Peter Druschel, Larry L. Peterson, and Norman Hutchinson. Beyond MicroKernel Design: Decoupling Modularity and Protection in Lipto. In Proceedings of the 12th International Conference on Distributed Computing Systems, pages 512--520, June 1992.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....There have been many attempts at defining minimal kernel services in modern operating systems. MIT s Exokerncl[4] is intended as a minimal kernel that directly exposes the hardware capabilities of the machine, leaving traditional OS abstractions up to implementations in user level hbrarics. Lipto s[5] nugget is a truly minimal kernel , managing low level resource allocation mechanisms such as processor alloca tion, memory management and interrupt processing. Spring s[7] nucleus is similar, supporting domains (virtual address spaces) threads and doors (which handle object oriented calls ....

P. Druschel, L. L. Peterson, and N. C. Hutchinson. Beyond micro-kernel design: Decoupling mod- ularity and protection in Lipto. In Twelfth International Conference on Distributed Computing Systems, pages 512 520, Yokohama, Japan, June 1992.

....boundary. To call a module across a protection boundary in most operating system is different from calling a module inside the own protection domain. Because this difference is a big hindrance on the way to reusability, this problem has already been investigated in the microkernel context [22]. Our goal was a reuse of components in different configurations without code modifications. Although the portal mechanism was designed with this goal the programmer must keep several points in mind when using a portal. Depending on whether the called service is located inside the domain or in ....

....An important difference between JX and previous extensible systems is, that in JX the translator is part of the operating system. This allows several optimizations as described in the paper. Modularity and protection. Orthogonality between modularity and protection was brought forward by Lipto [22]. The OSF [15] attacked the specific problem of collocating the OSF 1 UNIX server, which was run on top of the Mach microkernel, with the microkernel. They were able to achieve a performance only 8 slower than a monolithic UNIX. The special case of code reuse between the kernel and user ....

P. Druschel, L. L. Peterson, and N. C. Hutchinson. Beyond micro-kernel design: Decoupling modularity and protection in Lipto. In Proc. of Twelfth International Conference on Distributed Computing Systems, pp. 512-520, 1992.

....with the bulk of operating systems research, which seeks to develop and integrate new ideas into operating systems themselves. Thus, to reduce the e#orts required to change the OS, a large body of research has investigated how the operating system should be restructured so that it is extensible [8, 13, 15, 35]. In these systems, new functionalTo appear in the 18th Symposium on Operating Systems Principles (SOSP 18) October 21 24, 2001, Chateau Lake Louise, Banff, Canada. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided ....

....monitored, the operations must be performed incrementally. Note that Douceur and Bolosky s statistical sampler is a good candidate for inclusion here [12] 6. OTHER RELATED WORK Many influential research projects have investigated how to restructure operating systems so that they are extensible [8, 13, 15, 35]; if adopted, these systems solve many of the problems of how to incorporate new functionality into the OS. However, given that not all commercial operating systems will be restructured, other work has investigated how to allow developers to add functionality to the OS or to use the OS in new ways ....

P. Druschel, L. L. Peterson, and N. Hutchinson. Beyond Micro-Kernel Design: Decoupling Modularity and Protection in Lipto. In Proceedings of the 12th International Conference on Distributed Computing Systems, pages 512--520, June 1992.

....have been many attempts at defining minimal kernel services in modern operating systems. MIT s Exokernel[4] is intended as a minimal kernel that directly exposes the hardware capabilities of the machine, leaving traditional OS abstractions up to implementations in user level libraries. Lipto s[5] nugget is a truly minimal kernel , managing low level resource allocation mechanisms such as processor allocation, memory management and interrupt processing. Spring s[7] nucleus is similar, supporting domains (virtual address spaces) threads and doors (which handle object oriented calls ....

P. Druschel, L. L. Peterson, and N. C. Hutchinson. Beyond micro-kernel design: Decoupling modularity and protection in Lipto. In Twelfth International Conference on Distributed Computing Systems, pages 512--520, Yokohama, Japan, June 1992.

.... Consequently, it is extremely difficult to add significant new functionality to these systems [16, 1, 42] In response to this problem, a number of recent research projects have addressed the issue of extensible operating systems; these include SPIN [7, 5] VINO [45, 41] Exokernel [20] Lipto [17], and Fluke [21] This paper addresses the problem of providing extensibility for existing production operating systems such as Solaris, through the technique of interposition on existing kernel interfaces. Interposition is useful as an extension mechanism because it is transparent, it permits the ....

....Over the years, a number of systems have attempted to reduce the cost of adding new kernel functionality by restructuring the operating system with extensibility as a design goal. Systems built using this approach include Hydra [53] 1 Mach [1] SPIN [7, 5] VINO [45, 41] Exokernel [20] Lipto [17], and Fluke [21] Many of these systems have successfully demonstrated greatly reduced costs of adding new functionality. However, the cost of starting over from scratch can be prohibitive; for example, Microsoft has spent over 300M developing Windows NT [55] Thus, it is likely that the need to ....

[Article contains additional citation context not shown here]

Peter Druschel, Larry L. Peterson, and Norman Hutchinson. Beyond Micro-Kernel Design: Decoupling Modularity and Protection in Lipto. In Proceedings of the 12th International Conference on Distributed Computing Systems, pages 512-- 520, June 1992.

....or with previous versions of operating systems, neither of which should change when developers offer additional functionality. This is exemplified by the replication of file objects in the Spring operating system[24] by a location transparent object invocation mechanism in the Lipto system[15], and by object migration on uniprocessor platforms in Apertos[56] Performance improvements derived from program configuration typically correct mismatches between desired vs. current program or system primitives, policies, and state. Since such mismatches may arise at any time during a ....

P. Druschel, L. Peterson, and N. Hutchinson. Beyond Microkernel Design: Decoupling Modularity and Protection in Lipto. In Proc. of the 12th International Conference on Distributed Computing Systems, pages 512--520, June 1992.

....protection domains, although this can be handled by x kernel. The authors of x kernel argue that domains should not necessarily correspond to protocol layers for reasons of efficiency. They feel that modularity and protection are orthogonal issues and systems can be designed to reflect this [DP92]. In typical implementations of the x kernel, all the core network protocols would be presumably well tested and hence trustworthy enough to configure into the kernel address space, rather than placing each protocol in a different domain. 2.3.2 Basic Operation of the x kernel It should first ....

Peter Druschel and Larry L. Peterson. Beyond micro-kernel design: Decoupling modularity and protection in lipto. In Proceedings of 12th International Conference on Distributed Computing Systems, 1992.

....same IObj interface to communicate with any other object, even those in the same protection domain. This feature is useful when building operating systems since various modules can be configured into the same or different domains as desired when trading off performance with protection, a la Lipto [3]. Unlike Lipto, OIL s location transparency is dynamic so that objects with open connections can migrate. An object s view of the connection does not change when an endpoint moves, and it does not need to take any special action (nor even be aware of the migration) It is vital, however, that ....

P. Druschel, L. L. Peterson, and N. C. Hutchinson. Beyond micro-kernel design: Decoupling modularity and protection in Lipto. In Twelfth International Conference on Distributed Computing Systems, pages 512--520, Yokohama, Japan, June 1992.

.... the support of passive objects as the basic structuring mechanism has been made [Ford 93] The most important advantages of passive protection domains are their ability to better represent the common case of synchronous communication, their documented ability to support optimized implementations [Druschel 92] Chase 94] Carter et al. 93] and the ease with which they can be managed in user level client code. The last advantage is especially important in making shared libraries a good vehicle for passive protection domains. 2.1.1 Shared Library Limitations Most commercial operating systems support ....

P. Druschel et. al. "Beyond Microkernel Design: Decoupling Modularity and Protection in Lipto." In Proceedings of the 12th International Conf. on Distributed Computing Systems, IEEE Computer Society Press, Los Alamitos, CA, pp. 512-520.

....because the role of each processing element depends on the application. In this way, object metaobject separation addresses the open ended property. Meta level context management is comparable to the work on user level thread management done by [Anderson et al. 91] Marsh et al. 91] and [Druschel et al. 92] Unlike these systems, however, threads are not managed by objects with kernel support. They are implemented as Contexts and are created in a metaspace. The dominant feature of object metaobject separation is the independence of its objects from their metaspace. 6 Conclusion Object metaobject ....

Peter Druschel, Larry L. Peterson, and Norman C. Hutchinson. Beyond Micro-Kernel Design: Decoupling Modularity and Protection in Lipto. In Proceedings of the 12th International Conference on Distributed Computing Systems, pp. 512--520, June 1992.

....of supporting multiple implementations that sit on top of the micro kernel. A flexible dynamic linking facility along with a reflective dispatch mechanism provides much of the flexibility of this system. Spring has been built from scratch and UNIX services are being emulated as servers. Lipto [Druschel, 1992] allows for the dynamic composition of interfaces quite like the substrate approach. The communication between interfaces and implementation is essentially reified to handle crossing protection and machine boundaries. The composition of different interfaces is seen as a process of configuration, ....

P. Druschel, L. Peterson & N. Hutchinson (1992) Beyond Micro-Kernel Design: Decoupling Modularity and Protection in Lipto, 12th Intl. Conf. on Distributed Syst. (ICDCS), IEEE , pp. 512-520.

....interfaces or with previous versions of operating systems, neither of which should change when developers offer additional functionality. This is exemplified by the replication of file objects in the Spring operating system[31] by a location transparent invocation mechanism in the Lipto system[15], and by object migration in the Apertos system for uniprocessor platforms[71] Performance improvements derived from program configuration typically correct mismatches between desired vs. current program or system primitives, policies, and state. Since such mismatches may arise at any time during ....

P. Druschel, L. Peterson, and N. Hutchinson. Beyond microkernel design: Decoupling modularity and protection in Lipto. In Proc. of the 12th Internacional Conference on Distributed Computing Systems, pages 512--520, June 1992.

....of control is represented explicitly as part of threads, easily visible to and usable by the microkernel. This permits well known optimizations to control transfer, such as those described in LRPC[1] and numerous other optimizations in flexibly structured or shared address space systems e.g. Lipto[5], Opal[3] 2 , FLEX[2] and Mach In Kernel Servers[8, 6] Passive objects can be smaller and more lightweight, because they involve less storage overhead. In an active object model, all objects must own a full set of threads and their associated processing 2 Opal claims that threads remain ....

Peter Druschel, Larry L. Peterson, and Norman C. Hutchinson. Beyond micro-kernel design: Decoupling modularity and protection in Lipto. In Proc. of the 12th International Conference on Distributed Computing Systems, pages 512--520, Yokohama, Japan, June 1992.

....of normal Unix pipes in a monolithic 4.3 BSD system on the same hardware. In that implementation pipe buffers are always 4K in size. 4. 4 Same Domain Communication One well known way to reduce the overall performance overhead in decomposed systems is to decouple modularity from protection [7]: make all inter module communication go through well defined RPC like interfaces that can cross process and machine boundaries, but allow the resulting system to be configured so that several modules share the same protection domain and RPC between them is optimized to simple procedure calls. ....

P. Druschel, L. L. Peterson, and N. C. Hutchinson. Beyond micro-kernel design: Decoupling modularity and protection in Lipto. In Proc. of the 12th International Conference on Distributed Computing Systems, pages 512--520, Yokohama, Japan, June 1992.

.... difficult to add significant new functionality to these systems [15, 1, 40] In response to this problem, a number of recent research projects have explored novel operating system architectures to support untrusted extensions; these include SPIN [7, 5] VINO [43, 39] Exokernel [19] Lipto [16], and Fluke [20] Unfortunately, the architectures employed by these projects required substantial implementation effort and are not generally available in commodity systems. In contrast, by leveraging the technique of interposition, our extension mechanism requires only trivial operating ....

....taken by a number of systems over the years which have attempted to reduce the cost of adding new operating system functionality by restructuring the operating system to be extensible. Systems built using this approach include Hydra [50] Mach [1] SPIN [7, 5] VINO [43, 39] Exokernel [19] Lipto [16], and Fluke [20] While many of these systems have successfully demonstrated greatly reduced costs of adding new functionality, the cost of wholesale replacement of existing commodity operating systems prohibitive; for example, Microsoft has spent over 300M developing Windows NT [52] ....

[Article contains additional citation context not shown here]

Peter Druschel, Larry L. Peterson, and Norman Hutchinson. Beyond Micro-Kernel Design: Decoupling Modularity and Protection in Lipto. In Proceedings of the 12th International Conference on Distributed Computing Systems, pages 512-- 520, June 1992.

....The SPIN extensible microkernel [4] allows client code to be dynamically added to the kernel, although the focus is on extensibility rather than reuse. Anderson s proposal [2] to implement extensibility by moving functionality out of the kernel and up to the application level, also seen in Lipto [6] and Aegis [7] allows for structuring system services as a library of reusable classes. ....

Drushel, P., Peterson, L., Hutchinson, N. C., "Beyond Microkernel Design: Decoupling Modularity and Protection in Lipto" Proc. 12th Int. Conf. on Distributed Computing Systems, pp. 512--520, Yokohama, Japan (June 1992).

....arguments. Even for I O intensive programs, such as ls, the use of in server client technology reduced the total running time by 10 . 4 Related Work There are a number of systems that provide various aspects of FLEX, although none supports its full generality of optimizations. Like FLEX, Lipto [5] provides architectural support for modules that is independent of protection domains, and thereby allows communications between modules to be optimized using techniques similar to those described above. However, it was not designed to work with existing system implementations, and currently does ....

P. Druschel, L.L. Peterson, and N.C. Hutchinson. Beyond micro-kernel design: Decoupling modularity and protection in Lipto. In Proceedings of the 12th International Conference on Distributed Computing Systems, pages 512--520, June 1992.

....services provided by the microkernel (and accessed via system calls) and those provided by servers (and perhaps accessed via object invocation) Moreover, most still map a server to a protection domain. A notable exception that emphasises orthogonality between modularity and protection is Lipto [28], which is reviewed in detail in section 2.2. Program Families An alternative approach to the design of (statically) flexible system software, which predates the recent interest in microkernels and object orientation, is based on the use of program families. Parnas [53] defines program families ....

....identical to the use of references to ordinary C objects. Garbage collection of acyclic persistent data structures based on reference counting is also supported [20] Finally, dsm can be used to access remote persistent objects. 2. 2 Lipto Orthogonality of Modularity and Protection Lipto [27, 28] is an object oriented operating system developed at the University of Arizona between 1991 and 1993. Lipto was developed as a prototype implementation of an objectoriented architecture for a family of portable distributed operating systems. Goals and Approach The primary goal of the Lipto ....

Peter Druschel, Larry L. Peterson, and Norman C. Hutchinson. Beyond micro-kernel design: Decoupling modularity and protection in Lipto. In Proceedings of the 12 th International Conference on Distributed Computing Systems, pages 512--520. IEEE Computer Society Press, June 1992.

....requested operation, and then returns to the client task with the results. No synchronization, rescheduling, or full context switch need be done. Thread migration also permits optimizations such as those done in LRPC[3] and in other flexibly structured or shared address space systems, e.g. Lipto[15], FLEX[7] and Mach In Kernel Servers[22, 17] In these systems there is some degree of inter domain memory sharing or protection relaxation, thus blurring domain boundaries. RPC implemented by threads that migrate from one domain to another can take advantage of this boundary blurring, providing ....

Peter Druschel, Larry L. Peterson, and Norman C. Hutchinson. Beyond micro-kernel design: Decoupling modularity and protection in Lipto. In Proc. of the 12th International Conference on Distributed Computing Systems, pages 512--520, Yokohama, Japan, June 1992.

....a functional decomposition where most of the OS implementation is collocated with application code in userlevel domains, and only a small set of trusted functionality is centralized. We are currently exploring this approach in the context of Lipto, a composable, object oriented operating system [6]. 3.1 Composable, Object Oriented Structure The goal of incremental customization implies a system structure where individual software components can be modified or replaced, without requiring an understanding of the system in its entirety. This suggests an object oriented structure, where the ....

P. Druschel, L. L. Peterson, and N. C. Hutchinson. Beyond micro-kernel design: Decoupling modularity and protection in Lipto. In Proc. of the Twelfth Int. Conf. on Distributed Computing Systems, pages 512--520, Yokohama, (Japan), June 1992.

....research. These are summarized below. Note that in the case of Lipto, many of the ideas guide the implementation of the x kernel in Mach described above. In the case of Scout, the project is just getting underway. Lipto: An operating system that explicitly decouples modules and protection domains [Drus92]. Starting with the premise that modular operating system design is a good idea, this paper argues that modularity and protection should be treated as orthogonal issues. That is, modules should first be designed based on sound software engineering principles, and later partitioned into protection ....

Druschel, P., Peterson, L. L., and Hutchinson, N. C. Beyond micro-kernel design: Decoupling modularity and protection in Lipto. In Proceedings of the Twelfth International Conference on Distributed Computing Systems, pages 512--520, Yokohama, Japan., June 1992.

No context found.

Peter Druschel, Larry L. Peterson, and Norman Hutchinson. Beyond MicroKernel Design: Decoupling Modularity and Protection in Lipto. In Proceedings of the 12th International Conference on Distributed Computing Systems, pages 512--520, June 1992.

No context found.

Druschel, P., Peterson, L. L. and Hutchinson, N. C. Beyond micro-kernel design: decoupling modularity and protection in Lipto. In Proceedings of the 12th International Conference on Distributed Computing Systems, Yokohama, Japan, IEEE, 512-520, 1992.

No context found.

Peter Druschel, Larry Peterson, and Norman Hutchinson. Beyond microkernel design: Decoupling modularity and protection in Lipto. In Proc. of the 12th Internacional Conference on Distributed Computing Systems, pages 512--520, June 1992.

No context found.

P. Druschel et. al., Beyond Microkernel Design: Decoupling Modularity and Protection in Lipto, Proc. 12th Intl. Conf. on Distributed Computing Syst., IEEE, pp. 512-520.

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