The Ubuntu Linux Distribution represents a massive investment of time and human effort to produce a reliable computing experience for users. To accomplish these goals, software bugs must be tracked and fixed. However, as the number of users increase and bug reports grow advanced tools such as data mining must be used to increase the effectiveness of all contributors to the project. Thus, this report involved collecting a large amount of bug reports into a database and calculating relevant statistics. Because of the diversity and quantity of bug reports, contributors must find which bugs are most relevant and important to work on. One study in this report created an automatic way to determine who is best fit to solve a particular bug by using classification techniques. In addition, this report explores how to initially classify if a bug report will be eventually marked invalid or not. / text

Ο σκοπός της παρούσας εργασίας είναι η ανάπτυξη ενός daemon που θα ελέγχει ένα σύνολο από virtual machines, και θα τα χρησιμοποιεί προκειμένου να εξομοιώνονται λειτουργίες δικτύων υπολογιστών. Κάθε ενεργό στιγμιότυπο ενός virtual machine θα έχει ασφαλώς το ρόλο ενός (εικονικού) υπολογιστή. Οι λειτουργίες που υλοποιεί ο κώδικας είναι η δημιουργία, ο έλεγχος και η μεταβολή ενός δικτύου εικονικών υπολογιστών, μέσω ενός μενού επιλογών, το οποίο ταυτόχρονα παρέχει πληροφορίες για κάθε εικονικό υπολογιστή. Η υλοποίηση του δικτύου γίνεται με τη χρήση του User Mode Linux (ενός Linux virtual machine)ενώ κάθε ενεργό UML στιγμιότυπο (UML instance) του virtual machine έχει το ρόλο ενός εικονικού υπολογιστή. Η ευελιξία που παρέχεται από τα Virtual Machines είναι τεράστια, και τα καθιστά ιδανικά για το δίκτυο που θα κάνουμε. Η συμπεριφορά του εξάλλου θα είναι όμοια με αυτή ενός πραγματικού δικτύου. / Creation of a daemon process, used to control a large number of Linux Virtual Machines and create a Virtual Machine network out of them.

Το πρότυπο IEC61499 ορίζει το Function Block ως νέο τρόπο ανάπτυξης συστημάτων ελέγχου και αυτοματισμού. Τα συστήματα αυτά αποτελούνται από κατανεμημένες, ενσωματωμένες συσκευές οι οποίες διασυνδέονται μέσω βιομηχανικών δικτύων πραγματικού χρόνου. Λόγω του κατανεμημένου χαρακτήρα των συστημάτων αυτών, η εύρεση και επιδιόρθωση σφαλμάτων και ο έλεγχος της ορθής λειτουργίας τους θα πρέπει να γίνεται στο περιβάλλον των ενσωματωμένων αυτών συστημάτων. Στα πλαίσια αυτής της διπλωματικής δίνεται μία υλοποίηση για την κάλυψη της παραπάνω ανάγκης. Ο χρήστης μέσω μίας γραφικής διεπαφής, έχει την δυνατότητα να εκτελεί βασικές λειτουργίες απασφαλμάτωσης στο περιβάλλον των ενσωματωμένων συστημάτων, σε πραγματικό χρόνο, με την χρήση του RTAI και του RTnet. / The IEC 61499 standard defines Function Block as a new way of developing control and automation systems. These systems consist of distributed embedded devices which interconnect via real time industrial networks. Due to the distributive character of these systems, debugging and operation integrity check, should be done on target environment. This dissertation provides a tool for covering this need. Via a graphical user interface the user has the ability to perform basic real time debugging operations in the target enviroment, using RTAI and RTnet.

Voice over IP technology (VoIP) has recently gained popularity among consumers. Many popular VoIP services exist only as software for PCs. The need of taking such services out of the PC, into a stand-alone device has been discovered, and this thesis work deals with the development of such a device. The thesis work is done for Häger Scandinavia AB, a Swedish telephone manufacturer. This thesis work covers the design of a complete prototype of a table-top VoIP telephone running an embedded Linux Operating system. Design areas include product development, hardware design and software design.The result is a working prototype with hardware and corresponding Linux device drivers. The prototype can host a Linux application adapted to it. Conclusions are that the first hardware version has worked well and that using an open-source operating system is very useful. Further work consists of implementing a complete telephony software application in the system, evaluation of system requirements and adapting the prototype for a commercial design.

There is a great variety of software solutions which improve quality of work and increase productivity. Nevertheless there still is a demand for specialized software sollutions, often coupled to particular production systems. In this work author approaches such a concrete subject of computer hardware and repair in small and medium enterprise. Proposed information system not only allows internal administration of service requests within a company, but also provides complete status and process overview for customers accessing company's intranet. This is a unique solution of a kind as others are too general and do not fullfil specific demands posed in the specification. The main subject of this work is software design, development and investigation. Analysis of current software technology platforms was performed and the best deployment platform LAMP (Linux-Apache-MySQL-PHP) was selected. Modular system design provided easy system development and future extendability as well as integration into other portals. Final resulting information system incorporates a number of advanced networking and programming technologies: template engine, certificate based security, data encryption engine and others. Implemented software is customized to meet the needs of particular enterprise and is currently used as part of its' intranet and service network. Legal open source technologies were mostly used for developing the product.

L'acc??s permanent et s??curis?? aux ressources, donn??es et services propos??s par une entreprise est devenu au fil des ann??es un point critique dans la strat??gie de mise en place de l'infrastructure r??seau. Situ?? ?? l'entr??e du r??seau interne et charg?? de faire respecter la politique de s??curit?? mise en place par l'administrateur, le pare-feu est bien souvent l'unique point d'acc??s par lequel transitent toutes les connexions avec l'ext??rieur, et repr??sente de ce fait un unique point de d??faillance 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 pr??senter, d'??valuer et de comparer deux solutions reconnues du monde du logiciel libre : les conntrack-tools sous Linux, et pfsync/CARP sous OpenBSD. On pr??sente ??galement une nouvelle impl??mentation de canaux d'??changes d'??tats de connexions entre les pare-feux sous Linux, bas?? sur le protocole TIPC.

This thesis introduces Relative links or rlinks, which are directed labeled links from one file to another in a file system. Rlinks provide a clean way to build and share related-file information without creating additional files and directories. Rlinks form overlay graphs between files of a file system, thus providing useful alternate views of the file system. This thesis implements rlinks for the Linux kernel and modifies the storage structure of the Ext2 file system to store the rlinks.

Detta projekt undersöker en praktisk lösning av virtualisering i Ubuntu-server med kvm och virt-manager för användning i en moln- eller Network-as-a-service-miljö. Projektet inkluderar även en jämförelse mellan webbservermjukvaran NginX och Apache2 och en jämförelse mellan videokonferensmjukvaran BigBlueButton och OpenMeetings genom att mäta CPU, Minnes och Nätverksbelastning till de virtuella servrarna vid 1 till 20 uppkopplingar från en klientmaskin. Utifrån projektets resultat rekommenderas Apache2 som webbserver då installationen är enklare och skillnaden i resursanvädning är försummbar och Openmeetings som videokonferesserver då detta alternativ är det mer kompletta.

Kernel patches are frequently released to fix security vulnerabilities and bugs. However, users and system administrators often delay installing these updates because they require a system reboot, which results in disruption of service and the loss of application state. Unfortunately, the longer an out-of-date system remains operational, the higher is the likelihood of a system being exploited. Approaches, such as dynamic patching and hot swapping, have been proposed for updating the kernel. All of them either limit the types of updates that are supported, or require significant programming effort to manage. We have designed a system that checkpoints application-visible state, updates the kernel, and restores the application state. By checkpointing high-level state, our system no longer depends on the precise implementation of a patch and can apply all backward compatible patches. The results show that updates to major kernel releases can be applied with minimal changes.

Recently, various special purpose processors have been developed and are frequently being used for different specialized tasks. Prominent among these are the communication processors, which are generally used within an embedded system environment. Such processors can run relatively advanced and general purpose operating systems such as uCLinux, which is a freely available embedded Linux distribution. In this work, a prototype SoHo (Small office / Home office) router is designed and implemented using Motorola MCF5272 as the core communication processor and uCLinux as the operating system. The implementation relies purely on the existing hardware resources of an available development board and the publicly available open source utilities of uCLinux. The overall development process provides an embedded system implementation and configuration example.