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Microprocessors: technology, architecture and applications
Minicomputers and microprocessors M. Healey. Hodder and Stoughton (1976), 353 pp, hardback £9.50, paperback £6.25. Martin Healey has taken the view that in the areas of programming and interfacing and even. in their internal architecture, there is little which is fundamentally different between microprocessors and minicomputers. The basic skills of the minicomputer systems designer and programmer are still required by the microprocessor user even if they must be supplemented by a more detailed hardware knowledge. As a result he can offer a book which explains the techniques of computing both to the systems analyst who needs more knowledge about the hardware modules which he is putting together, and to the engineer, faced with the so-called microprocessor revolution who has no computer experience. The clearly-stated aim of the book is to explain to such people how the mini- or microcomputer works. This it does very competently, putting the central processing unit (CPU) in its rightful place as but a module, albeit a very important one, of a system which is dependent on memories and peripherals to function at all. The CPU is explained by reference to a hypothetical computer which, together with the extensions and refinements introduced in later chapters, includes most of the features of today's minicomputers. Typical instructions are analysed by reference to the hardware which must implement them. A separate chapter deals with the restrictions caused by the short word lengths of most microprocessors and the inevitable multiword ins~ruc,tions are again related to the internal architecture of the CPU. Block diagrams are giyen of typical 8-bit word length microprocessors but multichip processors are only briefly mentioned as representing an alternative means of constructing the larger word length machines which were dealt with. under the minicomputer heading. In a book which is more concerned with how computers are used rather than how they are designed it is important that the vital interface with the outside world is well-covered. The various
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inch,ads of transferring data and control information from the computer are well explained and brief descriptions are given of the many peripheral devices which are available to the minicomputer users and which could, of course, be interfaced to microprocessors if the necessary interface design were accomplished. Perhaps the last statement highlights the main weakness of the book as a work of reference for the new breed of microprocessor users for, despite the fact that microprocessors are just computers, there is still a world of difference between taking delivery of a minicomputer system and receiving through the post a J iffybag containing a few integrated circuits. Again, despite the claims made by manufacturers about the ease of use of their devices and the laudable attempts of some to provide adequate software and hardware back-up, it is generally found that a great deal of ancillary equipment, often including a minicomputer system, and a considerable hardware and software knowledge is necessary before any but the most trivial systems can be built from these chips. To be fair, this fundamental difference is mentioned in the text and the advice to treat the microprocessor as just a more complex integrated circuit is well intentioned but a more
thorough exposition of the work necessary before results can be expected with microprocessors would be welcome in a book which serves as an introduction to the subject. No claims are made to teach computer programming and the single chapter on software just explains the significance of the various software modules such as assemblers, loaders and compilers which the beginner will encounter. Again, the usefulness of the book to the complete beginner would be enhanced if it did contain enough on this subject for it to be used as a continuous work of reference at least during the first stages of program writing. Despite the above comments the basic aims of the book, to explain the fundamentals of computing devices to beginners, including those who are skilled in other branches of engineering, are well fulfilled. Clearly, few engineers in the future are going to escape the impact of large and small computers and the author is undoubtedly right in his assumption that the writing of computer programs deserves to push out the finer points of logic minimization in the training of engineers. As a result, the fundamentals of digital circuits are relegated to the appendix together with descriptions of binary number systems and memory devices. One final important point is that the book is sufficiently well-bound to stand up to repeated reference.
D. Daclt, Hewlett-Packard, West Lothian, Scot~and.
Microprocessors-technology,architecture and applications D. R. McGlyn. John Wiley & Sons, Chichester, UK. 320 pp (June 1976) $13.00. The 'microprocessor revolution', the In the introductory chapter it is microprocessor bandwagon '-whatever stated that 'the development of microphrase is used to describe the phenomprocessors may have been an evolenon, there is no doubting the wideutionary step in the semiconductor spread and intense interest in these component industry, but it is a revoldevices. Technology always has been a utionary step in the data processing, fast-moving field and microprocessor instrumentation, and industrial control technology is no exception. One result field.' The chapter ends with the conof this is a lack of books on the subject clusion '. . . . . that the microprocessor and so I was very interested to receive is one of the most significant technothis book. logical advances in recent years and
microprocessors
should have a major influence in the economics and design characteristics of systems in the electronics and data processing industries'. I thought that these opinions stated the case very well, especially at a time when nearly every issue of electronics and the computer journals contain articles on microprocessors and indeed this review appears in the first issue of a journal devoted entirely to microprocessors. The sub-title of the book is 'Technology, Architecture and Applications' and although these topics are covered, there is a strong emphasis on device technology and architectural aspects of the devices rather than the technology and architectural aspects of systems and applications. As a result of this, the book is likely to be of most interest to designers of graduate engineer level in the computer and electronic device industries. Managers in any area where microprocessors are likely to make an impact will, 1 think, find the first two chapters (introduction and system design) rewarding reading but may find later chapters on the details of microprocessor device manufacture and the descriptions of specific microprocessors, rather irrelevant. Similarly, applications and system design engineers may find the chapters on device technology and the device survey generally interesting but rather irrelevant and the applications chapters more than a little disappointing. Technology has clearly been interpreted in this book as the technology of the devices and the semiconductor processes used in their manufacture. I found this part of the book easy to read and it explains clearly the differe~ces between the various processes that are often rather glibly referred to in manufacturers' literature on new devices. The really valuable material, however, appears at the end of this section where the problems of technological obsolescence and market saturation are raised. However, despite these elegant observations on the dangers of technological obsolescence I was most amused to see the statement only 10 pages further on that 'Since there is a price differential between the two products (Intel 8008 and 8080) the 8080 should not be considered as a replacement for the older 8008, but merely directed to more
vol 1 no I september 76
sophisticated applications that cannot adequately be handled by the 8008.' The architectural and software aspects of microprocessors are covered from a computer scientist's viewpoint. The starting point is understandably the yon Neumann architecture but I. was surprised to find this followed by a much more detailed description of stack architecture though the relevance to microprocessors of stack processors that are '. . . . . particularly adapted to executing a . . . . . language such as ALGOL, COBOL or PL/I' is not explained clearly. The remainder of the architectural topic is explained well though the descriptions of the more common ancillary devices, e.g. RAM and UART, were very brief and not very informative, especially when compared with the healthy three pages devoted to ROM. Software for microprocessors is a problem for any introductory text as there is the dilemma of explaining the techniques and methods involved while avoiding the production of a programming primer which would require a book to itself. This problem is very sensibly approached in the book by the judicious use of easily understandable examples. Aids for software development are also described but here there is the incredible statement that 'although the use of high level languages may be acceptable for hobby or instructional purposes, the development of microprocessor systems for commercial applications places much more critical requirements on the software.' Taken together with the earlier comments on the falling cost of hardware, I was really surprised that the rapid increase of interest in high-level languages in the microprocessor field had not influenced the author. My own opinion is that as soon as an existing high-level language is suitably modified for microprocessor applications or an appropriate new language is produced, the take-up of this technique will be extremely rapid and is likely to be widespread within two or three years. This section of the book also describes cross-assemblers in a way that is not only totally incorrect, but is also at variance with the definition given in the glossary. The glossary is really very good and comprehensive (reprinted with permission of RCA).
Despite a few adverse criticisms, I think this book represents good value for money. There are very few books available on microprocessors and the alternative is to make use of lecture notes from courses on microprocessors and to follow the papers published in technical journals. I still look forward to seeing a comprehensive book on the application of microprocessors.
J. P. Stuart, Warren Spring Laboratory, Stevenage, UK.
Microcomputer dictionaryand guide Charles J. Sippe. Matrix Publishers Inc., Champagne, Illinois 61820, USA. $17.95. The number of new items, symbols and new techniques which lie in the wake of the microcomputer revolution make such a publication an essential life-raft for the engineer and designer. The author has compiled about 5000 terms which relate to microcomputer technology. The text defines terms which are commonly used as well as giving clear explanations of products, procedures, systems, techniques and components. There are eight sections which cover: the definitions of microelectronic terms, symbols, units and constants of electronics, electronic and computer acronyms and abbreviations, computer language summaries for APL, BASIC and FORTRAN., Computer number and binary switching systems and definitions of programmable calculator terms.
Microprocessors D. Wright, D. Shipperlee and A. G. Davies. The City University, Dept. of Electrical and Electronic Engineering, St. John Street, London, EC1V4PB. The publication stems from a course sponsored by the Department and by the Circuits and Systems Chapter of the UK and Republic of Ireland Section of the IEEE. The course reviews digital systems, the programming method, the characteristics of typical microprocessors (such as the 8080 and the GI CP1600), and outlines the criteria for selection.
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inch,ads of transferring data and control information from the computer are well explained and brief descriptions are given of the many peripheral devices which are available to the minicomputer users and which could, of course, be interfaced to microprocessors if the necessary interface design were accomplished. Perhaps the last statement highlights the main weakness of the book as a work of reference for the new breed of microprocessor users for, despite the fact that microprocessors are just computers, there is still a world of difference between taking delivery of a minicomputer system and receiving through the post a J iffybag containing a few integrated circuits. Again, despite the claims made by manufacturers about the ease of use of their devices and the laudable attempts of some to provide adequate software and hardware back-up, it is generally found that a great deal of ancillary equipment, often including a minicomputer system, and a considerable hardware and software knowledge is necessary before any but the most trivial systems can be built from these chips. To be fair, this fundamental difference is mentioned in the text and the advice to treat the microprocessor as just a more complex integrated circuit is well intentioned but a more
thorough exposition of the work necessary before results can be expected with microprocessors would be welcome in a book which serves as an introduction to the subject. No claims are made to teach computer programming and the single chapter on software just explains the significance of the various software modules such as assemblers, loaders and compilers which the beginner will encounter. Again, the usefulness of the book to the complete beginner would be enhanced if it did contain enough on this subject for it to be used as a continuous work of reference at least during the first stages of program writing. Despite the above comments the basic aims of the book, to explain the fundamentals of computing devices to beginners, including those who are skilled in other branches of engineering, are well fulfilled. Clearly, few engineers in the future are going to escape the impact of large and small computers and the author is undoubtedly right in his assumption that the writing of computer programs deserves to push out the finer points of logic minimization in the training of engineers. As a result, the fundamentals of digital circuits are relegated to the appendix together with descriptions of binary number systems and memory devices. One final important point is that the book is sufficiently well-bound to stand up to repeated reference.
D. Daclt, Hewlett-Packard, West Lothian, Scot~and.
Microprocessors-technology,architecture and applications D. R. McGlyn. John Wiley & Sons, Chichester, UK. 320 pp (June 1976) $13.00. The 'microprocessor revolution', the In the introductory chapter it is microprocessor bandwagon '-whatever stated that 'the development of microphrase is used to describe the phenomprocessors may have been an evolenon, there is no doubting the wideutionary step in the semiconductor spread and intense interest in these component industry, but it is a revoldevices. Technology always has been a utionary step in the data processing, fast-moving field and microprocessor instrumentation, and industrial control technology is no exception. One result field.' The chapter ends with the conof this is a lack of books on the subject clusion '. . . . . that the microprocessor and so I was very interested to receive is one of the most significant technothis book. logical advances in recent years and
microprocessors
should have a major influence in the economics and design characteristics of systems in the electronics and data processing industries'. I thought that these opinions stated the case very well, especially at a time when nearly every issue of electronics and the computer journals contain articles on microprocessors and indeed this review appears in the first issue of a journal devoted entirely to microprocessors. The sub-title of the book is 'Technology, Architecture and Applications' and although these topics are covered, there is a strong emphasis on device technology and architectural aspects of the devices rather than the technology and architectural aspects of systems and applications. As a result of this, the book is likely to be of most interest to designers of graduate engineer level in the computer and electronic device industries. Managers in any area where microprocessors are likely to make an impact will, 1 think, find the first two chapters (introduction and system design) rewarding reading but may find later chapters on the details of microprocessor device manufacture and the descriptions of specific microprocessors, rather irrelevant. Similarly, applications and system design engineers may find the chapters on device technology and the device survey generally interesting but rather irrelevant and the applications chapters more than a little disappointing. Technology has clearly been interpreted in this book as the technology of the devices and the semiconductor processes used in their manufacture. I found this part of the book easy to read and it explains clearly the differe~ces between the various processes that are often rather glibly referred to in manufacturers' literature on new devices. The really valuable material, however, appears at the end of this section where the problems of technological obsolescence and market saturation are raised. However, despite these elegant observations on the dangers of technological obsolescence I was most amused to see the statement only 10 pages further on that 'Since there is a price differential between the two products (Intel 8008 and 8080) the 8080 should not be considered as a replacement for the older 8008, but merely directed to more
vol 1 no I september 76
sophisticated applications that cannot adequately be handled by the 8008.' The architectural and software aspects of microprocessors are covered from a computer scientist's viewpoint. The starting point is understandably the yon Neumann architecture but I. was surprised to find this followed by a much more detailed description of stack architecture though the relevance to microprocessors of stack processors that are '. . . . . particularly adapted to executing a . . . . . language such as ALGOL, COBOL or PL/I' is not explained clearly. The remainder of the architectural topic is explained well though the descriptions of the more common ancillary devices, e.g. RAM and UART, were very brief and not very informative, especially when compared with the healthy three pages devoted to ROM. Software for microprocessors is a problem for any introductory text as there is the dilemma of explaining the techniques and methods involved while avoiding the production of a programming primer which would require a book to itself. This problem is very sensibly approached in the book by the judicious use of easily understandable examples. Aids for software development are also described but here there is the incredible statement that 'although the use of high level languages may be acceptable for hobby or instructional purposes, the development of microprocessor systems for commercial applications places much more critical requirements on the software.' Taken together with the earlier comments on the falling cost of hardware, I was really surprised that the rapid increase of interest in high-level languages in the microprocessor field had not influenced the author. My own opinion is that as soon as an existing high-level language is suitably modified for microprocessor applications or an appropriate new language is produced, the take-up of this technique will be extremely rapid and is likely to be widespread within two or three years. This section of the book also describes cross-assemblers in a way that is not only totally incorrect, but is also at variance with the definition given in the glossary. The glossary is really very good and comprehensive (reprinted with permission of RCA).
Despite a few adverse criticisms, I think this book represents good value for money. There are very few books available on microprocessors and the alternative is to make use of lecture notes from courses on microprocessors and to follow the papers published in technical journals. I still look forward to seeing a comprehensive book on the application of microprocessors.
J. P. Stuart, Warren Spring Laboratory, Stevenage, UK.
Microcomputer dictionaryand guide Charles J. Sippe. Matrix Publishers Inc., Champagne, Illinois 61820, USA. $17.95. The number of new items, symbols and new techniques which lie in the wake of the microcomputer revolution make such a publication an essential life-raft for the engineer and designer. The author has compiled about 5000 terms which relate to microcomputer technology. The text defines terms which are commonly used as well as giving clear explanations of products, procedures, systems, techniques and components. There are eight sections which cover: the definitions of microelectronic terms, symbols, units and constants of electronics, electronic and computer acronyms and abbreviations, computer language summaries for APL, BASIC and FORTRAN., Computer number and binary switching systems and definitions of programmable calculator terms.
Microprocessors D. Wright, D. Shipperlee and A. G. Davies. The City University, Dept. of Electrical and Electronic Engineering, St. John Street, London, EC1V4PB. The publication stems from a course sponsored by the Department and by the Circuits and Systems Chapter of the UK and Republic of Ireland Section of the IEEE. The course reviews digital systems, the programming method, the characteristics of typical microprocessors (such as the 8080 and the GI CP1600), and outlines the criteria for selection.
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