systems, but little direct reference is made to modelsconstructed on these lines or to computer vision systemsbuilt according to these models. On the other hand, thisbook is a good source for the 'artificial intelligence paradigm'applied to vision systems.

This book should form a useful reference for anyoneseriously interested in computer vision, pattern recognitionor image processing. There are no answers given to currentpractical problems and little information is given on per-formance — the emphasis is on methods. However, thereis much here to stimulate thought and further research. Itis left to the designer to choose the most appropriate setof techniques and mould them into a useful computer-visionsystem.

M.J.P. BOLTON

Using the Unix systemRichard GauthierPrentice-Hall International, 1982, 297pp., £14.20ISBN: 8359-8164-9

Traditionally, operating systems were written specificallyfor a particular brand of hardware and, for large mainframes,were generated to include only those portions needed tocontrol a given configuration. The development of portablesystems, such as Unix, means that a machine and its operatingsystem may be considered, and even purchased, separately.This has placed a greater emphasis on the availability of soft-ware facilities and has increased the interest in ease of useof the total system and its user friendliness. One thereforeneeds to know, before the software is purchased and themanuals become available, exactly what to expect. Recourseto journals and technical publications is one answer, but atext written specifically for prospective users is probably moreappropriate.

'Using the Unix system' has been written for people withsome knowledge of computing, who are therefore assumed toknow what an operating system is likely to do, but who haveno experience of Unix. It is, however, assumed that thereader has access to a Unix system so that he/she may ex-periment with the commands as they are discussed.

Chapters 2-4 cover logging into the system and creatingand manipulating files. The editor is discussed, then thefile system with details of directories and permissions. Thissection introduces the need for particular facilities within asystem, shows how Unix is commanded to perform certainfunctions which support the required facility and gives ex-amples of the use of the commands. Chapters 6 and 8 arewritten in the same style, and cover the basics of the Unixshell.

By contrast, chapters 5 and 7 are presented much morein the style of extracts from a manual. A wide range of Unixcommands are covered with plenty of detail and examples.However, there is less linking material and it is thus moredifficult to obtain any feeling for the overall philosophyand structure.

The final chapter, chapter 9, which constitutes aboutone quarter of the book, is entitled 'System administrator'.As this implies it deals with the duties and tasks of the 'super-user' who looks after the system for the user community.Topics such as start up, shut down and dumps are discussedwith details of the commands to perform these. There arealso useful sections on trouble shooting. Reading this chapterdoes fill in some of the general information lacking earlier;however, it is unlikely that anyone would tackle this jobwithout access to a full systems manual.

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As a 'new user' text the early chapters with their tutorialapproach give a good introduction. However, the style anddetail of the remainder of the book does not seem to followhappily. Full details of commands and options can be foundin the Unix manuals. Surprisingly the facility to print sectionsof the manual is not mentioned.

The Unix system is very open. Many systems are small,having few users. Its considerable cult following has arisenjust because it can be used in an informal way for softwaredevelopment within a project group. So to whom does theauthor aim his text? The software team who themselveswill control and run their new Unix machine seems the targetreadership. As a textbook for students using Unix, the ex-amples form a good beginning. However, their system admini-strator might be less happy about the 'superuscr' detailsdivulged in chapter 9. Also a general system overview wouldmake the book more helpful to them, as well as to thosewho wish to compare Unix with their present system.

Finally a warning: there seem to be a number of typo-graphical errors remaining in the text and the layout of theexamples, while usually very clear, is occasionally misleading.This latter may be due to the computer formatting and type-setting used in the preparation of the text!

WENDY J. MILNE

Microcomputer system designM.J. Flynn, N.R. Harris and D.P. McCarthy (Eds.)Lecture notes in computer science, Vol. 126, Springer-Verlag,1982, 397pp.ISBN: 3-540-11172-7

This book contains a set of articles based on the CREST-sponsored 'Advanced course on microcomputer system design'given at Trinity College, Dublin, in 1981.

As a software engineer with limited hardware experience,I found the first two chapters of greatest interest, but hard-ware-oriented engineers would probably find the two langu-age chapters and the operating system chapter more relevant.Approximately one half of the book is concerned with hard-ware topics, and the other half is concerned with softwareand architecture. This seems to be about the right balanceas it is generally agreed that microcomputer specialists needto be competent in both hardware and software.

The problem, however, is that many readers will findthat they are familiar with a substantial part of material,and only two or three chapters will interest them. The materialcovered starts with VLSI technology, treated in the usualmanner, but with extra emphasis on fabrication science andtechnology. This is followed with a chapter by Prof. Lewin,on computer aided design. David AspinalPs chapter on clas-sifying the microprocessor at the instruction set level is fol-lowed by one by Flynn on customising microcomputers forspecific tasks. Two chapters by Perrott on sequential andconcurrent languages are followed with one on microcomputeroperating systems by Harris. The final two chapters, by Popeand Wirth, cover distributed systems and a personal computer,respectively. This problem of unevenness in appeal is notunique to this book, but applies equally to the range ofbooks produced from the CREST courses.

For the postgraduate student, for which these coursesare designed, and possibly for 3rd-year undergraduates, thesebooks provide a good basic introduction to the subject,and this volume on microcomputers is no exception; it canbe thoroughly recommended for this group of readers.

ROY D. DOWSING

IEE PROC, Vol. 130, Pt. E, No. 3, MAY 1983