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by bad416f1f5a2 1341 days ago
Erlang’s formulas are incredibly applicable to things we work on today - and shockingly unknown to many developers.

I’ve used them several times to show that a proposed system is mathematically impossible: “if the backend processes n requests/sec with a max response time of X, and the P95 of the backend is Y, the queue satisfaction is 0%”. People think you’re a wizard while you’re just plugging numbers into a century-old formula.

3 comments

I worked for a Usenet provider for a number of years designing and writing the software that powered their Usenet feeding infrastructure. The Usenet feed is basically a giant stream of articles, and we used queuing theory to scale out the systems that read it in, process it, and distribute it to readers.

My experience with the formula's is a little different from yours. People thought what I showed them couldn't be true. "If the feed is X articles/second and system's P95 is Y, the backlog will continue to grow," would often be met with, "That can't be true ..."

Totally! I worked for a time, in the mid 00s, at a company that built realtime dashboards for old school telephone call centres (contact centers) and it was there that I became aware of the other (original) meaning of Erlang, beyond the nifty cool up and coming programming language.

For a while for me everything was about queuing theory. Since then I keep forgetting and remembering things about this later.

Strikes me that I would like to have an easy to use and generic library for Rust with the various formulas etc. in it.

What's the other original meaning? Googling I find no meanings except the programming language, although it was originally used by telecom. But it seems to be the same language originally used by telecom that is now getting use elsewhere, not two languages with the same name or two meanings, no? https://en.wikipedia.org/wiki/Erlang_(programming_language)
Agner Krarup Erlang, Danish mathematician and originator of queueing theory. The language is named after him.
Ahh, thanks! I had always assumed it was named after the Er- in Ericsson :).
I think it's a clever name pulling from both.
Or look into TFA - it (person, distribution, unit) appears ten times :-)
Nice, thanks!
In Denmark Erlang is probably more know for his logarithm tables since those were used for many years in the schools before calculators became normal