Requirements modeling It’s important to revisit the model concept before we proceed What's modeling as applied to system? It’s a graphical representation of a concept or process that systems developers can analyze, test, and modify Systems analysts usually describe an information system by using a set of business data, object, network and process models. A business model will describe information that a system must provide and may consist of diagrams, charts, and documentation Requirements modelling is a fact-finding process aimed at describing the current system and identification of the requirements for the new system. A system requirement is a characteristic or feature that must be included in an information system to satisfy business needs and should be acceptable to users. System requirements serve as a benchmark to measure the overall acceptability of the system. Hence the need to properly document the system requirements System requirements are classified into five categories namely: • Outputs • Inputs • Processes • Performance • Security & control. Hence a requirements model will include all the five elements Input: Output: system inputs represent data that enter the system. It could be manual or automatic System outputs represent information produced by the system. It may be electronic or printed Process: System processes are logical rules applied to transform data into meaningful information. Performance: Performance refers to the following system characteristics; Speed, volume, capacity, availability, and reliability Security& control:Security and control requirements looks at hardware, software, and controls that safeguard and protect the system and its data from threats both external and internal.