KylinX

Unikernel specializes a minimalistic LibOS and a target application into a standalone single-purpose virtual machine (VM) running on a hypervisor, which is referred to as (virtual) appliance . Compared to traditional VMs, Unikernel appliances have smaller memory footprint and lower overhead while guaranteeing the same level of isolation. On the downside, Unikernel strips off the process abstraction from its monolithic appliance and thus sacrifices flexibility, efficiency, and applicability. In this article, we examine whether there is a balance embracing the best of both Unikernel appliances (strong isolation) and processes (high flexibility/efficiency). We present KylinX, a dynamic library operating system for simplified and efficient cloud virtualization by providing the pVM (process-like VM) abstraction. A pVM takes the hypervisor as an OS and the Unikernel appliance as a process allowing both page-level and library-level dynamic mapping. At the page level, KylinX supports pVM fork plus a set of API for inter-pVM communication (IpC, which is compatible with conventional UNIX IPC). At the library level, KylinX supports shared libraries to be linked to a Unikernel appliance at runtime. KylinX enforces mapping restrictions against potential threats. We implement a prototype of KylinX by modifying MiniOS and Xen tools. Extensive experimental results show that KylinX achieves similar performance both in micro benchmarks (fork, IpC, library update, etc.) and in applications (Redis, web server, and DNS server) compared to conventional processes, while retaining the strong isolation benefit of VMs/Unikernels.

Studies of GEANT4 performance for different ATLAS detector geometries and code compilation methods

Full detector simulation is known to consume a large proportion of computing resources available to the LHC experiments, and reducing time consumed by simulation will allow for more profound physics studies. There are many avenues to exploit, and in this work we investigate those that do not require changes in the GEANT4 simulation suite. In this study, several factors affecting the full GEANT4 simulation execution time are investigated. A broad range of configurations has been tested to ensure consistency of physical results. The effect of a single dynamic library GEANT4 build type has been investigated and the impact of different primary particles at different energies has been evaluated using GDML and GeoModel geometries. Some configurations have an impact on the physics results and are, therefore, excluded from further analysis. Usage of the single dynamic library is shown to increase execution time and does not represent a viable option for optimization. Lastly, the static build type is confirmed as the most effective method to reduce the simulation execution time.

ALGORITHM FOR DYNAMIC FORMATION OF A DIGITAL WATERMARK IN THE PROGRAM MEMORY

An algorithm for embedding digital watermarks into the memory of the executable program is proposed. Digital watermarks are used for copy protection and copyright confirmation of digital objects. The proposed approach makes it possible to form a digital watermark in the operative memory of an executable program for a limited period of time. The address of the embedded information in RAM is random, which greatly complicates its detection and identification. Extraction of digital watermark is performed by passphrase. The embedding, extraction and removal of a digital watermark is implemented using a dynamic library, which is an integral part of the user authentication process, which prevents third-party removal of the digital watermark.