Focus on design principles and on a process for doing design = To produce a precise, complete, high- quality foundation for product implementation

 Design principle  Designing in teams  Design standards  Designing for reuse  Designing for usability  Designing for testability  Design reviews & inspections

 Creative process; produce complete and precise specification of how to build a product  Complete design defines the principal parts, describe how they interact, and how they put together to produce the finished result.

 After the requirements have been defined, the entire software process concerns various levels of design;  The high-level design must produce a SDS （ Software Design Specification) ， which includes the complete functional specifications of each component, its interface and its state behavior

PRODUCT Component Part2Component Part1Component Part n Team Member 1Team Member nTeam Member 2 Designed & Implemented Designed & Implemented Designed & Implemented SDS the complete functional specifications of each component, its interface and its state behavior.

 The detailed design defines the logical structure, all the loop initialization and stepping conditions, the detailed state structure, and the state transitions for every pr ogram.  If the High-level design is vague or imprecise, the engineers have to fill the gap component incompatibilities, detected in integration & system test..

 High-level design differs from detailed design only in scope and detail.  In TSPi, the high-level design process is described in the design phase. The detailed-design process is described in the implementation phase.

 Using entire team  Design Studies  Using all the team’s talents Who should design each part? In what order? How do the parts fit together?

 Common problem in designing large software system = the need to define the overall system structure. If not, difficult to divide the work.  To have the entire team work together on the overall structure design. => An attractive alternative

 The entire team brainstorms the initial design ideas.  Once the team has picked a general approach, only one or two engineers are usually needed to document the highest level design, specify the interfaces, allocate system functions among the components, and define the overall program structure and logic.  And identify other team tasks could do:- design studies, standards development, and reuse.

 Design Studies › While the system designers are producing the external component specifications, other could think about alternative ways to design the components => to build the prototype, and user interface.

 Using All the Team’s Talents › Powerful range of skills and knowledge › To get all the members to fully contribute  Ask if anyone has further ideas or relevant knowledge on the topics Speak up

 Some important types of design standards; › Naming conventions › Interface formats › System and error messages › Defect standards* › LOC counting › Design representation standards

 Design Representation Standards  To know having the complete design, need a specification for what a complete design contains  Need to precisely document every design by using the 4 PSP design templates › The operational scenario template › The functional specification template › The state specification template › The logic specification template COMPLETE & PRECISE

 Reuse is a potentially powerful way to increase team productivity.  By establishing a reuse program, you can often save engineering time in development cycles.  Teams generally achieve higher reuse level when s/o produces an initial reuse standard and specifies a starter set of reusable parts:- › Reuse interface standards › Reuse documentation standards › Reuse part quality › Application support.

Reuse Interface Standards  One key issue of reuse: make parts convenient to use. To define reusable functions that are self-contained & cleanly isolated  Ex: the call-return interfaces

Reuse Documentation Standards Reuse Part Quality High Quality  Because give up if its first defect found.  To achieve the high part quality Use a fully defined process & conduct personal reviews & peer inspections of both the design and the code Application Support

 One way to make products usable is to produce scenarios for every key user function (reflect the kind of system you believe the users will want.)  *** Good idea to prototype and demonstrate all user interfaces.

 Black-box testing  White-box testing

 For improving the quality of your design.  A well-document design design analysis (check each design element => interfaces, state behavior.

 A development strategy  A development plan  A completed and inspected SRS Can’t do a competent design job unless you have a high-quality SRS that has been Inspected. The team must have agree on how to represent the completed design.

The development manager leads the team through…  Decide on the overall product structure.  Name the product components.  Allocate product function to components  Produce the component external specifications  Allocate use-cases function to these components.  Identifying the design tasks to be completed and documented.

 The quality/process manager leads the team to produce the design standards and name glossary.

 [Overall design specified and the components named] => produce the design specifications  The development manager lead  Lay out the design of the SDS document + identify the work needed to produce & dividing this work into sections. Allocate & get the commitment

 Each team member  Produces and reviews his or her portions of the SDS document  Provides these to the development manager  The development manager produces a composite SDS draft.

 to produce the integration test plan while you are producing the design specifications check & verify all interfaces  Inspect the integration test plan when inspect the SDS.

 The quality/process manager leads all the team through inspecting the SDS draft and integration test plan. to find maximum no. of design defects. to ensure all team understand the design. The inspection is documented in form INS and defects are recorded in LOGD.

 Team member fix the identified errors in SDS/ integration test plan  The development manager obtains the updated SDS and integration test plan sections and c ombine them into a final SDS and integration test plan  Distributes.

 The support manager baselines an official SDS copy, which the team can now change only by using the change control procedure (form CCR).

The final design products are …  The completed, inspected and corrected SDS, + all design material  The completed, inspected and corrected integration test plan  The design standard and name glossary  The completed inspection forms (INS)  Updated SUMP and SUMQ forms  Update time, size, defect  Updated the project notebook (copy all design materials)

 To ensure that engineers produce high- quality design.

Produce overall design Divide into principal components Design B Design ADesign C The development manager SDS

 Precise, complete, high-quality  How the product part interact  How assembled to the finished system

 Deciding on the overall product structure  Allocating product functions to components  Producing the component external specifications  Deciding which components & functions to develop in each development cycle. + REUSE and STANDARDS