User manual

Computer Gateway User Manual 3-1 5/96
3
HOST COMPUTER SOFTWARE COMPONENTS
Section 3
This section discusses the types of support programs and communication program interfaces that
can be used as the base for development of host processor-resident application programs.
This section deals with the ways in which applications interfaces to CG functions can be
constructed with the host-to-CG data link messages as a foundation. It is only a guide; the
exact requirements/specifications can vary from user to user. The assumption is that you
will develop an environment that will support the needs of your applications programs.
Some of the major elements that you will need to consider are
• Bisynch or HDLC data link
• A communications executive
• A dispatcher to activate host-resident application programs
• ACP installation/deinstallation
• A data table builder
The balance of this section is devoted to the description of a sample system that provides an
application-program development and execution environment and uses the set of CG data-
link messages described by this manual. This sample system description is included to
provide you with design ideas for your own system.
3.1 SAMPLE SYSTEM OVERVIEW
The sample system provides an environment that permits users to develop and execute
application programs that can exchange data with nodes on the TDC 3000
X
LCN. In this
system, the application developer works through a set of higher level interfaces that shield
him from details of the host processor to CG interface. It is composed of elements in both
the host processor and the Computer Gateway (CG). The following descriptions
emphasize the host processor portion of those elements.
Before delving into the components and structure of the host-processor software, we first
should look at the two key elements that this structure must support; the application
programs (called "Advanced Control Programs" or ACPs) and the Data Definition Tables.