Lecture.10a.edited

Finalizing Design Specifications

Finalizing Design Specifications

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The Process of Finalizing Design Specifications

Less costly to correct and detect errors during the design phase.

Take logical design information and turn it into a blueprint for the physical information system.

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The Process of Finalizing Design Specifications

Can be paper-based or computer-based.

Can be written, graphical, or combination of the two.

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The Process of Finalizing Design Specifications (Cont.)

Can be high-level broad-based or detailed as possible.

Format and amount of detail will be driven by intended audience.

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The Process of Finalizing Design Specifications (Cont.)

Good specifications should be stated simply, completely, unambiguous, and have attributes that make requirements more understandable.

Deliverables and Outcomes for Traditional Projects A set of physical design specifications for the

entire system, including detailed specifications for each separate part of the system. Include functional descriptions for each part of the

system. input received and output generated for each

program and its component parts.

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Deliverables and Outcomes for Traditional Projects (Cont.) Complete design specification is

comprehensive. Design specifications can be based on:

Traditional methods. Agile methodologies (eXtreme programming).

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Specification Documents

Contains: Overall system description. Interface requirements. System features. Nonfunctional requirements. Other requirements. Supporting diagrams and models.

Specification Documents (Cont.) Computer-based requirements management

tools make it easier to keep documents up to date, add additional requirements and link related requirements.

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Specification Documents (Cont.)

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Figure 13-3 A screen from DOORS© Enterprise Requirements Suite(a product of Telelogic AB)

Specification Documents (Cont.)

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Figure 13-4 A screen from Compuware Optimal Trace requirements management and definition solution

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Structure Chart Structure Chart: a hierarchical diagram that

shows how an information system is organized. Shows how an information system is organized in

hierarchical models. Shows how parts of a system are related to one

another. Shows breakdown of a system into programs and

internal structures of programs written in third- and fourth-generation languages.

Structure Chart (Cont.)

Structure chart is composed of modules. Modules: a self-contained component of a

system that is defined by its function. Functions or subroutines in the resulting computer

program (COBOL, BASIC, FORTRAN). Method in object-oriented language.

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Structure Chart (Cont.)

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Figure 13-5 An illustration of the hierarchy of a structure chart

Structure Chart (Cont.)

Data couple: a diagrammatic representation of the data exchanges between two modules in a structure chart.

Flag: a diagrammatic representation of a message passed between two modules.

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Structure Chart (Cont.)

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Figure 13-6 Special symbols used in structure charts – Data couples and control flag

Structure Chart (Cont.)

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Figure 13-7 How to read a structure chart – (a) Nonoverlapping arrows

Structure Chart (Cont.)

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Figure 13-7 How to read a structure chart – (b) Overlapping arrows

Structure Chart (Cont.)

Serves two functions: Helps analyst think in a structured

way about the task a module is designed to perform.

Acts as a communication tool between analyst and programmer.

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