From molly-guard to moggy-guard

In ancient lore, a molly-guard was a shield to prevent tripping of some Big Red Switch by clumsy or ignorant hands. Originally used of the plexiglass covers improvised for the BRS on an IBM 4341 after a programmer’s toddler daughter (named Molly) frobbed it twice in one day

The Great Beast of Malvern, the computer designed on this blog for performing repository surgery, sits to the left of my desk. This is Zola the cat sitting on it, as he sometimes does to hang out near one of his humans.

What you cannot quite see in that picture is the Power Switch of the Beast, located near the right front corner of the case top – alas, where an errant cat foot can land on it. Dilemma! I do not want to shoo away the Zola, for he is a wonderfully agreeable cat. On the other hand, it is deucedly inconvenient to have one’s machine randomly power-cycled while hacking.

Fortunately, I am a tool-using sophont and there is an elegant solution to this problem.

The solution is an ordinary refrigerator magnet. Being a magnet, it adheres to the ferrous-metal case top just firmly enough not to be easily pushed aside by a cat foot, but is readily moved by human fingers. Here it is in the ‘unsafe’ position:

And in the ‘safe’ position:

EDIT: Thanks to a brilliant comment by andyjpb. I have retitled this post and changed the following lexical item.

Thus, your word of the day: “moggy-guard”. Like a molly-guard, but for cats.

35 thoughts on “From molly-guard to moggy-guard

  1. Zola looks wonderfully healthy, and that resting location suggests that he’s strongly bonded with you. Congratulations on finding a new feline partner that fits into your household.

    • >Zola looks wonderfully healthy, and that resting location suggests that he’s strongly bonded with you. Congratulations on finding a new feline partner that fits into your household.

      To both of us, actually. But that’s not surprising in a Maine Coon – it’s a breed that wants to bond to humans, and if treated with even minimum kindness will become affectionate and sociable. If you speak cat kinesics reasonably well and make a point of being nice to your Coon it will love you back with touching intensity. Zola is like that.

      We still miss Sugar, but Zola is a worthy successor.

  2. I had to make a cat guard for my UPS after the cat turned it off TWICE by pressing down the recessed off button for 5 seconds. The beast says it was an accident. Hah.

  3. > And it’s not magnetic enough to cause internal issues. Brilliant!

    To my understanding it would take a very powerful magnet, very close to the hard drive, to cause issues these days.

  4. @Random832 –

    > > And it’s not magnetic enough to cause internal issues. Brilliant!

    > To my understanding it would take a very powerful magnet, very close to the hard drive, to cause issues these days.

    And in a happy coincidence, the main storage device of the GBoM is an SSD.

    (There is a real spinning-rust device in it for auxiliary storage, but that’s nominally transient and so would not be a tremendous loss if corrupted. At least, that’s how Wendell and I envisioned it when we did the build / disk partitioning / system config.)

  5. Zola: You may have foiled me this time, human, but just you wait: soon, in a few months’ time, the case fans of your precious Great Beast will be clogged with my shed fur! Muahahahahahahahaha!

    • >the case fans of your precious Great Beast will be clogged with my shed fur! Muahahahahahahahaha!

      Unlikely. Zola doesn’t shed the fine mist of fur Sugar did. Instead we find discrete clumps.

      Also, I would believe Zola jumping over the moon before I would believe the evil-laugh part. He’s looked genuinely upset on the few occasions his humans were displeased with him.

  6. Finding a simple solution depends on being given a problem which has one.

    If we leave a window open our cat goes outside, fetches live snakes, brings them inside and lets them loose in the house. They slither around inside for a few days until we run into them (usually in the hall on the way to the bathroom early in the morning) , catch them, and put them outside.

    The cat does not like being shut inside or, because of the cat-eating coyotes, being shut outside, so the open window is, from the cat’s point of view, the only good option.

    That magnet is clever. Have not found a such a good solution to the snakes.

  7. @Dan: My latest case came with a topside power switch too. It left me baffled for a few moments figuring out “front” and “top” when assembling it. I too wonder why this kind of design happened.

    • > I too wonder why this kind of design happened.

      My only guess is a desire to make the button readily accessible to a human finger when the case sits on the floor.

  8. > He’s looked genuinely upset on the few occasions his humans were displeased with him.

    Ah, but upset can mean many things. It could be “Puny humans. You will rue the day you gave me attitude. Mbwahahahaha!”

    • >Ah, but upset can mean many things. It could be “Puny humans. You will rue the day you gave me attitude. Mbwahahahaha!”

      *snrk* You have so never met this cat. Who wandered in randomly while I was typing the previous sentence and nuzzled my leg. I believe the accompanying chirp meant something rather like “It makes me feel happy/secure to be be near a pridemate.” Which is different from “I love you.”; that is more kinesic (leg-stropping, head butts) and unlikely to be accompanied by a vocalization other than loud purring.

      Er, I have to stop typing now. He has jumped up on my desk and is purring in my face; that means he wants serious attention…

  9. I’ve had a similar problem, though with no great solutions so far. My UPS was drastically decreasing the uptime on my box.

    You see, my UPS has a 3cm diameter bright blue LED-lit button to turn it on and off in the front-middle of it. This button is 100% irresistible to little fingers. And believe me, I understand: it’s a bright blue button, it needs to be pressed. However, this button cuts the power to my desktop, which is unhelpful for the health of the power supply, hardware, and file system.

    I tried all manner of mollyguards, to no avail. I even duck-taped a sheet of cardboard across the front. That slowed them down, but eventually one of them tore the tape off and lifted the flap and… whrrr…. no more power. This happens in a matter of moments, too, usually while cooking dinner or something.

    Eventually, I just moved the box out of the living room. So now they’d have to sneak into the office to hit the power. :)

  10. ESR

    > it’s a breed that wants to bond to humans

    Don’t all breeds? The reason cats tend to be feminine and dogs masculine is that they were bred by women and men respectively for traits they liked. Or found useful. Surely wanting to bond is a trait cat breeders preferred? I am not a cat guy but I think the idea that cats bond with houses not people is a myth. I get it, they were bred by women who often spent most their adult lives in the same house, so cats do like their homes, fine, still there was enough population migration going on to prefer breeding for human-bonding traits. America is a good example, if a cat really bonds to the house it stays behind in Europe, or stays on the East Coast and does not go West with the family.

    • >Don’t all breeds?

      It varies more than you apparently know. There’s a gradient of human-friendless, with Coons at the extreme positive end and old breeds that have been little messed with by the cat fancy nearest them. By “old breeds” I mean for example: the Norwegian Forest Cat (of which Coons are probably a landrace), Burmese cats, and Lake Vans.

      The breed standards specify appearance, not personality, so cat breeders wouldn’t select for that even if they knew how. It’s a different set of selective pressures than the normal one over the last 3KY, which was basially “you don’t catch mice and play nice, you don’t get fed.”

  11. I had to rig one of these up on my UPS after discovering that my all-too-clever calico likes to frob the switch. She’ll sit there and hit it, causing the UPS to feep, over and over for… well, longer than I thought such a thing would hold a cat’s interest. Of course, she then hops up on top of it and stands on the switch. Hence, the need for a kitty-guard.

    Of course, now Max has figured out how to get the kitty-guard *off*, so I need a better one.

  12. > *snrk* You have so never met this cat.

    Oh, I took your word for it in the cat’s character the first time. But the stereotype of cats as would be tyrants is just irresistibly funny.

    By the way, speaking of molly guards and other terms from the Jargon File, did you hear that the Dallas tornado siren system was baggy-pantsed recently? Apparently the sirens activated on DTMF tones transmitted in the clear over radio. Somebody figured out what the appropriate codes and frequency were, and started spamming the activation signal, so when the city tried turning them off, they got activated again right away. It ended up taking something like three hours for the city to physically disable each siren on-site.

    • >Apparently the sirens activated on DTMF tones transmitted in the clear over radio

      Wut? OK, that was awful system design. Somebody should be fish-slapped.

  13. esr on 2017-04-14 at 15:48:31 said:
    >> Apparently the sirens activated on DTMF tones transmitted in the clear over radio
    > Wut? OK, that was awful system design. Somebody should be fish-slapped.

    Remember that the discussion about the Emergency Broadcast System from the Hacker File post?

    https://en.wikipedia.org/wiki/Specific_Area_Message_Encoding Note that they *originally* were going to use DTMF for that. Depending on when Dallas built that system it might have been made to be compatible and fully automatic with weather alerts generated by the national weather service. Then things went a different way, but their system was already in place (guessing here).

  14. > Somebody should be fish-slapped.

    Well, I don’t know about the people who designed the system, but the people who maintained it (and didn’t stop to think if it should be replaced with something more robust) got to spend from something like 23:30 to 2:30 at work, instead of in bed, with sirens droning in the background. Does that count as sufficient fish-slapping?

  15. I must dissent mildly. Controlling things by DTMF tones over a radio transmission is a longstanding practice, since the early 1970s. That siren network may well have been designed in that era. As long as it worked, why spend lots of money on replacing it?

    That one guy was able to control the network across the entire city tells me that the siren controllers were listening to the output of a repeater, and that they didn’t simply shut off the repeater to thwart the attack (and that it didn’t time out) says that the repeater in question was used for other things and its loss would have caused other, potentially worse, problems. Again, this is not uncommon systems design in older times.

    Further still, as long as the attack went on would have been ample time to use DF gear to find him. The timing was probably calculated not just to cause maximum annoyance but also to lessen the likelihood that those assets could be deployed in time. Still, I’m certain the FCC’s enforcement folks would love to find out who did it…because he’s facing some pretty heavy penalties. The FCC takes a very, very dim view of unauthorized transmissions on public safety frequencies.

  16. As long as it worked, why spend lots of money on replacing it?

    Because it was a known (or should-have-been-known) security vulnerability. A Wired article has a comment pointing out the same attitude you are showing as a problem:

    “In my experience [networks are] left that insecure due to ignorance of security rather than laziness,” says Jake Williams, founder of the system security firm Rendition Infosec. “Often, even when we confront organizations with serious security findings, they are dumbfounded about how or why an attacker might abuse them.” He adds that when it comes to exposure of digital infrastructure, administrators are often “ignorant of the potential impact.”

    Frankly, I’m impressed they were apparently able to retrofit an encryption system overnight, if that’s what was in fact done rather than, say, changing the frequencies and not telling anyone. My guess is that they secured the repeater you hypothesized, rather than all of the sirens, immediately anyway, but that at least limits the scope of future attacks.

  17. Hi ESR.

    I hope it is not too late to add to this thread productively.

    To protect an object, and increase cat loiter time on it, try a folded bath towel. In my many years (I remember Ike very vaguely), I have never met a cat who could resist a soft cushiony cloth layer atop a flat surface. Towels are better than blankets for this because they absorb things well and are far more rugged: they can be laundered often.

    Best wishes.

  18. For a software solution, you could do one of the following, assuming Linux:

    If your system is using systemd, edit “/etc/systemd/logind.conf” and set “HandlePowerKey=ignore”, otherwise edit “/etc/acpi/events/powerbtn-acpi-support” and set “action=” (delete stuff to the right of “=”).

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