41,091 research outputs found
MGSim - Simulation tools for multi-core processor architectures
MGSim is an open source discrete event simulator for on-chip hardware
components, developed at the University of Amsterdam. It is intended to be a
research and teaching vehicle to study the fine-grained hardware/software
interactions on many-core and hardware multithreaded processors. It includes
support for core models with different instruction sets, a configurable
multi-core interconnect, multiple configurable cache and memory models, a
dedicated I/O subsystem, and comprehensive monitoring and interaction
facilities. The default model configuration shipped with MGSim implements
Microgrids, a many-core architecture with hardware concurrency management.
MGSim is furthermore written mostly in C++ and uses object classes to represent
chip components. It is optimized for architecture models that can be described
as process networks.Comment: 33 pages, 22 figures, 4 listings, 2 table
ScotGrid: Providing an Effective Distributed Tier-2 in the LHC Era
ScotGrid is a distributed Tier-2 centre in the UK with sites in Durham,
Edinburgh and Glasgow. ScotGrid has undergone a huge expansion in hardware in
anticipation of the LHC and now provides more than 4MSI2K and 500TB to the LHC
VOs. Scaling up to this level of provision has brought many challenges to the
Tier-2 and we show in this paper how we have adopted new methods of organising
the centres, from fabric management and monitoring to remote management of
sites to management and operational procedures, to meet these challenges. We
describe how we have coped with different operational models at the sites,
where Glagsow and Durham sites are managed "in house" but resources at
Edinburgh are managed as a central university resource. This required the
adoption of a different fabric management model at Edinburgh and a special
engagement with the cluster managers. Challenges arose from the different job
models of local and grid submission that required special attention to resolve.
We show how ScotGrid has successfully provided an infrastructure for ATLAS and
LHCb Monte Carlo production. Special attention has been paid to ensuring that
user analysis functions efficiently, which has required optimisation of local
storage and networking to cope with the demands of user analysis. Finally,
although these Tier-2 resources are pledged to the whole VO, we have
established close links with our local physics user communities as being the
best way to ensure that the Tier-2 functions effectively as a part of the LHC
grid computing framework..Comment: Preprint for 17th International Conference on Computing in High
Energy and Nuclear Physics, 7 pages, 1 figur
TrustShadow: Secure Execution of Unmodified Applications with ARM TrustZone
The rapid evolution of Internet-of-Things (IoT) technologies has led to an
emerging need to make it smarter. A variety of applications now run
simultaneously on an ARM-based processor. For example, devices on the edge of
the Internet are provided with higher horsepower to be entrusted with storing,
processing and analyzing data collected from IoT devices. This significantly
improves efficiency and reduces the amount of data that needs to be transported
to the cloud for data processing, analysis and storage. However, commodity OSes
are prone to compromise. Once they are exploited, attackers can access the data
on these devices. Since the data stored and processed on the devices can be
sensitive, left untackled, this is particularly disconcerting.
In this paper, we propose a new system, TrustShadow that shields legacy
applications from untrusted OSes. TrustShadow takes advantage of ARM TrustZone
technology and partitions resources into the secure and normal worlds. In the
secure world, TrustShadow constructs a trusted execution environment for
security-critical applications. This trusted environment is maintained by a
lightweight runtime system that coordinates the communication between
applications and the ordinary OS running in the normal world. The runtime
system does not provide system services itself. Rather, it forwards requests
for system services to the ordinary OS, and verifies the correctness of the
responses. To demonstrate the efficiency of this design, we prototyped
TrustShadow on a real chip board with ARM TrustZone support, and evaluated its
performance using both microbenchmarks and real-world applications. We showed
TrustShadow introduces only negligible overhead to real-world applications.Comment: MobiSys 201
DIVERSE: a Software Toolkit to Integrate Distributed Simulations with Heterogeneous Virtual Environments
We present DIVERSE (Device Independent Virtual Environments- Reconfigurable, Scalable, Extensible), which is a modular collection of complimentary software packages that we have developed to facilitate the creation of distributed operator-in-the-loop simulations. In DIVERSE we introduce a novel implementation of remote shared memory (distributed shared memory) that uses Internet Protocol (IP) networks. We also introduce a new method that automatically extends hardware drivers (not in the operating system kernel driver sense) into inter-process and Internet hardware services. Using DIVERSE, a program can display in a CAVEâ„¢, ImmersaDeskâ„¢, head mounted display (HMD), desktop or laptop without modification. We have developed a method of configuring user programs at run-time by loading dynamic shared objects (DSOs), in contrast to the more common practice of creating interpreted configuration languages. We find that by loading DSOs the development time, complexity and size of DIVERSE and DIVERSE user applications is significantly reduced. Configurations to support different I/O devices, device emulators, visual displays, and any component of a user application including interaction techniques, can be changed at run-time by loading different sets of DIVERSE DSOs. In addition, interpreted run-time configuration parsers have been implemented using DIVERSE DSOs; new ones can be created as needed.
DIVERSE is free software, licensed under the terms of the GNU General Public License (GPL) and the GNU Lesser General Public License (LGPL) licenses.
We describe the DIVERSE architecture and demonstrate how DIVERSE was used in the development of a specific application, an operator-in-the-loop Navy ship-board crane simulator, which runs unmodified on a desktop computer and/or in a CAVE with motion base motion queuing
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