Introduction to Data Management

Developing Applications With PATHWAY
15873 Tandem Computers Incorporated 6-11
Depending on the requirements of your application, you might distribute PATHWAY
objects over a single Tandem computer system by running different modules on
different CPUs. You can distribute PATHWAY functions over different physical or
geographical locations by spreading a single PATHWAY system across a network of
computer systems, or by configuring two or more PATHWAY systems to
communicate across a network, as shown in Figure 6-4. In this figure, a TCP in one
PATHWAY system forms a link across a communication line to a server class that is
controlled by the PATHMON in another PATHWAY system. Notice that in cases
where more than one PATHWAY system is involved, each system is monitored by its
own PATHMON process.
The tasks you perform to set up and manage a PATHWAY system depend on the
applications that your system will support. Generally, however, they include the
following basic steps:
1. Starting PATHMON. In this step, you assign a process name to the PATHMON
process that controls your PATHWAY system. You will use this name later to
refer to your PATHMON when you issue commands to it.
2. Choosing your interface to PATHMON. Here, you select either the PATHCOM
command interpreter or the PATHWAY programmatic interface as your means of
entering commands to PATHMON. You accomplish the remaining steps by
entering commands through the interface chosen.
3. Starting PATHCOM or your management application process. Now, you open
communication with your PATHMON. This action allows you to enter commands
directly from your terminal or from an EDIT file (if PATHCOM is used), or from a
program (if a management application process is used).
4. Starting your PATHWAY system. In this step, you either create and start a new
PATHWAY system, or restart an existing system. Creating and starting a new
system involves:
a. Configuring PATHMON by specifying a backup CPU for PATHMON, if you
are running your PATHMON as a GUARDIAN 90 process pair.
b. Configuring your PATHWAY system by specifying certain limits for your
system, plus specific system-wide attributes. The limits determine the
maximum number of objects of each type (TERMs, SERVERs, and so forth) that
you can define for your system during subsequent configuration.