Pathmaker Programming Guide

Before You Begin
Pathmaker Application Development Overview
3–4 067868 Tandem Computers Incorporated
Bottom-Up Versus
Top-Down
Application Development
When using the Pathmaker product, it is possible to implement an application's
requesters and services in any order you choose, but generally the development
proceeds in a bottom-up or top-down order. There are certain advantages and
disadvantages to each approach that should be considered when choosing how you
will use the Pathmaker product to implement the components of your application.
Bottom-Up
With the bottom-up approach, all of the services for the application are created first.
Then the lowest-level requesters in the application hierarchy are created, followed by
each higher level of requester.
Using the bottom-up approach, the process of coordinating the components of the IPC
messages between each requester and service, as well as parameters between
requesters, can be done as part of requester definition and service definition and does
not have to be performed as a separate step.
The finished services are packaged together into servers which are then generated and
compiled. The requesters can be generated and compiled as they are completed.
The bottom-up approach reduces the need to regenerate and recompile your
requesters, thus letting you complete the whole application rapidly and with less
“back-tracking.” This approach is probably the easiest one for a novice Pathmaker
user.
The major tasks for creating a Pathmaker application using the “bottom-up” approach
are illustrated in Figure 3-1.