The Design and implementation of a real-time system using the unix operating system
Dongye Pan · Journal of International Crisis and Risk Communication Research · 1989
The structured development methodology for real-time systems of Ward and Mellor is an extension of the more wellknown Yourdon's structured design methodology for sequential systems. This real time methodology considers the evolution of a system in three stages: 1. build an essential model, 2. build an implementation model, and 3. build a system. A bottle filling system (BFS) is employed as a case study to demonstrate the different stages of software development under Ward and Mellor's methodology. All designs are developed and documented on an IBM PC with the support of the Yourdon Analyst/Designer Toolkits. The final system is coded in C on a Gould computer running the UNIX operating system. Using the BFS, comparisons are made between three methodologies for designing real-time systems: Hatley's real-time system specification, Jackson's system design and programming, and Ward and Mellor's structured development methodology for real-time systems.