Common Information Model (computing)

The Common Information Model (CIM) is an open standard that defines how managed elements in an IT environment are represented as a common set of objects and relationships between them. This is intended to allow consistent management of these managed elements, independent of their manufacturer or provider.

Overview

One way to describe CIM is to say that it allows multiple parties to exchange management information about these managed elements. However, this falls short in expressing that CIM not only represents these managed elements and the management information, but also provides means to actively control and manage these elements. By using a common model of information, management software can be written once and work with many implementations of the common model without complex and costly conversion operations or loss of information.

The CIM standard is defined and published by the Distributed Management Task Force (DMTF). A related standard is Web-Based Enterprise Management (WBEM, also defined by DMTF) which defines a particular implementation of CIM, including protocols for discovering and accessing such CIM implementations.

Schema and specifications

The CIM standard includes the CIM Infrastructure Specification and the CIM Schema:

• CIM Infrastructure Specification

The CIM Infrastructure Specification defines the architecture and concepts of CIM, including a language by which the CIM Schema (including any extension schema) is defined, and a method for mapping CIM to other information models, such as SNMP. The CIM architecture is based upon UML, so it is object-oriented: The managed elements are represented as CIM classes and any relationships between them are represented as CIM associations. Inheritance allows specialization of common base elements into more specific derived elements.

• CIM Schema

The CIM Schema is a conceptual schema which defines the specific set of objects and relationships between them that represent a common base for the managed elements in an IT environment. The CIM Schema covers most of today's elements in an IT environment, for example computer systems, operating systems, networks, middleware, services and storage. The CIM Schema defines a common basis for representing these managed elements. Since most managed elements have product and vendor specific behavior, the CIM Schema is extensible in order to allow the producers of these elements to represent their specific features seamlessly together with the common base functionality defined in the CIM Schema.

CIM is the basis for most of the other DMTF standards (e.g. WBEM or SMASH). It is also the basis for the SMI-S standard for storage management.

Versions

• The latest version 2.21 of the CIM Schema was published on March 19, 2009.
• The latest version 2.5 of the CIM Infrastructure Specification was published on May 1, 2009.
• The latest version 1.1 of the CIM Compliance Specification was published on December 15, 2003.
• The latest version 2.2 of the CIM Specification was published on June 14, 1999.

Implementations

Many vendors provide implementations of CIM in various forms:

• Most operating systems provide a CIM implementation. For example, the Windows Management Instrumentation (WMI) API available in Microsoft Windows 2000 and higher implements CIM, so do some GNU/Linux distributions with the SBLIM project on sourceforge.
• The storage area network industry has heavily bought into using CIM and WBEM: their usage of CIM is called Storage Management Initiative - Specification (SMI-S) which is a standard defined by the SNIA.
• Most server manufacturers collaborate in the DMTF under the SMASH initiative to define CIM based management of servers.
• The DASH initiative in the DMTF attempts to define CIM based management of desktop computers.

There is also a growing tools market around CIM.

See also

• CUA
• SNMP
• DMTF
• SNIA
• WBEM
• SMASH
• SMI-S
• WMI
• List of computer standards

External links

• DMTF CIM Standard — including CIM Schema and CIM Infrastructure Specification
• CIM definition at linktionary.com
• CIM definition at networkcomputing.com
• CIM definition at searchstorage.techtarget.com
• CIM Tutorial from WBEM Solutions
• SBLIM project on sourceforge
• OpenDRIM project