Inside the Chip

ZX Computing

Patrick Cain

An understanding of a microchip is not necessary to use a computer, but I should imagine that most programmers have wondered from time to time what type of magic takes place between input and output to effect this phenomenon which takes up so much of our time. Some will naturally enough have investigated the subject further others will probably have thought the investigation too involved and contented themselves with a niggling curiosity, it is to these people that "Inside The Chip" by H. Davis and M. Wharton readily lends itself. Like the other books in the series "Inside The Chip" is not intended, nor does it attempt, to be a text book. As the others do, it touches on the main principles of its subject without becoming entangled in an analysis of the practical unit. The book is a journey inside the chip, explaining on the way what the chip is, how it works and describing some of the amazing things it can do. The guides on the journey are a team of micro sized men who draw the readers attention to the different types of chips, what each type is used for and what many of the jargon terms associated with chips mean. The analogy works well. 27 pages on and the reader will have been introduced, in a simplified way, to the electronic theory, discovered how chips are designed, how they are made and how the different types of chips are used. Registers, control circuits, addresses and the microprocessor's clock are all dealt with in the same way. The book is concise, informative and is fun to read. Little effort is required as a result to get this far and many of those niggling queries ought to be by now disappearing or maybe perhaps becoming sufficiently interesting to examine closer. Part two is less colourful; but nonetheless as interesting as it comes to terms with slightly more involved notions, 'Input and Output', inside the ALU, a simple logic circuit to build, how the ALU does arithmetic, hints on building circuits, each is handled with the same uncomplicated ease as the earlier topics. Certainly not Cambridge research level yet, but sufficient information within the 48 pages to either whet an appetite or satisfy a less inquisitive mind. Given that you can't read every book, some are too time consuming, some are mostly irrelevant, some are too involved: "Inside the Chip" is perhaps one you should read. Written by H. Davies and M. Wharton "Inside the Chip" is a book that is probably worthy of a glimpse from most people. ISBN 0-86020-729-3.

Personal Computer News

Nickie Robinson

Inside The Chip, by H Davies and M Wharton, Understanding Computer Graphics, by J Tatchell and L Howarth, Machine Code for Beginners, by L Watts and M Wharton, all published by Usborne, at £1.99 paperback, £3.99 hardback each 48 pages. These three slim volumes for beginners are colurfully illustrated making them easy to read. Robots demonstrate the tasks of the computer, some of them biking along eight pathways to eight section garages representing eight bit bytes, while others pin up notices or choose library books, depicting RAM and ROM. Colour is cut off towards the end of each book, and black and white pages bring them to a less visually stimulating close. Understanding Computer Graphics, by far the easiest to read, begins by describing how a picture is produced on screen and includes a clear explanation of the size of memory needed to produce pictures of differing resolution and colour. The rest of the book is dedicated to practical aspects of computer graphics - simulation, computer aided design, animation and computer art. The book ends with four graphics programs to run, with conversion charts for the BBC, Spectrum, Dragon and Apple. Inside the Chip starts enticingly with an illustration of a silicon chip beside an open tube of sweets. But the going gets tougher with explanations of registers, control circuits and logic circuits, among others. There are interesting sections on how chips are made and their origin and design. Practical circuits are included for those who like to dabble. Machine Code for Beginners is a brave attempt to simplify a difficult subject. Having fought through the explanation you have the opportunity to test your new-found skills by writing a simple program to add two numbers together. If you make this hurdle you are ready for flags, jumps, subroutines and conditional branches. You'll know you've arrived at this testing section of the book - it will be in black and white.