"...A more rigorous way is
to define a spec, a succinct description of every allowable
behavior of the system, and prove that an implementation
always generates outputs consistent with the spec."

-IronFleet: Proving Practical Distributed Systems Correct

"What does it mean for a system to be correct? One can
informally enumerate a set of properties and hope they are
sufficient to provide correctness..."

Marc Brooker on LinkedIn: One aspect of the work we describe in Systems Correctness Practices At AWS… One aspect of the work we describe in Systems Correctness Practices At AWS (https://lnkd.in/gBSfXebN) is the work Ankush Desai and team have been doing on…

This is a fantastic idea (comparing observed application traces with an offline specification) and a form of runtime verification:

www.linkedin.com/posts/marc-b...

To this day, Ruby is my favorite language to _write_. I don't use it at work, but it's still my go to language for "thinking out loud".

For example, I wanted to calculate the powerset of an array:

`0.upto(arr.length).map { |i| arr.combination(i).to_a }.flatten(1)`

I'll always love method chaining

Alex Kesling on Apache Arrow DataFusion, Wed, Feb 5, 2025, 6:30 PM | Meetup We're pleased to present **Alex Kesling** on **Apache Arrow DataFusion: a Fast, Embeddable, Modular Analytic Query Engine** ([Read the Paper](http://andrew.nerdnetworks.org

Yo!

Come check out Alex Kesling on Apache Arrow DataFusion, Feb 5th at #paperswelove #nyc

📅 RSVP: www.meetup.com/papers-we-lo...
📜 Paper: andrew.nerdnetworks.org/other/SIGMOD...
💬 PWL Discord: discord.gg/6gupsBg4qp

#meetup #compsci #data

The Collatz conjecture is a concise example of why branch coverage doesn't mean correctness: concerningquality.com/collatz-conj...

All of his papers are worth reading. He's looked into other data generation strategies beyond pure-random, as well as how to think about the effectiveness of the coverage of a PBT run.

A coworker reminded me of this post - Queues Don't Fix Overload: ferd.ca/queues-don-t.... It does a great job framing a system as a set of interacting queues. This has become my mental model for sure.

Here's a post looking into the effect of response time distribution on various queueing characteristics. It uses SimPy to simulate several minutes of operation in a queue in various different configurations.

concerningquality.com/queue-simula...