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[[File:Open System Environment Reference Model.jpg|thumb|320px|Illustration of the Openopen-system Systemenvironment Environmentreference Reference Modelmodel, 1995.<ref name="Hun95"> Joseph I. Hungate et al. (1995) [http://nvl.nist.gov/pub/nistpubs/jres/100/6/j16ce-hun.pdf Conference Report APPLICATION PORTABILITY PROFILE AND OPEN SYSTEM ENVIRONMENT USER’S FORUM Gaithersburg, MD May 9–10, 1995] in: ''Journal of Research of the National Institute of Standards and Technology''. Volume 100, Number 6, November–December 1995</ref>]]
'''Open-system System Environmentenvironment (OSE) Referencereference Modelmodel (RM)''' or ''OSE Referencereference Modelmodel'' (OSE/RM) is one of the first [[reference model]]s for [[Enterpriseenterprise Architecturearchitecture]]. It provides a [[software framework|framework]] for describing [[open system]] concepts and defining a lexicon of terms, that can be agreed upon generally by all interested parties. <ref name="Hun95"/>
== Overview ==
The Openopen-system System Environmentenvironment (OSE) forms an extensible framework that allows services, interfaces, protocols, and supporting data formats to be defined in terms of nonproprietary specifications that evolve through open (public), consensus-based forums. A selected suite of specifications that defines these interfaces, services, protocols, and data formats for a particular class or ___domain of applications is called a profile.<ref name="Hun95"/>
Two types of elements are used in the model: entities consisting of the application software, application platform, and platform external environment; and interfaces including the application program interface and external environment interface.
== History ==
The Openopen-system Systemenvironment Environmentreference Reference Modelmodel (OSE/RM) refines the core POSIX model defined by the POSIX Working Group 1003.0 of the [[Institute of Electrical and Electronics Engineers]] (IEEE). This model wanted to address interoperation for a communications, computing, and entertainment infrastructure. The OSE/RM is also identified at the international level in Joint Technical Committee 1 (JTC1) Technical Report (TR) 14250.<ref name="Hun95"/> A profile by the [[NIST]] (1996) identifies some standards that can be adapted to the identified OSE services.<ref name="ACF">[http://www.acf.hhs.gov/nhsitrc/it_planning/pdf/consolidated_definitions.pdf Consolidated Definitions and References] at acf.hhs.gov. Accessed 12 Dec 2008.</ref>
The [[NIST]] has hosted workshops and conducts other support activities to assist users in addressing open systems requirements, preparing for the use of new technology, and identifying the international, national, industry and other open specifications that are available for building open systems frameworks, such as the government's Applicationsapplications Portabilityportability Profileprofile for the Openopen-system System Environmentenvironment. NIST sponsors the semiannual Users' Forum on Application Portability Profile (APP) and Open System Environment (OSE) to exchange information and respond to NIST proposals regarding the evaluation and adoption of an integrated set of standards to support the APP and OSE. The quarterly Open Systems Environment Implementors' Workshop (OIW), co-sponsored by NIST and the [[Institute of Electrical and Electronics Engineers]] (IEEE) Computer Society, provides a public international technical forum for the timely development of implementation agreements based on emerging OSE standards.<ref>[http://www.itl.nist.gov/lab/bulletns/archives/b595.txt STANDARDS FOR OPEN SYSTEMS: MORE FLEXIBILITY FOR FEDERAL USERS] NIST Bulletin 1996. Accessed 13 Dec 2008.</ref>
== OSE/RM topics ==
The three classes of OSE reference model entities are described as follows:<ref name="Hun95"/>
* ''Application Softwaresoftware'' : Within the context of the OSE Reference Model, the application software includes data, documentation, and training, as well as programs.
* ''Application Platformplatform'' : The application platform is composed of the collection of hardware and software components that provide the generic application and system services.
* ''Platform Externalexternal Environmentenvironment'' : The platform external environment consists of those system elements that are external to the application software and the application platform (e.g., services provided by other platforms or peripheral devices).
=== Classes of interfaces ===
** Communication services
** Internal system services
* ''External Environmentenvironment Interfaceinterface (EEI)'' : The EEI is the interface that supports information transfer between the application platform and the external environment, and between applications executing on the same platform. Consisting chiefly of protocols and supporting data formats, the EEI supports interoperability to a large extent. An EEI is categorized in accordance with the type of information transfer services provided.
=== Types of information transfer services ===
In its simplest form, the OSE/RM illustrates a straightforward user-supplier relationship: the application software is the user of services and the application platform/ external environment entities are the suppliers. The API and EEI define the services that are provided.<ref name="Hun95"/>
=== OSE Profileprofile ===
A profile consists of a selected list of standards and other specifications that define a complement of services made available to applications in a specific ___domain. Examples of domains might include a workstation environment, an embedded process control environment, a distributed environment, a transaction processing environment, or an office automation environment, to name a few. Each of these environments has a different cross-section of service requirements that can be specified independently from the others. Each service, however, is defined in a standard form across all environments.<ref name="Hun95"/>
An OSE profile is composed of a selected list of open (public), consensus-based standards and specifications that define services in the OSE/RM. Restricting a profile to a specific ___domain or group of domains that are of interest to an individual organization results in the definition of an organizational profile.<ref name="Hun95"/>
=== APP Serviceservice Areasareas ===
[[File:APP Service Areas and the OSE-RM.jpg|thumb|240px|left|APP Service Areas and the OSE-RM]]
The Application Portability Profile (APP) is an OSE profile designed for use by the U.S. Government. It covers a broad range of application software domains of interest to many Federal agencies, but it does not include every ___domain within the U.S. Government’s application inventory. The individual standards and specifications in the APP define data formats, interfaces, protocols, or a mix of these elements.
* Graphics services (GS)
* Network services (NS)
[[File:Detailed DoD Technical Reference Model.jpg|thumb|240px|Detailed DoD Technicaltechnical Referencereference Modelmodel of the [[TAFIM]], is based on the Open System Environment model.<ref name = "DoD96V2"> Department of Defense (1996). ''Technical Architecture Framework for Information Management. Vol. 2''. April 1996</ref>]]
Each service area is defined in the following sections. The figure illustrates where each of these services areas relates to the OSE/RM. Assume that [[software engineering]] services are applicable in all areas. Each of the APP service areas addresses specific components around which interface, data format, or protocol specifications have been or will be defined. Security and management services are common to all of the
service areas and pervade these areas in one or more forms.<ref name="Hun95"/>
== Applications ==
Basically the Openopen-system System Environmentenvironment model is a basic building block of several Technicaltechnical Referencereference Modelsmodels and Technicaltechnical Architecturearchitecture. A [[Technicaltechnical Architecturearchitecture]] identifies and describes the types of applications, platforms, and external entities; their interfaces; and their services; as well as the context within which the entities interoperate. A Technicaltechnical Architecturearchitecture is based on a Technicaltechnical Referencereference Modelmodel (TRM) and the selected standards that further describe the TRM elements (the profile). The Technicaltechnical Architecturearchitecture is the basis for selecting and implementing the infrastructure to establish the target architecture.<ref name="ACF"/>
A [[Technicaltechnical Referencereference Modelmodel]] can be defined as a taxonomy of services arranged according to a conceptual model, such as the Open System Environment model. The enumerated services are specific to those needed to support the technology computing style (e.g., distributed object computing) and the industry/business application needs (e.g., Human Services, financial). <ref name="ACF"/>
== See also ==
* [[Enterprise Architecturearchitecture framework]]
* [[Federal Enterpriseenterprise Architecturearchitecture]]
* [[GERAM]]
* [[TAFIM]]
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