Questions about the challenges of solving problems with multiple cooperating but separate agents.

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14 views

'Working on Distributed Systems(Distributed Computing/Parallel Computing)" [closed]

How should I start afresh in 'Working on Distributed Systems(Distributed Computing/Parallel Computing)"??? Actually, I want to be more specific in this. I want to code and build some change in the ...
0
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0answers
35 views

Why is this issue of Dynamo, the storage system of Amazon, so sensitive? [closed]

In section 6.3 (Divergent Versions: When and How Many?) of the seminal paper about Dynamo, the storage system of Amazon@SOSP'07, the authors remarked that Experience shows that the increase in the ...
3
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0answers
65 views

totally ordered multicast with Lamport timestamp

I'm studying Distributed Systems and synchronization and I didn't catch this solution of totally ordered multicast with Lamport timestamps. I read that it doesn't need ack to deliver a message to the ...
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0answers
28 views

What are the models of distributed storage systems in the literature?

To understand the effectiveness and/or efficiency of a protocol implemented in distributed storage systems, it is often desirable to evaluate it in a quantitative way under a hypothetical model. ...
1
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1answer
30 views

How does Paxos maintain the promise that future proposal will not break the current chosen value without knowing the future?

I was studying Paxos from: http://research.microsoft.com/en-us/um/people/lamport/pubs/paxos-simple.pdf and I was trying to understand page 4, specifically, the following paragraph: "To maintain the ...
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13 views

How do we make sure in Paxos that we don't propose a different value if a majority has formed?

I was studying Paxos from: http://research.microsoft.com/en-us/um/people/lamport/pubs/paxos-simple.pdf and I was confused about one specific part. How does or why does property $P2^b$ satisfy ...
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0answers
21 views

What guarantees Paxos to converge? (i.e. not run forever without a consensus)

I was studying Paxos from: http://research.microsoft.com/en-us/um/people/lamport/pubs/paxos-simple.pdf and was wondering, what guarantees Paxos to converge and not run forever without a ...
2
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42 views

Why does a prepare message wants a promise that an acceptor is never to accept a proposal numbered less than its propose sequence value? (Paxos)

I was studying Paxos from: http://research.microsoft.com/en-us/um/people/lamport/pubs/paxos-simple.pdf On page 4 of the paper, at the bottom where they outline what a prepare request looks like: "A ...
2
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0answers
48 views

Rational of why Paxos only issues new values if its value is the largest one in the majority that he can see?

I was studying Paxos from: http://research.microsoft.com/en-us/um/people/lamport/pubs/paxos-simple.pdf I was reading page 4 of the paper where it says condition $P2^c$: "For any v and n, if a ...
2
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1answer
27 views

What does it mean that numbers are “totally ordered”? (paxos made simple)

I was studying Paxos from: http://research.microsoft.com/en-us/um/people/lamport/pubs/paxos-simple.pdf and on page 3 it says "Since all numbers are totally ordered, condition P2 guarantees the ...
2
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1answer
25 views

What is so special about a majority and why is it the key for Paxos to work? (Paxos made simple)

I was studying Paxos from: http://research.microsoft.com/en-us/um/people/lamport/pubs/paxos-simple.pdf and I was wondering, what is so special about a majority of nodes having a value? Why is that ...
1
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1answer
18 views

How does FDS (flat datacenter storage) make optimizations around locality unnecessary?

I was reading the following computer systems paper: https://www.usenix.org/system/files/conference/osdi12/osdi12-final-75.pdf And I was trying to understand why it claims that it does not need data ...
3
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1answer
76 views

Why does appending permutations of servers at the end of hash table avoid bottlenecks?

I was reading the following FDS paper: https://www.usenix.org/system/files/conference/osdi12/osdi12-final-75.pdf The paper has a TLT (tract locator table) for identifying where to write in each ...
2
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1answer
27 views

Why does the following function distribute things in a binomial distribution?

I was reading the following FDS paper: https://www.usenix.org/system/files/conference/osdi12/osdi12-final-75.pdf and it says that the the following hash function does not distribute things uniformly ...
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0answers
22 views

simulation of Randomized distributed algorithms [closed]

I want to implement various Randomized Distributed algorithms for MIS, Broadcast, Coloring in Radio Networks. I want use very high level language or any simulator for this. Please suggest on this.
4
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1answer
98 views

Lamport's Byzantine Generals Algorithm

I've stumbled at the first OralMessage algorithm in Lamport, et al's paper. I've searched the web and there are dozens of sites, restating in exactly the same terms and examples, which isn't helping ...
3
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0answers
49 views

Widely-used and fundamental distributed algorithms [closed]

I've been reading text books about distributed algorithms. They usually present a large collection of algorithms under various hypothesis and guarantees, with their proof of correctness. But they ...
2
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22 views

Polylogarithmic value-bounded concurrent data structures such as max register, counter, and monotone circuit

While reading the research paper Polylogarithmic Concurrent Data Structures from Monotone Circuits [@JACM'2012] by James Aspnes, Hagit Attiya, and Keren Censor-Hillel, I am not sure about some points ...
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1answer
21 views

In a BOINC project, how are responses checked for accuracy? [closed]

More specifically, how can project administrators be sure that the answers they receive from nodes are correct and not just simple calculations performed quickly and submitted as complete work units? ...
2
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1answer
42 views

What can distributed computing do besides parallel computing?

I have some experiences of working on clusters and grids for parallel computing. But I wonder what distributed computing can do besides parallel computing? If I understand correctly, parallel ...
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0answers
24 views

Differences in services provided by grid computing and cloud computing [closed]

What are differences in services provided by grid computing and cloud computing? From http://ccskguide.org/cloud-computing-vs-grid-computing/ and ...
2
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0answers
23 views

Efficiently estimating latency quantiles of a distributed system

I'm building a load test harness for a distributed system. Currently I'm using the "Cormode, Korn, Muthukrishnan, and Srivastava" method to estimate latency quantiles of system responses. I'm now ...
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3answers
229 views

Maximum degree of concurrency in task dependency graphs

I've been researching ways of modeling and executing tasks which are dependent on each other (but in an acyclic way) and came up with task graphs. But the question that's bugging me is how can I find ...
0
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1answer
89 views

Distribution algorithm according to weighted parameters (with a min-max constraint)

I'm trying to solve the following problem related to distribution- I have a list L of items (I1, I2,....In) sorted in order of importance, I1 being the most important. Each item has multiple tags ...
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0answers
48 views

Peer discovery: What class of network algorithm prioritises low latency above all else?

I'm trying to flesh out a proposed application model where all peers in a distributed network discover each other in the least possible propagation time. But I'm reached the limit of my knowledge of ...
5
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2answers
237 views

Why do you have to worry about cache coherence if you are using shared memory?

Wikipedia says that shared memory comes with lots of costs associated with cache coherence costs. But I thought the whole idea of shared memory is that all the CPUs access the same memory? So if one ...
2
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1answer
67 views

Distributed problems in Financial Services?

When we talk about distributed computing - it often refers to problems in biology or web search where there is a large quantity of data to process, or email where there is a large number of concurrent ...
6
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2answers
111 views

Theoretical foundations of robust and distributed services

I have the notion of a social network which is robust against malicious attacks from the outside. My vision is a system that is structurally built up as a distributed network of equal servers that ...
0
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1answer
50 views

Coordinated Attack Problem Different Requirements

There is a famous Coordinated Attack Problem. Let define a simple message-passing system $S$ with requirements Uniform Agreement: No two processes decide dierently. Validity: (a) If all processes ...
3
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1answer
69 views

Consensus and Perfect Failure Detector

I try to get a better understanding about Failure Detectors in the field of Distributed Computing. Let consider the algorithm for reaching consensus with Perfect Failure Detector, it's named as ...
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2answers
36 views

Broadcast with Limited Spreading

Let consider well-known problem in distributed computing Broadcast Problem in network with stopping crashes. The most appropriate solution to the broadcast problem is flooding algorithm, when the ...
3
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1answer
154 views

Coordinated Attack Problem On The Arbitrary Graph

Let consider a general version of Two Generals' Problem, when there are $n$ generals located on the arbitrary graph and they should agree on exactly the same value whether to attack or not to attack. ...
2
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1answer
40 views

What is a “wasteful” execution? And a “schedule”?

I'm trying to understand what this text means in my textbook about distributed leader election algorithms, but I can't make any sense of it. Either they didn't explain what was meant, or I missed it ...
7
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0answers
145 views

Who are the legislators of Paxos?

In the seminal distributed systems paper The Part Time Parliament (the Paxos protocol), Leslie Lamport names fictional legislators who are involved in the Paxon parliament protocol. According to this ...
2
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1answer
60 views

Principles of Distributed Computing - “processors” and “states”

So I'm learning about distributed computing, and I do understand a lot of the prerequisite material on algorithms and automata and whatnot... but I'm curious about the definitions I'm seeing as I read ...
3
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1answer
83 views

Is this simplified consensus problem easier than the original?

There is a famous Consensus Problem in Distributed Computing. Let's consider and try to find the best possible algorithm for a simplified version of the consensus problem. Assumptions: a process ...
5
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1answer
83 views

Formalisms in concurrent and/or distributed programming?

My background came from imperative languages, primarily C, C++, and Python. I picked up Scala, Erlang, and a bit of Haskell a few years later and have since become very interested in functional ...
7
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2answers
79 views

Algorithm of Communication with Failures

I am interested in Distributed Algorithms especially in communication in network with failures. I look for the proof of the following randomized algorithm of communication in network with failures. ...
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0answers
35 views

Is this protocol suitable for transaction services?

The paper Eventually-Serializable Data Services (PODC'96) presented an eventually-serializable data service. In the abstract, it says: … and generalizes their algorithm (in the related work Lazy ...
2
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0answers
26 views

Throughput measure

I have to implement a limitation algorithm in order to avoid to reach a throughput limit imposed by the service I'm interacting with. The limit is specified as «N request over 1 day» where N is of ...
2
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1answer
590 views

Destination-based vs source-based routing

I understand that destination-based routing builds the "route" from the destination backwards to the source (e.g. if using a spanning tree, then the tree is routed at the destination). With ...
2
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1answer
128 views

Slow MIS Distributed Algorithm

I am interested in precise time complexity of distributed algorithm for finding MIS (Maximum Independent Set) of a given graph $G$. I investigate the Slow MIS distributed algorithm (from these ...
7
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1answer
988 views

How do Functional Reactive Programming and the Actor model relate to each other?

FRP is about streaming events and behaviours through pure functions. The Actor model - at least, as implemented in Akka - is about streaming immutable messages (which can be considered to be discrete ...
2
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1answer
144 views

Maximimal Independent Set on Ring and Path

Let's consider distributed version of algorithm for finding MIS of any graph $A$. For details, MIS - Maximimal Independent Set. Slow version of distributed algorithm for MIS, page 2 - Distributed ...
2
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0answers
267 views

k-Trees Graph Coloring

There is an exercise in Distributed Algorithm I have some difficulties to solve. There are few ideas, however nothing useful at the time. I will appreciate any help with it. Graph $G$ is a $k$-tree ...
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1answer
142 views

Label Assignment Problem

I try to solve an exercise in Distributed Algorithm described as follow. Let's define a label assignment problem as follow. There is a anonymous network (vertices don't have unique ID's , nodes don't ...
3
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0answers
90 views

Proof of message complexity on the network

I try to provide a strict and mathematical rigorous proof to the following problem in Distributed Algorithms. Prove or make a contradiction: if to vertices $a$ and $b$ on the network $G$ are located ...
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0answers
194 views

Bond energy and vertical partitioning to get a vertical fragmentation in distributed dbms

Can anybody please solve the following problem step-by-step with explanations, using bond energy and vertical partitioning to obtain a vertical fragmentation of the set of attributes. I need to ...
2
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1answer
153 views

Distributed 6-color Vertex Coloring

I am trying to understand the distributed 6-color algorithm for vertex coloring (on page 10). Here is a short description Idea of the algorithm: We start with color labels that have $\log n$ bits. ...
0
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0answers
49 views

In DDBMS, What meaning of corresponding sites?

The last step in the design process is the physical design, which maps the local conceptual schemas to the physical storage devices available at the corresponding sites. What meaning of corresponding ...