SC.3 Grand Design (Traditional Procedure)
SZ.3 Grand Design (Traditionelles Vorgehen)
The traditional procedure for a system development is frequently referred to as "Big Bang", "One Shot" or "Grand Design".
Typical in this procedure is the linear chronological course of the system development (phase model). During each phase, the entire System is handled in its complete functionality. The complete conclusion of a phase is the requirement for the beginning of the next phase.
Therefore, the traditional procedure is a special case in the incremental development (realization in increments).
The sequence of SD activities during the Grand Design are illustrated in Figure SC.3.
Figure SC.3: Sequence of SD Activities in Grand Design
Time T 0-Start
Initialization of project and beginning of activities with regard to the contents of submodel SD.
Time T 1-Complete User Requirements
From the point of view of activity SD1 - System Requirements Analysis, the System has been completely processed at T1. This means:
Time T 2-Completion of the System Development and System Transition
At time 2, the system development is completed and the System transferred for use.
The following steps are required for the realization:
After the System has been transferred, the development project is completed.
The schematically regulated and relatively rigid development procedure of a project as the one just described can-with sufficient experience in the application field-be planned and realized with foresight and limited risks by the specification of requirements.
The special problematics of the phase-oriented procedure are based on the limited and costly mechanisms for the consideration of unexpected changes and the inexperienced handling of requirements insufficiently or badly explained.
Based on experience, such a procedure can be dependably and successfully applied only when requirements are very clearly defined and when technical and user-level risks for the project are low.
Therefore, one of the special tasks of the PM is a sensible risk management that detects risks at a very early stage and is thus able to change the development strategy.
Based on changes detected and specified early, the quality assurance tasks must be planned and realized regularly. If the above mentioned risks can be eliminated, no special procedures with regard to quality assurance have to be observed.
The structured generation of the System according to the product structure is covered in the regulations of the configuration management. Since the System transfer into the system application is realized with one step, the delivery is simple.
The following list of advantages and disadvantages and the listing of the most important requirements support decision-making for the selection of the illustrated Grand Design procedure.
- Great planning and handling experience based on the availability of stable User Requirements,
- problem-free change of contractor after completion of each phase.
The mentioned individual advantages and disadvantages must be investigated and evaluated. They cannot be applied to all projects but have to be assessed on the basis of the user-level and Technical Requirements and the marginal conditions to be observed.
- Inflexible reaction to unpredictable changes,
- necessity of early definition of User Requirements and the corresponding specification for the entire development time,
- late System delivery.