonStop Kernel.
Users interact with your application by using devices and processes controlled by your
requester programs. Often these devices are terminals through which the users enter and
retrieve transaction data. They might also, however, be intelligent devices such as
personal computers, workstations, point-of-sale devices, or automatic teller machines
(ATMs). Or, they might be Guardian processes that provide transaction input from a file
or other batch medium.
Server processes receive requests from requester processes to access a database to add,
retrieve, or modify information. Server processes process request messages and send
reply messages with the results of the work on the database.