GUIDES FOR BEGINNERS

John Gilbert reviews the latest titles on the bookshelf.

Publishers are beginning to realise that there are few general introductory books to computers on the market. Several new titles have been released in the last few months and they have steered clear of introductions to specific machines.

The Pre-computer book by F A Wilson is published by Bernard Babani. The book has an odd title but that is the only strange thing about it. Wilson provides an introduction for the complete beginner. The concept of the computer is examined, together with such diverse subjects as number bases, hardware and simple programming. As a result it covers a great deal in very few pages.

The book will satisfy your curiosity if you want to know what a byte is or where to find the ROM of a machine, but if you are looking for very detailed information, this general guide is not for you and does not pretend to be.

The Pre-computer Book costs £1.95 and is one of the least expensive books which have been reviewed to date.

Another book for the complete beginner is Programming for Real Beginners from Shiva Publishing. The author is Philip Crookall. It is a general introduction to computers and does not stay on the theme of programming. It may be useful to someone who is beginning a course in computer studies and would suit anyone doing CSE or O level. It is available for £2.95.

For people who want to go a few stages further, Century Books thinks that it has provided the definitive text on Sinclair machines with its Century Computer Programming Course. What it has done is to publish a massive tome of text which is not indexed in any way. The book contains some interesting information on both machines but there is no way to find the information quickly. A proper index would, most probably, occupy another 10 pages.

While the expansion into the general sector of the market has been taking place, more Spectrum books have appeared. The state of play seems to be that anyone will do anything for a Spectrum.

The Century Computer Programming Course is written by Peter Morse, Ian Adamson, Ben Anrep and Brian Hancock. It costs £9.95 and is well worth the money.

The recent release of the Complete Spectrum ROM Disassembly, by Dr Ian Logan and Dr Frank O'Hara, must be a great relief to many machine code programmers who want to get to grips with the Z-80A processor inside the machine.

The book is published by Melbourne House and gives a detailed breakdown of all the routines in the ROM, including information on I/O routines, arithmetic and floating point calculations and the re-start routines at the beginning of the ROM.

The Complete Spectrum ROM Disassembly costs £9.95. It is slightly overpriced, although the information is worth having.

A book on machine code, Spectrum Machine Code, has been published by Shiva. The authors are Ian Stewart and Robin Jones and their handling of the subject is excellent, so far as it goes.

The book is very thin, although it provides a great deal of information. The chapters on the display and attribute files of the Spectrum are very interesting and will be of immense value to anyone who wants to use machine code graphics within programs.

Spectrum Machine Code is part of the Shiva Friendly Micro series and costs £5.25.

Advanced Graphics with the Sinclair ZX Spectrum by I O Angell and B J Jones is published by Macmillan Press. The authors are obviously academics, as the book seems to be aimed at those with a great technical understanding of the Spectrum and also a knowledge of Cartesian Co-ordinate geometry. It is written rather like a treatise, with many references to other books in the main text.

It is well-presented and provides plenty of technical information. The authors show how to develop arcade-quality graphics and also go into the realms of three-dimensional animation. The problem is that many Spectrum users would lose their way in the book, not because of any failing on their part but because of the authors' narrative style. Advanced Graphics with the Sinclair ZX Spectrum costs £9.95.

The ZX Spectrum - Your Personal Computer is published by Prentice/Hall International and written by Ian McLean, Simon Rushbrook Williams and Peter Williams.

The first third of it is taken-up by drawings of the Spectrum keyboard with marks showing the relevant key positions. Some readers may regard that as an insult to their intelligence, as all of those key functions are marked clearly on the Spectrum.

There are, however, several redeeming features. The text is clearly set out and the examples are excellent. The chapter on loading and saving programs is useful but merely repeats the one in the Spectrum manual.

It is a useful adjunct to the Spectrum manual and costs £5.95.

Melbourne House (Publishers) Ltd, Glebe Cottage, Glebe House, Station Road, Cheddington, Leighton Buzzard, Bedfordshire LU7 7NA.

Bernard Babani (Publishing) Ltd, The Grampians, Shepherd's Bush Road, London, W6 7NF.

Shiva Publishing Ltd, 4 Church Lane, Nantwich, Cheshire, CW5 5RQ.

Macmillan Press, 4 Little Essex Street, London, WC2R 3LF.

Prentice/Hall International, 66 Wood lane End, Hemel Hempstead, Herts, HP2 4RG.

'Advanced Graphics with the Sinclair ZX Spectrum' should on successful completion enable the reader to produce screen displays on par with anything available commercially.

Now for the bad news. Such ability is not easily gained and to understand the text fully a good deal of previous knowledge is necessary. The authors, both members of the Department of Computer Science, University of London, are undoubtedly well qualified to instruct on computer graphics and their work has produced an almost complete text book for the subject.

It is intended, according to the introduction, that the book may be read on different levels - either to simply gain from it the graphic displays provided by the listings therein, or to understand how those displays have been produced and then be capable of equivalent ingenuity. I would suggest that the cost of £9.95 would be prohibitive if your intention is only to realise the former.

By understanding the text the reader on completion will understand the theory and techniques of producing pie charts, bar charts, geometric drawings, engineering drawings and arcade type video games. Before undertaking study of the book the reader should have a good working knowledge of BASIC and some knowledge of machine code. No knowledge of graphics at any level is necessary, the authors rightly feel that any knowledge of graphics necessary will be given in the book. Further it is recommended that readers should be familiar with Cartesian coordinates. I would suggest that a knowledge of geometry and algebra beyond this will be required in order that the reader may concentrate on the graphics theory content rather than the mathematics.

Throughout the discussion it is assumed that a 48K is being used, although an appendix does give notes on how and where to make alterations should a 16K version be used. The approach has been to accompany each piece of theory with a worked example, similar to the method of maths or physics books. Where problems are likely to become over-complex or involve a modular approach has been adopted, breaking each larger work area into smaller more readily understandable ones. Without doubt this is effective, allowing the reader to progress at his or her own pace and to move forward when the reader feels he or she has mastered what has gone before. In this way no body of work ever seems inconquerable.

Chapter one looks at those commands which are concerned with graphics. I hope I won't be accused of shrinking from my task if I say that the following chapters analyse and explore what can be achieved by implementing these commands and their mathematical and computing aspects. Significant graphic displays will not be possible without an understanding of the mathematics used to generate them. It should be understood then that the maths can get heavy. It is the nature of any advanced study to be beyond the scope of one book where, in order to keep this book to a finite size, it has been necessary to restrict a discussion; however, further reading has been recommended.

Chapter fourteen, by way of a conclusion, looks at a practical video game and, with reference to what has gone before, examines it to discover how it was constructed. Chapter fifteen points to how this newly acquired skill and knowledge can be put to use by suggesting some major graphics projects; by this stage they should be within the ability of the reader.

The book aims at truly 'advanced' graphics in design and implementation and thus it does require a serious study and degree of commitment. The rewards it will pay are high.

Advanced Graphics with the Sinclair ZX Spectrum is written by IO Angell and BJ Jones. It is published by Macmillan Press and costs £9.95. ISBN 0 333 35050 2.