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Practical databases
control - the DBMS or the user? And how much information about transactions is used to solve the problem? The first section considers general purpose database management systems, such as System R, designed to intercept all access requests or synchronization calls (such as lock requests), and to detect and avoid the synchronization anomalies. A model of schedulers is defined, the construction of schedulers is discussed and, finally, the prototype of such a scheduler is covered. The second section takes an updateintensive transaction system (such as an airline or hotel reservation system),
having known sets of transactions accessing a fixed database. Special synchronization strategies are noted, a data description language and a data manipulation language are presented - the languages are equipped with appropriate logic, and a few constructs are shown. Then the problem of proving serializability of transaction system is examined. The book ends with an outline of the directions of future work. It is not clear whom the book is aimed at, and at times the text gets quite involved. It contains some heavy mathematics. Perhaps this is
justified, as the monograph is part of the 'Lecture notes in computer science' series and treats the topic as a new development in computer science research and teaching: quickly, informally, and at a high level. The printing and the binding of the book are good, and the author is at home in the subject. I wonder whether some more effort could have been exerted to make the book a little easier to read, and less forbidding.
Practical databases
data manipulation languages, schemas, subschemas, and all of the other esoteric jargon of the field. In fact schema does not appear in the index. It is intimately involved with the hierarchial structure of IMS/DLI with only passing references to the CODASYL network model or the relational model. However, the book primarily addresses the data and its interrelations rather than the implementation under any particular database management system. The weakness in the book is its illustrations. While they are plentiful and pertinent, the notation does become a little awkward to follow at times. But more importantly, the organization of the printed page often puts text and illustration on separate pages when they need to be consulted together to comprehend the ideas being expressed. This volume summarizes without jargon, and with minimal limitations due to implementations, the database design process in a phase by phase approach. It identifies many design aids that possible can be developed to aid the designer. As such it can serve as an introduction or a supplement to larger, more detailed or more implementation specific volumes.
How to design filters
Computer-assisted data base design, G U Hubbard, Van Nostrand Reinhold Data Processing Series (1981 ) 285 pp, £21.20 Being responsible for the design of a database, I welcomed the opportunity to read and review this book. The title words 'Computer-assisted...' implied that I might find help in reducing the labour of designing complex data structures. Halfway through, I finally decided that the computer aids described represented either wishful thinking, a new project justification, or a closely held research project. In any event they were not readily available to the average database designer. I then continued to read with this new conception and decided that George Hubbard had attempted to pass on his own experience in an attempt to help other database designers. In addition he has defined goals for database system developers to meet in providing design aids. This book probably should be read by database designers of limited experience as it presents a usable data related approach, from concept to implementation, for database design. It does not get into the details of data description/definition languages,
volume 14 number 3 may 1982
Richard Holekamp, Computervision, ~VIA, USA
Subhendu Chaudhari, Computervision, MA, USA
Active filter design handbook for use with programmable pocket calculators and minicomputers, G S Moschytz and Petr Horn, ]ohn Wiley (1981) 316 pp, £16.00 The continuing advances in microelectronics are producing a rapid reorganization of the methodology of electrical filter design. In particular, the availability of high performance, low cost, operational amplifiers, is resulting in the replacement of traditional passive LC filters by active RC filters usually at a lower cost/performance ratio. However, a systematic design procedure of active filters has yet to emerge. This book attempts to establish a computeraided procedure for the optimal design of low cost, low tolerance, active filters. The handbook provides the design equations and flow charts for 23 basic types of second order sections. These are grouped into three categories: low-Q, medium-Q and high-Q, with each category containing equations for lowpass, highpass, bandpass and bandstop characteristics. Program listings for the complete design procedure are given in Fortran and in Basic, with the individual design equations also given as program records for the T1-SR59 hand calculator.
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having known sets of transactions accessing a fixed database. Special synchronization strategies are noted, a data description language and a data manipulation language are presented - the languages are equipped with appropriate logic, and a few constructs are shown. Then the problem of proving serializability of transaction system is examined. The book ends with an outline of the directions of future work. It is not clear whom the book is aimed at, and at times the text gets quite involved. It contains some heavy mathematics. Perhaps this is
justified, as the monograph is part of the 'Lecture notes in computer science' series and treats the topic as a new development in computer science research and teaching: quickly, informally, and at a high level. The printing and the binding of the book are good, and the author is at home in the subject. I wonder whether some more effort could have been exerted to make the book a little easier to read, and less forbidding.
Practical databases
data manipulation languages, schemas, subschemas, and all of the other esoteric jargon of the field. In fact schema does not appear in the index. It is intimately involved with the hierarchial structure of IMS/DLI with only passing references to the CODASYL network model or the relational model. However, the book primarily addresses the data and its interrelations rather than the implementation under any particular database management system. The weakness in the book is its illustrations. While they are plentiful and pertinent, the notation does become a little awkward to follow at times. But more importantly, the organization of the printed page often puts text and illustration on separate pages when they need to be consulted together to comprehend the ideas being expressed. This volume summarizes without jargon, and with minimal limitations due to implementations, the database design process in a phase by phase approach. It identifies many design aids that possible can be developed to aid the designer. As such it can serve as an introduction or a supplement to larger, more detailed or more implementation specific volumes.
How to design filters
Computer-assisted data base design, G U Hubbard, Van Nostrand Reinhold Data Processing Series (1981 ) 285 pp, £21.20 Being responsible for the design of a database, I welcomed the opportunity to read and review this book. The title words 'Computer-assisted...' implied that I might find help in reducing the labour of designing complex data structures. Halfway through, I finally decided that the computer aids described represented either wishful thinking, a new project justification, or a closely held research project. In any event they were not readily available to the average database designer. I then continued to read with this new conception and decided that George Hubbard had attempted to pass on his own experience in an attempt to help other database designers. In addition he has defined goals for database system developers to meet in providing design aids. This book probably should be read by database designers of limited experience as it presents a usable data related approach, from concept to implementation, for database design. It does not get into the details of data description/definition languages,
volume 14 number 3 may 1982
Richard Holekamp, Computervision, ~VIA, USA
Subhendu Chaudhari, Computervision, MA, USA
Active filter design handbook for use with programmable pocket calculators and minicomputers, G S Moschytz and Petr Horn, ]ohn Wiley (1981) 316 pp, £16.00 The continuing advances in microelectronics are producing a rapid reorganization of the methodology of electrical filter design. In particular, the availability of high performance, low cost, operational amplifiers, is resulting in the replacement of traditional passive LC filters by active RC filters usually at a lower cost/performance ratio. However, a systematic design procedure of active filters has yet to emerge. This book attempts to establish a computeraided procedure for the optimal design of low cost, low tolerance, active filters. The handbook provides the design equations and flow charts for 23 basic types of second order sections. These are grouped into three categories: low-Q, medium-Q and high-Q, with each category containing equations for lowpass, highpass, bandpass and bandstop characteristics. Program listings for the complete design procedure are given in Fortran and in Basic, with the individual design equations also given as program records for the T1-SR59 hand calculator.
173