A Software Development Process for Small-Scale Embedded Systems
- Created: Tuesday, 31 January 2006
The cornerstone artifact of the analysis phase is a software requirements document (SRD) that details the requirements in textual use-case sequences, toplevel state description, and a hardware interface list. This is an artifact that is maintained throughout the product lifecycle. The product SRD largely consists of textual use-case sequences, which drive the rest of the development (i.e. object identification via sequence diagrams, test cases, and schedule).
Avoid any process of requirements discovery that includes partial design and implementation of the software product; this is very inefficient. Changes in the requirements will occur, prompting updates to the SRD, but an efficient development process means that the designers should make every attempt to unambiguously define the requirements of the customer up front. The process should also accommodate existing processes within the design company, including manufacturing, quality assurance, marketing, and engineering requirements.
Earlier, small-scale application development was defined as following a waterfall and iterative process. An iteration is the software development of one or more use-case scenarios. A schedule, developed as part of the analysis, defines the order of iterations for the implementation and test phases of the process. This order is decided based on customer needs, risk identification, and the importance of each use to the end product. Designers should schedule uses that contain risk items first, using functionality as the variable, and commit to delivering product on time.