L'accès permanent et sécurisé aux ressources, données et services proposés par une entreprise est devenu au fil des années un point critique dans la stratégie de mise en place de l'infrastructure réseau. Situé à l'entrée du réseau interne et chargé de faire respecter la politique de sécurité mise en place par l'administrateur, le pare-feu est bien souvent l'unique point d'accès par lequel transitent toutes les connexions avec l'extérieur, et représente de ce fait un unique point de défaillance potentiel (« single point-of-failure »). Afin de pallier cette faiblesse, plusieurs solutions de redondances de pare-feux ont vu le jour. Ce document a pour but de présenter, d'évaluer et de comparer deux solutions reconnues du monde du logiciel libre : les conntrack-tools sous Linux, et pfsync/CARP sous OpenBSD. On présente également une nouvelle implémentation de canaux d'échanges d'états de connexions entre les pare-feux sous Linux, basé sur le protocole TIPC.

Användningen av Linux i inbyggda system fortsätter att öka för varje år. Öppen källkod och nya verktyg för utvecklandet av Linux för inbyggda system har inte bara gjort Linux till ett kostnadseffektivt val, utan även ett tidseffektivt val. Målet med den här undersökningen har varit att åt LVI undersöka en möjlig migration av operativsystem i deras inbäddade system från Windows XP Embedded till ett inbyggt Linuxbaserat operativsystem för ARM-processorer med stöd för OCR-behandling. Linux och öppen källkod till inbyggda system för med sig en hel del fördelar. Några av dessa inkluderar låg kostnad, full kontroll över ditt inbyggda system samt möjligheten att testa och utvärdera mjukvara helt gratis. För att komma fram till ett resultat har vi undersökt vilka alternativ som finns och om det finns stöd för de funktioner som LVI använder sig av. Resultatet av den här undersökningen är en redovisning av de val man står inför och vad som kan lämpa sig bäst för LVI. Vi har främst undersökt Yocto Project och Buildroot i denna undersökning och anser att Yocto Project är ett bra val för LVI. Två enklare applikationer har även skrivits där bildhantering och maskinläsning uppvisas. Applikationerna har utvecklats i C++ med hjälp av OpenCV och Tesseract-ocr.

Context Light weight process virtualization has been used in the past e.g., Solaris zones, jails in Free BSD and Linux’s containers (LXC). But only since 2013 is there a kernel support for user namespace and process grouping control that make the use of lightweight virtualization interesting to create virtual environments comparable to virtual machines. Telecom providers have to handle the massive growth of information due to the growing number of customers and devices. Traditional databases are not designed to handle such massive data ballooning. NoSQL databases were developed for this purpose. Cassandra, with its high read and write throughputs, is a popular NoSQL database to handle this kind of data. Running the database using operating system virtualization or containerization would offer a significant performance gain when compared to that of virtual machines and also gives the benefits of migration, fast boot up and shut down times, lower latency and less use of physical resources of the servers. Objectives This thesis aims to investigate the trade-off in performance while loading a Cassandra cluster in bare-metal and containerized environments. A detailed study of the effect of loading the cluster in each individual node in terms of Latency, CPU and Disk throughput will be analyzed. Method We implement the physical model of the Cassandra cluster based on realistic and commonly used scenarios or database analysis for our experiment. We generate different load cases on the cluster for Bare-Metal and Docker and see the values of CPU utilization, Disk throughput and latency using standard tools like sar and iostat. Statistical analysis (Mean value analysis, higher moment analysis and confidence intervals) are done on measurements on specific interfaces in order to show the reliability of the results. Results Experimental results show a quantitative analysis of measurements consisting Latency, CPU and Disk throughput while running a Cassandra cluster in Bare Metal and Container Environments. A statistical analysis summarizing the performance of Cassandra cluster while running single Cassandra is surveyed. Conclusions With the detailed analysis, the resource utilization of the database was similar in both the bare-metal and container scenarios. From the results the CPU utilization for the bare-metal servers is equivalent in the case of mixed, read and write loads. The latency values inside the container are slightly higher for all the cases. The mean value analysis and higher moment analysis helps us in doing a finer analysis of the results. The confidence intervals calculated show that there is a lot of variation in the disk performance which might be due to compactions happening randomly. Further work can be done by configuring the compaction strategies, memory, read and write rates.

This project is part of research funded by NASA Langley in field of Unmanned Aerial Vehicles (UAVs) and is based on past work conducted at Virginia Commonwealth University. Dr. Mark A. Motter of NASA Langley intends to use the new autopilot system to test aircraft with many control surfaces. The goal of this project is to port an existing UAV autopilot system that has more computing power than the previous generation system to allow for more advanced flight control algorithms.The steps taken to complete this project include choosing a new hardware platform, porting C flight control software from a MicroBlaze platform to a PowerPC platform, and developing FPGA based hardware to interface with external sensors. The Suzaku-V based system was shown to have much better computing performance than the previous system, and several successful test flights have proved the viability of the new autopilot system.

As mobile computers such as laptops and cellphones are becoming more and more powerful, the options for those who traditionally required a more powerful desktop PC, such as video editors or gamers seem to have grown slightly. One of these new options are external Graphics Processing Units (eGPUs). Where a laptop is used along with an external GPU, connected via Intel’s Thunderbolt 3. This is however a rather untested method. This paper discusses the performance of eGPUs in a variety of operating systems (OS’s). For this research, performance benchmarking was used to investigate the performance of GPU intensive tasks in various operating systems. It was possible to determine that the performance across operating systems does indeed differ greatly in some usecases, such as games. While other use cases such as computational and synthetictests perform very similarly independently of which system (OS) is used. It seems that the main limiting factor is the GPU itself. It also appears to be the case that the interface with which the GPU is connected to a computer does indeed impact performance, in a very similar way between different OS’s. Generally, games seem to loose more performance than synthetic and computational tasks when using an externalGPU rather than an internal one. It was also discovered that there are too many variables for any real conclusions to be drawn from the gathered results. This as theresults were sometimes very inconclusive and conflicting. So while the outcomes can be generalized, more research is needed before any definitive conclusions can be made.

In recent times Cloud Computing has become an accessible technology which makes it possible to provide online services to end user by the network of remote servers. With the increase in remote servers and resources allocated to these remote servers leads to performance degradation of service. In such a case, the environment on which service is made run plays a significant role in order to provide better performance and adds up to Quality of Service. This paper focuses on Bare metal and Linux container environments as request response time is one of the performance metrics to determine the QOS. To improve request response time platforms are customized using real-time kernel and compiler optimization flags to optimize the performance of a service. UDP packets are served to the service made run in these customized environments. From the experiments performed, it concludes that Bare metal using real-time kernel and level 3 Compiler optimization flag gives better performance of a service.

Este trabajo consiste en el desarrollo e implementación de un prototipo de espirómetro de flujo para computadora, tomando como guía las recomendaciones dadas por la American Thoracic Society (ATS Medical Section of the American Lung Association) y de la Sociedad Española de Neumología y Cirugía Torácica SEPAR. La espirometría es una prueba médica que consiste en la medición del volumen y flujo respiratorio espirado por el paciente; y es una de las primeras pruebas que se realizan en pacientes que presenten anomalías respiratorias. / Tesis

NFS is the dominant network file system used to share files between UNIX-derived operating system based hosts. At the onset of this research it was found that the tested NFS implementations did not achieve data writing throughput across a Gigabit Ethernet LAN commensurate with throughput achieved with the same hosts and network for packet streams generated without NFS. A series of tests were conducted involving variation of many system parameters directed towards identification of the bottleneck responsible for the large throughput ratio between non-NFS and NFS data transfers for high speed networks. Ultimately it was found that processor, disk, and network performance are not the source of low NFS throughput but rather it is caused by an avoidable NFS behavior, the effects of which worsen with increasing network latency.

The CubeSat pico-satellite is gaining popularity in both the educational and aerospace industries. Due to a lack of experience and constrained hardware capabilities, most of the university missions have been educational in nature. Cal Poly's project, PolySat, has gained significant experience from the launch of five CubeSats and has designed an entirely new hardware platform based on the knowledge gained from these missions. This hardware is a significant upgrade from what the previous missions used and has greatly increased the capabilities of the software, including supporting the use of the open source operating system Linux. Leveraging the previous PolySat experience, a new design approach has been followed for the development of a fault tolerant and flexible software architecture. As a result, a set of processes and custom libraries that run within Linux have been designed and implemented. Furthermore, an emphasis has been placed on fault tolerance with two features: a software watchdog and digital command signing capability. Lastly, a survey of related CubeSat projects and software fault tolerance papers has been conducted to determine that this new system is sufficient to meet the desired goals.

<p>For many years OSE has been a common used operating system, with real time extensions enhancements, in embed-ded systems. But in the last decades, Linux has grown and became a competitor to common operating systems and, in recent years, even as an operating system with real time extensions. With this in mind, ÅF was interested in replacing the quite expensive OSE with some distribution of the open source based Linux on a PowerPC MPC8360. Therefore, our purpose with thesis is to implement Linux on the named platform and make some tests to see if it is possible to replace OSE with Linux. Using Linux has several advantages, for example it is free of charge to use and over the years the popularity of Linux within the developer community has resulted in numerous tools and utilities available for free.</p><p>As a result, this study shows that Linux with real time extensions on the MPC8360 PowerPC platform is a viable alternative to OSE regarding cost efficiency, flexibility, adaptability and competence available on the market.</p><p>Further studies can be done towards benchmarking for I/O systems and implementing support for more hardware on the MPC8360 AF platform.</p>