System Configuration
Encyclopedia
A system configuration in systems engineering
Systems engineering
Systems engineering is an interdisciplinary field of engineering that focuses on how complex engineering projects should be designed and managed over the life cycle of the project. Issues such as logistics, the coordination of different teams, and automatic control of machinery become more...

 defines the computers, processes, and devices that compose the system and its boundary. More general the system configuration is the specific definition of the elements that define and/or prescribe what a system is composed of.

Alternatively the term system configuration can be used to relate to a model (declarative) for abstract generalized systems. In this sense the usage of the configuration information is not tailored to any specific usage, but stands alone as a data set.

Sample Configuration

The following is a basic SC XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....

 System Configuration:




































Description:
This provides information about a single "site" (MyHouse) and specifies that there is one host with user-setup and mysql-db components. The host must have an account on it for a user named mysql, with appropriate parameters. Notice that the configuration schema requires no XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....

 tags that are Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

- or UNIX
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

-specific. It simply presents data' as standalone information – with no pretense for how the data is to be used.

This is the hallmark for a good system configuration model.

Further Extensions

The above model can be extended. For example, the user could have more attributes like "preferences" and "password". The components could depend on other components. Properties can be defined that get passed into sub-elements. The extensions can be endless (WATCHOUT: complexity) and must be managed and well-thought-out to prevent "breaking" the idea of the system configuration.

Usage

The usage for the model in practical terms falls into several categories: documentation
Documentation
Documentation is a term used in several different ways. Generally, documentation refers to the process of providing evidence.Modules of Documentation are Helpful...

, deployment
System deployment
The deployment of a mechanical device, electrical system, computer program, etc., is its assembly or transformation from a packaged form to an operational working state....

 & operations.

Documentation

One use of the configuration is to simply record what a system is. This documentation could in turn become quite extensive, thus complicating the data model. It is important to distinguish between configuration data and descriptive data. Of course comments can be applied at any level, even in most tools, however the bloating of the data can reduce its usefulness. For example, the system configuration is not a place to record historical changes, or descriptions of design and intent for the various elements. The configuration data is simply to be "what it is" or "what we want it to be", not "how to get it there" or "what it was".

Deployment

Deployment involves interpreting a configuration data set and acting on that data to realize the configure the system accordingly. This may simply be a validation of what's there to confirm that the configuration is in effect.

Examples include a Perl library launched from the command line to read the configuration and begin launching processes on the local or remote hosts to install components. Also while the system is running, there may be a SystemConfiguration service that provides an interface (i.e. CORBA
Çorba
Chorba , ciorbă , shurpa , shorpo , or sorpa is one of various kinds of soup or stew found in national cuisines across Middle East...

 IDL interfaces) for other system applications to use to access the configuration data, and perform deployment-like actions.

Operations

When the system is in operation, there may be uses for the configuration data by specific kinds of services in the system. For example, a Secnager may access the configuration to acquire the MD5 passwords for the user accounts that are allowed to login to hosts remotely. A system monitor service (see: system monitoring
System Monitoring
A system monitor in systems engineering is a process within a distributed system for collecting and storing state data.- Overview :The configuration for the system monitor takes two forms:# configuration data for the monitor application itself, and...

) may use the data to determine "what to monitor" and "how to monitor" the system elements. A PresentationManager might use the data to access menu-items and views based on user access privileges.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK