NonStop Systems Introduction for H-Series RVUs

Glossary
NonStop Systems Introduction for H-Series RVUs—540083-001
Glossary-3
database.
database. A collection of tables containing data, all objects that depend on the tables, and
all catalogs in which the tables and objects are registered.
database consistency. The state of a database in which items satisfy established criteria.
For example, an account balance must equal credits to the balance minus debits to the
balance. When the database satisfies these criteria, it is considered to be consistent. In
general, a database is consistent when it is accurate and all changes generated by
transactions are complete. Database consistency is defined by the application, which
establishes the values and relationships of database fields and records.
database management system (DBMS). A product, such as SQL/MX, that serves as the
interface between a user or program (for example, a server program on a NonStop
system) and the database. Among its many functions, the DBMS controls access to
and organization of data within the database.
data integrity. The condition of a database when its data values are accurate, valid, and
consistent according to rules established for changing the database. See also
database consistency.
data store. See real-time data store.
DBMS. See database management system (DBMS).
disk process. In the NonStop environment, the operating system software that performs
read, write, and lock operations on disk volumes and creates TMF audit records. See
also audit records and file system.
distributed application. (1) An application in which the functions are split among the clients
and the server. (2) An application that is distributed among processors in a system or
among nodes in a network.
distributed data. Information (for example, customer names and addresses, inventory
items, and personnel records) that resides on more than one node in a network and
can be accessed by authorized users from any node in that network.
distributed database. A database whose objects reside on more than one node in a
network and whose objects can be accessed from any node in the network.
distributed processing. A type of processing environment in which resources are
distributed among processors within a single system or spread across a network of
systems. A user on any network node can, if properly authorized, access resources
and database files anywhere within the network.
dual ported. The capability of an I/O controller, ServerNet adapter, or peripheral device to
receive data and commands from two sources although only one source has access at
any particular point in time. A dual-ported I/O controller or ServerNet adapter can
receive data and commands from two processors; a dual-ported peripheral device
(such as a disk drive) can receive data and commands from two I/O controllers.