SYSTEM DEVELOPMENT:
The goals of the system development process are to develop or acquire all of the components of a system and then to integrate these components to create the final system. The requirements are the bridge between the procurement and the development processes. Once contracts for the system components have been agreed, more detailed requirements engineering then takes place.
Plan-driven processes are used in systems engineering because different parts of the system are being developed at the same time. For systems that include hardware and other equipment, changes during development can be very expensive or, sometimes, practically impossible. It is essential therefore, that the system requirements are fully understood before hardware development or building work begins.
Reworking the system design to solve hardware problems is rarely possible. For this reason, more and more system functionality is being assigned to the system software. This allows some changes to be made during system development, in response to new system requirements that inevitably arise. One of the most confusing aspects of systems engineering is that companies use different terminology for each stage of the process. The process structure also varies. Sometimes, requirements engineering is part of the development process and sometimes it is a separate activity.
However, there are essentially six fundamental activities in systems development:
1. Requirements development: The high-level and business requirements identified during the procurement process have to be developed in more detail. Requirements may have to be allocated to hardware, software, or processes and prioritized for implementation.
2. System design: This process overlaps significantly with the requirements development process. It involves establishing the overall architecture of the system, identifying the different system components and understanding the relationships between them.
3. Subsystem engineering: This stage involves developing the software components of the system; configuring off-the-shelf hardware and software, designing, if necessary, special-purpose hardware; defining the operational processes for the system; and redesigning essential business processes.
4. System integration: During this stage, the components are put together to create a new system. Only then do the emergent system properties become apparent.
5. System testing: This is usually an extensive, prolonged activity where problems are discovered. The subsystem engineering and system integration phases are re-entered to repair these problems, tune the performance of the system, and implement new requirements. System testing may involve both testing by the system developer and acceptance/user testing by the organization that has procured the system.
6. System deployment: This is the process of making the system available to its users, transferring data from existing systems, and establishing communications with other systems in the environment. The process culminates with a ‘go live’ after which users start to use the system to support their work.
