1,128 research outputs found
A Peer-to-Peer Middleware Framework for Resilient Persistent Programming
The persistent programming systems of the 1980s offered a programming model
that integrated computation and long-term storage. In these systems, reliable
applications could be engineered without requiring the programmer to write
translation code to manage the transfer of data to and from non-volatile
storage. More importantly, it simplified the programmer's conceptual model of
an application, and avoided the many coherency problems that result from
multiple cached copies of the same information. Although technically
innovative, persistent languages were not widely adopted, perhaps due in part
to their closed-world model. Each persistent store was located on a single
host, and there were no flexible mechanisms for communication or transfer of
data between separate stores. Here we re-open the work on persistence and
combine it with modern peer-to-peer techniques in order to provide support for
orthogonal persistence in resilient and potentially long-running distributed
applications. Our vision is of an infrastructure within which an application
can be developed and distributed with minimal modification, whereupon the
application becomes resilient to certain failure modes. If a node, or the
connection to it, fails during execution of the application, the objects are
re-instantiated from distributed replicas, without their reference holders
being aware of the failure. Furthermore, we believe that this can be achieved
within a spectrum of application programmer intervention, ranging from minimal
to totally prescriptive, as desired. The same mechanisms encompass an
orthogonally persistent programming model. We outline our approach to
implementing this vision, and describe current progress.Comment: Submitted to EuroSys 200
Recommended from our members
FutureGRID: A Program for long-term research into GRID systems architecture
Proceedings of the 2003 UK e-Science All Hands Meeting, 31st August - 3rd September, Nottingham UKThis is a project to carry out research into long-term GRID architecture, in the University of Cambridge
Computer Laboratory and the Cambridge eScience Center, with support from the Microsoft Research
Laboratory, Cambridge.
It is part of a larger vision for future systems architectures for public computing platforms, including
both scientitic GRID and commodity level computing such as games, peer2peer computing and storage
services and so forth, based on work in the laboratories in recent years into massively scaleable distributed systems for storage, computation, content distribution and collaboration[26]
The simplicity project: easing the burden of using complex and heterogeneous ICT devices and services
As of today, to exploit the variety of different "services", users need to configure each of their devices by using different procedures and need to explicitly select among heterogeneous access technologies and protocols. In addition to that, users are authenticated and charged by different means. The lack of implicit human computer interaction, context-awareness and standardisation places an enormous burden of complexity on the shoulders of the final users. The IST-Simplicity project aims at leveraging such problems by: i) automatically creating and customizing a user communication space; ii) adapting services to user terminal characteristics and to users preferences; iii) orchestrating network capabilities. The aim of this paper is to present the technical framework of the IST-Simplicity project. This paper is a thorough analysis and qualitative evaluation of the different technologies, standards and works presented in the literature related to the Simplicity system to be developed
A framework for P2P application development
Although Peer-to-Peer (P2P) computing has become increasingly popular over recent years, there still exist only a very small number of application domains that have exploited it on a large scale. This can be attributed to a number of reasons including the rapid evolution of P2P technologies, coupled with their often-complex nature. This paper describes an implemented abstraction framework that seeks to aid developers in building P2P applications. A selection of example P2P applications that have been developed using this framework are also presented
From distributed coordination to field calculus and aggregate computing
open6siThis work has been partially supported by: EU Horizon 2020 project HyVar (www.hyvar-project .eu), GA No. 644298; ICT COST Action IC1402 ARVI
(www.cost -arvi .eu); Ateneo/CSP D16D15000360005 project RunVar (runvar-project.di.unito.it).Aggregate computing is an emerging approach to the engineering of complex coordination for distributed systems, based on viewing system interactions in terms of information propagating through collectives of devices, rather than in terms of individual devices and their interaction with their peers and environment. The foundation of this approach is the distillation of a number of prior approaches, both formal and pragmatic, proposed under the umbrella of field-based coordination, and culminating into the field calculus, a universal functional programming model for the specification and composition of collective behaviours with equivalent local and aggregate semantics. This foundation has been elaborated into a layered approach to engineering coordination of complex distributed systems, building up to pragmatic applications through intermediate layers encompassing reusable libraries of program components. Furthermore, some of these components are formally shown to satisfy formal properties like self-stabilisation, which transfer to whole application services by functional composition. In this survey, we trace the development and antecedents of field calculus, review the field calculus itself and the current state of aggregate computing theory and practice, and discuss a roadmap of current research directions with implications for the development of a broad range of distributed systems.embargoed_20210910Viroli, Mirko; Beal, Jacob; Damiani, Ferruccio; Audrito, Giorgio; Casadei, Roberto; Pianini, DaniloViroli, Mirko; Beal, Jacob; Damiani, Ferruccio; Audrito, Giorgio; Casadei, Roberto; Pianini, Danil
Cross-layer Peer-to-Peer Computing in Mobile Ad Hoc Networks
The future information society is expected to rely heavily on wireless technology. Mobile access to the Internet is steadily gaining ground, and could easily end up exceeding the number of connections from the fixed infrastructure. Picking just one example, ad hoc networking is a new paradigm of wireless communication for mobile devices. Initially, ad hoc networking targeted at military applications as well as stretching the access to the Internet beyond one wireless hop. As a matter of fact, it is now expected to be employed in a variety of civilian applications. For this reason, the issue of how to make these systems working efficiently keeps the ad hoc research community active on topics ranging from wireless technologies to networking and application systems.
In contrast to traditional wire-line and wireless networks, ad hoc networks are expected to operate in an environment in which some or all the nodes are mobile, and might suddenly disappear from, or show up in, the network. The lack of any centralized point, leads to the necessity of distributing application services and responsibilities to all available nodes in the network, making the task of developing and deploying application a hard task, and highlighting the necessity of suitable middleware platforms.
This thesis studies the properties and performance of peer-to-peer overlay management algorithms, employing them as communication layers in data sharing oriented middleware platforms. The work primarily develops from the observation that efficient overlays have to be aware of the physical network topology, in order to reduce (or avoid) negative impacts of application layer traffic on the network functioning. We argue that cross-layer cooperation between overlay management algorithms and the underlying layer-3 status and protocols, represents a viable alternative to engineer effective decentralized communication layers, or eventually re-engineer existing ones to foster the interconnection of ad hoc networks with Internet infrastructures. The presented approach is twofold. Firstly, we present an innovative network stack component that supports, at an OS level, the realization of cross-layer protocol interactions. Secondly, we exploit cross-layering to optimize overlay management algorithms in unstructured, structured, and publish/subscribe platforms
Data Storage and Dissemination in Pervasive Edge Computing Environments
Nowadays, smart mobile devices generate huge amounts of data in all sorts of gatherings.
Much of that data has localized and ephemeral interest, but can be of great use if shared
among co-located devices. However, mobile devices often experience poor connectivity,
leading to availability issues if application storage and logic are fully delegated to a
remote cloud infrastructure. In turn, the edge computing paradigm pushes computations
and storage beyond the data center, closer to end-user devices where data is generated
and consumed. Hence, enabling the execution of certain components of edge-enabled
systems directly and cooperatively on edge devices.
This thesis focuses on the design and evaluation of resilient and efficient data storage
and dissemination solutions for pervasive edge computing environments, operating with
or without access to the network infrastructure. In line with this dichotomy, our goal can
be divided into two specific scenarios. The first one is related to the absence of network
infrastructure and the provision of a transient data storage and dissemination system
for networks of co-located mobile devices. The second one relates with the existence of
network infrastructure access and the corresponding edge computing capabilities.
First, the thesis presents time-aware reactive storage (TARS), a reactive data storage
and dissemination model with intrinsic time-awareness, that exploits synergies between
the storage substrate and the publish/subscribe paradigm, and allows queries within a
specific time scope. Next, it describes in more detail: i) Thyme, a data storage and dis-
semination system for wireless edge environments, implementing TARS; ii) Parsley, a
flexible and resilient group-based distributed hash table with preemptive peer relocation
and a dynamic data sharding mechanism; and iii) Thyme GardenBed, a framework
for data storage and dissemination across multi-region edge networks, that makes use of
both device-to-device and edge interactions.
The developed solutions present low overheads, while providing adequate response
times for interactive usage and low energy consumption, proving to be practical in a
variety of situations. They also display good load balancing and fault tolerance properties.Resumo
Hoje em dia, os dispositivos mĂłveis inteligentes geram grandes quantidades de dados
em todos os tipos de aglomeraçÔes de pessoas. Muitos desses dados tĂȘm interesse loca-
lizado e efĂȘmero, mas podem ser de grande utilidade se partilhados entre dispositivos
co-localizados. No entanto, os dispositivos mĂłveis muitas vezes experienciam fraca co-
nectividade, levando a problemas de disponibilidade se o armazenamento e a lĂłgica das
aplicaçÔes forem totalmente delegados numa infraestrutura remota na nuvem. Por sua
vez, o paradigma de computação na periferia da rede leva as computaçÔes e o armazena-
mento para além dos centros de dados, para mais perto dos dispositivos dos utilizadores
finais onde os dados são gerados e consumidos. Assim, permitindo a execução de certos
componentes de sistemas direta e cooperativamente em dispositivos na periferia da rede.
Esta tese foca-se no desenho e avaliação de soluçÔes resilientes e eficientes para arma-
zenamento e disseminação de dados em ambientes pervasivos de computação na periferia
da rede, operando com ou sem acesso Ă infraestrutura de rede. Em linha com esta dico-
tomia, o nosso objetivo pode ser dividido em dois cenĂĄrios especĂficos. O primeiro estĂĄ
relacionado com a ausĂȘncia de infraestrutura de rede e o fornecimento de um sistema
efĂȘmero de armazenamento e disseminação de dados para redes de dispositivos mĂłveis
co-localizados. O segundo diz respeito Ă existĂȘncia de acesso Ă infraestrutura de rede e
aos recursos de computação na periferia da rede correspondentes.
Primeiramente, a tese apresenta armazenamento reativo ciente do tempo (ARCT), um
modelo reativo de armazenamento e disseminação de dados com percepção intrĂnseca
do tempo, que explora sinergias entre o substrato de armazenamento e o paradigma pu-
blicação/subscrição, e permite consultas num escopo de tempo especĂfico. De seguida,
descreve em mais detalhe: i) Thyme, um sistema de armazenamento e disseminação de
dados para ambientes sem fios na periferia da rede, que implementa ARCT; ii) Pars-
ley, uma tabela de dispersĂŁo distribuĂda flexĂvel e resiliente baseada em grupos, com
realocação preventiva de nós e um mecanismo de particionamento dinùmico de dados; e
iii) Thyme GardenBed, um sistema para armazenamento e disseminação de dados em
redes multi-regionais na periferia da rede, que faz uso de interaçÔes entre dispositivos e
com a periferia da rede.
As soluçÔes desenvolvidas apresentam baixos custos, proporcionando tempos de res-
posta adequados para uso interativo e baixo consumo de energia, demonstrando serem
pråticas nas mais diversas situaçÔes. Estas soluçÔes também exibem boas propriedades de balanceamento de carga e tolerùncia a faltas
Fault Tolerant Adaptive Parallel and Distributed Simulation through Functional Replication
This paper presents FT-GAIA, a software-based fault-tolerant parallel and
distributed simulation middleware. FT-GAIA has being designed to reliably
handle Parallel And Distributed Simulation (PADS) models, which are needed to
properly simulate and analyze complex systems arising in any kind of scientific
or engineering field. PADS takes advantage of multiple execution units run in
multicore processors, cluster of workstations or HPC systems. However, large
computing systems, such as HPC systems that include hundreds of thousands of
computing nodes, have to handle frequent failures of some components. To cope
with this issue, FT-GAIA transparently replicates simulation entities and
distributes them on multiple execution nodes. This allows the simulation to
tolerate crash-failures of computing nodes. Moreover, FT-GAIA offers some
protection against Byzantine failures, since interaction messages among the
simulated entities are replicated as well, so that the receiving entity can
identify and discard corrupted messages. Results from an analytical model and
from an experimental evaluation show that FT-GAIA provides a high degree of
fault tolerance, at the cost of a moderate increase in the computational load
of the execution units.Comment: arXiv admin note: substantial text overlap with arXiv:1606.0731
A Taxonomy of Data Grids for Distributed Data Sharing, Management and Processing
Data Grids have been adopted as the platform for scientific communities that
need to share, access, transport, process and manage large data collections
distributed worldwide. They combine high-end computing technologies with
high-performance networking and wide-area storage management techniques. In
this paper, we discuss the key concepts behind Data Grids and compare them with
other data sharing and distribution paradigms such as content delivery
networks, peer-to-peer networks and distributed databases. We then provide
comprehensive taxonomies that cover various aspects of architecture, data
transportation, data replication and resource allocation and scheduling.
Finally, we map the proposed taxonomy to various Data Grid systems not only to
validate the taxonomy but also to identify areas for future exploration.
Through this taxonomy, we aim to categorise existing systems to better
understand their goals and their methodology. This would help evaluate their
applicability for solving similar problems. This taxonomy also provides a "gap
analysis" of this area through which researchers can potentially identify new
issues for investigation. Finally, we hope that the proposed taxonomy and
mapping also helps to provide an easy way for new practitioners to understand
this complex area of research.Comment: 46 pages, 16 figures, Technical Repor
- âŠ