Introduction to Pathmaker

Overview of Pathway
Introduction to Pathmaker and Pathway
1–18 067867 Tandem Computers Incorporated
Running Applications With
Pathway
The preceding discussion presented the definitions and functions of a requester, a
service, and a server and explained how these components of a Pathway OLTP
application are created (without the Pathmaker product). This subsection examines
the various components of a running Pathway system.
Process
In a Tandem computer system, a process is essentially any running program. Each
time a program is executed, the operating system creates a process. For instance, if a
user runs two separate programs, two processes are created. Likewise, if two users
run the same program concurrently, the operating system creates two processes. (An
oval is usually used to symbolize a process.)
PATHMON
PATHMON is the supervising process of the Pathway environment; in this capacity, it
manages all other processes in a running Pathway system. PATHMON is provided by
Pathway and is started by the system operator.
PATHCOM
PATHCOM is the process that provides a command language interface, allowing the
system operator to control and direct PATHMON. PATHCOM is provided by
Pathway and is usually started by the system operator whenever it is needed.
SCREEN COBOL Library
The SCREEN COBOL library contains the requester programs after they are compiled
by the SCOBOLX compiler provided with Pathway. This library consists of these files:
POBJDIR and POBJCOD and, optionally, POBJSYM.
TCP (Terminal Control Process)
TCPs are the processes provided by Pathway that concurrently manage multiple
terminals and transactions. TCPs interpret SCREEN COBOL programs (requesters) on
individual end user terminals and handle message routing and preliminary editing of
user input. The TCP locates and interprets the SCREEN COBOL programs in the
SCREEN COBOL library.
Note In the figures found in this manual, the word requester enclosed in an oval represents SCREEN COBOL
code being interpreted and controlled by a TCP.
The primary function of a TCP is to handle the complexities associated with
multiterminal environments. Because the TCP handles these complexities, application
developers can concentrate on the needs of the business and code the requesters to
operate as though they were designed for a simple single-terminal environment. TCPs
are started by the system operator.