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>

<p>Here at ISY research is performed on network processors. In order to evaluate the processors there is a need to have full control of every aspect of the transmission. This is not the case if you use a proprietary technology. Therefore the need for a well documented gigabit Ethernet network interface has emerged. </p><p>The purpose of this thesis work has been to design and implement an open source gigabit Ethernet controller in a FPGA together with a device driver for the Linux operating system Implementation has been done in Verilog for the hardware part and the software was developed in C.</p><p>We have implemented a fully functional gigabit Ethernet interface onto a Xilinx Virtex II-1500 FPGA together with a Linux device driver. The design uses approximately 7200 LUTs and 48 block RAMs including the opencores PCI bridge.</p>

<p>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.</p>

<p>This thesis makes a comparative study of the security systemsSystrace (used primarily with OpenBSD) and SELinux (usedexclusively with Linux), trying to answer the question as to whichtype of security is offered by each respective system, and wheneach should be used. The key difference between SELinux andSystrace seems to be their mode of operation, where SELinux,built around the LSM framework in the Linux kernel, works withtype enforcement on files, sockets and other objects, whereasSystrace works on a strict system call basis. The two systems areseen to serve two different purposes which sometimes overlap,but in just as many cases provide solutions for entirely differentquality priorities.</p>

No description available.

<p>Voice over IP (VoIP) traffic in a multi-hop wireless mesh network (WMN) suffers from a large overhead due to mac/IP/UDP/RTP headers and time collisions. A consequence of the large overhead is that only a small number of concurrent VoIP calls can be supported in a WMN[17]. Hop-to-hop packet aggregation can reduce network overhead and increase the capacity. Packet aggregation is a concept which combines several small packets, destined to a common next-hop destination, to one large packet. The goal of this thesis was to implement packet aggregation on a Linux distribution and to increase the number of concurrent VoIP calls. We use as testbed a two-hop WMN with a fixed data rate of 2Mbit/s. Traffic was generated between nodes using MGEN[20] to simulate VoIP behavior. The results from the tests show that the number of supported concurrent flows in the testbed is increased by 135% compared to unaggregated traffic.</p>

In this thesis, we exercised the componentization technique to componentize the Netfilter architecture in Linux network system. Netfilter is a software architecture for filtering packets. System administrator can register packet-matching rules and target handling function into the system. Netfilter matches packets according to the rules and processes them by the corresponding target functions. By componentizing the architecture, we can improve the elasticity and the reusability of Netfilter. Hot-swapping is an important procedure in componentized software system. In this study, we implemented hot-swapping based on the work developed by Fan[1]. It stores the relocation information of exporting symbols into the module symbol table. With this information, we are able to dynamically change the caller-callee relationship of modular components at run time. In addition, we extend their work to allow the same modular component to be loaded into Linux kernel for more than once so that the same component can be replicated in the system. We started with decomposing all the ¡§hook¡¨ functions into smaller and simpler components and then for each component, we added in-ports and out-ports and registered its own iptables, and we fixed the limitation of only one instance of a module allowed in kernel and broke the hard rule in iptables. As a result, after Netfilter componentization, we are able to illustrate new configurations that cannot be done in the original architecture, and the system becomes further compact with only necessary components loaded in the system. This reflects in slight performance improvement in our experiments, which is not usually seen in other frameworks due to componentization overhead.

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.

Embedded system plays an important role in various industry applications. An embedded system is consisting of software and hardware. The hardware platform of conventional embedded system is typically based on IC chips that have fixed resources. Besides, with the development of FPGA, an emerging approach for designing embedded system is implementing soft IP cores on FPGAs. Soft IP cores are synthesizable hardware blocks described in HDL language. Their source code can be either open or close to public. For example, OpenRISC 1200, is an open source 32-bit RISC microprocessor. In addition, the increasing complexity of embedded system forces software developers to consider operating system support to reduce their workload. Thus, in this thesis, a prototype of open source IP based embedded system with Linux is implemented on Atlys (Xilinx Spartan-6) FPGA board and the goal is to evaluate if the system is appropriate for industrial applications. The hardware platform is ORPSOC, which is a reference SoC design based on OpenRISC 1200 processor. For software, Linux operating system is installed. Furthermore, an application executes on Linux is developed that reads the output of an I2C compass sensor-LSM303DLM. With the success of the application and the investigation of license issues, the conclusion is drawn that open source IP based embedded system with Linux is usable for industry. Although comparing to conventional embedded system, the open source IP based embedded system with Linux has following cons, such as high product cost, basic-supported development environment and more difficult software development if Linux driver doesn’t support the hardware. However, its pros are high flexibility and scalability, high software portability, low software development difficulty and high reusability that make it more suitable for industry usage.