Fault tolerance is essential in a production-grade service delivery network. One of the solution is build a clustered environment to keep system failure to a minimum. This thesis examines the use of high availability and load balancing services using open source tools in GNU/Linux. The thesis discusses some general technologies of high availability computing as virtualization, synchronization and mirroring. To build relatively cheap high availability clusters is suitable DRDB tool. DRDB is tool for build synchronized Linux block devices. This paper also examines Linux-HA project, Redhat Cluster Suite, LVS, etc. Content Delivery Networks (CDN) replicate content over several mirrored web servers strategically placed at various locations in order to deal with the flash crowds. A CDN has some combination a request-routing and replication mechanism. Thus CDNs offer fast and reliable applications and services by distributing content to cache servers located close to end-users. This work examines open-source CDNs Globule and CoralCDN and test performance of this CDNs in global deployment.

This work is engaged in access control mechanism in GNU/Linux operating systems. At first discretionary and mandatory access control are compared and examine basic technologies based on mandatory access control. More closely is focused on project SELinux, whose generation of new rules is explained. Within the thesis is made application for logging evaluation and for writing new Type Enforcement rules.

The work is given an analysis of Open Source Software (further referred as OSS), which allows use and create computer clusters. It explored the issue of clustering and construction of clusters. All installations, configuration and cluster management have been done on the operating system GNU / Linux. Presented OSS makes possible to compile a storage cluster, cluster with load distribution, cluster with high availability and computing cluster. Different types of benchmarks was theoretically analyzed, and practically used for measuring cluster’s performance. Results were compared with others, eg. the TOP500 list of the best clusters available online. Practical part of the work deals with comparing performance computing clusters. With several tens of computational nodes has been established cluster, where was installed package OpenMPI, which allows parallelization of calculations. Subsequently, tests were performed with the High Performance Linpack, which by calculation of linear equations provides total performance. Influence of the parallelization to algorithm PEA was also tested. To present practical usability, cluster has been tested by program John the Ripper, which serves to cracking users passwords. The work shall include the quantity of graphs clarifying the function and mainly showing the achieved results.

Účelem této práce je popis protokolu 40Gb Ethernet, popis směrovacího procesu v jádře Linux a navrhnout a provést testování výkonnosti směrování se síťovým adaptérem pro 40Gb Ethernet. Výsledky a nastavení pro získání maximální výkonnosti směrování jsou dále popsány v této práci.

Tato práce se v první části zabývá představením technologií a nástrojů pro centrální správu a přihlašování uživatelů v GNU/Linux. Ukazuje využití adresářových služeb v síťové infrastruktuře, konkrétně služby NIS a její porovnání s dnes pravděpodobně nejrozšířenější adresářovou službou LDAP. Dále práce popisuje proces autentizace na klientských stanicích, konkrétně použití PAM a NSS a možné rozšíření celého systému zavedením cache díky démonu SSSD. Druhá část popisuje návrh a implementaci NIS provideru pro SSSD.

This master thesis discourses upon problems with automatic building and testing of network security solution AVG for Linux/FreeBSD on platforms GNU/Linux and FreeBSD. This work introduces AVG for Linux/FreeBSD and its usage.  Compilation and link are discussed from the source code to the distribution packages, which users can install on your computer. Also, the repository term was introduced, containing the information about their creation and usage. The part about AVG for Linux/FreeBSD testing discusses suitable  automatic testing proposals for this product and implementation of the best solutions. In the practical part, the testing tool was developed. AVG for Linux/FreeBSD was tested using the test tool and implemented test set.

The object of this mater’s thesis is to analyze current situation of information system at municipal office of Blansko and to review it. Subsequently to suggest other possible solutions and improvements. Formulation of economic and other advantages and possible disadvantages and problems that can occur in case of implementation of other OpenSource components.

In this thesis, we present the design and implementation of a CubeSat receiver system using the Universal Software Radio Peripheral (USRP) and GNU Radio. The goal of this project is to develop a low-cost and flexible ground station capable of receiving telemetry and payload data from CubeSats in real time. The CubeSat receiver operates in the UHF frequency range with a center frequency of 435 MHz and uses a software-defined radio (SDR) approach to provide wideband signal processing and demodulation capabilities. The satellite transceiver transmits an Ax.25 Transciever packet every 1 second using the Pumpkin CubeSat kit programmed in MPLab. To achieve this goal, we discuss the design considerations for the receiver system, including the selection of suitable hardware components and the development of custom software blocks in GNU Radio. We also developed the GFSK-based transmitter and receiver in GNU Radio, as well as a tracking system for the satellite. To decode the Ax.25 radio packet transmitted by the Pumpkin CubeSat kit, we developed an Ax.25 deframer in GNU Radio to decode the received signal. Our results demonstrate that the CubeSat receiver is capable of receiving and demodulating AX.25 formatted radio signals from Transciever. Additionally, we show that the receiver system is scalable and can be easily adapted for use with other CubeSat missions. Overall, our work provides a practical solution for CubeSat communication and lays the groundwork for future developments in low-cost CubeSat ground station technology.

The goal of software-defined radio (SDR) is to move the processing of radio signals from the analog domain to the digital domain — to use digital microchips instead of analog circuit components. Until faster, higher-precision analog-to-digital (ADCs) and digital-to-analog converters (DACs) become affordable, however, some analog signal processing will be necessary. We still need to convert high-radio frequency (RF) signals that we receive to low intermediate-frequency (IF) or baseband (centered on zero Hz) signals in order for ADCs to sample them and feed them into microchips for processing. The reverse is true when we transmit. Amplification is also needed on the receive side to fully utilize the dynamic range of the ADC and power amplification is needed on the transmit side to increase the power output from the DAC for transmission. Analog filtering is also needed to avoid saturating the ADC or to filter out interference when receiving and to avoid transmitting spurs. The analog frequency conversion, amplification and filtering section of a radio is called the RF front end. This thesis describes work on a new RF front end daughterboard for the Universal Software Radio Peripheral, or USRP. The USRP is a software-radio hardware platform designed to be used with the GNU Radio software radio software package. Using the Motorola RFIC4 chip, the new daughterboard receives RF signals, converts them to baseband and does analog filtering and amplification before feeding the signal into the USRP for processing. The chip also takes transmit signals from the USRP, converts them from baseband to RF and amplifies and filters them. The board was designed and laid out by Randall Nealy. I wrote the software driver for GNU Radio. The driver defines the interface between the USRP and the RFIC chip, controls the physical settings, and calculates and sets the hundreds of variables necessary to operate this extremely complex chip correctly. It allows plug-and-play compatibility with the current USRP daughterboards and supplies additional functions not available in any other daughterboard. / Master of Science

Arguably, the Schumpeterian ideology of “creative destruction” saying that eventually even the most secure monopoly will be destroyed by a new technology, a new idea, or a shift in tastes could be applied to open source software. Currently, the proprietary software holds a strong position in the software market. Nevertheless, one could see a surge in articles and acceptance among organisations concerning open source software. Proprietary software companies like Microsoft are still gaining ground within the Swedish municipalities. Although one get the impression that municipalities generally are positive toward open source software, the decision-making process often results in choosing a proprietary software alternative. However, one could question which are the underlying factors and to what extent are these factors affecting the decision-making process of municipalities integrating or migrating into open source software? In order to study this phenomenon, we chose a quantitative approach using a questionnaire as the tool for data gathering. The sample consisted of 100 randomly selected municipalities. A pre study was made through an interview in order to strengthen the accuracy of the questionnaire which later on was sent out to the IT manager at each municipality in the sample. The organisational-, environmental-, user- and system level are four main factors affecting the decision-making process concerning open source software. Among these, the organisational factor was the only one which had a significant negative impact on the decision-making process concerning open source software. The importance of being able to integrate different software increases the need for compatibility which, according to the IT managers, is facilitated using a standardized software environment offered by for example Microsoft.