Tài liệu Module 10: Completing Physical Design ppt

Module 10: Completing Physical Design 352 Module 10: Completing Physical Design Module Overview Module 3: A Services-Based Approach to Solution Design Module 4: Business Solution Conceptual Design Module 5: Business Solution Logical Design Module 6: Beginning Physical Design Module 1: Course Overview Module 2: Solution Design Using the MSF Module 7: Selecting Solution Technologies Module 8: Solution Design and the Component Object Model Module 9: Designing Solutions with Microsoft Technologies Module 10: Completing the Physical Design Module 11: Designing the Presentation Layer Module 12: Introduction to Functional Specifications Designing Business Solutions Physical Design Specification Review Activity 10.2: Refining Preliminary Distribution for Performance Module 10: Completing the Physical Design Physical Design Rationalization Basics Rationalization: Distribution and Packaging Activity 10.1: Creating and Distributing Preliminary Components Activity 10.3: Factors Impacting the Programming Model Module 10: Completing Physical Design 353 ! !! ! Overview " Physical Design Rationalization Basics " Rationalization: Distribution and Packaging " Activity 10.2: Refining Preliminary Distribution for Performance " Physical Design Specification " Activity 10.3: Factors Impacting the Programming Model " Review In this module In this module After completing this module, you will be able to: " Complete the rationalization step of physical design. " Derive a physical design from a logical design. " Describe the deliverables of a physical design specification. " Describe a component specification. Slide Objective To provide an overview of the module topics and objectives. 354 Module 10: Completing Physical Design ! !! ! Physical Design Rationalization Basics In this section In this section " Deliverables of the Rationalization Baseline " Distribution and Packaging Strategy " Packaging Terminology: Cohesion " Packaging Terminology: Coupling " Distribution and Packaging Strategy Considerations The focus of the rationalization step is on designing services-based components and developing a distribution strategy for those components. In this section, you will learn about how to determine a strategy for the distribution and packaging of the services that you have designed. You will also learn about how coupling and cohesion will affect your packaging strategy. Slide Objective To provide an overview of the topics and activities in this section. Module 10: Completing Physical Design 355 Deliverables of the Rationalization Baseline Task Determining a packaging and distribution strategy Transforming objects into services-based components Distributing components across topologies Using strategy and prototypes to refine packaging and distribution Deliverable Packaging and distribution strategy Services-based preliminary components Deployment model " Future network topology " Future data topology " Future component topology Baselined deployment model Rationalization Baseline Rationalization The rationalization baseline results in several deliverables. These deliverables describe the technologies, strategies, and topologies that you have designed for the solution. Slide Objective To list the deliverables of the rationalization baseline. 356 Module 10: Completing Physical Design Distribution and Packaging Strategy " Distribution Strategy $ Rationale for determining which services go where in the solution architecture $ Distribution is services-based, not component-based " Packaging Strategy $ Rationale for determining which services go into which components $ May have multiple strategies in a single solution The rationalization step is an iterative process that strives for the optimum solution at a particular point in time. The following strategies can be used to help determine an appropriate overall component distribution and packaging strategy: " Scalability involves the ability to quickly and easily extend the solution to handle more transactions or more use. " Performance involves the response time of the system and the speed with which a system performs application tasks. " Manageability involves the ease with which an application can be managed on all levels. " Reuse involves the ease with which components can be reused by other applications. " Business context involves the separate business functions such as accounting or sales. " Granularity involves the number of services and objects that are packaged in a component. Slide Objective To define what is meant by distribution and packaging strategy. Lead-in One of the main goals of the rationalization step is the distribution of services and the packaging of those services into components. Delivery Tip Do not spend too much time on this topic; it is just the introduction to distribution and packaging. The details are presented in the next section. Module 10: Completing Physical Design 357 Packaging Terminology: Cohesion " Defines how well internal parts of a component relate to one another $ High level: Print Timesheet Component contains only services that help it to print timesheets $ Low level: Application Server Component contains all services that exist on the application server " High cohesion is the goal $ Provides a better definition of the component’s function and behavior Cohesion refers to how the operations in a specified unit, a component, are related. The closer the relation between the services is, the higher the reliability of the component. Cohesion is beneficial when it is as follows: " Functional A unit does only one thing. This is the strongest type of cohesion. " Sequential A unit contains operations that must be performed in a specific order and that must share the same data. " Communicational Operations in a unit use the same data but aren’t related in any other way. This type of cohesion minimizes communication overhead in the system. " Temporal Operations are combined, because they are all performed simultaneously. Not all cohesion, however, is beneficial. Other types of cohesion can result in a solution that is poorly organized and difficult to understand, debug, and modify. Ineffective types of cohesion include the following: " Procedural Operations are grouped together because they are executed in a specific order. Unlike sequential cohesion, the operations do not share any of the same data. " Coincidental Operations are grouped without any discernible interrelationship. Slide Objective To define cohesion as an aspect of packaging and to define the importance of a high level of cohesion. Lead-in When packaging services into components, it is important to take into account how the services of a component relate to each other. Delivery Tip The concepts of cohesion and coupling are important to the process of distribution and packaging of services. Make sure that the students understand these concepts. Facilitate a discussion if it is required. 358 Module 10: Completing Physical Design Packaging Terminology: Coupling " Defines how each component relates externally to other components $ Tight: Component relies heavily on other components in order to accomplish its function $ Loose: Component is not dependent or less dependent on other components to accomplish its function " Loose coupling is the goal $ Provides greater component independence, enables distribution flexibility, and leads to better-defined and simpler interfaces Typically, the looser the link that binds components to each other, the freer the designer is to use individual components without causing problems. A component should depend as little as possible on other components. If a dependency exists, however, the connection between those components must be as clear as possible for easier definition and greater simplicity in determining interfaces. Slide Objective To define component coupling and the importance of loose coupling. Lead-in When packaging services into components, it is also important to take into account how components relate to each other. Delivery Tip The concepts of cohesion and coupling are important to the process of distribution and packaging of services. Make sure that the students understand these concepts. Facilitate a discussion if it is required. Module 10: Completing Physical Design 359 Distribution and Packaging Strategy Considerations " Each strategy will be greatly impacted by solution architecture and infrastructure $ If strategy involves performance and a one-user solution, then services may all reside on one computer $ If strategy involves performance and thousands of users, then services may be distributed across many computers " Balance is required when multiple strategies are used $ Performance and reuse may mean one machine but many small components When deciding on a strategy for distributing and packaging the services of the business solution, you to must consider the solution and physical requirements and constraints. Although a single strategy — such as installing all services on a single machine — might work in some cases, you will more likely have to use multiple strategies to accomplish your goals. When using multiple strategies, you should strive for a balance between the various requirements and constraints of the solution. Slide Objective To describe two considerations when distributing and packaging services. Lead-in When deciding how to distribute and package the solution services, you must take into account solution and physical requirements. 360 Module 10: Completing Physical Design ! !! ! Rationalization: Distribution and Packaging " Creating Preliminary Components " Transforming Objects into Components " Distributing Preliminary Components " Activity 10.1: Creating and Distributing Preliminary Components " Validating Distribution and Packaging " Refining Distribution and Packaging In this section In this section Creating and refining a component topology is a crucial aspect of the services- based approach to business solution design. In this section, you will learn how to create an initial component topology and how to validate and refine the topology. Slide Objective To provide an overview of the topics and activities in this section. [...]... Overview Designing Business Solutions Module 8: Solution Design and the Component Object Model Module 7: Selecting Solution Technologies Module 2: Solution Design Using the MSF Module 3: A Services-Based Approach to Solution Design Module 4: Business Solution Conceptual Design Module 5: Business Solution Logical Design Module 6: Beginning Physical Design Now that you have finished the physical design, ... project 382 Module 10: Completing Physical Design Looking Forward Slide Objective To provide a context in which students can frame what they have just learned and foreshadow what they will be learning Module 12: Introduction to Functional Specifications Module 11: Designing the Presentation Layer Module 10: Completing the Physical Design Module 9: Designing Solutions with Microsoft Technologies Module 1:... Specification Baseline Physical Design Baseline The specification baseline is the final step of physical design and leads to the physical design baseline The deliverables of physical design specification include a programming model; component specifications for interfaces, attributes, and services; and the baseline of the component specification 370 Module 10: Completing Physical Design Component Specification... components in the physical design stage This will reduce complexity and confusion during the development process Module 10: Completing Physical Design 381 Review Questions Slide Objective To reinforce module objectives by reviewing key points Lead-in The review questions cover some of the key concepts taught in the module " Complete the rationalization step of physical design " Derive a physical design from... components 376 Module 10: Completing Physical Design Also, as previously discussed in Module 8, COM components can support a single interface or dual interfaces These interfaces can be defined through IDispatch or IClassfactory Certain clients can access only certain interfaces; for example, ASP can use only objects that implement the IDispatch automation interface Module 10: Completing Physical Design 377... Module 10: Completing Physical Design ! Review Slide Objective To reinforce module objectives by reviewing key points Lead-in In this section, you will learn some practical guidelines for practicing the concepts of this module, and you will test yourself on your understanding of those concepts " Guidelines " Review Questions " Looking Forward In this section In this section 379 380 Module 10: Completing. .. across the network topology Module 10: Completing Physical Design 365 Validating Distribution and Packaging Slide Objective To discuss the process of validating the solution design " Validate as a fundamental aspect of design, not as a distinct design step " Use validation as the trigger for design iteration and evolution " Validate against the packaging strategy, the design goals, the application... section In this section In this section, you will learn about the specification step of physical design First, you will learn about the programming model and aspects of the programming model You will then learn about component interfaces and how to complete the physical design Module 10: Completing Physical Design 369 Deliverables of the Specification Baseline Slide Objective To list the deliverables... constraints or requirements After completing this activity, you will be able to: " Modify a component topology based on an additional packaging and distribution strategy 367 368 Module 10: Completing Physical Design ! Physical Design Specification Slide Objective To provide an overview of the topics and activities in this section " Deliverables of the Specification Baseline " Component Specification... as a night clerk or general manager 374 Module 10: Completing Physical Design " Finally, you should carefully consider the method for distributing the application Remember that three logical layers do not necessarily translate into three physically distributed tiers For example, some business services tend to reside on the client, so you should have as many physical tiers as are required to meet the . Module 10: Completing Physical Design 352 Module 10: Completing Physical Design Module Overview Module 3: A Services-Based Approach. Solution Design Module 4: Business Solution Conceptual Design Module 5: Business Solution Logical Design Module 6: Beginning Physical Design Module 1: