Programming with non-heap memory in the real time specification for Java

Bollella, G.; Reinholtz, Kirk; Canham, Tim; Carson, V.; Champlin, Virgil; Dvorak, D.; Giovannoni, Brian; Indictor, Mark; Meyer, K.; Murray, Alex

doi:10.1145/949437.949443

Cited by 16 publications

(10 citation statements)

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“…In their work, returning objects are allocated in immortal memory using memory pools (objects of fixed size) and memory blocks (byte arrays to allocate varying size objects). The use of memory pools in regions other than immortal memory are explored in [25] where the communication between several components participating in a real-time control loop is described. Each component is defined in a scoped memory and has its own pool of objects in a scoped memory other than immortal.…”

Section: Patternsmentioning

confidence: 99%

Safety‐critical Java for embedded systems

Schoeberl

Dalsgaard

Hansen

et al. 2016

Concurrency and Computation

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Phone +45 4525 3351 compute@compute.dtu.dk www.compute.dtu.dk IMM-PhD-2014-340 Summary (English) Safety-critical systems are real-time systems whose failure can have severe or catastrophic consequences, possibly endangering human life. Many safety-critical systems incorporate embedded computers used to control different tasks. Software running on safety-critical systems needs to be certified before its deployment and the most time-consuming step of this process is the testing and verification phase. Due to the increasing complexity in safety-critical systems there is a need for new technologies that can facilitate testing and verification activities.The safety-critical specification for Java aims at providing a reduced set of the Java programming language that can be used for systems that need to be certified at the highest levels of criticality. Safety-critical Java (SCJ) restricts how a developer can structure an application by providing a specific programming model and by restricting the set of methods and libraries that can be used. Furthermore, its memory model do not use a garbage-collected heap but scoped memories.In this thesis we examine the use of the SCJ specification through an implementation in a time-predictable, FPGA-based Java processor. The specification is now in a mature state and with our implementation we have proved its feasibility in an embedded platform. Moreover, we have explored how simple hardware extensions can reduce the execution time of time-critical operations required by the SCJ specification.The scoped memory model used in SCJ is perhaps one of its most difficult features to use correctly. Therefore, in this work we have also studied practical aspects of its usage by developing scoped memory use patterns and reusable libraries aiming at facilitating the development of complex software systems.ii Summary (Danish)Sikkerhedskritiske systemer er realtidssystemer. Hvis sådanne systemer fejler, kan det have alvorlige eller katastrofale konsekvenser, muligvis livsfarlige konsekvenser. Mange sikkerhedskritiske systemer inkorporerer embeddede computere, som bruges til at kontrollere forskellige opgaver. Software, som kører på sikkerhedskritiske systemer, skal certificeres, før softwaren udrulles, og det mest tidskraevende skridt i denne proces er test-og verifikationsfasen. På grund af den stigende kompleksitet i sikkerhedskritiske systemer er der behov for nye teknologier til at facilitere test-og verifikationsaktiviteter.Den sikkerhedskritiske specifikation for Java har til formål at levere en reduceret udgave af Java-programmeringssproget, som kan bruges til systemer, der skal kunne certificeres på de højeste kritikalitetsniveauer. Safety Critical Java (SCJ) begraenser, hvordan en udvikler kan strukturere en applikation, ved at levere en specifik programmeringsmodel og ved at begraense de metoder og biblioteker, som kan anvendes. Derudover benytter hukommelsesmodellen i SCJ ikke en heap, der er garbage-collected, men afgraensede hukommelser.I denne afhandling undersøger vi brugen a...

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Section: Patternsmentioning

confidence: 99%

Safety‐critical Java for embedded systems

Schoeberl

Dalsgaard

Hansen

et al. 2016

Concurrency and Computation

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show abstract

“…Returning objects are allocated in immortal memory using memory pools (fixed size objects) and memory blocks (byte arrays to allocate varying size objects). Memory pools in regions other than immortal memory are explored in [2]. This work describes the communication between several components participating in a real-time control loop.…”

Section: Related Workmentioning

confidence: 99%

Patterns for safety-critical Java memory usage

Rios

Nilsen²,

Schoeberl

2012

Proceedings of the 10th International Workshop on Java Technologies for Real-Time and Embedded Systems

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Scoped memories are introduced in real-time Java profiles in order to make object allocation and deallocation time and space predictable. However, explicit scoping requires care from programmers when dealing with temporary objects, passing scope-allocated objects as arguments to methods, and returning scope-allocated objects from methods. To simplify the correct usage of scopes, programming patterns may be helpful. We present patterns for simple subroutines, sequences of subroutine calls, and nested calls, where the patterns avoid memory leaks and unnecessary copying of values. The patterns are illustrated by implementations in the safety-critical Java profile.

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“…The design and implementation of RTSJ virtual machines have been documented in [11,17,2]. Several papers have reported on experience with programming with RTSJ [10,29,34,19,2].…”

Section: Related Work: Programming With Scoped Memorymentioning

confidence: 99%

Scoped types and aspects for real-time Java memory management

et al. 2007

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Abstract. Real-time systems are notoriously difficult to design and implement, and, as many real-time problems are safety-critical, their solutions must be reliable as well as efficient and correct. While higher-level programming models (such as the Real-Time Specification for Java) permit real-time programmers to use language features that most programmers take for granted (objects, type checking, dynamic dispatch, and memory safety) the compromises required for real-time execution, especially concerning memory allocation, can create as many problems as they solve. This paper presents Scoped Types and Aspects for Real-Time Systems (STARS) a novel programming model for real-time systems. Scoped Types give programmers a clear model of their programs' memory use, and, being statically checkable, prevent the run-time memory errors that bedevil the RTSJ. Adopting the integrated Scoped Types and Aspects approach can significantly improve both the quality and performance of a real-time Java systems, resulting in simpler systems that are reliable, efficient, and correct.

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Programming with non-heap memory in the real time specification for Java

Cited by 16 publications

References 0 publications

Safety‐critical Java for embedded systems

Safety‐critical Java for embedded systems

Patterns for safety-critical Java memory usage

Scoped types and aspects for real-time Java memory management

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