Digital test text caters for academia and researchers Hideo Fujiwara

"Logic testing and design for testability" MIT Press, Cambridge, ~VIA, USA (1985) £34.95 pp x + 284

For reasons that escape me, there is a shortage of books on digital testing. Nobody now denies that the subject is just as important as digital design and yet books on design must outnumber books on testing by at least 20 to one. A new book on testing is therefore an event which should be heralded with due ceremony, provided it contributes to the topic in an authoritative way. Professor Fujiwara's book does just that but in a limited way.

The book has been organized into two major sections: the first part on logic testing and the second part on design for testability. Both sections follow a classical sequence of topics. Part 1 introduces the testing requirement and comments briefly on types of failure mechanisms and their related fault effects. The core of Part 1 concentrates on test generation algorithms and fault simulation techniques, with detailed discussion of the Boolean difference, D-algorithm, PODEM and FAN algorithms, followed by the principles of parallel, deductive and concurrent fault simulation tech- niques. The presentation of these topics is mathematically based (where appropriate) but only lightly illustrated through very simple examples.

Part 2 starts with a discussion on what 'testability' means and how, in the end, it is related to cost. The author then pursues the ways in which the costs of test application and test generation can be reduced by such techniques as designing for minimum test sequences or partitioning. During the course of this discussion the author also introduces the topics of syndrome testability and Read- Muller canonical forms. Part 2 concludes with a chapter on scan design (with discussion of the LSSD,

scan-set and random-access variants) and built-in test (use of linear- feedback-style registers and BILBO).

The book has clearly been written by an academic and is of most value to other academics. From a practitioners viewpoint, there is too much missing. For example, there is nothing on the use of fault collapsing or sampling techniques to reduce the fault-simulator target fault lists, and hence run time. The important subject of testing LSI and VLSI devices such as ROM, RAM and even microprocessors is also ignored. The RAPS variant of PODEM is not described; neither is the concept of the serial shadow shift register discussed despite the fact that this particular form of scan design is an important and powerful means of implementing scan through the use of standard off-the-shelf (merchant) devices.

I also found the book to be light on illustrative examples. Algorithms and procedures that are illustrated are done so with very simple examples. The reader wishing to extrapolate to larger and more realistic problems

will have some difficulty. The real world differs quite considerably from the illustrative five-gate example!

For this reason, I hesitate to recommend the book for students, although as a course reference text the book is useful. I would be concerned, however, at the lack of commercial judgement on the topics. The Boolean difference technique is not used in industry other than by those engaged in 'semi-academic' research, whereas an algorithm such as PODEM is used extensively. Judgements of this sort are missing in the text.

Overall, I would say that the book is useful to those entering the subject at an academic research level. It is of limited value to students and even less so to engineers and their managers in industry. Nevertheless, Professor Fujiwara has produced a useful reference text and, for anybody who is seriously trying to progress the 'state of the art', I would recommend purchase.

R G Bennetts GenRad DEC, Fareham, UK

Data comms for industry and management

Fred Halsall

"Introduction to data communi- cations and computer networks" Addison-Wesley, Wokingham, UK (1985) £12.95 pp ix + 27

This book is well titled in that it deals exclusively with data communi- cations between computers them- selves and their peripheral data entry and data exit devices, as well as the various networking methods that are being evolved to allow satisfactory implementation of a data communi- cation service.

The author claims that a primary aim has been to assemble much of the published information which is only available in standard documents

into a form suitable for use by a student or practising engineer wishing to gain a general under- standing of the subject. I believe he has succeeded in this objective.

The book is based upon a series of lectures given to electronics engineering and computer science students and no attempt is made to hide its origins. Each chapter commences with a list of points that are to be presented to the reader and concludes with a number of problems which the reader should be able to tackle successfully if he has absorbed the material thoroughly.

Chapters and subsections have been written as complete entities

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H alsall (Continued)

and consequently there is consider- able repetition of basic statements. This structure makes it irritating to read in lengthy sessions, but since the book is intended to be used as either a teaching aid or a reference book into which the engineer can dip at will to learn about a particular aspect, this is of little consequence.

The layout of the book will make it quite attractive to management as well as to students and designers. It is well illustrated and the diagrams and tables are well located in the text. It is only occasionally that the explan- ations become heavy going - - this is almost inevitable where the subject matter is very complex.

After a brief description of distri- buted system architectures taking up some nine pages, the book expands into data transmission basics including control circuits, synchron- ization and error detection methods. The jargon of the subject is intro- duced and well explained and then subsequently used in context with a handy glossary at the end to jog the memory. The subjects of error control, flow control and link management are dealt with in some depth before the various types of electrical inter- face are described. The importance of modems and how they contribute in the communication function is given adequate attention.

Having covered the basic features of data transmission, networks are dealt with in a useful fashion. Both wide area and local area networks (LANs) are encompassed and the common as well as the distinguishing characteristics are highlighted. The subject of the ubiquitous ISO seven- layer model has a chapter dedicated to it and for the curious it is possible, for example, to get a sensible under- standing of the purpose and behaviour of any particular layer without having to plough through a lot of intro- ductory material.

The various topologies of LANs are described and the characteristics of the several access methods discussed. The depth is adequate for a general understanding of the subject and the diagrams are quite helpful as are the comments on performance

criteria. It is understandable that, with the speed at which developments are occuring in this area, applications of LANs in industry are not dealt with, nor is the MAP activity promoted by GM mentioned.

The book concludes with two appendices giving some insight into the mysteries of forward error control and data encryption.

In my view, this is a book to be recommended for technical libraries

in industry and managers' book cases alike. It is useful for anyone wishing to learn quickly what data communi- cation is about generally, or alterna- tively to find out a bit more about some particular aspects. It is a bonus that the set problems even allow you to test for what you have learned!

Lionel Thompson Hawker Siddeley Ltd,

Welwyn Garden City, UK

Interactive graphics guide based on IBM PC Chan S Park

'Interactive microcomputer graphics' Addison-Wesley, Wokingham, UK (1985) £36.95 pp xviii + 458

This hardback text is intended for students and practitioners of computer graphics, and uses the IBM PC as a basis for much of the descrip- tion and as a host for the software examples given, which are numerous. This choice should ensure that a large proportion of readers are able to experiment with the techniques described. The book is targetted as an introductory text to computer graphics, or to supplement more advanced programming and manage- ment science courses; the latter is covered by the fourth part of the text.

The hardware and graphics characteristics of the IBM PC are described in part one, at an easily assimilated level. The basic commands available on the PC are described and examples are given of their use. Exercises for the reader, and references, are given at the end of each chapter.

As might be expected, the text is liberally illustrated with clear figures and several full-colour graphics examples.

Part two covers basic mathematics behind 2D and 3D graphics, and hidden line and surface removal. Coordinate systems and 3D rotation are covered in an easy-to-read manner, as are the other topics.

Having covered some basic concepts in parts one and two, part three describes the design of a graphics package, again for the IBM

PC, although it could be ported to other systems without much difficulty. This package handles 2D and 3D plotting, rotation, scaling and trans- lation, data manipulation and input from the keyboard. Complete program source listings in BgSlC are provided and the reader is urged to extend the programs for their own applications.

Part four covers the application of graphics to a particular task, namely management decision making. While this may seem an odd subject for inclusion in a text on interactive microcomputer graphics, the author justifies it on the pretext that it provides a complete discrete example of a real application. I think he is justified in this, although the inclusion is clearly due to a personal interest in this topic.

Multiple regression analysis and economic risk simulation are covered, with software provided.

An appendix covers methods of plotting 3D histograms and stacked bar charts.

One useful feature in the book is a tear-out postcard, offering to dispatch an IBM-compatible floppy disc with all the software in the book for $49.95. There is also a card enabling the reader to take out a licensing agreement- - i t would be interesting to know what proportion of readers take this up.

At £36.95 the book is not cheap. However, its clear illustrations, easy reading style and the material covered make it a worthwhile acquisition for anyone interested in interactive graphics.

Ion Leslie Logica, Swindon, UK

174 microprocessors and microsystems