Tag: tw

Speaking at QCon London 2016

I am pleased to announce that I’ll be speaking at this year’s QCon London. I’ll be speaking in the “Modern CS in the real world” track, hosted by none other than Adrian Colyer, from the morning paper.  The abstract for my talk,  Making the Impossible Possible is as follows: In this talk, we explore how to construct resilient Read More

Azure Latency Pilot Study: Part 4 – Variation in results with time

So far in this study, we have only considered the aggregated measurements and how they vary depending on the VMs used. In this post, we will considered how the RTT measurements may have changed over time. The following 5 plots show the RTT as observed by each machine over time. The y axis stops as Read More

Azure Latency Pilot Study: Part 3 – Machine specific results

In this post we will be looking at the results for the Azure latency Pilot study described last week. Yesterday, we started by looking at the aggregated results and found that the measured RTT was larger then expected. Today, we will look at how the results vary depending on which VMs the measurements where taken Read More

Azure Latency Pilot Study: Part 2 – Aggregated results

This is post we will be looking at the results for the Azure latency Pilot study described last week. We will starting by looking at the aggregate results, disregarding the time a measurement was taken and which machines the measurement was taken between. The 22332 data points have been processed in Python3, in particular using Read More

Adding machines can decrease availability of a distributed system

TL;DR: Run distributed systems using majority quorum on an odd number of machines. Paxos, Raft, Viewstamped Replication and many other consensus algorithms operate on majority quorums. A majority quorum is any subset of nodes containing at least a strict majority of nodes. These algorithms all require a majority quorum to agree to a value before its Read More

Chronicle of Coracle: Parsing Protocol Specific Parameters

This is the first post in the “Chronicle of Coracle” series to document daily life using OCaml for systems programming. Today, I’ll be adding protocol specific parameters to Coracle, this mostly involves working with the Yojson and Cmdliner libraries. Once completed, Coracle will be able to accept JSON files like: {“nodes”: 50,”loss”: 0.0, “termination”:1000, “consensus”: Read More

#C3S2015 Trip Report – Day 0

Hello from a lovely little spa hotel in a forest in Estonia. After an excellent dinner and many coffees, our first session started at 9pm (yes! they are working us hard already). We received a warm welcome from Olaf Meaneel (TUT) to the first ever cyber security summer school (C3S2015). Dr Parag Pruthi kicked off Read More

Paper Notes: Ethical Privacy Guidelines for Mobile Connectivity Measurements [Report Nov’13]

Ethical Privacy Guidelines for Mobile Connectivity Measurements is the first item on the C3S reading list, below is my brief notes on this November 2013 report by the Oxford Internet Institute. The stated purpose of this report is to inform networking researchers about the best practices for preserving data subject privacy when performing active measurement of mobile Read More

Paper Notes: The Network is Reliable [ACMQ July’14]

The Network is Reliable is an excellent article which attempts to formalise the discussion on real world failures for distributed systems. There is currently great debate on whether the assumption that network partitions are rare is too strong or too weak, for modern networks. Much of the data which we could use to answer this question is not published, Read More

EuroSysDW’15 Poster on Unanimous

Here is the draft of my EuroSys doctoral workshop workshop poster. I would appreciate any feedback on the poster, I hope to sent it to the printers in 3/4 hours.   Read More

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