Linux Security

Information age has brought a new colossal change in a person’s habitual life. The level of computer literacy has grown greatly and even a middle level specialist is able to perform the tasks intended for the programming experts. Computers integrated into the network provide a huge amount of confidential and sensitive information that has an impact on individuals as well as on the economies of enterprises or even affects the whole country

Challenges Using Linux as a Real-Time Operating System

Human-in-the-loop (HITL) simulation groups at NASA and the Air Force Research Lab have been using Linux as a real-time operating system (RTOS) for over a decade. More recently, SpaceX has revealed that it is using Linux as an RTOS for its Falcon launch vehicles and Dragon capsules. As Linux makes its way from ground facilities to flight critical systems, it is necessary to recognize that the real-time capabilities in Linux are cobbled onto a kernel architecture designed for general purpose computing. The Linux kernel contain numerous design decisions that favor throughput over determinism and latency. These decisions often require workarounds in the application or customization of the kernel to restore a high probability that Linux will achieve deadlines

Faults in Linux 2.6

In August 2011, Linux entered its third decade. Ten years before, Chou et al. published a study of faults found by applying a static analyzer to Linux versions 1.0 through 2.4.1. A major result of their work was that the drivers directory contained up to 7 times more of certain kinds of faults than other directories. This result inspired numerous efforts on improving the reliability of driver code. Today, Linux is used in a wider range of environments, provides a wider range of services, and has adopted a new development and release model. What has been the impact of these changes on code quality? To answer this question, we have transported Chou et al.'s experiments to all versions of Linux 2.6; released between 2003 and 2011. We find that Linux has more than doubled in size during this period, but the number of faults per line of code has been decreasing. Moreover, the fault rate of drivers is now below that of other directories, such as arch. These results can guide further development and research efforts for the decade to come. To allow updating these results as Linux evolves, we define our experimental protocol and make our checkers available

Minimalist's Linux Cluster

Using barebone PC components and NIC's, we construct a linux cluster which has 2-dimensional mesh structure. This cluster has smaller footprint, is less expensive, and use less power compared to conventional linux cluster. Here, we report our experience in building such a machine and discuss our current lattice project on the machine.Comment: 3 pages, 2 figures, Proceedings of the Lattice 03 Conference (Tsukuba, Japan

Latency Performance for Real-Time Audio on BeagleBone Black

In this paper we present a set of tests aimed at evaluating the responsiveness of a BeagleBone Black board in real-time interactive audio applications. The default Angstrom Linux distribution was tested without modifying the underlying kernel. Latency measurements and audio quality were compared across the combination of different audio interfaces and audio synthesis models. Data analysis shows that the board is generally characterised by a remarkably high responsiveness; most of the tested configurations are affected by less than 7ms of latency and under-run activity proved to be contained using the correct optimisation techniques

A TCP/IP Network Emulator

In this paper a Linux based framework of a TCP/IP emulator is introduced. Several advantages can be noted. Firstly, the maintenance of large numbers of processors is unnecessary. Secondly, compared with simulators constructed with conceptual codes, our emulator framework makes it possible to test the interaction and behaviour of TCP/IP in real Linux network environments. Thirdly, the wired network is fully controlled by a single processor enabling us to separate TCP/IP behaviour over the wireless network, which helps distinguish performance functions that occur due to noisy wireless links. The framework was tested on two Linux processors over an IEEE802.11b wireless link. The simulations show that the complex topology of the heterogeneous network was "realistically" constructed