Introduction to TRANSFER Delivery System

TRANSFER Processes The TRANSFER Environment
2-16 109426—Introduction to TRANSFER Delivery System
TRANSFER Processes
The processes in a TRANSFER system are clients, servers, TRANSFER asynchronous
processes, and agents.
Clients
Clients are requester processes that provide the interface between correspondents and
TRANSFER. Tandem supplies certain clients, such as the electronic mail
applications—PS MAIL 6530, PS MAIL 3270, and PS MAIL TTY—and customers can
develop their own clients.
Clients allow the correspondent to interact with TRANSFER. For example, the
correspondent can create new items, assemble them into packages, send these packages,
retrieve incoming packages, and request various administrative services.
Every application that uses TRANSFER must have one or more clients. Most clients
are written as SCREEN COBOL program units that execute within the PATHWAY
terminal control processes (TCPs).
Typically, you write a client in a TRANSFER application to assume the following
responsibilities:
■ Establish and end a session for a correspondent
■ Manage the terminal interface, based on the screens that are designed and the code
that is written to accept and display data on those screens
■ Compose items and packages at a depot
■ Assign delivery parameters, such as package priority and timeframes
■ Send packages for delivery
■ Detect and react to certain error conditions
As illustrated in Figure 2-5, a client can define a menu that allows a correspondent to
select functions by pressing appropriate function keys.