Introduction to Data Management

6 Developing Applications
With PATHWAY
15873 Tandem Computers Incorporated 6-1
During the evolution of the Tandem NonStop systems, the mainstay software product
for OLTP application development, configuration, execution, and maintenance has
been the PATHWAY transaction processing system. PATHWAY furnishes the
software needed to support the requester and server modules that make up your
applications and the interprocess communication messages by which these modules
interact with one another.
PATHWAY provides screen presentation services, manages interaction between
requesters and servers, automatically creates and manages backup processes for
application fault tolerance, and manages system resources under varying workloads.
These services free you from the need to write the detailed, complex code normally
associated with such operations.
PATHWAY applications can be created either through the PATHMAKER application
generator or through PATHWAY itself. The use of PATHMAKER with PATHWAY is
recommended in most cases because it so greatly simplifies the development process.
But in some cases, you might want to use PATHWAY by itself; you would do this, for
instance, when you want to code a server in a language other than COBOL85, or when
maintaining a PATHWAY application originally developed without PATHMAKER.
Thousands of PATHWAY applications, developed before the introduction of
PATHMAKER, presently run on NonStop systems all over the world.
You can, in fact, develop and run Tandem system applications without using
PATHWAY at all. People seldom do this, however, because they want to take
advantage of the powerful PATHWAY productivity features.
Features The main benefits and features of PATHWAY are described in the next few pages.
Application Development
Benefits
PATHWAY supports applications made up of requesters and servers, as described
earlier in this manual. This feature simplifies the development process by providing
several advantages.
Easy Development Tasks
PATHWAY applications are easy to develop. PATHWAY allows you to break each
application into small requester and server modules that separate the tasks of terminal
handling from those that involve the database. An example, which involves an order-
processing application, appears in Figure 6-1. The PATHWAY application structure
allows you to design, code, and test each module separately. Furthermore, you can
use the PATHMAKER application code generator to create these modules
automatically.