The Business Designer produced the initial Subsystem Operation Survey placeholder during the Operation Analysis task.
Next, working from the white-box steps and the Operation Realizations, the Subsystem Operations are identified and
their behavior specified. As with the identification of business system operations, there might not be a unique
subsystem operation for each white-box step; that is, as you examine the set of white-box steps and their associated
exchange of messages, input-output entities, and so forth., you might find that it is possible to define a smaller set
of Subsystem Operations to fulfill their needs.
The operations can also be resorted by locality or by process, thus showing the association of a set of Subsystem
Operations with each locality or with each process. The locality sort gives an indication of the load at a locality
(and so is useful for reasoning about the capacity of the components that support the locality). In this form, the
survey sorted by locality becomes a property of the Business Deployment Model.
When a Subsystem Operation is hosted at multiple localities, this indicates that at least part of the subsystem is
replicated. There is no implication that these replicated portions necessarily share data or are kept in
synchronization. These are design choices which depend on the application and reason for replication; for example, the
processing required might be identical, but occur for a different business segment. In the extreme, all of a
subsystem's operations can be hosted at multiple localities, meaning that, effectively, the subsystem itself is
replicated. The need to identify replicated instances uniquely also depends on the reasons for replication.
The process sort allows the Business Designer to reason about concurrency issues: if you were to view a Subsystem
Operation as a discrete piece of functionality available to business actors, then, as a first approximation, operations
associated with the same process cannot be performed in parallel. This might lead the Business Designer to reconsider
the process allocation, or consider process replication, or to examine the perceived latency problem at a lower level
of detail, for example, through examination of time-slicing options, and process sharing when an operation blocks (to
do input-output, for example). These techniques can give acceptable responsiveness, whereas a delaying of the start of
an operation (strictly serializing operations) might be intolerable. In this form, the survey sorted by process becomes
a property of the Business Design Model.
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