Module 6: Beginning Physical Design 181
Module 6: Beginning Physical Design 181
Physical Design in the Design Process
Conceptual Design
Logical Design
Physical Design
Components,
User Interface, and
Physical Database
Scenarios
Services and Objects,
User Interface, and
Logical Database
Physical design is the third phase of the MSF Design Process Model. Physical
design involves clearly defining the components and their location so that the
development team can begin to develop. Its inputs are the business object
model and the other supporting information created in logical design. Its output
is the solution deployment model, the component specification, and a list of
candidate implementation technologies.
Slide Objective
To place physical design in
context with the rest of the
design process.
Lead-in
As you learned in Module 2,
physical design is the third
phase in the MSF Design
Process.
182 Module 6: Beginning Physical Design
182 Module 6: Beginning Physical Design
Physical Design: The Search for Structure
"
Definition
The process of describing components,
services, and technologies of the
solution from the perspective of the
development team
"
Purpose
To apply real-world technology
constraints to the logical model,
including implementation and
performance considerations
"
Output
A set of components, user interface
design for a particular platform, and a
physical database design
Physical Design
Components,
User Interface, and
Physical Database
Physical design is the process of describing the components, services, and
technologies of the solution from the perspective of the development team.
Physical design takes into account performance and implementation issues, and
applies technology and technology constraints to a logical design.
Physical design can be likened to the third stage of designing a house. After the
basic architectural plan is complete, the plans for wiring, plumbing, heating,
and ventilation — the internals of the house — are created for the contractors.
This module does not address user-interface design or data-store design.
The user-interface design is presented in Module 11: Designing the
Presentation Layer, and the data-store design is covered in a separate course,
Course 1609: Designing Data Services and Data Modeling.
Slide Objective
To explain physical design,
its purpose, and its output.
Lead-in
Physical design is the
process of describing
components, services, and
technologies of the solution
from the perspective of the
development team.
Note
Module 6: Beginning Physical Design 183
Module 6: Beginning Physical Design 183
Goals of Physical Design
"
Transform the logical design into a set of component
candidates
"
Provide a baseline for evaluating implementation design
opportunities
"
Determine the implementation technologies and
strategies
"
Create a structural view of the solution from the
development team’s perspective
"
Articulate the solution design at the level of detail
required for development
Physical design uses the outputs of logical design to produce a component
specification for the proposed solution. This specification describes the
application from the development team’s perspective and will be used by the
development team to create the actual components for the application.
Physical design also provides a baseline that leads to the development of the
application. This baseline provides opportunities for developing prototypes and
beginning the Developing Phase of the MSF Design Process.
During physical design, the project team will evaluate candidate technologies to
determine the technologies that should be used to develop the solution.
Physical design should describe the solution in sufficient detail so that the
development team can create the application that the design describes. The
physical design phase leads to the functional specification, which is the primary
source of information for the development team.
Slide Objective
To describe some of the
goals of the physical design
phase.
184 Module 6: Beginning Physical Design
184 Module 6: Beginning Physical Design
Perspective of Physical Design
The physical design
perspective is from the
point of view of the
developers
Conceptual
Logical
Physical
Business
Solution
The physical design is from the perspective of the development team. This
perspective allows the design to begin to take a form that a development team
can use to create the solution by using specific technologies. In this sense,
physical design looks at the design from a more technical viewpoint. Basically,
physical design provides a bridge between logical design and implementation.
Slide Objective
To explain the perspective
that should be used during
the physical design phase.
Lead-in
Whereas logical design
viewed the problem from the
perspective of the project
team, physical design views
the problem from the
perspective of the
development team.
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Module 6: Beginning Physical Design 185
Perspective Captured in Component Specifications
"
Describes the solution at a greater level of detail
"
Defines the internal structure of the components
"
Applies physical constraints to the solution
"
Provides:
$
A bridge between logical design and implementation
$
Implementation clarity for the developers
$
Simplified work estimation and segmentation
Because physical design is from the development team's perspective, this
perspective is captured in a format that is most useful to a developer — that of a
component specification.
The component specification contains the level of detail that developers require
to begin building the components of the business solution. The component
specification defines how those components should be built and determines
what technologies and constraints are applicable to the development.
The component specification provides the transition from the logical design and
its models to the actual implementation. It clearly states what must be built,
how much effort it should take, and how the development effort should be
divided.
Slide Objective
To introduce component
specifications and their use
during physical design.
Lead-in
Physical design involves
reaching a level of detail
that is appropriate for
implementation. Component
specifications are one part
of this process, because
they define how the
individual components are
to be developed.
186 Module 6: Beginning Physical Design
186 Module 6: Beginning Physical Design
Clarifying Physical Design
Physical design is not
Coding
Technology deployment
But it enables you to
Create detailed component
specifications for development
Determine where the components
should reside
Choose technologies
During the physical design phase, the project team produces component
specifications and deployment topologies that the development team will use to
create the solution.
It is important to realize that this phase is still part of designing the solution and
not developing the deployable release.
Slide Objective
To further explain the
physical design phase by
giving examples of what
physical design is and is
not.
Lead-in
To further clarify what
physical design entails, let
us look at some examples of
what it is and is not.
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Module 6: Beginning Physical Design 187
Value of Physical Design
"
Evaluates implementation options
"
Provides a flexible design that is based on components
"
Becomes the basis for cost, schedule, and resource
estimates
"
Seeks compatibility with the enterprise architecture
"
Can be traced to usage scenarios through the logical
design
During physical design, you begin to look at candidate technologies that may be
used to develop the solution. You also begin designing the components that the
development team will create.
While you are considering technologies and development options during
physical design, you can also begin to determine more accurately the costs and
schedule for implementation of the project.
During physical design, you can determine how different implementation
options fit within the enterprise architecture. In this stage of development, you
can eliminate gaps and conflicts with the business environment before those
conflicts have a negative impact on the project schedule or project cost.
Physical design is the final step in the path from the original scenarios
developed in conceptual design, through logical design, to implementation. The
final implementation can be traced all the way back to the original business
goals and the vision statement.
Slide Objective
To describe the value that
the physical design phase
brings to the overall MSF
Design Process.
Lead-in
The physical design phase
brings great value to the
overall design in many
ways, including the
following.
188 Module 6: Beginning Physical Design
188 Module 6: Beginning Physical Design
Activity 6.1: Risks of Skipping Physical Design
In this activity, based on the course material preceding this activity, you will
take part in a class discussion to identify what the possible risks are of not
doing physical design.
After completing this activity, you will be able to:
"
Articulate the value of doing physical design and the risks of not doing
physical design.
Slide Objective
To introduce the activity.
Module 6: Beginning Physical Design 189
Module 6: Beginning Physical Design 189
!
!!
!
Physical Design Process
"
Physical Design and the MSF Process Model
"
Physical Design Steps
"
Deliverables of Physical Design
In this section
In this section
In this section, you will learn when the physical design phase takes place in the
overall MSF Design Process Model. You will also learn of the separate steps
that make up the physical design phase. Finally, you will look at some concepts
related to the physical design and the actual implementation of the solution.
Slide Objective
To provide an overview of
the topics and activities in
this section.
190 Module 6: Beginning Physical Design
190 Module 6: Beginning Physical Design
Physical Design and the MSF Process Model
Vision
Approved
Vision
Approved
Project Plan
Approved
Project Plan
Approved
Conceptual Design
Logical Design
Physical Design
Baseline
Physical design begins before the team baselines logical
design and baselines before the team reaches the Project Plan
Approved Milestone
Physical design begins before the project team has baselined the logical design
and is baselined before the team reaches the Project Plan Approved Milestone.
Physical design should begin when the project team agrees that logical design
has produced the outputs for it to use. As soon as portions of the logical design
have been completed, those portions can be taken into the physical design
phase.
Slide Objective
To explain where the
physical design phase takes
place in the overall MSF
Design Process.
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