24,939 research outputs found
Fault-tolerant meshes and hypercubes with minimal numbers of spares
Many parallel computers consist of processors connected in the form of a d-dimensional mesh or hypercube. Two- and three-dimensional meshes have been shown to be efficient in manipulating images and dense matrices, whereas hypercubes have been shown to be well suited to divide-and-conquer algorithms requiring global communication. However, even a single faulty processor or communication link can seriously affect the performance of these machines.
This paper presents several techniques for tolerating faults in d-dimensional mesh and hypercube architectures. Our approach consists of adding spare processors and communication links so that the resulting architecture will contain a fault-free mesh or hypercube in the presence of faults. We optimize the cost of the fault-tolerant architecture by adding exactly k spare processors (while tolerating up to k processor and/or link faults) and minimizing the maximum number of links per processor. For example, when the desired architecture is a d-dimensional mesh and k = 1, we present a fault-tolerant architecture that has the same maximum degree as the desired architecture (namely, 2d) and has only one spare processor. We also present efficient layouts for fault-tolerant two- and three-dimensional meshes, and show how multiplexers and buses can be used to reduce the degree of fault-tolerant architectures. Finally, we give constructions for fault-tolerant tori, eight-connected meshes, and hexagonal meshes
Fault tolerant architectures for integrated aircraft electronics systems, task 2
The architectural basis for an advanced fault tolerant on-board computer to succeed the current generation of fault tolerant computers is examined. The network error tolerant system architecture is studied with particular attention to intercluster configurations and communication protocols, and to refined reliability estimates. The diagnosis of faults, so that appropriate choices for reconfiguration can be made is discussed. The analysis relates particularly to the recognition of transient faults in a system with tasks at many levels of priority. The demand driven data-flow architecture, which appears to have possible application in fault tolerant systems is described and work investigating the feasibility of automatic generation of aircraft flight control programs from abstract specifications is reported
Scalable fault-tolerant quantum computation in DFS blocks
We investigate how to concatenate different decoherence-free subspaces (DFSs)
to realize scalable universal fault-tolerant quantum computation. Based on
tunable interactions, we present an architecture for scalable quantum
computers which can fault-tolerantly perform universal quantum computation by
manipulating only single type of parameter. By using the concept of
interaction-free subspaces we eliminate the need to tune the couplings between
logical qubits, which further reduces the technical difficulties for
implementing quantum computation.Comment: 4 papges, 2 figure
Advanced information processing system: Local system services
The Advanced Information Processing System (AIPS) is a multi-computer architecture composed of hardware and software building blocks that can be configured to meet a broad range of application requirements. The hardware building blocks are fault-tolerant, general-purpose computers, fault-and damage-tolerant networks (both computer and input/output), and interfaces between the networks and the computers. The software building blocks are the major software functions: local system services, input/output, system services, inter-computer system services, and the system manager. The foundation of the local system services is an operating system with the functions required for a traditional real-time multi-tasking computer, such as task scheduling, inter-task communication, memory management, interrupt handling, and time maintenance. Resting on this foundation are the redundancy management functions necessary in a redundant computer and the status reporting functions required for an operator interface. The functional requirements, functional design and detailed specifications for all the local system services are documented
Holonomic quantum computing in symmetry-protected ground states of spin chains
While solid-state devices offer naturally reliable hardware for modern
classical computers, thus far quantum information processors resemble vacuum
tube computers in being neither reliable nor scalable. Strongly correlated many
body states stabilized in topologically ordered matter offer the possibility of
naturally fault tolerant computing, but are both challenging to engineer and
coherently control and cannot be easily adapted to different physical
platforms. We propose an architecture which achieves some of the robustness
properties of topological models but with a drastically simpler construction.
Quantum information is stored in the symmetry-protected degenerate ground
states of spin-1 chains, while quantum gates are performed by adiabatic
non-Abelian holonomies using only single-site fields and nearest-neighbor
couplings. Gate operations respect the symmetry, and so inherit some protection
from noise and disorder from the symmetry-protected ground states.Comment: 19 pages, 4 figures. v2: published versio
Distributed Quantum Computation Architecture Using Semiconductor Nanophotonics
In a large-scale quantum computer, the cost of communications will dominate
the performance and resource requirements, place many severe demands on the
technology, and constrain the architecture. Unfortunately, fault-tolerant
computers based entirely on photons with probabilistic gates, though equipped
with "built-in" communication, have very large resource overheads; likewise,
computers with reliable probabilistic gates between photons or quantum memories
may lack sufficient communication resources in the presence of realistic
optical losses. Here, we consider a compromise architecture, in which
semiconductor spin qubits are coupled by bright laser pulses through
nanophotonic waveguides and cavities using a combination of frequent
probabilistic and sparse determinstic entanglement mechanisms. The large
photonic resource requirements incurred by the use of probabilistic gates for
quantum communication are mitigated in part by the potential high-speed
operation of the semiconductor nanophotonic hardware. The system employs
topological cluster-state quantum error correction for achieving
fault-tolerance. Our results suggest that such an architecture/technology
combination has the potential to scale to a system capable of attacking
classically intractable computational problems.Comment: 29 pages, 7 figures; v2: heavily revised figures improve architecture
presentation, additional detail on physical parameters, a few new reference
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