Notes

The client/server computing model provides opportunities to achieve true open system computing.
Applications may be created and implemented without regard to the hardware platforms or the
technical characteristics of the software. Thus, users may obtain client services and transparent access
to the services provided by database, communications, and applications servers. Operating systems
software and platform hardware are independent of the application and masked by the development
tools used to build the application.
In this approach, business applications are developed to deal with business processes invoked by the
existence of a user-created "event." An event such as the push of a button, selection of a list element,
entry in a dialog box, scan of a bar code, or flow of gasoline occurs without the application logic being
sensitive to the physical platforms.
Client/server applications operate in one of two ways. They can function as the front end to an existing
application—the more limited mainframe-centric model discussed in Chapter 1—or they can provide
data entry, storage, and reporting by using a distributed set of clients and servers. In either case, the use
—or even the existence—of a mainframe host is totally masked from the workstation developer by the
use of standard interfaces such as SQL.