I’m a partially retired professor, computer scientist, engineer, and a litigation support person. My principal research interests are real-time systems, programming languages, and software engineering.
Proceedings of the 6th international workshop on Java technologies for real-time and embedded systems
Java Technologies for Real-time and Embedded Systems, Sep 24, 2008
Over 90 percent of all microprocessors are now used for real-time and embedded applications, and ... more Over 90 percent of all microprocessors are now used for real-time and embedded applications, and the behavior of many of these applications is constrained by the physical world. Higher-level programming languages and middleware are needed to robustly and productively design, implement, compose, integrate, validate, and enforce real-time constraints along with conventional functional requirements and reusable components. Designing real-time and embedded systems that implement their required capabilities, are dependable and predictable, and are parsimonious in their use of limited computing resources is hard; building them on time and within budget is even harder. Moreover, due to global competition for market share and engineering talent, companies are now also faced with the problem of developing and delivering new products in ever decreasing time frames. Embedded applications also include mission-critical and safety-critical systems in which critical human infrastructures and even human life is sometimes at stake. Therefore it is essential that the production of real-time embedded systems take advantage of languages, tools, and methods that enable higher software productivity. Ideally, developers should use a programming language that shields them from many accidental complexities, such as type errors, memory management, and steep learning curves. The Java programming language has become an attractive choice because of its safety, productivity, relatively low maintenance costs, and the availability of well trained developers. Although it has good software engineering characteristics, Java has often been deemed unsuitable for developing real-time embedded systems, mainly due to under-specification of thread scheduling and the presence of garbage collection. Recently, to address these problems, some significant advances have been made in real-time garbage collection algorithms and a number of extensions to Java have been introduced by such efforts as the Java Community Process Expert Group for the Real-Time Specification for Java (RTSJ). The intent of these specifications is the development of real-time applications by extending the Java memory model, providing stronger semantics in thread scheduling, and so on. Interest in real-time Java in both the research community and industry, because of its challenges and its potential impact on the development of embedded and real-time applications, has recently undergone a significant increase. This industry interest in robust, time-constrained computational platforms comes not only from developers of traditional embedded applications such as industrial automation, but also, for example, from developers of investment trading applications. Topics of interest to this workshop include, but are not limited to: • New real-time programming paradigms and language features •Industrial experience and practitioner reports •Real-Time garbage collection for Java •Real-time design patterns and programming idioms •Formal models of real-time computation •Extensions to the RTSJ •Virtual machines and execution environments •Memory management and real-time garbage collection •Compiler analysis and implementation techniques •Distributed real-time Java and Java-based distributed real-time middleware •Scheduling frameworks, feasibility analysis, and timing analysis •High-integrity and safety critical system support •Java-based real-time operating systems and processors •Exploiting multi-core systems and Java •Direct device management in Java •Transactional memory and Java
While there are many kinds of real-time systems in use, in production, or planned that have requi... more While there are many kinds of real-time systems in use, in production, or planned that have requirements for real-time database functionality, there is little common understanding of the underlying requirements that lead to such implementations. This situation extends both to the implementation community which must produce these systems as well as to the research community seeking to understand the fundamental principles that describe their behavior.
In recent years, various approaches to real-time execution of Java have proven their worth in num... more In recent years, various approaches to real-time execution of Java have proven their worth in numerous commercial and defense applications. The Real-time Specification for Java has extended the Java platform with a range of features needed for real-time computing. As the use of real-time Java has become more widespread, the demand for Java in real-time applications with safety requirements has led to an effort to define a new standard—JSR-302 Safety-Critical Java (SCJ). The goal of this standard is to facilitate the creation of safety-critical Java applications capable of certification under standards such as DO 178B level A or IEC61508 for SIL 4. JSR-302 is nearing completion and will soon be released for public review. This paper introduces some of the primary goals, challenges, and proposed solutions for safety-critical Java and its relationship with the Real-time Specification for Java. Keywords:
Proceedings of the 6th international workshop on Java technologies for real-time and embedded systems - JTRES '08
Over 90 percent of all microprocessors are now used for real-time and embedded applications, and ... more Over 90 percent of all microprocessors are now used for real-time and embedded applications, and the behavior of many of these applications is constrained by the physical world. Higher-level programming languages and middleware are needed to robustly and productively design, implement, compose, integrate, validate, and enforce real-time constraints along with conventional functional requirements and reusable components. Designing real-time and embedded systems that implement their required capabilities, are dependable and predictable, and are parsimonious in their use of limited computing resources is hard; building them on time and within budget is even harder. Moreover, due to global competition for market share and engineering talent, companies are now also faced with the problem of developing and delivering new products in ever decreasing time frames. Embedded applications also include mission-critical and safety-critical systems in which critical human infrastructures and even human life is sometimes at stake. Therefore it is essential that the production of real-time embedded systems take advantage of languages, tools, and methods that enable higher software productivity. Ideally, developers should use a programming language that shields them from many accidental complexities, such as type errors, memory management, and steep learning curves. The Java programming language has become an attractive choice because of its safety, productivity, relatively low maintenance costs, and the availability of well trained developers. Although it has good software engineering characteristics, Java has often been deemed unsuitable for developing real-time embedded systems, mainly due to under-specification of thread scheduling and the presence of garbage collection. Recently, to address these problems, some significant advances have been made in real-time garbage collection algorithms and a number of extensions to Java have been introduced by such efforts as the Java Community Process Expert Group for the Real-Time Specification for Java (RTSJ). The intent of these specifications is the development of real-time applications by extending the Java memory model, providing stronger semantics in thread scheduling, and so on. Interest in real-time Java in both the research community and industry, because of its challenges and its potential impact on the development of embedded and real-time applications, has recently undergone a significant increase. This industry interest in robust, time-constrained computational platforms comes not only from developers of traditional embedded applications such as industrial automation, but also, for example, from developers of investment trading applications. Topics of interest to this workshop include, but are not limited to: • New real-time programming paradigms and language features •Industrial experience and practitioner reports •Real-Time garbage collection for Java •Real-time design patterns and programming idioms •Formal models of real-time computation •Extensions to the RTSJ •Virtual machines and execution environments •Memory management and real-time garbage collection •Compiler analysis and implementation techniques •Distributed real-time Java and Java-based distributed real-time middleware •Scheduling frameworks, feasibility analysis, and timing analysis •High-integrity and safety critical system support •Java-based real-time operating systems and processors •Exploiting multi-core systems and Java •Direct device management in Java •Transactional memory and Java
The International Series in Engineering and Computer Science
These four sample application domains, while certainly not representative of all real-time applic... more These four sample application domains, while certainly not representative of all real-time applications potentially using databases, illustrate some of the widely diverse requirements involved. It is interesting to note that the numerical values for the application data characteristics shown for each domain are gen- erally stated neither in the “official” application requirements documentation, nor in the design documentation that reflects derived application requirements.
While there are many kinds of real-time systems in use, in production, or planned that have requi... more While there are many kinds of real-time systems in use, in production, or planned that have requirements for real-time database functionality, there is little common understanding of the underlying requirements that lead to such implementations. This situation extends both to the implementation community which must produce these systems as well as to the research community seeking to understand the fundamental principles that describe their behavior.
To successfully engineer a large scale real-time system project, we need a disciplined approach t... more To successfully engineer a large scale real-time system project, we need a disciplined approach to both the logical complexity and the timing complexity inherent in these systems. The logical complexity is managed by the software engineering methodology embodied in Ada while the timing complexity is supported by formal real-time scheduling algorithms [3, 4, 5, 6]. From a software engineering point of view, formal scheduling algorithms translate the complex timing constraints into simple resource utilization constraints. As long as the utilization constraints of CPU, I/O channel and communication media are observed, the deadlines of periodic tasks and the response time requirements of aperiodic tasks will both be met. There is considerable freedom to modify software provided that the resource utilization remains within specified bounds. Furthermore, should there be a transient overload, the number of tasks missing their deadlines will be a function of the magnitude of the overload an...
Predictable systems are systems in which correctness arguments consider both the appropriateness ... more Predictable systems are systems in which correctness arguments consider both the appropriateness and the timeliness of delivered results. Such systems exhibit both statistical timing as well as bounded duration timing ex- pectations. Such systems require suitable architectural techniques that do not preclude meeting the timing ex- pectations. This paper provides a summary of some of these issues and the architectural concerns that surface when addressing timing constraints in performance critical systems. The currently well-known design meth- ods are examined for their suitability to describe and re- cord architectures with predictable performance. Rele- vant changes resulting in a suitable method for real-time object-oriented analysis to are suggested.
Proceedings Third IEEE Real-Time Technology and Applications Symposium
This paper proposes a methodology for high-level error propagation analysis of real-tame data-int... more This paper proposes a methodology for high-level error propagation analysis of real-tame data-intensive systems. A formal system an C-style programming language is proposed to provide a research framework for various issues on real-time system designs. A symbolic procedure is then presented to formally verify the amount of data errors tolerable to systems.
Predictable real-time avionics design using Ada tasks and Rendezvous study
ACM SIGAda Ada Letters, 1990
As a part of the Software Engineering Institute's Real-Time Software in Ada project, personne... more As a part of the Software Engineering Institute's Real-Time Software in Ada project, personnel from IBM, the Naval Weapons Center, and SEI carried out an effort to construct a realistic hard real-time avionics application using Ada, including Ada tasking and rendezvous. In this joint study, an important goal was to determine how to use the Ada language as it was designed to be used in a hard real-time system, rather than continuing the current practice of avoiding the very constructs Ada's designers created to meet real-time requirements. In this paper, we present the avionics problem considered, as well as a high-level overview of an Ada solution to the problem which uses Ada tasking and rendezvous, resulting in a solution fully capable of predictably meeting its time constraints.
... Software Engineering Institute 0 Generic Avionics Software Specification C. Douglass Locke Da... more ... Software Engineering Institute 0 Generic Avionics Software Specification C. Douglass Locke David R. Vogel IBM Federal Sector Division ... Page 3. Technical Report CMU/SEI-90-TR-8 ESD-TR-90-209 December 1990 Generic Avionics Software Specification C. Douglass Locke ...
Proceedings of the 6th international workshop on Java technologies for real-time and embedded systems
Java Technologies for Real-time and Embedded Systems, Sep 24, 2008
Over 90 percent of all microprocessors are now used for real-time and embedded applications, and ... more Over 90 percent of all microprocessors are now used for real-time and embedded applications, and the behavior of many of these applications is constrained by the physical world. Higher-level programming languages and middleware are needed to robustly and productively design, implement, compose, integrate, validate, and enforce real-time constraints along with conventional functional requirements and reusable components. Designing real-time and embedded systems that implement their required capabilities, are dependable and predictable, and are parsimonious in their use of limited computing resources is hard; building them on time and within budget is even harder. Moreover, due to global competition for market share and engineering talent, companies are now also faced with the problem of developing and delivering new products in ever decreasing time frames. Embedded applications also include mission-critical and safety-critical systems in which critical human infrastructures and even human life is sometimes at stake. Therefore it is essential that the production of real-time embedded systems take advantage of languages, tools, and methods that enable higher software productivity. Ideally, developers should use a programming language that shields them from many accidental complexities, such as type errors, memory management, and steep learning curves. The Java programming language has become an attractive choice because of its safety, productivity, relatively low maintenance costs, and the availability of well trained developers. Although it has good software engineering characteristics, Java has often been deemed unsuitable for developing real-time embedded systems, mainly due to under-specification of thread scheduling and the presence of garbage collection. Recently, to address these problems, some significant advances have been made in real-time garbage collection algorithms and a number of extensions to Java have been introduced by such efforts as the Java Community Process Expert Group for the Real-Time Specification for Java (RTSJ). The intent of these specifications is the development of real-time applications by extending the Java memory model, providing stronger semantics in thread scheduling, and so on. Interest in real-time Java in both the research community and industry, because of its challenges and its potential impact on the development of embedded and real-time applications, has recently undergone a significant increase. This industry interest in robust, time-constrained computational platforms comes not only from developers of traditional embedded applications such as industrial automation, but also, for example, from developers of investment trading applications. Topics of interest to this workshop include, but are not limited to: • New real-time programming paradigms and language features •Industrial experience and practitioner reports •Real-Time garbage collection for Java •Real-time design patterns and programming idioms •Formal models of real-time computation •Extensions to the RTSJ •Virtual machines and execution environments •Memory management and real-time garbage collection •Compiler analysis and implementation techniques •Distributed real-time Java and Java-based distributed real-time middleware •Scheduling frameworks, feasibility analysis, and timing analysis •High-integrity and safety critical system support •Java-based real-time operating systems and processors •Exploiting multi-core systems and Java •Direct device management in Java •Transactional memory and Java
While there are many kinds of real-time systems in use, in production, or planned that have requi... more While there are many kinds of real-time systems in use, in production, or planned that have requirements for real-time database functionality, there is little common understanding of the underlying requirements that lead to such implementations. This situation extends both to the implementation community which must produce these systems as well as to the research community seeking to understand the fundamental principles that describe their behavior.
In recent years, various approaches to real-time execution of Java have proven their worth in num... more In recent years, various approaches to real-time execution of Java have proven their worth in numerous commercial and defense applications. The Real-time Specification for Java has extended the Java platform with a range of features needed for real-time computing. As the use of real-time Java has become more widespread, the demand for Java in real-time applications with safety requirements has led to an effort to define a new standard—JSR-302 Safety-Critical Java (SCJ). The goal of this standard is to facilitate the creation of safety-critical Java applications capable of certification under standards such as DO 178B level A or IEC61508 for SIL 4. JSR-302 is nearing completion and will soon be released for public review. This paper introduces some of the primary goals, challenges, and proposed solutions for safety-critical Java and its relationship with the Real-time Specification for Java. Keywords:
Proceedings of the 6th international workshop on Java technologies for real-time and embedded systems - JTRES '08
Over 90 percent of all microprocessors are now used for real-time and embedded applications, and ... more Over 90 percent of all microprocessors are now used for real-time and embedded applications, and the behavior of many of these applications is constrained by the physical world. Higher-level programming languages and middleware are needed to robustly and productively design, implement, compose, integrate, validate, and enforce real-time constraints along with conventional functional requirements and reusable components. Designing real-time and embedded systems that implement their required capabilities, are dependable and predictable, and are parsimonious in their use of limited computing resources is hard; building them on time and within budget is even harder. Moreover, due to global competition for market share and engineering talent, companies are now also faced with the problem of developing and delivering new products in ever decreasing time frames. Embedded applications also include mission-critical and safety-critical systems in which critical human infrastructures and even human life is sometimes at stake. Therefore it is essential that the production of real-time embedded systems take advantage of languages, tools, and methods that enable higher software productivity. Ideally, developers should use a programming language that shields them from many accidental complexities, such as type errors, memory management, and steep learning curves. The Java programming language has become an attractive choice because of its safety, productivity, relatively low maintenance costs, and the availability of well trained developers. Although it has good software engineering characteristics, Java has often been deemed unsuitable for developing real-time embedded systems, mainly due to under-specification of thread scheduling and the presence of garbage collection. Recently, to address these problems, some significant advances have been made in real-time garbage collection algorithms and a number of extensions to Java have been introduced by such efforts as the Java Community Process Expert Group for the Real-Time Specification for Java (RTSJ). The intent of these specifications is the development of real-time applications by extending the Java memory model, providing stronger semantics in thread scheduling, and so on. Interest in real-time Java in both the research community and industry, because of its challenges and its potential impact on the development of embedded and real-time applications, has recently undergone a significant increase. This industry interest in robust, time-constrained computational platforms comes not only from developers of traditional embedded applications such as industrial automation, but also, for example, from developers of investment trading applications. Topics of interest to this workshop include, but are not limited to: • New real-time programming paradigms and language features •Industrial experience and practitioner reports •Real-Time garbage collection for Java •Real-time design patterns and programming idioms •Formal models of real-time computation •Extensions to the RTSJ •Virtual machines and execution environments •Memory management and real-time garbage collection •Compiler analysis and implementation techniques •Distributed real-time Java and Java-based distributed real-time middleware •Scheduling frameworks, feasibility analysis, and timing analysis •High-integrity and safety critical system support •Java-based real-time operating systems and processors •Exploiting multi-core systems and Java •Direct device management in Java •Transactional memory and Java
The International Series in Engineering and Computer Science
These four sample application domains, while certainly not representative of all real-time applic... more These four sample application domains, while certainly not representative of all real-time applications potentially using databases, illustrate some of the widely diverse requirements involved. It is interesting to note that the numerical values for the application data characteristics shown for each domain are gen- erally stated neither in the “official” application requirements documentation, nor in the design documentation that reflects derived application requirements.
While there are many kinds of real-time systems in use, in production, or planned that have requi... more While there are many kinds of real-time systems in use, in production, or planned that have requirements for real-time database functionality, there is little common understanding of the underlying requirements that lead to such implementations. This situation extends both to the implementation community which must produce these systems as well as to the research community seeking to understand the fundamental principles that describe their behavior.
To successfully engineer a large scale real-time system project, we need a disciplined approach t... more To successfully engineer a large scale real-time system project, we need a disciplined approach to both the logical complexity and the timing complexity inherent in these systems. The logical complexity is managed by the software engineering methodology embodied in Ada while the timing complexity is supported by formal real-time scheduling algorithms [3, 4, 5, 6]. From a software engineering point of view, formal scheduling algorithms translate the complex timing constraints into simple resource utilization constraints. As long as the utilization constraints of CPU, I/O channel and communication media are observed, the deadlines of periodic tasks and the response time requirements of aperiodic tasks will both be met. There is considerable freedom to modify software provided that the resource utilization remains within specified bounds. Furthermore, should there be a transient overload, the number of tasks missing their deadlines will be a function of the magnitude of the overload an...
Predictable systems are systems in which correctness arguments consider both the appropriateness ... more Predictable systems are systems in which correctness arguments consider both the appropriateness and the timeliness of delivered results. Such systems exhibit both statistical timing as well as bounded duration timing ex- pectations. Such systems require suitable architectural techniques that do not preclude meeting the timing ex- pectations. This paper provides a summary of some of these issues and the architectural concerns that surface when addressing timing constraints in performance critical systems. The currently well-known design meth- ods are examined for their suitability to describe and re- cord architectures with predictable performance. Rele- vant changes resulting in a suitable method for real-time object-oriented analysis to are suggested.
Proceedings Third IEEE Real-Time Technology and Applications Symposium
This paper proposes a methodology for high-level error propagation analysis of real-tame data-int... more This paper proposes a methodology for high-level error propagation analysis of real-tame data-intensive systems. A formal system an C-style programming language is proposed to provide a research framework for various issues on real-time system designs. A symbolic procedure is then presented to formally verify the amount of data errors tolerable to systems.
Predictable real-time avionics design using Ada tasks and Rendezvous study
ACM SIGAda Ada Letters, 1990
As a part of the Software Engineering Institute's Real-Time Software in Ada project, personne... more As a part of the Software Engineering Institute's Real-Time Software in Ada project, personnel from IBM, the Naval Weapons Center, and SEI carried out an effort to construct a realistic hard real-time avionics application using Ada, including Ada tasking and rendezvous. In this joint study, an important goal was to determine how to use the Ada language as it was designed to be used in a hard real-time system, rather than continuing the current practice of avoiding the very constructs Ada's designers created to meet real-time requirements. In this paper, we present the avionics problem considered, as well as a high-level overview of an Ada solution to the problem which uses Ada tasking and rendezvous, resulting in a solution fully capable of predictably meeting its time constraints.
... Software Engineering Institute 0 Generic Avionics Software Specification C. Douglass Locke Da... more ... Software Engineering Institute 0 Generic Avionics Software Specification C. Douglass Locke David R. Vogel IBM Federal Sector Division ... Page 3. Technical Report CMU/SEI-90-TR-8 ESD-TR-90-209 December 1990 Generic Avionics Software Specification C. Douglass Locke ...
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