NonStop Systems Introduction

Glossary
NonStop Systems Introduction—527825-001
Glossary-2
client
client. An application program that requests services to be performed. In the client/server
model, the client program generally resides on a workstation or personal computer and
requests services of a server program on a NonStop system.
client/server model. A model for distributing applications. In general, but not always, the
client process resides on a personal computer or workstation and the server process
resides on a more powerful server machine. Communication takes the form of request
and reply pairs, which are initiated by the client and serviced by the server. (A server
can make requests of another server, thus acting as a client.) Client/server computing
is often used to connect different types of workstations or personal computers to a host
computer system by means of supported communications protocols.
cluster. A collection of servers, or nodes, that can function either independently or
collectively as a processing unit. See also ServerNet cluster.
commit. The act of completing a transaction so that changes to the database are recorded
and stable. Protected resources are released after the transaction is completed.
Common Object Request Broker Architecture (CORBA). A language-independent and
location transparent distributed object model specified by the object management
group (OMG). See also NonStop CORBA.
communications controller. A hardware component that manages communications lines
or devices.
communications protocol. See protocol.
concurrency. The ability of many users to access the same table in a database.
consistency. The property of an automated transaction that ensures that work done by a
transaction must take resources from one consistent state to another consistent state.
container. See EJB container.
CORBA. See Common Object Request Broker Architecture (CORBA)
.
CORBA object. An object abstraction, defined using an IDL interface, to which client
requests are directed. A CORBA object can be located by its reference. Exactly how
the CORBA object satisfies a request is transparent to the client.
CPU. See central processing unit (CPU).
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