We present HVMTP, a time predictable and portable java virtual machine (JVM) implementation with applications in resource-constrained, hard real-time embedded systems, which implements all levels of the safety critica...
详细信息
We present HVMTP, a time predictable and portable java virtual machine (JVM) implementation with applications in resource-constrained, hard real-time embedded systems, which implements all levels of the safety critical java (SCJ) specification. time predictability is achieved by a combination of time-predictable algorithms, exploiting the programming model of the SCJ profile and harnessing static knowledge of the hosted SCJ system. This paper presents HVMTP in terms of its design and capabilities and demonstrates how a complete timing model of the JVM represented as a network of timed automata can be obtained using the tool TETASARTS(JVM). The timing model readily integrates with the rest of the TETASARTS tool set for temporal verification of SCJ systems. We will also show how a complete timing scheme in terms of safe worst-case execution times and best-case execution times of the java bytecodes can be derived from the model. Furthermore, we take a first look at how to support the new java 8 language feature of Lambda expressions in a SCJ context - we look in particular at how the invokedynamic bytecode can be implemented in a time-predictable way and integrated in HVMTP. Copyright (c) 2016 John Wiley & Sons, Ltd.
java is an object oriented programming language introduced by Sun Microsystems in 1995. From this date, java has received a high interest from both industry actors and researchers. java presents many benefits such as ...
详细信息
ISBN:
(纸本)9781450316880
java is an object oriented programming language introduced by Sun Microsystems in 1995. From this date, java has received a high interest from both industry actors and researchers. java presents many benefits such as reliability of code, portability because its neutral architecture, and security in distributed environments, which leads it a privileged technology to develop embedded and distributed applications. Even though java has issues as threads and automatic garbage collection, it has problems regarding its use in real-time systems, which must be solved. Since 1997 several research works has been focused on the limits of the java language and its execution environment to seek the possibility for real-time technology using java. This paper outlines and discusses the investigated issues and the developed supporting technology that allows the construction of real-time systems using java.
Embedded systems are highly used in every field. Embedded system often required to provide real-time response. As embedded systems become more and more complex, and the time to market becomes shorter;there is a need i...
详细信息
ISBN:
(纸本)9781538625996
Embedded systems are highly used in every field. Embedded system often required to provide real-time response. As embedded systems become more and more complex, and the time to market becomes shorter;there is a need in the embedded systems community to find better programming languages that let the programmers develop correct code faster: The programming languages used today typically C and/or Assemblers-are just too error-prone. The java technology has therefore gained a lot of interest from developers of embedded systems in the last few years [1]. To use java in real-time/Safety-Critical systems calls for significantly green predictable code execution. Techniques to achieve this include Ahead-Of-time compilation, incremental Garbage Collection and the use of RTSJ-compliant Virtual Machine. However those are not enough as time-predictability can without trouble be ruined through using the same antique library (lazy initialization, array resizing, and so forth.). To reap actual time predictability one should have a time deterministic library. This paper introduces such open deliver library known as Javolution suitable for embedded or server-aspect applications and used for safety important application global [2]. This paper also presents an overview of the most recent and important studies in the area of real-time java computing. We will study and analysis of java variations for real-time systems.
In order to claim conformance with a java Specification Request, a java implementation has to pass all tests in an associated Technology Compatibility Kit. This paper presents a model-based development of a Technology...
详细信息
In order to claim conformance with a java Specification Request, a java implementation has to pass all tests in an associated Technology Compatibility Kit. This paper presents a model-based development of a Technology Compatibility Kit test suite and a test execution tool for the draft safety-critical java profile specification. The java Modeling Language is used to model conformance constraints for the profile. java Modeling Language annotations define contracts for classes and interfaces. The annotations are translated by a tool into runtime assertion checks. Hereby, the design and elaboration of the concrete test cases are simplified, because the expected results are derived from contracts and thus do not need to be provided explicitly. Bottom-up testing is applied for testing methods of the safety-critical java classes, whereas top-down testing is applied for testing global properties, such as protocols, memory management, and real-time properties, including scheduling. The tests are executed using a simplified version of JUnit, which makes the test suite executable on resource-constrained platforms. Copyright (c) 2017 John Wiley & Sons, Ltd.
time predictability is a first class requirement in safety critical system design. Techniques exist for the timing analysis of programs designed in memory managed languages, but these require detailed knowledge of mem...
详细信息
ISBN:
(纸本)9781538615744
time predictability is a first class requirement in safety critical system design. Techniques exist for the timing analysis of programs designed in memory managed languages, but these require detailed knowledge of memory allocation. Moreover, enforcing hard real-time guarantees for systems designed in such garbage collected languages is difficult, because of the so called collection pause - however incremental. This paper proposes a novel solution whereby a separate reference counting unit replaces the garbage collector. We present the underlying concepts of the Reference Counting Memory Management Unit (RCMMU) and its use for garbage collection. In addition, we present an implementation that includes a specialized memory arrangement that allows for object management transactions to occur concurrently with program execution, with no resultant impact upon program performance. The RCMMU has been targeted for use with java but can be adopted to be used with other memory managed languages. The hardware-implemented RCMMU removes all overhead associated with garbage collection operations when compared against a software-only collector. Additionally, it simplifies the static worst-case execution time analysis of programs.
In order to claim conformance with a java Specification Request, a java implementation has to pass all tests in an associated Technology Compatibility Kit. This paper presents a model-based development of a Technology...
详细信息
In order to claim conformance with a java Specification Request, a java implementation has to pass all tests in an associated Technology Compatibility Kit. This paper presents a model-based development of a Technology Compatibility Kit test suite and a test execution tool for the draft safety-critical java profile specification. The java Modeling Language is used to model conformance constraints for the profile. java Modeling Language annotations define contracts for classes and interfaces. The annotations are translated by a tool into runtime assertion checks. Hereby, the design and elaboration of the concrete test cases are simplified, because the expected results are derived from contracts and thus do not need to be provided explicitly. Bottom-up testing is applied for testing methods of the safety-critical java classes, whereas top-down testing is applied for testing global properties, such as protocols, memory management, and real-time properties, including scheduling. The tests are executed using a simplified version of JUnit, which makes the test suite executable on resource-constrained platforms. Copyright (c) 2017 John Wiley & Sons, Ltd.
Currently, java has been gradually applied in embedded real-time areas like robotics, control system, etc. owning to its advantages like robustness, security, etc. In order to improve the performance of java's exe...
详细信息
Currently, java has been gradually applied in embedded real-time areas like robotics, control system, etc. owning to its advantages like robustness, security, etc. In order to improve the performance of java's execution engine for embedded real-time applications, JPOR-32, an embedded real-time java processor, is designed. Based on it, this paper presents the automatic memory management (AMM) mechanism for embedded real-time java processor. JPOR-32 provides architectural support as well as instruction level support for AMM. Its preprocessing mechanism reduces the complexity of the implementation of AMM, enhances the run-time efficiency, and promotes predictability of the worst-case execution time. The system design of JPOR-32 makes AMM of class area avoided, and the optimized design of instruction set provides effective support for space checking and garbage collection scheduling. This paper also proposes an object reference format which provides supports for objects tracing, heap scanning, synchronization, etc., and lays the foundation for the implementation of suitable garbage collection algorithm. Moreover, this paper gives the analysis of the feature of runtime environment of embedded java processor, and implements a suitable improved generational garbage collector.
Now, as a popular language for the development of sever and desktop applications, java is also playing a more and more important role in embedded development owning to its features like platform independence, high dev...
详细信息
ISBN:
(纸本)9783642181337
Now, as a popular language for the development of sever and desktop applications, java is also playing a more and more important role in embedded development owning to its features like platform independence, high development efficiency, etc. Accordingly, JPOR-32, a 32-bit java processor optimized for real-time specification for java, is designed. In this paper, taking JPOR-32 as an example, the instruction execution stage design for embedded real-time java processor is presented. The run time operand stack and method stack is implemented, which lays the foundations of execution of instruction set based on stack. For instruction execution stage, this paper presents on emphasis the control signal operation mechanism and the instruction execution stage data path.
This article deals with a simple optimization for a level-5 protocol called JRMP (java's Remote Method Protocol), which is used in a distribution model named java's RMI (java's Remote Method Invocation). T...
详细信息
This article deals with a simple optimization for a level-5 protocol called JRMP (java's Remote Method Protocol), which is used in a distribution model named java's RMI (java's Remote Method Invocation). The main JRMP subprotocol, namely Stream, has been enhanced with a simple and direct multiplexing mechanism that offers the possibility of transferring several parallel request-response interactions without opening new TCP/IP connections. The overhead required to process headers and the advantages stemmed from the approach in terms of response-time are explored on a switched-ethernet benchmark application.
暂无评论