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HelenOS VFS-FUSE connector
Bouška, Zdeněk ; Děcký, Martin (advisor) ; Yaghob, Jakub (referee)
This master thesis deals with the implementation of a connector between FUSE filelesystem drivers and HelenOS native VFS interface. The thesis first describes the way of finding the best solution and the potential possibilities. The low level layer solution is described as the best. Then the concern is focused on the real implementation of the connector. The implementation was successful, so the thesis describes in detail the parts of the fully functional solution in real-life HelenOS system. The solution enables almost no need of changes to be made in both FUSE and Helenos VFS. The connector implementation is demonstrated on a real-life FUSE filesystem Exfat ported to HelenOS. Powered by TCPDF (www.tcpdf.org)
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Read-Copy-Update for HelenOS
Hraška, Adam ; Děcký, Martin (advisor) ; Podzimek, Andrej (referee)
Multicore processors have become prevalent and spurred interest in scalable synchronization mechanisms, such as Read-Copy Update. While RCU is popular in monolithic operating system kernels it has yet to see an implementation in a microkernel environment. In this thesis we design and implement RCU for the microkernel operating system HelenOS. Moreover, we explore potential uses of RCU in HelenOS and illustrate its utility in both the kernel and user space. Benchmarks demonstrate that the RCU implementation provides linearly scalable read-sides and incurs significantly less overhead than traditional locking even if uncontended. Furthermore, RCU was used in user space to speed up traditional locking 2.6 times in the common case. In the kernel, RCU ensured linear scalability of a previously non-scalable futex subsystem. Powered by TCPDF (www.tcpdf.org)
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HelenOS port to Xen hypervisor
Benhák, Tomáš ; Děcký, Martin (advisor) ; Tůma, Petr (referee)
The goal of the master thesis is the paravirtualization of HelenOS operating system for Xen hypervisor on IA-32. The result of the thesis is a prototype implementation which allows to run HelenOS as a PV guest under Xen hypervisor. The thesis analyses the Xen hypervisor interface with respect to the paravirtualized operating system running under it, the relevant parts of HelenOS kernel and changes in them forced by the paravirtualization.
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Security containers and access rights in HelenOS
Henek, Štěpán ; Děcký, Martin (advisor) ; Bulej, Lubomír (referee)
Title: Security containers and access rights in HelenOS Author: Štěpán Henek Department: Department of Software Engineering Supervisor: Mgr. Martin Děcký Supervisor's e-mail address: decky@ksi.mff.cuni.cz Abstract: The goal of this thesis is to design and implement security containers (contexts) for tasks and access rights mechanisms for microkernel operating systems. The access rights mechanisms implement common paradigms such as user identification, groups of users, system entities (tasks, files) ownership, user capabilities and access control lists. Moreover, the design allows to implement hierarchical security domains, where each domain is able to delegate a subset of its permissions to its subdomains. The design also enables the implementa- tion of containers, which mutually isolate those tasks, which are situated in security domains with an empty intersection. The thesis comprises of an analysis and evaluation of possible approaches, a prototype imple- mentation in HelenOS with respect to its specific properties (emphasis on a small context switch overhead, delegation of security mechanisms to privileged user space tasks, etc.) and also com- parison with implementations of security containers and access rights mechanisms in generally available operating systems. Keywords: security contexts, access...
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Support for NUMA hardware in HelenOS
Horký, Vojtěch ; Děcký, Martin (advisor) ; Libič, Peter (referee)
The goal of this master thesis is to extend HelenOS operating system with the support for ccNUMA hardware. The text of the thesis contains a brief introduction to ccNUMA hardware, an overview of NUMA features and relevant features of HelenOS (memory management, scheduling, etc.). The thesis analyses various design decisions of the implementation of NUMA support -- introducing the hardware topology into the kernel data structures, propagating this information to user space, thread affinity to cores and nodes, memory allocation policies, load balancing, etc. The thesis also contains a prototype implementation of ccNUMA support in HelenOS for the AMD64 platform and a brief evaluation and comparison with ccNUMA support in other monolithic and microkernel-based operating systems.
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HelenOS as Xen hypervisor
Dolejš, Jan ; Děcký, Martin (advisor) ; Ježek, Pavel (referee)
The aim of the master thesis is to create a prototype implementation of the interface of the Xen hypervisor within the HelenOS operating system. The target architecture of this prototype implementation is IA-32. The result of the thesis is a port of HelenOS which can be uses to run the selected para-virtualized domain. The thesis contains a brief introduction to the methods of virtualization and describes the main differences between them. Thesis also describes the parts of the architecture of the Xen hypervisor and the HelenOS operating system, which will be modified in the prototype implementation. The most important part of this thesis is to select of the t testing domain as well as analyze and describe all changes, which were required for the do-main's operation.
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HelenOS ext4 filesystem driver
Princ, František ; Děcký, Martin (advisor) ; Babka, Vlastimil (referee)
HelenOS is an experimental operating system based on microkernel. It's developed by people related to Faculty of Mathematics and Physics at Charles University in Prague. The present implementantion is prepared to support a scale of filesystems because of VFS abstraction, but actually only a few of filesystems are supported. Ext4 is modern filesystem, developed Linux kernel developers. The previous releases ext2 and especially ext3 are still very popular in many Linux distributions. Imple- mentation of ext2/3/4 filesystems can be also found in other unix-based operating systems, for example *BSD or OpenSolaris. The main goal of this thesis is to extend HelenOS operating system to support previously mentioned filesystems.
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HelenOS Monitoring
Kozina, Stanislav ; Děcký, Martin (advisor) ; Tůma, Petr (referee)
The main purpose of an operating system is to supply the user programs with persistent, simple and enough powerful service interface. However for practical use of the system it is often necessary to know the current state of the system, how much resources the system is using and which user programs consume the biggest portion of them. In the thesis we discuss the possibilities of the operating system monitoring in common. For HelenOS system (which was missing any monitoring facility) such interface was created. Next to the monitoring services we designed and implemented a simple statistical pro ler. Both the user programs and the whole operating system can be pro led. Two userspace applications were created for this purpose.
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