The COMQUAD Component Container Architecture and Contract Negotiation

Component-based applications require runtime support to be able to guarantee non-functional properties. This report proposes an architecture for a real-time-capable, component-based runtime environment, which allows to separate non-functional and functional concerns in component-based software development. The architecture is presented with particular focus on three key issues: the conceptual architecture, an approach including implementation issues for splitting the runtime environment into a real-time-capable and a real-time-incapable part, and details of contract negotiation. The latter includes selecting component implementations for instantiantion based on their non-functional properties

Components + Security = OS Extensibility

Component-based programming systems have shown themselves to be a natural way of constructing extensible software. Well-defined interfaces, encapsulation, late binding and polymorphism promote extensibility, yet despite this synergy, components have not been widely employed at the systems level. This is primarily due to the failure of existing component technologies to provide the protection and performance required of systems software. In this paper we identify the requirements for a component system to support secure extensions, and describe the design of such a system on the Mungi OS

Communication in Microkernel-Based Operating Systems

Communication in microkernel-based systems is much more frequent than system calls known from monolithic kernels. This can be attributed to the placement of system services into their own protection domains. Communication has to be fast to avoid unnecessary overhead. Also, communication channels in microkernel-based systems are used for more than just remote procedure calls. In distributed systems, which also have a componentized design, it is state of the art to use tools to generate stubs for the communication between components. The communication interfaces of components are described in an interface definition language (IDL). In contrast to distributed systems, components of a microkernel-based system run on the same architecture and message delivery is guaranteed. In this Thesis, I explore the different kinds of communication, which can be used in microkernel-based systems, as well as their possible representation in IDL. Specifically, I introduce the syntax to describe kernel objects in IDL. I discuss the complexity of IDL compilers and its relation to the complexity of the IDL. Furthermore, I evaluate the performance of the communication stubs generated by different IDL compilers and discuss techniques to minimize performance overhead in generated stubs. I validated these techniques by implementing the Drops IDL Compiler - Dice. Finally, this Thesis presents a mechanism to measure the frequency and performance of invocations of generated communication code. I used this technique to conduct measurements in highly complex systems and introducing the least possible overhead

Communication in Microkernel-Based Operating Systems

Communication in microkernel-based systems is much more frequent than system calls known from monolithic kernels. This can be attributed to the placement of system services into their own protection domains. Communication has to be fast to avoid unnecessary overhead. Also, communication channels in microkernel-based systems are used for more than just remote procedure calls. In distributed systems, which also have a componentized design, it is state of the art to use tools to generate stubs for the communication between components. The communication interfaces of components are described in an interface definition language (IDL). In contrast to distributed systems, components of a microkernel-based system run on the same architecture and message delivery is guaranteed. In this Thesis, I explore the different kinds of communication, which can be used in microkernel-based systems, as well as their possible representation in IDL. Specifically, I introduce the syntax to describe kernel objects in IDL. I discuss the complexity of IDL compilers and its relation to the complexity of the IDL. Furthermore, I evaluate the performance of the communication stubs generated by different IDL compilers and discuss techniques to minimize performance overhead in generated stubs. I validated these techniques by implementing the Drops IDL Compiler - Dice. Finally, this Thesis presents a mechanism to measure the frequency and performance of invocations of generated communication code. I used this technique to conduct measurements in highly complex systems and introducing the least possible overhead

Communication in Microkernel-Based Operating Systems

Communication in microkernel-based systems is much more frequent than system calls known from monolithic kernels. This can be attributed to the placement of system services into their own protection domains. Communication has to be fast to avoid unnecessary overhead. Also, communication channels in microkernel-based systems are used for more than just remote procedure calls. In distributed systems, which also have a componentized design, it is state of the art to use tools to generate stubs for the communication between components. The communication interfaces of components are described in an interface definition language (IDL). In contrast to distributed systems, components of a microkernel-based system run on the same architecture and message delivery is guaranteed. In this Thesis, I explore the different kinds of communication, which can be used in microkernel-based systems, as well as their possible representation in IDL. Specifically, I introduce the syntax to describe kernel objects in IDL. I discuss the complexity of IDL compilers and its relation to the complexity of the IDL. Furthermore, I evaluate the performance of the communication stubs generated by different IDL compilers and discuss techniques to minimize performance overhead in generated stubs. I validated these techniques by implementing the Drops IDL Compiler - Dice. Finally, this Thesis presents a mechanism to measure the frequency and performance of invocations of generated communication code. I used this technique to conduct measurements in highly complex systems and introducing the least possible overhead

MMP

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 129-135).Reliability and security are quickly becoming users' biggest concern due to the increasing reliance on computers in all areas of society. Hardware-enforced, fine-grained memory protection can increase the reliability and security of computer systems, but will be adopted only if the protection mechanism does not compromise performance, and if the hardware mechanism can be used easily by existing software. Mondriaan memory protection (MMP) provides fine-grained memory protection for a linear address space, while supporting an efficient hardware implementation. MMP's use of linear addressing makes it compatible with current software programming models and program binaries, and it is also backwards compatible with current operating systems and instruction sets. MMP can be implemented efficiently because it separates protection information from program data, allowing protection information to be compressed and cached efficiently. This organization is similar to paging hardware, where the translation information for a page of data bytes is compressed to a single translation value and cached in the TLB. MMP stores protection information in tables in protected system memory, just as paging hardware stores translation information in page tables. MMP is well suited to improve the robustness of modern software. Modern software development favors modules (or plugins) as a way to structure and provide extensibility for large systems, like operating systems, web servers and web clients. Protection between modules written in unsafe languages is currently provided only by programmer convention, reducing system stability.(cont.) Device drivers, which are implemented as loadable modules, are now the most frequent source of operating system crashes (e.g., 85% of Windows XP crashes in one study [SBL03]). MMP provides a mechanism to enforce module boundaries, increasing system robustness by isolating modules from each other and making all memory sharing explicit. We implement the MMP hardware in a simulator and modify a version of the Linux 2.4.19 operating system to use it. Linux loads its device drivers as kernel module extensions, and MMP enforces the module boundaries, only allowing the device drivers access to the memory they need to function. The memory isolation provided by MMP increases Linux's resistance to programmer error, and exposed two kernel bugs in common, heavily-tested drivers. Experiments with several benchmarks where MMP was used extensively indicate the space taken by the MMP data structures is less than 11% of the memory used by the kernel, and the kernel's runtime, according to a simple performance model, increases less than 12% (relative to an unmodified kernel).by Emmett Jethro Witchel.Ph.D

System Support for Distributed Energy Management in Modular Operating Systems

This thesis proposes a novel approach for managing energy in modular operating systems. Our approach enables energy awareness if the resource-management subsystem is distributed among multiple operating-system modules. There are four key achievements: a model for modularization-aware energy management; the support for exposed and distributed energy accounting and allocation; the use of different energy-management interaction protocols; and, finally, the support virtualization of energy effects

Stub-Code Performance is Becoming Important

After ipc mechanisms finally got fast, stub-code efficiency is getting a performance issue for local client/server RPCs and inter-component communication. Inefficient and unnecessary complex marshalling code can almost double communication costs. We have developed an experimental new IDL compiler that produces near-optimal stub code for gcc and the L4 microkernel. The current experimental IDL compiler is neither portable nor adaptable but generates in most cases stub code that is 3 times shorter (and faster) than the code generated by a commonly used portable IDL compiler