Formal Specification in the Revision of GKS: An Illustrative Example

Electronic Workshops in Computing

1997

Many of the reported experiences in the industrial use of formal methods concern the development of products or product families, where the utility of the method is linked to direct savings in development costs or improved assurance of quality. However, one other area in which formal description techniques make a valuable contribution is in the development and documentation of International Standards, where the cost of using formal methods can be paid off both through increased quality of products that implement a given standard, and through the improved inter-operability of different implementations that comes from having a precise definition of the expected behaviour of a conforming implementation. The process of standardization within ISO/IEC is complex, and affords the oppertunity to use formal methods at different stages and in different ways. This paper illustrates how formal methods have been used in the development of two standards, the computer graphics standard, GKS, and the multi-media standard, PREMO. Formal methods have been used at different points during their development. This paper concludes with an appraisial of the work done and some thoughts about future directions. 2nd BCS-FACS Northern Formal Methods Workshop Formal Methods and Standards-An Idiosyncratic View The cycle of ballot, comment, revise, re-ballot, is a long one, but it does ensure that technical material is given thorough review. Published standards are reviewed at least every 5 years, at which stage the standard may be confirmed, revised, or withdrawn. There are three principles that underlie ISO/IEC standardization (adapted from [21]): Consensus views of manufacturers, vendors and users, consumer groups, testing laboratories, governments, engineering professions and research organizations are all taken into account. All may be represented in national standards-making bodies (such as BSI) and all have the opportunity to participate in the work. Industry-wide International Standards are meant to be global solutions to satisfy industries and customers world wide. Voluntary standardization is market driven and therefore based on voluntary involvement of all interests in the market place.

“…Much effort went into defining a clean architecture for the revised standard. A specification was given in OBJ [7].…”

Section: The Graphical Kernel System Gksmentioning

confidence: 99%

Formal Methods and Standards - An Idiosyncratic View

Electronic Workshops in Computing

1997

“…Such usage might include helping to clarify difficult parts of the design, or ensuring that the concepts on which the standard is built are complete and well-defined. There are examples of this approach for graphics standards already in the literature [6,7,2,5,9,14] which have helped to capture insights into the design of ISO 7942:1985, the Graphical Kernel System (GKS) and its revision which is currently underway in SC24. The ISO Directives foresee that such a formal description might be published as an ISO Technical Report to accompany the standard as a separate document, though none of the formal description work on GKS has been published in this way.…”

Section: Introductionmentioning

confidence: 99%

PREMO ‐ An Initial Approach to a Formal Definition

Computer Graphics Forum

Duke

Hagen³

et al. 1994

Self Cite

Many descriptions of multimedia programming systems are starting to appear in the literature, but little work has yet been done on how to formally specify and reason about such systems. This paper is a contribution on the use of formal description techniques for the specification of multimedia systems and explores a style in which the Object‐Z notation from the University of Queensland can be used to specify some of the properties and functionality of such systems. The work has been carried out with reference to the role of formal description techniques in the presentation of ISO/IEC International Standards and in particular to the Premo project in ISO/IEC JTCl/SC24.

“…A number of papers have now appeared in the literature describing different aspects of the revision to the ISO/IEC standard, the Graphical Kernel System (GKS) [I, 2,3]. At the time of writing this paper, the revised document [6] had reached the status of Draft International Standard (DIS) and a letter ballot on progression to International Standard was in progress.…”

Section: Introductionmentioning

confidence: 99%

GKS‐9x: The Design Output Primitive, an Approach to a Specification.

Nehlig

Computer Graphics Forum

1994

This paper describes an approach to the formal definition of the design primitive introduced in the revision of the ISO/IEC computer graphics standard, GKS. The paper starts with a general description of the design primitive and then describes the specification (which is given in the Z notation) and the motivation for the approach taken in some detail. The paper concludes with a reflection on the contribution of this work, and the descriptive style adopted an the GKS revision, to the role of formal description in the presentation of graphics standards.