science

Open-system environment reference model

Open-system environment reference model is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Open-system environment reference model rather than just read about it. In short: Open-system environment (OSE) reference model (RM) or OSE reference model (OSE/RM) is a 1990 reference model for enterprise architecture. It provides a framework for describing open system concepts and defining a lexicon of terms, that can be agreed upon generally by all interested parties.

Key takeaways

Open-system environment reference model belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Open-system environment reference model to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Open-system environment reference model from memory before moving on to harder problems.

Reference excerpt

Open-system environment (OSE) reference model (RM) or OSE reference model (OSE/RM) is a 1990 reference model for enterprise architecture. It provides a framework for describing open system concepts and defining a lexicon of terms, that can be agreed upon generally by all interested parties. This reference model is meant as an environment model, complementary to the POSIX architecture for open systems. It offers 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. This reference model served in the 1990s as a basic building block of several technical reference models and technical architectures. In 1996 this reference model was standardized in the ISO/IEC TR 14252 titled "Information technology -- Guide to the POSIX Open System Environment (OSE)".

History The development of the open-system environment reference model started early 1990s by the NIST as refinement of the POSIX (Portable Operating System Interface) standard. POSIX is a standard for maintaining compatibility between operating systems, and addresses interoperation for communications, computing, and entertainment infrastructure. Its development started late 1980s by the POSIX Working Group 1003.0 of the Institute of Electrical and Electronics Engineers (IEEE). The NIST 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 applications portability profile for the open-system environment. 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.

OSE/RM topics The open-system environment (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. 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.

APP service areas

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. The services defined in the APP tend to fall into broad service areas. These service areas are:

Operating system services (OS) Human/computer interface services (HCI) Data management services (DM) Data interchange services (DI) Software engineering services (SWE) Graphics services (GS) Network services (NS) 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.

Classes of interfaces There are two classes of interfaces in the OSE reference model: the application program interface and the external environment interface:

Application programming interface (API) : The API is the interface between the application software and the application platform. Its primary function is to support portability of application software. An API is categorized in accordance with the types of service accessible via that API. There are four types of API services in the OSE/RM: Human/computer interface services Information interchange services Communication services Internal system services External environment interface (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.

OSE profile 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. 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.

OSE reference model entities The three classes of OSE reference model entities are described as follows:

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Open-system environment reference model

Start with the simplest possible case. Write down what Open-system environment reference model claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Open-system environment reference model before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Open-system environment reference model ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Open-system environment reference model

In research: Open-system environment reference model appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Open-system environment reference model in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Open-system environment reference model is common in secondary-school and first-year university syllabi. It links to neighbouring topics Enterprise modelling, Reference models, so understanding it makes those chapters shorter.
In everyday life: Look for Open-system environment reference model outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Open-system environment reference model in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Open-system environment reference model means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Open-system environment reference model out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Open-system environment reference model in simple terms?

Why does Open-system environment reference model matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Open-system environment reference model?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Open-system environment reference model.