A software process is better conceived out of products' and their changes, in place of viewing it directly in terms of constituent activities. This approach allows separating purely technical aspects from others, such as managerial ones; makes it easy to define the effects of activities; and enable us to analyse and control the ripple effects of modifications. The paper presents an example of this approach as applied t o an algebraic methodology, based on OBJ. The software process model explained in the paper can also be viewed as a n environment for software development with OBJ. St. OBJ, the environment, is described in OBJ itself. keywords -software process model, software process description, algebraic specification, formal method, OBJ, programming language, programming environment

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We have described QuickDraw, a typical graphics package, using OBJ2, a powerful algebraic language now in the phase of experimental use as a specification language. The results testify the applicability of OBJ2 to some practical problem domains, as well as the premonitioned advantages the use of formal specification techniques brings. The work also sheds some critical lights upon the design of QuickDraw; we detect incomplete procedure definitions, and find imprecise the classification of procedures.keywordsformal specification, algebraic language, graphics package 2 OBJ2 in Brief OBJ2 is a state-of-the-art programming language whose descriptive level is of such height as to be regarded as an attractively powerful specification language. In our research discussed here OBJ2 works as the latter self. The language is based upon algebraic semantics, composed of set of types, or sorts, in the usage of OBJ2, and equations among terms of each sort. It gives denotational semantics as initial algebra [12], on the one hand; on the other, the equations are operationally regarded as rewrite rules [17,28]. Some of the advanced features incorporated are [3,4,5,6]: 1. sophisticated mechanism of parameterisation. 0270-5257/88/0000/0334$01 .OO 0 1988 IEEE Recommended by: J. Mylopoulos 2. support given to ordered sorts.3. a powerful rewrite engine that recognises such properties ezpressions, constructed by recursively instantiating parameters. In a module expression a sort or operator can be renamed, as is by BitPattern here. Thus the parameterisation of OBJ2 allows you to: as associativity.structs.