In <i>DevOps</i> (and <i>Lean</i>, <i>TPS</i>) the more advanced form of this is the <i>Poka-Yoke</i> (<a href="https://en.wikipedia.org/wiki/Poka-yoke" rel="nofollow">https://en.wikipedia.org/wiki/Poka-yoke</a>). Poka-yokes don't just add safety, they also guide the human away from making a mistake.<p>The canonical example is the automatic shift knob in a car. The shift knob is designed to 1) prevent you from accidentally shifting all the way back into reverse without pressing the shift button, and 2) prevents you from leaving park or neutral without depressing the brake pedal. This way you don't damage the drivetrain or accidentally cause the car to roll forward/backward.<p>Poka-yoke is a form of defensive design (<a href="https://en.wikipedia.org/wiki/Defensive_design" rel="nofollow">https://en.wikipedia.org/wiki/Defensive_design</a>). For a beautiful example of defensive design, see the average electric kettle. If water boils over the top it won't short the device, if it boils dry it'll stop operating, the handle and body are plastic to prevent burning yourself, the handle is ergonomic to make carrying 1.5L of sloshing boiling water not cause you to spill it, the cord is detached from the kettle so you don't yank the cord and spill the boiling water, the switches are located on the bottom away from hot steam, and the lids usually lock while in operation, again to prevent damage from spillage or steam. It's the simplest and safest possible way to boil water, and it's $20.

That page is copied verbatim from <a href="https://unsung.aresluna.org/molly-guard-in-reverse/" rel="nofollow">https://unsung.aresluna.org/molly-guard-in-reverse/</a> (which is linked at the top). The original page also has much better formatting.

There's a great piece of software called "molly-guard", which intercepts calls to "poweroff" and "reboot" and similar. It checks if it's being invoked via an SSH session, and if so, it asks you to type the name of the system you're shutting down. That way, you never accidentally shut down a remote server when you meant to shut down your own system (or a different server).

Samsung learned about molly guards the hard way - recall of millions of products after accidental fires from people/pets activating the front-panel dials.<p>see <a href="https://arstechnica.com/tech-policy/2024/08/samsung-recalls-1-1m-electric-stoves-after-fires-caused-injuries-killed-pets/" rel="nofollow">https://arstechnica.com/tech-policy/2024/08/samsung-recalls-...</a><p><pre><code> Luckily, there’s an easy solution recently devised that can prevent this safety hazard in homes across America, Samsung said. Customers concerned about unintentional activations can request free knob locks and covers that Samsung confirmed made it much harder to accidentally turn on the stove. During the meeting, the CPSC shared data showing that across 338 incidents between January 1, 2018, and May 30, 2024, stoves from “ten specific manufacturers” were involved in fires causing 31 injuries and two deaths. Additionally, the CPSC had recorded “two other fatal incidents where a range was accidentally turned on when a knob was bumped, but the manufacturer is unknown.” ...Companies said the CPSC data would help them “fully understand the issues” and “make sure that reasonable and foreseeable circumstances would be addressed” without impacting compliance with the Americans with Disabilities Act. </code></pre> After mentioning this article to relatives, one said they had nixed buying one product because of the front dials. Then we heard from a relative in another city who bought a house due to a newborn baby - one of the additional purchases was a oven/stove/range with front panel dials.

I'm reminded of this legendary HN comment: <a href="https://news.ycombinator.com/item?id=16530398">https://news.ycombinator.com/item?id=16530398</a>

> There is no worse feeling for a programmer than waking up, walking up to the machine that was supposed to work through the night, and seeing it did absolutely nothing, stupidly waiting for hours for a response to a question that didn't even matter.<p>No, there's one worse feeling. Walking up to the machine that was supposed to work throughout the night, and seeing it had a surprise update that rebooted the system.<p>One of my favorite things about ditching Windows.

I feel like modern tv remotes are the opposite of this principle. It is often the case that almost every single button will when pushed in some way interrupt the current program, often jumping out to a different menu or changing to a different program or something. It makes handling the remote or trying to change the volume a fraught experience.

Fun: the “Molly” in question is Ed Krol’s daughter - he’s the guy who wrote the <i>Whole Internet User’s Guide and Catalog</i>.<p><a href="https://en.wikipedia.org/wiki/Ed_Krol" rel="nofollow">https://en.wikipedia.org/wiki/Ed_Krol</a>

I once was a communications contractor for the major NJ power utility. One of their long time field techs (let’s just refer to him as Mr. T) was giving a tour of a substation that was built from the looks of it in the 50s. I have, you see, this bad habit of leaning on things… well Mr. T, without missing a beat, slid his forearm between my hip and a faded green Bakelite knob, the kind that goes in and out rather than twisting. He informed me that if I had leaned any further I would have shut off half of Newark.

Oh! Then perhaps the long press required for the iPhone’s action button to trigger is a Molly guard!<p>Also, perhaps `rm` should be molly guarded to move things to the trash on all systems by default, and delete only if forced to by a flag.<p>Note: I’d have expected Molly to be a cat, because they tend to be pretty good at disrupting things in my experience.

Sometimes a pop-up appears that I blindly accept because I happen to be typing something with spaces. Wish that button was protected somehow.

I personally know a guy who shut down an oil factory by pressing the molly guard button, just because the button looked interesting.

best molly-guard depicited in "The Good Place": <a href="https://www.youtube.com/watch?v=etJ6RmMPGko" rel="nofollow">https://www.youtube.com/watch?v=etJ6RmMPGko</a>

Fun random fact, Eventbrite was first a security company called Molly Guard. I spent years cleaning out the 'mg-' prefixes from the code.

This sounded at first like a mouth guard, to stop someone from grinding their teeth.

I do wish those were a thing on flat touch sensitive induction cooktops! (For all those pesky water droplets causing the cooktop to error out and turning itself off)

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“Mollyguarding” sounds like a great derogation of unnecessary safety measures. Stop mollyguarding me!

I've been looking for this!

Just please don't start adding molly-guards to your software. The concept only makes sense in the physical world, e.g. where the "important button", that you might never have to press, needs to be in reach all the time. In software, there are better solutions.

Does the disk drive or sim card slot ejector really qualify as Molly Guard?

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