Author: Matt Chung
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My first lawn seeds germinating!
After watching dozens of YouTube videos on lawn care, I decided about two weeks ago to overseed the front lawn and water the grass twice a day (I really used to think that the earth would just magically nourish our yard). And up until this morning, I wasn’t entirely sure if all my effort was…
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iperf3 3 and TCP maximum segment size (MSS)
The above diagram I diagrammed illustrates the impact to a network packet when setting the maximum segment size in iperf3. With an MSS of 1436, the segment (i.e. TCP payload) ends up 1424, due to the overhead of the 12 byte TCP options.
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Got the COVID-19 Pfizer vaccination
What did we do? Jess and I received our first dose of the Pfizer vaccination, our second dose scheduled for 3 weeks from now. We were able to get the vaccination since Jess had heard, through a mom’s group she’s part of, that breastfeeding mothers (along with their partners) were eligible through a Kaiser clinic.…
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PAXOS made moderately complex – slots
In the paper “PAXOS made moderately complex”, the authors introduce unfamiliar concepts not mentioned in the original PAXOS paper, concepts such as slots, slot in, slot out, and WINDOW. I found these concepts difficult to understand despite reading both the accompanying pseudo code as well as their Python implementation. This post aims to shed light…
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PAXOS – I’m coming for you!
I’m now half way through Distributed Computing course at Georgia Tech and us students are now tackling the penultimate project: building a replicated state machine using PAXOS. This project will be challenging (probably going to require 40+ hours) and it’ll put my theoretical knowledge to the test and reflect back, in a couple weeks, how…
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Understanding linearizability
I’m preparing for my Distributing Systems midterm and I was struggling to understand the differences between serializability and linearizability (why are these two words so difficult to spell right). Apparently, these two concepts are very different. To gain some clarity, I searched online and found this awesome YouTube video posted by Martin Kleppmann ; in…
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Speaking up for others
Ever since I was little boy, if any of my friends were bullied or picked on, and I noticed they couldn’t defend themselves, I would speak up on their behalf. Speaking up for others has always come naturally for me and it’s habit that I still flex even as an adult. However, these days, I’m…
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Distributed system snapshots: consistent vs inconsistent cuts
In “Consistent Global States of Distributed Systems: Fundamental Concepts and Mechanisms”, the authors propose capturing a distributed system’s computation using a time series graph. Each row in the graph represents a process (e.g. P1, P2, P3), and each tick (e.g. e1, e2) within that row represent a an event: a local event, a send message…
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COVID-19 stunting Elliott’s social skills
Like almost every other parent, my wife and I are doing our best to shelter our 16-month year old daughter, Elliott, in the midst of the COVID-19 pandemic, us parents trying to fabricate a bubble with some sense of normalcy. Up until recently, I tricked myself into believing that we could mask (or minimize) the…
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PAXOS (not) made simple
Leslie Lamport, a world renounced computer scientist, first published the paper “Part-time parliament” back in 1990. Unfortunately, that paper well not well received, primarily due to the fact that the consensus protocol was described in the context of obscure ancient Paxos civilization. The paper was not was received among computer scientists and Leslie Lamport followed…
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The FLP theorem: impossibility of achieving consensus within distributed systems
For this week, my distributed systems course just assigned us students a reading assignment: “Impossibility of distributed consensus with one faulty process“. Apparently, this paper is a seminal piece of work that goes on to describe and prove that, given a single process failure within a distributed system, the underlying system cannot achieve consensus (i.e.…
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YouTube Review: “My Guitar Teacher TOMO FUJITA Gives Words of Wisdom”
I recently watched a YouTube video titled “My Guitar Teacher TOMO FUJITA Gives Words of Wisdom”. In this video (below), YouTuber Mary Spender interviews Tomo Fujita, a guitar instructor who taught at Berkelee school of music for over 20 years; he takes his years of accumulated knowledge and shares some words of wisdom. From this…
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Week in Review: 2021/01/17 – 2021/01/24
Not too much to report this week. Not because nothing happened, but because I wasn’t at diligent in capturing this week’s activities; I was on-call this week and carrying the pager almost always disrupts my flow, this week being no exception. My pager alarmed me out of bed several times (e.g. 12:30 AM, 2:30 AM,…
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Why is Lamport’s Scalar Clock only consistent, not strongly consistent?
For the last couple days, I’ve been watching the distributed systems video lectures and reading the recommended papers that cover logical clocks. Even after making multiple passes on the material, the concepts just haven’t clicked: I cannot wrap my mind around why Lamport’s clocks satisfy only consistency — not strong consistency. But now I think…
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8 fallacies of distributed computing
Rotem-Gal-Oz, A. (2005). Fallacies of Distributed Computing Explained. Cognitive biases (built-in patterns of thinking) and fallacies (errors in thoughts) creep into our every day lives, sometimes with us not even knowing it. For example, ever wonder why you work just a little harder, a little quicker, when you think someone is standing over your shoulder,…
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What are good models and what models are good?
Schneider, F. B. (1993). What good are models and what models are good. Distributed Systems, 2, 17–26. Paper Summary In his seminal paper on models (as they apply to distributed systems), Schnedier describes the two conventional ways — experimental observation; modeling and analysis — we normally develop an intuition when studying a new domain. And…
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Distributed Computing – Lesson 1 Summary
Summary Distributed systems are everywhere: social media, internet of things, single server systems — all part of larger, distributed systems. But how do you define a distributed system? A distributed system is, according to Leslie Lamport (father of distributed computing), a system in which failure of some component (or node) impacts the larger system, rendering…
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Spring 2021: Distributed Computing
Yes! I’m finally registered for the distributed computing course. This course is hot off the press! It’s spanking brand new to the OMSCS program and offered for the first time this (Spring 2021) term. I’ve been eagerly waiting over two years for a course centering around distributed systems, combining both theory and practice. The course…
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2020 year in review
Survival First things first: I’m grateful for surviving this difficult, weird and straight-up dystopian year. 2020 was the absolute worst; although the year will permanently leave its mark in our memories, we’re all ready to leave it behind, ready to move on. Who could have, apart from maybe Bill Gates during during 2014 Ted Talk,…
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Two memorable quotes from Ira Glass’s interview
While perusing Aaron’s Swartz’s blog, I stopped and read his post titled “Writing A Book: Part 2”. In this post, Aaron swoons over Ira Glass’s unparalleled storytelling skills. Wanting to learn more about Ira, I whipped out my iPhone, opened up my YouTube app, and loaded a (podcast) interview where Ira Glass shares his thoughts…
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Just a thought: On working from home
Like almost everyone else working remotely due to the COVID-19 global pandemic, I struggled with adjusting to the work from home situation, more than I could’ve possibly anticipated. I found difficulty in my daily routines suddenly disappearing; my deeply ingrained habits vanished out of thin air: no more commuting to the office; no more breathing…
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Reader expectations and three dimensions for emphasizing writing
Fred the dog beater Look at the above example, the four sentences. Now, take each of those sentences and imagine you poll an audience of 100 people, asking them the following question: “Does the author want you [the reader] to give Fred either a thumbs up or thumbs up?” How do you think the audience…
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You should NOT always prefer active over passive voice
Like many other aspiring authors, I’m always sharpening my writing skills, dozens of writing books (including one of my favorites: On Writing by Stephen King) lined up on my bookshelf. Almost all these books share the same stance when comparing the active and passive voices. They strongly prefer the active voice over the passive voice.…
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Want to improve your craft of writing? Imitate!
There are no shortcuts to becoming a great writer. As Stephen King says, great writers need to read a lot and write a lot. But that’s not enough. Nope. I’d argue you need to take writing one step further: imitate good writing. Imitating great tennis players When I was a young boy, about 8 or…