Jochen Liedtke

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First-generation μ-kernels have a reputation for being too slow and lacking sufficient flexibility. To determine whether L4, a lean second-generation μ-kernel, has overcome these limitations, we have repeated several earlier experiments and conducted some novel ones. Moreover, we ported the Linux operating system to run on top of the L4 μ-kernel and(More)
Inter-process communication (ipc) has to be fast and effective, otherwise programmers will not use remote procedure calls (RPC), multithreading and multitasking adequately. Thus ipc performance is vital for modern operating systems, especially μ-kernel based ones. Surprisingly, most μ-kernels exhibit poor ipc performance, typically requiring(More)
th ACM Symposium on Operating System Principles SOSP December Copper Mountain Resort Colorado From a software technology point of view the kernel concept is superior to large integrated kernels On the other hand it is widely believed that a kernel based systems are inherently ine cient and b they are not su ciently exible Contradictory to this belief we(More)
Jochen Liedtke GMD — German National Research Center for Information Technology * jochen.liedtke@gmd .de From a software-technology point of view, the p-kernel concept is superior to large integrated kernels. On the other hand, it is widely believed that (a) p-kernel based systems are inherently inefficient and (b) they are not sufficiently flexible.(More)
3rd IEEE Real-time Technology and Applications Symposium (RTAS), June 1997 in Montreal, Canada Cache-partitioning techniques have been invented to make modern processors with an extensive cache structure useful in real-time systems where task switches disrupt cache working sets and hence make execution times unpredictable. This paper describes an(More)
Multiserver systems, operating systems composed from a set of hardware-protected servers, initially generated significant interest in the early 1990's. If a monolithic operating system could be decomposed into a set of servers with well-defined interfaces and well-understood protection mechanisms, then the robustness and configurability of operating systems(More)
6th Workshop on Hot Topics in Operating Systems (HotOS) May 5-6, 1997, Chatham (Cape Code), Massachusetts Extensibility can be based on cross-address-space communication or on grafting application-speci c modules into the operating system. For comparing both approaches, we need to explore the best achievable performance for both models. This paper reports(More)
We present a framework that allows applications to build and customize VM services on the L4 microkernel. While the L4 microkernel’s abstractions are quite powerful, using these abstractions effectively requires higher-level paradigms. We propose the dataspace paradigm which provides a modular VM framework. The modularity introduced by the dataspace(More)
For a general acceptance, -kernels must be fast and not burden applications. For ful lling these conditions, cache architectures require -kernels to be small. The L4 -kernel shows that smallness can be achieved. 1. -kernels must be small This is not obvious. Most rst-generation -kernels were large; typically they need 300 Kbyte of code and 140 system calls.(More)