Introduction to TRANSFER Delivery System

Developing TRANSFER Applications Sample TRANSFER Application
Introduction to TRANSFER Delivery System—109426 5-3
Developing Agents
An agent is a program that is invoked by a TRANSFER asynchronous process when a
package arrives at a depot. With the exception of the vacation agent and the print-on-
delivery agent, which are supplied by Tandem, all agents are user-written.
An agent can be a SCREEN COBOL requester program or a PATHWAY server. You
write agents according to the kind of work you want them to do:
■ In general, an agent that makes requests of TRANSFER server classes to retrieve,
save, or send packages should be a requester written in SCREEN COBOL.
■ An agent that accesses an input-output device or that performs string handling or
complex computations should be a server written in COBOL, FORTRAN, Pascal,
C, or TAL.
■ Any agent that performs both of these kinds of work should be written in SCREEN
COBOL and should direct requests to a special application-defined server class.
Sample TRANSFER Application
Figure 5-1 illustrates a sample TRANSFER application. A department store has three
sites connected by data communication lines; those sites are:
■ \SALES is a node in a sales office where customers order merchandise from the
store catalog; the office has a staff of salespeople and order-entry clerks.
■ \WHSE is a node in a warehouse with inventory, shipping, and receiving
departments; the staff consists of warehouse workers, inventory-control personnel,
clerks, and supervisors.
■ \CORP is a node at the corporate headquarters; it houses the purchasing, accounts
payable, personnel, and corporate sales departments; the executive offices; and
so on.
Like any business, the department store has a need for interoffice mail. Employees at all
three sites use PS MAIL for interoffice memos. The store also uses TRANSFER to
automate its catalog order procedures; the application facilitates communication among
order-processing, inventory, purchasing, and accounts-payable applications.