Binder, W., Design and Implementation of the JSEAL2 Mobile Agent Kernel, Symposium on Applications and the Internet (SAINT 2001.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....and Schneider [6] and Chander et al. 7] can apply desired security policies to arbitrary codelets without requiring these policies to be built directly into the Java system code, as done with Java s built in security system. Resource Management and Accounting. J Kernel [8] and J SEAL2 [9] both focus primarily on isolation of codelets. Bytecode rewriting is used to prevent codelets from interfering in each others operations. JRes [10] focuses more on resource accounting; bytecode rewriting is used to instrument memory allocation and object finalization sites. Optimization. Cream ....

....soft termination system could have performed periodic checks with more flexibility and lower overhead than trapping backward branches. Also, by modifying the garbage collector, we might have been able to enforce memory usage policies that are more robust than those used in JRes [10] and J SEAL2 [9], which assume that whoever allocated a block of memory should be responsible for paying for that memory. We implemented exactly such a mechanism to account for memory usage in IBM s RVM [24] by modifying the RVM s garbage collector [25] New pluggable garbage collection systems for Java, such ....

Binder, W.: Design and implementation of the J-SEAL2 mobile agent kernel. In: 2001 Symposium on Applications and the Internet, San Diego, CA, USA (2001)

....sharing between codelets. JRes [21] is a resource management system for Java. Bytecode rewriting is used to instrument memory allocation and object finalization in order to maintain a detailed account of memory usage. Again, termination is mentioned, but no specific details are provided. J SEAL2 [9] is a framework, written entirely in Java, for running Java codelets. Extended bytecode verification, combined with a limited degree of bytecode rewriting, is used to ensure that codelets do not violate protection domain boundaries. The result is that sharing among codelets is restricted. ....

....and Schneider [35] and Chander et al. 14] can apply desired security policies to arbitrary codelets without requiring these policies to be built directly into the Java system code, as done with Java s built in security system. Resource Management and Accounting. J Kernel [43] and J SEAL2 [9] both focus primarily on isolation of codelets. Bytecode rewriting is used to prevent codelets from interfering in each others operations. JRes [21] focuses more on resource accounting; bytecode rewriting is used to instrument memory allocation and object finalization sites. Optimization. Cream ....

W. Binder. Design and implementation of the J-SEAL2 mobile agent kernel. In 2001.

....low level incompatibilities. A single language approach is thus realistic and spares us from a large set of compatibility issues that occur in multi language environments. Furthermore, we accomodate with the constraint that the agents are restricted to a single execution platform (e.g. J SEAL2 [4]) supporting interoperability between different agent platforms is not the focus of this work. The components of the architecture are a service interface lookup and publication mechanism, and a mobile agent framework. Additionally, a development environment is needed to support the creation of ....

W. Binder. Design and implementation of the J-SEAL2 mobile agent kernel. In The 2001.

....must prevent denial of service attacks, such as agents allocating all available memory.For this purpose, accounting of physical resources (i.e. memory,CPU, network bandwidth, etc. and logical resources (i.e. number of threads, number of protection domains, etc. is crucial. Whereas J SEAL2 [5, 6] is primarily designed for mobile agents, the approach described here is in manyways applicable to other distributed programming paradigms practiced in Java, since the mobile agent paradigm is very comprehensive in terms of involved issues and technologies. The techniques employed in J SEAL2 could ....

....and CPU time consumed by nativecode. We are relying on modern inter modular register allocation algorithms implemented by state of the art JVMs to minimize the overhead of passing the accounting objects. 3. 3 Class loading The J SEAL2 kernel distinguishes between shared and replicated classes [6]. Shared classes are loaded by the system class loader (they exist only once in the JVM) while replicated classes, such as the classes of a mobile agent, are loaded by the class loader of a protection domain (they are reloaded in each domain) All JDK classes as well as most classes from the ....

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W. Binder. Design and implementation of the J-SEAL2 mobile agentkernel. In ### #### ######### ## ############ ### ### ######## ############, San Diego, CA, USA, Jan. 2001.

....similar approach for CPU accounting in Java has not been used before. Our current implementation supports o# line transformations of arbitrary Java classes (including JDK classes) We are also integrating resource reification and appropriate control mechanisms into the JSEAL2 mobile agent kernel [3], which requires load time rewriting of mobile objects. J SEAL2 is a secure mobile agent system implemented in pure Java, which supports the hierarchical process model of the Seal Calculus [22] that was first implemented by the JavaSeal mobile agent system [7] Resource reification in J SEAL2 ....

W. Binder. Design and implementation of the J-SEAL2 mobile agent kernel. In The 2001.

....have to be considered in the design and implementation of Java based platforms for Grid computing. Therefore, massive re engineering efforts are needed to create sufficiently secure and reliable platforms. 4. 4 A Java Micro Kernel for the Secure Execution of Mobile Code Here we present J SEAL2 [3, 4], a lightweight security layer that executes on top of standard Java runtime systems. It provides solutions to all the security problems mentioned before and, hence, represents a state of the art platform for the creation of secure environments for Grid computing. Several researchers have stressed ....

....by the mediator component. Frequently, continuous streams of data have to be processed by applications. The Net Data service supports (limited) buffering of data to ensure that enough input data is available to running applications. The optimized inter4ask com munication mechanisms of J SEAL2 [4] help to minimize the overhead of passing data streams over task boundaries. The system monitor has to detect whether the machine is busy or idle. If the computer is busy, applications shall be suspended in order to avoid an overloading of the machine. If the computer is idle, applications ....

Walter Binder. Design and implementation of the J-SEAL2 mobile agent kernel. In The 2001 Symposium on Applications and the Internet (SAINT-2001), San Diego, CA, USA, January 2001.

....or IllegalMonitorStateException, which can be caught by user code. Another solution to this problem involves rewriting of agent bytecode so that ThreadDeath exceptions are immediately thrown again by all exception handlers. This approach is used in the J SEAL2 mobile agent kernel [2]. Figure 1 shows a portion of Java code and its rewritten counterpart. For the ease of reading, we give the transformation at the Java level, whereas rewriting would be done actually at the JVM bytecode level. 3.3 Scheduling Neither the Java language [8] nor the JVM specification [10] specify ....

W. Binder. Design and implementation of the J-SEAL2 mobile agent kernel. In The 2001.

....denial of service attacks, such as mobile objects allocating all available memory. For this purpose, accounting of physical resources (i.e. memory, CPU, network bandwidth, etc. and of logical resources (i.e. number of threads, number of protection domains, etc. is crucial. Whereas J SEAL2 [5, 6] is primarily designed for mobile objects, the approach described here is in many ways applicable to other distributed programming paradigms practiced in Java, since the mobile object paradigm is very comprehensive in terms of involved issues and technologies. The techniques employed in J SEAL2 ....

....our implementation techniques, for which section 6 presents some performance measurements. Section 7 compares our approach with related work, whereas section 8 concludes the paper. 2. THE J SEAL2 MOBILE OBJECT KERNEL This section gives some basic background on the J SEAL2 mobile object kernel [5, 6], which we selected as the target platform to integrate our resource control model. For details regarding J SEAL2, see the web pages at http: www. jseal2.com . J SEAL2 is a micro kernel implemented in pure Java, which supports the hierarchical process model of the Seal Calculus [33] that was ....

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W. Binder. Design and implementation of the J-SEAL2 mobile agent kernel. In The 2001 Symposium on Applications and the Internet (SAINT-2001), San Diego, CA, USA, Jan. 2001.

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Binder, W., Design and Implementation of the JSEAL2 Mobile Agent Kernel, Symposium on Applications and the Internet (SAINT 2001.

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Binder W. Design and Implementation of the J-SEAL2 Mobile Agent Kernel . http://cui.unige.ch/~ecoopws/ws00/index.html 6th ECOOP Workshop on Mobile Object Systems: Operating System Support, Security, and Programming Languages , 2000.

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