As an instance for a large specification, an algebraic specification of the intel 8085 micro-processor is given. The specification is based on the concepts of hierarchical abstract types and conditional equations. With the help of the specification interpreter RAP, the specification is validated against some of its informal requirements. In the design of large software systems, a number of informal specification properties have to be considered such as style, readability, and structuredness of a specification. These properties are talked about using a couple of small examples.