of various ReqIF implementations. ReqIF Server is another tool that natively uses ReqIF. Operation RIF/ReqIF is a standardized meta-model, defined by an XML schema. Such files must conform to the schema and contain the description of the model (the datatypes), as well as the data. A successful data exchange between various tools only succeeds, if all parties agree on a common data model. The previously mentioned implementor forum is working on such a common model and also organizes tests with tools of the participating manufacturers, to ensure future interoperability. Structure of ReqIF files An OMG ReqIF file consists of XML with the root element , containing information regarding the file itself as well as the contained datatypes and requirements. The containers for requirements in ReqIF are called specification objects (), which have user-defined attributes. Each attribute has a data type, which is one of , , , , (with user-defined values) and XHTML, which is also for formatted text and embedded objects, including images. Some datatypes can be constrained further, e.g. the range of numerical values. Relationships between objects are represented as , which can also have attributes. At last, hierarchical trees create a structured view on SpecObjects, called . Multiple references on the same SpecObject are permitted. The structure of ReqIF is described in detail in the specification. There is also a free one-page reference of the data model available See also Requirement Requirements Modeling Framework References External links ProSTEP iViP page with Information and Specifications (German) Requirements Interchange Format (ReqIF): Request for Comments (English) OMG: Requirements Interchange Format (ReqIF) Specification (English) Free ReqIF viewer for Windows (no installation needed) (English) ReqIF.academy: Free library of ReqIF information (references, checklists, software, etc.) (English) reqifsharp: Free open-source ReqIF library for .NET (English) ReqEdit: ReqIF Tool for reading, writing, merging, comparing, importing from word, excel etc. (English) XML Computer file formats Software requirements