> I’ve been in software for 20 years and it’s the first time I hear “back pressure”. Am I too old already?

I first wrote code 50 years ago (I am 63yo) so yes, imo we are too old, but ...

It is worth noting that systems concepts/techniques often have analogues aka different names and histories in different fields and subfields.

If I were to "explain" back pressure to an ordinary person I might model my analogy to the logic of this ~classic joke:

Bob: Let's go to Trendio(TM) for dinner tonight!? Carol: Oh, nobody goes there anymore, it's too crowded!

Also, often a modern take-this-for-granted concept may be seen as an outgrowth of previous problems or solutions.

For example back pressure is conceptually adjacent to the clever~hack/design of random backoff in Ethernet.

Or if talking to a math geek or traffic planner you might relate it to ~modern understanding of congestion including oddities like possibly removing roads/routes to ~paradoxically improve traffic flow.

We are deep in the Information Age barreling towards Singularities, so none of us, young or old, see and understand but a tiny fraction of where we've been, are, or might be going.

Cue Calvin & Hobbes cartoon of us racing downhill in a fragile box.

Perhaps, as others have essentially suggested, merging your mind with an ~AI will help (albeit temporarily, imo). I prefer to think of us/greybeards as potentially Wise, yet, paradoxically, clueless.

Beginner's Mind, with likely no time/future for Mastery, is still potentially pleasant, and I would argue useful for Debugging.

Obviously this modern AI tsunami is phase shifting us all into debug~mode anyway, eh?

Backpressure occurs at many levels, even down to a single machine doing something. If you ever have a producer and a consumer interacting and the consumer can’t consume as fast as the producer can produce, you need some way to have the producer pause or slow down until the consumer catches up. That’s back pressure.

> it’s the first time I hear “back pressure”. Am I too old already?

It's the opposite, as you get older you will feel this more and more.

It's a sign that you didn't get into the "let's distribute every problem" rabbit hole. I don't think it correlates with age.

But the keep the concept in your mind in case you have to distribute some problem. It's a central one.

You've just never played Factorio.

Here’s a basic example https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/....

Services, systems, and/or databases eventually provide back pressure when they fail or get overloaded. The idea is to design in back pressure to let the system degrade gracefully rather than fail chaotically.

Somewhere surprising but if you never dealt with scaling issues of a certain nature it may have never came up.

Though you might be familiar with other terms that effectively mean the same thing, like counter pressure

Yes

(but worry yea not, just like someone said of another term: "Dependency Injection" is a 25-dollar term for a 5-cent concept, something is similar for this term. )