Introduction to Data Management

Developing Applications With PATHWAY
15873 Tandem Computers Incorporated 6-9
Managing a PATHWAY
Application
After you have developed and tested your application modules, you are ready to
configure a PATHWAY system to control and run the application. A PATHWAY
system consists of processes, definitions, and templates (patterns) for running and
controlling the programs that make up your application and the I/O devices used by
those programs. These processes, definitions, and templates are known as
PATHWAY objects. They include:
PATHMON—the PATHWAY Monitor process that monitors and controls your
PATHWAY system; PATHMON keeps records of object definitions, starts TCPs
and server processes, grants communication links between TCPS and server
processes, reports status information and system errors, and shuts down the
PATHWAY system by stopping individual objects in an orderly way
Terminal Control Processes (TCPS)—processes provided by Tandem to interpret
and execute your screen programs, and to coordinate communication between the
screen programs, their I/O devices or processes, the server processes, and
PATHMON
TERMs—definitions of tasks that use the screen programs to control I/O devices
or processes that are dedicated exclusively to your PATHWAY system; each task
runs as a thread in a TCP, which can handle many such tasks concurrently
PROGRAMs—templates for creating and starting TERMs for devices that are not
dedicated exclusively to your PATHWAY system; when a user runs an initial
screen program through a nondedicated device or process, the associated
PROGRAM automatically creates a temporary TERM to control that individual
device or process
SERVERs—definitions of server classes (multiple copies of server programs) that
receive transaction requests for work on a database; all members of the class run
copies of the same server program
Each PATHWAY system includes only one PATHMON. However, the number of
other objects in a PATHWAY system varies depending on the system configuration,
the workload, and the transaction processing applications that you run. A simple
PATHWAY system that contains all of these objects appears in Figure 6-3. Although
they are not configured as part of your PATHWAY system, the PATHCOM processes
and management application processes also interact with your PATHWAY system.
A PATHWAY system can include one PATHWAY application alone, or multiple
applications. For example, a small PATHWAY system might be devoted only to an
inventory control application. A PATHWAY system with multiple applications might
include an application for each of the following functions: order processing, accounts
payable, and accounts receivable, as well as inventory control. In this multiple
configuration, all applications run under the same PATHMON.