Introduction to Data Management

Managing Data on the Tandem Systems
15873 Tandem Computers Incorporated 2-9
Because devices are treated as files, you can write new programs without regard for
the physical location of specific devices or process code to be accessed. As far as your
application is concerned, interprocess communication appears identical to I/O with
physical devices.
Global Databases A growing business often adds geographically dispersed facilities that increase the
need for sharing information among computers at several locations. A network of
Tandem systems fills this need and offers the same capacity for continuous
availability, data integrity, and modular expansion to all systems in the network.
Processes access files and data without concern for their physical location. This
feature allows you to develop new applications for systems in a global network just as
you would for a single system. Complete hardware and software compatibility at
each network site lets you develop applications at one node and then transmit them to
another node where you bring them online. Without making any modifications, you
can run a program in the same way at any node in the network; the message system
establishes the logical connections to whatever peripheral devices the program needs.
A Tandem system network lets you create a global database that resides on more than
one node. Your application views this database as a single entity, even though
multiple files might actually be distributed geographically. Network-distributed
transactions can originate at any node and change portions of any files in the
database, no matter where they are located.
In a global database, for instance, a customer file can reside in a system in Chicago
while an order file exists in a system in New York. An authorized user in either city
accesses both files in exactly the same way. A single transaction can update multiple
files in both cities, and all required changes take place automatically.
Data Management
Software
In this section, you have seen some of the general features that underlie data
management on the Tandem systems. More specialized features are furnished by the
Tandem data management products, summarized as follows and discussed in the
remaining sections.
NonStop SQL distributed relational database management system—a facility for
defining and manipulating structures in relational databases; this system
processes commands based on the industry-standard Structured Query Language
(SQL) and used within server programs written in other languages (such as
COBOL)