Hardware description languages (HDL) such as VHDL and Verilog have found their way into almost every aspect of the design of digital hardware systems. Since their inception they gradually proved to be an essential part of modern design methodologies and design automation tools, ever exceeding their original goals of being description and simulation languages. Their use for automatic synthesis, formal proof, and testing are good examples. So far, HDLs have been mainly dealing with digital systems. However, integrated systems designed today require more and more analog parts such as A/D and D/A converters, phase locked loops, current mirrors, etc. The verification of the complete system therefore asks for the use of a single language. Using VHDL or Verilog to handle analog descriptions is possible, as it is shown in this book, but the real power is coming from true mixed-signal HDLs that integrate discrete and continuous semantics into a unified framework. Analog HDLs (AHDL) are considered here a subset of mixed-signal HDLs as they intend to provide the same level of features as HDLs do but with a scope limited to analog systems, possibly with limited support of discrete semantics. Analog and Mixed-Signal Hardware Description Languages covers several aspects related to analog and mixed-signal hardware description languages including: The use of a digital HDL for the description and the simulation of analog systems The emergence of extensions of existing standard HDLs that provide true analog and mixed-signal HDLs. The use of analog and mixed-signal HDLs for the development of behavioral models of analog (electronic) building blocks (operational amplifier, PLL) and for the design of microsystems that do not only involve electronic parts. The use of a front-end tool that eases the description task with the help of a graphical paradigm, yet generating AHDL descriptions automatically. Analog and Mixed-Signal Hardware Description Languages is the first book to show how to use these new hardware description languages in the design of electronic components and systems. It is necessary reading for researchers and designers working in electronic design.

An open process of restandardization, conducted by the IEEE, has led to the definitions of the new VHDL standard. The changes make VHDL safer, more portable, and more powerful. VHDL also becomes bigger and more complete. The canonical simulator of VHDL is enriched by new mechanisms, the predefined environment is more complete, and the syntax is more regular and flexible. Discrepancies and known bugs of VHDL'87 have been fixed. However, the new VHDL'92 is compatible with VHDL'87, with some minor exceptions. This book presents the new VHDL'92 for the VHDL designer. New features ar explained and classified. Examples are provided, each new feature is given a rationale and its impact on design methodology, and performance is analysed. Where appropriate, pitfalls and traps are explained. The VHDL designer will quickly be able to find the feature needed to evaluate the benefits it brings, to modify previous VHDL'87 code to make it more efficient, more portable, and more flexible. VHDL'92 is the essential update for all VHDL designers and managers involved in electronic design.

Models in System Design tracks the general trend in electronics in terms of size, complexity and difficulty of maintenance. System design is by nature combined with prototyping, mixed domain design, and verification, and it is no surprise that today's modeling and models are used in various levels of system design and verification. In order to deal with constraints induced by volume and complexity, new methods and techniques have been defined. Models in System Design provides an overview of the latest modeling techniques for use by system designers. The first part of the book considers system level design, discussing such issues as abstraction, performance and trade-offs. There is also a section on automating system design. The second part of the book deals with some of the newest aspects of embedded system design. These include co-verification and prototyping. Finally, the book includes a section on the use of the MCSE methodology for hardware/software co-design. Models in System Design will help designers and researchers to understand these latest techniques in system design and as such will be of interest to all involved in embedded system design.

Model Generation in Electronic Design covers a wide range of model applications and research. The book begins by describing a model generator to create component models. It goes on to discuss ASIC design and ASIC library generation. This section includes chapters on the requirements for developing and ASIC library, a case study in which VITAL is used to create such a library, and the analysis and description of the accuracy required in modeling interconnections in ASIC design. Other chapters describe the development of thermal models for electronic devices, the development of a set of model packages for VHDL floating point operations, a techniques for model validation and verification, and a tool for model encryption. Model Generation in Electronic Design is an essential update for users, vendors, model producers, technical managers, designers and researchers working in electronic design.

One of the main applications of VHDL is the synthesis of electronic circuits. Circuit Synthesis with VHDL is an introduction to the use of VHDL logic (RTL) synthesis tools in circuit design. The modeling styles proposed are independent of specific market tools and focus on constructs widely recognized as synthesizable by synthesis tools. A statement of the prerequisites for synthesis is followed by a short introduction to the VHDL concepts used in synthesis. Circuit Synthesis with VHDL presents two possible approaches to synthesis: the first starts with VHDL features and derives hardware counterparts; the second starts from a given hardware component and derives several description styles. The book also describes how to introduce the synthesis design cycle into existing design methodologies and the standard synthesis environment. Circuit Synthesis with VHDL concludes with a case study providing a realistic example of the design flow from behavioral description down to the synthesized level. Circuit Synthesis with VHDL is essential reading for all students, researchers, design engineers and managers working with VHDL in a synthesis environment.

Modeling in Analog Design highlights some of the most pressing issues in the use of modeling techniques for design of analogue circuits. Using models for circuit design gives designers the power to express directly the behaviour of parts of a circuit in addition to using other pre-defined components. There are numerous advantages to this new category of analog behavioral language. In the short term, by favouring the top-down design and raising the level of description abstraction, this approach provides greater freedom of implementation and a higher degree of technology independence. In the longer term, analog synthesis and formal optimisation are targeted. Modeling in Analog Design introduces the reader to two main language standards: VHDL-A and MHDL. It goes on to provide in-depth examples of the use of these languages to model analog devices. The final part is devoted to the very important topic of modeling the thermal and electrothermal aspects of devices. This book is essential reading for analog designers using behavioral languages and analog CAD tool development environments who have to provide the tools used by the designers.

A reactive system is one that is in continual interaction with its environment and executes at a pace determined by that environment. Examples of reactive systems are network protocols, air-traffic control systems, industrial-process control systems etc. Reactive systems are ubiquitous and represent an important class of systems. Due to their complex nature, such systems are extremely difficult to specify and implement. Many reactive systems are employed in highly-critical applications, making it crucial that one considers issues such as reliability and safety while designing such systems. The design of reactive systems is considered to be problematic, and p.oses one of the greatest challenges in the field of system design and development. In this paper, we discuss specification-modeling methodologies for reactive systems. Specification modeling is an important stage in reactive system design where the designer specifies the desired properties of the reactive system in the form of a specification model. This specification model acts as the guidance and source for the implementation. To develop the specification model of complex systems in an organized manner, designers resort to specification modeling methodologies. In the context of reactive systems, we can call such methodologies reactive-system specification modeling methodologies.

too vast, too complex, too grand ... for description. John Wesley Powell-1870 (discovering the Grand Canyon) VHDL is a big world. A beginner can be easily disappointed by the generality of this language. This generality is explained by the large number of domains covered - from specifications to logical simulation or synthesis. To the very beginner, VHDL appears as a "kit". He is quickly aware that his problem may be solved with VHDL, but does not know how. He does not even know how to start. In this state of mind, all the constraints that can be set to his modeling job, by using a subset of the language or a given design methodology, may be seen as a life preserver. The success of the introduction of VHDL in a company depends on solutions to many questions that should be answered months before the first line of code is written: * Why choose VHDL? * Which VHDL tools should be chosen? * Which modeling methodology should be adopted? * How should the VHDL environment be customized? * What are the tricks? Where are the traps? * What are the differences between VHDL and other competing HDLs? Answers to these questions are organized according to different concerns: buying the tools, organizing the environment, and designing. Decisions taken in each of these areas may have many consequences on the way to the acceptance and efficiently use of VHDL in a company.

Models in system design follow the general tendency in electronics in terms of size, complexity and difficulty of maintenance. While a model should be a manageable representation of a system, this increasing complexity sometimes forces current CAD-tool designers and model writers to apply modeling techniques to the model itself. Model writers are interested in instrumenting their model, so as to extract critical information before the model is complete. CAD tools designers use internal representations of the design at various stages. The complexity has also led CAD-tool developers to develop formal tools, theories and methods to improve relevance, completeness and consistency of those internal representations. Information modeling involves the representation of objects, their properties and relationships. Performance Modeling When it comes to design choices and trade-offs, performance is generally the final key. However performance estimations have to be extracted at a very early stage in the system design. Performance modeling concerns the set of tools and techniques that allow or help the designer to capture metrics relating to future architectures. Performance modeling encompasses the whole system, including software modeling. It has a strong impact on all levels of design choices, from hardware/software partitioning to the final layout. Information Modeling Specification and formalism have in the past traditionally played little part in the design and development of EDA systems, their support environments, languages and processes. Instead, EDA system developers and EDA system users have seemed to be content to operate within environments that are often extremely complex and may be poorly tested and understood. This situation has now begun to change with the increasing use of techniques drawn from the domains of formal specification and database design. This section of this volume addresses aspects of the techniques being used. In particular, it considers a specific formalism, called information modeling, which has gained increasing acceptance recently and is now a key part of many of the proposals in the EDA Standards Roadmap, which promises to be of significance to the EDA industry. In addition, the section looks at an example of a design system from the point of view of its underlying understanding of the design process rather than through a consideration of particular CAD algorithms. Meta-Modeling: Performance and Information Modeling contains papers describing the very latest techniques used in meta-modeling. It will be a valuable text for researchers, practitioners and students involved in Electronic Design Automation.

Hardware Component Modeling highlights the current status of the modeling of electronic components. It includes contributions from many of the leading researchers and practitioners in the field. The contents focus on four important topics. Standards: Three chapters describe current developments in employing standards for the use of component libraries. A major part of these chapters provides an excellent introduction to VITAL (an IEEE standard), its application and some of the issues in using and implementing it. There are, however, other standards with a role to play and these are also covered. Data Types: One chapter describes the latest techniques for using data types in modeling and simulation. Model Generation: One chapter describes a model generator for reusable component models and another describes a generator which takes actual physical data as its source and generates a functional model. Quality Assurance: Two chapters are devoted to improving the quality of models. One introduces a method for quantifying aspects of model quality and the other introduces quality concepts which can lead to an increase in model value through reuse and robustness.Hardware Component Modeling is a valuable reference for researchers and practitioners involved in the process of modeling electronic components.

Object-oriented techniques and languages have been proven to significantly increase engineering efficiency in software development. Many benefits are expected from their introduction into electronic modeling. Among them are better support for model reusability and flexibility, more efficient system modeling, and more possibilities in design space exploration and prototyping. Object-Oriented Modeling explores the latest techniques in object-oriented methods, formalisms and hardware description language extensions. The seven chapters comprising this book provide an overview of the latest object-oriented techniques for designing systems and hardware. Many examples are given in C++, VHDL and real-time programming languages. Object-Oriented Modeling describes further the use of object-oriented techniques in applications such as embedded systems, telecommunications and real-time systems, using the very latest techniques in object-oriented modeling. It is an essential guide to researchers, practitioners and students involved in software, hardware and system design.

In system design, generation of high-level abstract models that can be closely associated with evolving lower-level models provides designers with the ability to incrementally test' an evolving design against a model of a specification. Such high-level models may deal with areas such as performance, reliability, availability, maintainability, and system safety. Abstract models also allow exploration of the hardware versus software design space in an incremental fashion as a fuller, detailed design unfolds, leaving behind the old practice of hardware-software binding too early in the design process. Such models may also allow the inclusion of non-functional aspects of design (e.g. space, power, heat) in a simulatable information model dealing with the system's operation. This book addresses Model Generation and Application specifically in the following domains: Specification modeling (linking object/data modeling, behavior modeling, and activity modeling). Operational specification modeling (modeling the way the system is supposed to operate - from a user's viewpoint). Linking non-functional parameters with specification models. Hybrid modeling (linking performance and functional elements). Application of high-level modeling to hardware/software approaches. Mathematical analysis techniques related to the modeling approaches. Reliability modeling. Applications of High Level Modeling. Reducing High Level Modeling to Practice. High-Level System Modeling: Specification and Design Methodologies describes the latest research and practice in the modeling of electronic systems and as such is an important update for all researchers, design engineers and technical managers working in design automation and circuit design.

Co-Design is the set of emerging techniques which allows for the simultaneous design of Hardware and Software. In many cases where the application is very demanding in terms of various performances (time, surface, power consumption), trade-offs between dedicated hardware and dedicated software are becoming increasingly difficult to decide upon in the early stages of a design. Verification techniques - such as simulation or proof techniques - that have proven necessary in the hardware design must be dramatically adapted to the simultaneous verification of Software and Hardware. Describing the latest tools available for both Co-Design and Co-Verification of systems, Hardware/Software Co-Design and Co-Verification offers a complete look at this evolving set of procedures for CAD environments. The book considers all trade-offs that have to be made when co-designing a system. Several models are presented for determining the optimum solution to any co-design problem, including partitioning, architecture synthesis and code generation. When deciding on trade-offs, one of the main factors to be considered is the flow of communication, especially to and from the outside world. This involves the modeling of communication protocols. An approach to the synthesis of interface circuits in the context of co-design is presented. Other chapters present a co-design oriented flexible component data-base and retrieval methods; a case study of an ethernet bridge, designed using LOTOS and co-design methodologies and finally a programmable user interface based on monitors. Hardware/Software Co-Design and Co-Verification will help designers and researchers to understand these latest techniques in system design and as such will be of interest to all involved in embedded system design.

Hardware description languages (HDL) such as VHDL and Verilog have found their way into almost every aspect of the design of digital hardware systems. Since their inception they gradually proved to be an essential part of modern design methodologies and design automation tools, ever exceeding their original goals of being description and simulation languages. Their use for automatic synthesis, formal proof, and testing are good examples. So far, HDLs have been mainly dealing with digital systems. However, integrated systems designed today require more and more analog parts such as A/D and D/A converters, phase locked loops, current mirrors, etc. The verification of the complete system therefore asks for the use of a single language. Using VHDL or Verilog to handle analog descriptions is possible, as it is shown in this book, but the real power is coming from true mixed-signal HDLs that integrate discrete and continuous semantics into a unified framework. Analog HDLs (AHDL) are considered here a subset of mixed-signal HDLs as they intend to provide the same level of features as HDLs do but with a scope limited to analog systems, possibly with limited support of discrete semantics. Analog and Mixed-Signal Hardware Description Languages covers several aspects related to analog and mixed-signal hardware description languages including: The use of a digital HDL for the description and the simulation of analog systems The emergence of extensions of existing standard HDLs that provide true analog and mixed-signal HDLs. The use of analog and mixed-signal HDLs for the development of behavioral models of analog (electronic) building blocks (operational amplifier, PLL) and for the design of microsystems that do not only involve electronic parts. The use of a front-end tool that eases the description task with the help of a graphical paradigm, yet generating AHDL descriptions automatically. Analog and Mixed-Signal Hardware Description Languages is the first book to show how to use these new hardware description languages in the design of electronic components and systems. It is necessary reading for researchers and designers working in electronic design.

Models in System Design tracks the general trend in electronics in terms of size, complexity and difficulty of maintenance. System design is by nature combined with prototyping, mixed domain design, and verification, and it is no surprise that today's modeling and models are used in various levels of system design and verification. In order to deal with constraints induced by volume and complexity, new methods and techniques have been defined. Models in System Design provides an overview of the latest modeling techniques for use by system designers. The first part of the book considers system level design, discussing such issues as abstraction, performance and trade-offs. There is also a section on automating system design. The second part of the book deals with some of the newest aspects of embedded system design. These include co-verification and prototyping. Finally, the book includes a section on the use of the MCSE methodology for hardware/software co-design. Models in System Design will help designers and researchers to understand these latest techniques in system design and as such will be of interest to all involved in embedded system design.

Co-Design is the set of emerging techniques which allows for the simultaneous design of Hardware and Software. In many cases where the application is very demanding in terms of various performances (time, surface, power consumption), trade-offs between dedicated hardware and dedicated software are becoming increasingly difficult to decide upon in the early stages of a design. Verification techniques - such as simulation or proof techniques - that have proven necessary in the hardware design must be dramatically adapted to the simultaneous verification of Software and Hardware. Describing the latest tools available for both Co-Design and Co-Verification of systems, Hardware/Software Co-Design and Co-Verification offers a complete look at this evolving set of procedures for CAD environments. The book considers all trade-offs that have to be made when co-designing a system. Several models are presented for determining the optimum solution to any co-design problem, including partitioning, architecture synthesis and code generation. When deciding on trade-offs, one of the main factors to be considered is the flow of communication, especially to and from the outside world. This involves the modeling of communication protocols. An approach to the synthesis of interface circuits in the context of co-design is presented. Other chapters present a co-design oriented flexible component data-base and retrieval methods; a case study of an ethernet bridge, designed using LOTOS and co-design methodologies and finally a programmable user interface based on monitors. Hardware/Software Co-Design and Co-Verification will help designers and researchers to understand these latest techniques in system design and as such will be of interest to all involved in embedded system design.

Object-oriented techniques and languages have been proven to significantly increase engineering efficiency in software development. Many benefits are expected from their introduction into electronic modeling. Among them are better support for model reusability and flexibility, more efficient system modeling, and more possibilities in design space exploration and prototyping. Object-Oriented Modeling explores the latest techniques in object-oriented methods, formalisms and hardware description language extensions. The seven chapters comprising this book provide an overview of the latest object-oriented techniques for designing systems and hardware. Many examples are given in C++, VHDL and real-time programming languages. Object-Oriented Modeling describes further the use of object-oriented techniques in applications such as embedded systems, telecommunications and real-time systems, using the very latest techniques in object-oriented modeling. It is an essential guide to researchers, practitioners and students involved in software, hardware and system design.

Models in system design follow the general tendency in electronics in terms of size, complexity and difficulty of maintenance. While a model should be a manageable representation of a system, this increasing complexity sometimes forces current CAD-tool designers and model writers to apply modeling techniques to the model itself. Model writers are interested in instrumenting their model, so as to extract critical information before the model is complete. CAD tools designers use internal representations of the design at various stages. The complexity has also led CAD-tool developers to develop formal tools, theories and methods to improve relevance, completeness and consistency of those internal representations. Information modeling involves the representation of objects, their properties and relationships. Performance Modeling When it comes to design choices and trade-offs, performance is generally the final key. However performance estimations have to be extracted at a very early stage in the system design. Performance modeling concerns the set of tools and techniques that allow or help the designer to capture metrics relating to future architectures. Performance modeling encompasses the whole system, including software modeling. It has a strong impact on all levels of design choices, from hardware/software partitioning to the final layout. Information Modeling Specification and formalism have in the past traditionally played little part in the design and development of EDA systems, their support environments, languages and processes. Instead, EDA system developers and EDA system users have seemed to be content to operate within environments that are often extremely complex and may be poorly tested and understood. This situation has now begun to change with the increasing use of techniques drawn from the domains of formal specification and database design. This section of this volume addresses aspects of the techniques being used. In particular, it considers a specific formalism, called information modeling, which has gained increasing acceptance recently and is now a key part of many of the proposals in the EDA Standards Roadmap, which promises to be of significance to the EDA industry. In addition, the section looks at an example of a design system from the point of view of its underlying understanding of the design process rather than through a consideration of particular CAD algorithms. Meta-Modeling: Performance and Information Modeling contains papers describing the very latest techniques used in meta-modeling. It will be a valuable text for researchers, practitioners and students involved in Electronic Design Automation.

The VITAL specification addresses the issues of interoperability, backannotation and high performance simulation for sign-off quality ASIC libraries in VHDL. VITAL provides modeling guidelines and a set of pre-defined packages (containing pre-defined routines for modeling functionality and timing) to facilitate the acceleration of designs which use cells from a VITAL library. The VITAL Level-I guidelines constrain the modeling capabilities provided by VHDL in order to facilitate higher performance (Figure I). Accumulating "gains" Constrained "flexibility" Higher performance & Increased capacity Benefits Flexibility FujI VHDL 1076 Figure 1: VHDL and VITAL Even within the Level-I guidelines, there are several ways in which a model can be written. In this chapter, we highlight the various modeling trade-offs and provide guidelines which can be used for developing efficient models. We will also discuss the techniques that can be used by tool developers to accelerate the simulation of VIT AL based designs. 2.2. OVERVIEW OF A VITAL LEVEL-l ARCIDTECTURE The VITAL specification is versatile enough to support several modeling styles e.g., distributed delay style, pin-to-pin delay style etc. In general, a VITAL Level-I model can have the structure illustrated in Figure 2."

In system design, generation of high-level abstract models that can be closely associated with evolving lower-level models provides designers with the ability to incrementally test' an evolving design against a model of a specification. Such high-level models may deal with areas such as performance, reliability, availability, maintainability, and system safety. Abstract models also allow exploration of the hardware versus software design space in an incremental fashion as a fuller, detailed design unfolds, leaving behind the old practice of hardware-software binding too early in the design process. Such models may also allow the inclusion of non-functional aspects of design (e.g. space, power, heat) in a simulatable information model dealing with the system's operation. This book addresses Model Generation and Application specifically in the following domains: Specification modeling (linking object/data modeling, behavior modeling, and activity modeling). Operational specification modeling (modeling the way the system is supposed to operate - from a user's viewpoint). Linking non-functional parameters with specification models. Hybrid modeling (linking performance and functional elements). Application of high-level modeling to hardware/software approaches. Mathematical analysis techniques related to the modeling approaches. Reliability modeling. Applications of High Level Modeling. Reducing High Level Modeling to Practice. High-Level System Modeling: Specification and Design Methodologies describes the latest research and practice in the modeling of electronic systems and as such is an important update for all researchers, design engineers and technical managers working in design automation and circuit design.

A reactive system is one that is in continual interaction with its environment and executes at a pace determined by that environment. Examples of reactive systems are network protocols, air-traffic control systems, industrial-process control systems etc. Reactive systems are ubiquitous and represent an important class of systems. Due to their complex nature, such systems are extremely difficult to specify and implement. Many reactive systems are employed in highly-critical applications, making it crucial that one considers issues such as reliability and safety while designing such systems. The design of reactive systems is considered to be problematic, and p.oses one of the greatest challenges in the field of system design and development. In this paper, we discuss specification-modeling methodologies for reactive systems. Specification modeling is an important stage in reactive system design where the designer specifies the desired properties of the reactive system in the form of a specification model. This specification model acts as the guidance and source for the implementation. To develop the specification model of complex systems in an organized manner, designers resort to specification modeling methodologies. In the context of reactive systems, we can call such methodologies reactive-system specification modeling methodologies.

Model Generation in Electronic Design covers a wide range of model applications and research. The book begins by describing a model generator to create component models. It goes on to discuss ASIC design and ASIC library generation. This section includes chapters on the requirements for developing and ASIC library, a case study in which VITAL is used to create such a library, and the analysis and description of the accuracy required in modeling interconnections in ASIC design. Other chapters describe the development of thermal models for electronic devices, the development of a set of model packages for VHDL floating point operations, a techniques for model validation and verification, and a tool for model encryption. Model Generation in Electronic Design is an essential update for users, vendors, model producers, technical managers, designers and researchers working in electronic design.

Modeling in Analog Design highlights some of the most pressing issues in the use of modeling techniques for design of analogue circuits. Using models for circuit design gives designers the power to express directly the behaviour of parts of a circuit in addition to using other pre-defined components. There are numerous advantages to this new category of analog behavioral language. In the short term, by favouring the top-down design and raising the level of description abstraction, this approach provides greater freedom of implementation and a higher degree of technology independence. In the longer term, analog synthesis and formal optimisation are targeted. Modeling in Analog Design introduces the reader to two main language standards: VHDL-A and MHDL. It goes on to provide in-depth examples of the use of these languages to model analog devices. The final part is devoted to the very important topic of modeling the thermal and electrothermal aspects of devices. This book is essential reading for analog designers using behavioral languages and analog CAD tool development environments who have to provide the tools used by the designers.

One of the main applications of VHDL is the synthesis of electronic circuits. Circuit Synthesis with VHDL is an introduction to the use of VHDL logic (RTL) synthesis tools in circuit design. The modeling styles proposed are independent of specific market tools and focus on constructs widely recognized as synthesizable by synthesis tools. A statement of the prerequisites for synthesis is followed by a short introduction to the VHDL concepts used in synthesis. Circuit Synthesis with VHDL presents two possible approaches to synthesis: the first starts with VHDL features and derives hardware counterparts; the second starts from a given hardware component and derives several description styles. The book also describes how to introduce the synthesis design cycle into existing design methodologies and the standard synthesis environment. Circuit Synthesis with VHDL concludes with a case study providing a realistic example of the design flow from behavioral description down to the synthesized level. Circuit Synthesis with VHDL is essential reading for all students, researchers, design engineers and managers working with VHDL in a synthesis environment.

too vast, too complex, too grand ... for description. John Wesley Powell-1870 (discovering the Grand Canyon) VHDL is a big world. A beginner can be easily disappointed by the generality of this language. This generality is explained by the large number of domains covered - from specifications to logical simulation or synthesis. To the very beginner, VHDL appears as a "kit". He is quickly aware that his problem may be solved with VHDL, but does not know how. He does not even know how to start. In this state of mind, all the constraints that can be set to his modeling job, by using a subset of the language or a given design methodology, may be seen as a life preserver. The success of the introduction of VHDL in a company depends on solutions to many questions that should be answered months before the first line of code is written: * Why choose VHDL? * Which VHDL tools should be chosen? * Which modeling methodology should be adopted? * How should the VHDL environment be customized? * What are the tricks? Where are the traps? * What are the differences between VHDL and other competing HDLs? Answers to these questions are organized according to different concerns: buying the tools, organizing the environment, and designing. Decisions taken in each of these areas may have many consequences on the way to the acceptance and efficiently use of VHDL in a company.