SUNTONE ARCHITECTURE METHODOLOGY A 3-DIMENSIONAL ...

• Manageability—Manageability can be expressed in terms of how easy it is to monitor
a system and detect operational characteristics related to performance and failures,
how easy is to configure systems, the processes used for effecting this control
and the degree to which the system can be managed remotely.
• Accessibility—relates to the usability of applications across the full range of user
capabilities, languages, and devices.
• Flexibility—Flexibility relates to how easy is it to re-purpose the system to provide
different services. In flexible systems the individual components can be reorganized
to provide new services and used by different services.
• Other qualities—The list of capabilities is potentially inexhaustible. Other examples
include:
• Serviceability—how easy is it to repair the system and replace components, and to
what degree maintenance causes service interruption
• Interoperability—the capability of components to work with each other and the
ability to add new components
• Portability—the ability to move components from one environment to another or
replace platform components
• Reusability—the ability to use individual components or services in the building
of additional applications
• Usability—involves issues that make the user interface an application functionality
that is easy to use by the end user.
These Systemic Qualities are required at each tier of a dot-com architecture and are
not the responsibility of any given layer—instead the layers must complement and
cooperate in providing each quality within a given tier. Some qualities, such as security
or manageability, need to be pervasive—present at all layers in all tiers.
For this reason, the Sun 3-D Architectural Model represents these Systemic Qualities
as a separate dimension, orthogonal to the tiers and layers which represent the logical/distributed
partitioning and the platform layering. Viewing Systemic Qualities
(and the related QoS levels which need to be supported) in this way is one of the key
insights of the SunTone Architecture Methodology, and allows architectural
alternatives to be quantitatively and qualitatively evaluated for their ability to provide
these capabilities.
Sun Microsystems, Inc.
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