Information Technology Reference
In-Depth Information
a whole. Thus, an enterprise policy may determine performance or security
goals affecting the behaviour of nodes, nuclei, capsules, clusters or other ODP
functions. In particular, enterprise artefacts may need to be represented by
basic engineering objects so that references to them can result in implicit
interactions to determine their state or properties.
The designers producing a computational specification focus on compu-
tational objects representing the basic functionality of the system, and the
interactions at the interfaces of those objects. They do not care how this ba-
sic structure is distributed, replicated, migrated or made persistent. It is in
the engineering viewpoint that this distribution and the mechanisms necessary
to support it become the principal focus.
In general, a computational object has one corresponding basic engineering
object, and a computational interface will have one corresponding engineering
interface. However, there are exceptions:
1. When a computational object is a binding object, that computational
object will result in a corresponding local engineering binding or engi-
neering channel instead of a basic engineering object, and
2. When the given transparency schema requires use of a replication func-
tion, multiple basic engineering objects will be introduced to support
the required transparency.
Finally, the objects and interfaces in the engineering specification need to
be grounded in real resources, such as processors and networks. This involves
declaring a set of correspondences between, for example, the engineering nodes
and suitable technology objects defined in terms of implementable standards.
This is the subject of the next chapter.
