Glossary

This Glossary defines terms used in the Sun WBEM documentation. Many of these terms are familiar to developers, but have new or altered meaning in the WBEM environment.

alias

A symbolic reference in either a class or instance declaration to an object located elsewhere in a MOF file. Alias names follow the same rules as instance and class names. Aliases are typically used as shortcuts to lengthy paths.

aggregation relationship

A relationship in which one entity is made up of the aggregation of some number of other entities.

association class

A class that describes a relationship between two classes or between instances of two classes. The properties of an association class include pointers, or references, to the two classes or instances. All WBEM classes can be included in one or more associations.

Backus-Naur Form (BNF)

A metalanguage that specifies the syntax of programming languages.

cardinality

The number of values that may apply to an attribute for a given entity.

class

A collection or set of objects that have similar properties and fulfill similar purposes.

CIM Object Manager Repository

A central storage area managed by the Common Information Model Object Manager (CIM Object Manager). This repository contains the definitions of classes and instances that represent managed objects and the relationships among them.

CIM Schema

A collection of class definitions used to represent managed objects that occur in every management environment.

See also core model, common model, and extension schema.

The CIM is divided into the metamodel and the standard schema. The metamodel describes what types of entities make up the schema. It also defines how these entities can be combined into objects that represent managed objects.

common model

The second layer of the CIM schema, which includes a series of domain-specific but platform-independent classes. The domains are systems, networks, applications, and other management-related data. The common model is derived from the core model.

See also extension schema.

core model

The first layer of the CIM schema, which includes the top-level classes and their properties and associations. The core model is both domain- and platform-independent.

See also common model and extension schema.

Distributed Management Task Force (DMTF)

An industry-wide consortium committed to making personal computers easier to use, understand, configure, and manage.

domain

The class to which a property or method belongs. For example, if status is a property of Logical Device, it is said to belong to the Logical Device domain.

dynamic class

A class whose definition is supplied by a provider at runtime as needed. Dynamic classes are used to represent provider-specific managed objects and are not stored permanently in the CIM Object Manager Repository. Instead, the provider responsible for a dynamic class stores information about its location. When an application requests a dynamic class, the CIM Object Manager locates the provider and forwards the request. Dynamic classes support only dynamic instances.

dynamic instances

An instance that is supplied by a provider when the need arises and is not stored in the CIM Object Manager Repository. Dynamic instances can be provided for either static or dynamic classes. Supporting instances of a class dynamically allows a provider to always supply up-to-the-minute property values.

enumeration

Java term for getting a list of objects. Java provides an Enumeration interface that has methods for enumerating a list of objects. An individual object on this list to be enumerated is called an element.

extension schema

The third layer of the CIM Schema, which includes platform-specific extensions of the CIM Schema such as Solaris and UNIX.

See also common model and core model.

flavor

See qualifier flavor.

indication

An operation executed as a result of some action such as the creation, modification, or deletion of an instance, access to an instance, or modification or access to a property. Indications can also result from the passage of a specified period of time. An indication typically results in an event.

inheritance

The relationship that describes how classes and instances are derived from parent classes or superclasses. A class can spawn a new subclass, also called a child class. A subclass contains all the methods and properties of its parent class. Inheritance is one of the features that allows WBEM classes to function as templates for actual managed objects in the WBEM environment.

instance

A representation of a managed object that belongs to a particular class, or a particular occurrence of an event. Instances contain actual data.

instance provider

A type of provider that supports instances of system- and property-specific classes. Instance providers can support data retrieval, modification, deletion, and enumeration. Instance providers can also invoke methods.

See also property provider.

interface class

The class used to access a set of objects. The interface class can be an abstract class representing the scope of an enumeration.

See also enumeration and scope.

Interface Definition Language (IDL)

A generic term for a language that lets a program or object written in one language communicate with another program written in an unknown language.

key

A property that is used to provide a unique identifier for an instance of a class. Key properties are marked with the Key qualifier.

Key qualifier

A qualifier that must be attached to every property in a class that serves as part of the key for that class.

managed object

A hardware or software component that is represented as an instance of the CIM class. Information about managed objects is supplied by providers as well as the CIM Object Manager.

See also managed resource.

Managed Object Format (MOF)

A compiled language for defining classes and instances. The MOF compiler (mofc) compiles .mof text files into Java classes and adds the data to the CIM Object Manager Repository. MOF eliminates the need to write code, thus providing a simple and fast technique for modifying the CIM Object Manager Repository.

managed resource

A hardware or software component that can be managed by a management application. Hard disks, CPUs, and operating systems are examples of managed resources. Managed resources are described in WBEM classes.

See also managed object.

management application

An application or service that uses information originating from one or more managed objects in a managed environment. Management applications retrieve this information through calls to the CIM Object Manager API from the CIM Object Manager and from providers.

management information base

A database of managed objects.

metamodel

A CIM component that describes the entities and relationships representing managed objects. For example, classes, instances, and associations are included in the metamodel.

metaschema

A formal definition of the Common Information Model, which defines the terms used to express the model, its usage, and its semantics.

method

A function describing the behavior of a class. Including a method in a class does not guarantee an implementation of the method.

MOF file

A text file that contains definitions of classes and instances using the Managed Object Format (MOF) language.

Named Element

An entity that can be expressed as an object in the metaschema.

namespace

A directory-like structure that can contain classes, instances, and other namespaces.

object path

A formatted string used to access namespaces, classes, and instances. Each object on the system has a unique path which identifies it locally or over the network. Object paths are conceptually similar to Universal Resource Locators (URLs).

override

Indicates that the property, method, or reference in the derived class overrides the similar construct in the parent class in the inheritance tree or in the specified parent class.

polymorphism

The ability to alter methods and properties in a derived class without changing their names or altering interfaces. For example, a subclass can redefine the implementation of a method or property inherited from its superclass. The property or method is thereby redefined even if the superclass is used as the interface class.

Thus, the LogicalDevice class can define the variable status as a string, and can return the values "on" or "off." The Modem subclass of LogicalDevice can redefine (override) status by returning "on," "off," and "connected." If all LogicalDevices are enumerated, any LogicalDevice that happens to be a modem can return the value "connected" for the status property.

property

A value used to characterize the instances of a class. Property names cannot begin with a digit and cannot contain white space. Property values must have a valid Managed Object Format (MOF) data type.

property provider

A program that communicates with managed objects to access data and event notifications from a variety of sources, such as the Solaris operating environment or a Simple Network Management Protocol (SNMP) SNMP device. Providers forward this information to the CIM Object Manager for integration and interpretation.

qualifier

A modifier containing information that describes a class, an instance, a property, a method, or a parameter. The three categories of qualifiers are: those defined by the Common Information Model (CIM), those defined by WBEM (standard qualifiers), and those defined by developers. Standard qualifiers are attached automatically by the CIM Object Manager.

qualifier flavor

An attribute of a CIM qualifier that governs the use of a qualifier. WBEM flavors describe rules that specify whether a qualifier can be propagated to derived classes and instances and whether or not a derived class or instance can override the qualifier's original value.

range

A class that is referenced by a reference property.

reference

A special string property type that is marked with the reference qualifier, indicating that it is a pointer to other instances.

required property

A property that must have a value.

schema

A collection of class definitions that describe managed objects in a particular environment.

scope

An attribute of a CIM qualifier that indicates which CIM elements can use the qualifier. Scope can only be defined in the Qualifier Type declaration; it cannot be changed in a qualifier.

selective inheritance

The ability of a descendant class to drop or override the properties of an ancestral class.

Simple Network Management Protocol (SNMP)

A protocol of the Internet reference model used for network management.

singleton class

A WBEM class that supports only a single instance.

Solaris Schema

A Sun extension to the CIM Schema that contains definitions of classes and instances to represent managed objects that exist in a typical Solaris operating environment.

standard schema

A common conceptual framework for organizing and relating the various classes representing the current operational state of a system, network, or application. The standard schema is defined by the Distributed Management Task Force (DMTF) in the Common Information Model (CIM).

static class

A WBEM class whose definition is persistent. The definition is stored in the CIM Object Manager Repository until it is explicitly deleted. The CIM Object Manager can provide definitions of static classes without the help of a provider. Static classes can support either static or dynamic instances.

static instance

An instance that is persistently stored in the CIM Object Manager Repository.

subclass

A class that is derived from a superclass. The subclass inherits all features of its superclass, but can add new features or redefine existing ones.

subschema

A part of a schema owned by a particular organization. The Win32 and Solaris Schemas are examples of subschemas.

superclass

The class from which a subclass inherits.

transitive dependency

In a relation having at least three attributes R (A, B, C), the situation in which A determines B, B determines C, but B does not determine A.

trigger

A recognition of a state change (such as create, delete, update, or access) of a class instance, and update or access of a property. The WBEM implementation does not have an explicit object representing a trigger. Triggers are implied either by the operations on basic objects of the system (create, delete, and modify on classes, instances and namespaces) or by events in the managed environment.

Unified Modeling Language (UML)

A notation language used to express a software system using boxes and lines to represent objects and relationships.

Unicode

A 16-bit character set capable of encoding all known characters and used as a worldwide character-encoding standard.

UTF-8

An 8-bit transformation format that may also serve as a transformation format for Unicode character data.

virtual function table (VTBL)

A table of function pointers, such as an implementation of a class. The pointers in the VTBL point to the members of the interfaces that an object supports.

Win32 Schema

A Microsoft extension to the CIM Schema that contains definitions of classes and instances to represent managed objects that exist in a typical Win32 environment.