Predictive failures

Padlocks went on every reduction gearbox in the USN in the summer of 1972, after CV60's departure to Vietnam was delayed by 3 days due to a bucket of bolts being dumped into #3 Main Machinery Room reduction gear. The locks were custom made for the application and not otherwise available, to serve as a tamper-evident seal. You could easily cut one off but you couldn't get a replacement. #3 main gear was cleaned up and large burrs filed off, but still made a thump with every revolution for the entire 'Nam cruise. (This followed a 3 fatality fire in 3-Main which delayed departure by 3 weeks, done skillfully enough to be deemed an accident.)

I was assigned to 3-Main on CV60 for the shipyard overhaul following the 'Nam cruise and heard the stories from those who were there. The reduction gear thump went away entirely after a full power run following overhaul, something rarely done except for testing on account of the ~million gallon a day fuel consumption.

So not claustrophobic and like cool and quiet - you would have made a good submariner.

Glen

I had an intern, an EE senior, who was afraid of 3.3 volts.

I told him to touch an FPGA to see how warm it was getting, and he refused.

Some FPGAs require supply sequencing, as may as four.

LM3880 is a dedicated powerup sequencer, most cool.

When we want to measure actual junction temperature of a mosfet, we use the substrate diode. Or get lazy and thermal image the top of the package.

....

That's what happens when they grow up having never accidentally touched the top cap of a 40KG6A/PL519

Until it does. There is nothing inherent in the design of any of these products that requires another "service" to provide the ADVERTISED functionality.

Our stove and refrigerator have WiFi "apps" -- that rely on a tie-in to the manufacturer's site (no charge but still, why do they need access to my stovetop?).

Simple solution: router has no radio! Even if the appliances wanted to connect (ignoring their "disable WiFi access" setting), there's nothing they can connect *to*.

I think that is a generational issue. My neighbor just bought camera and, when she realized it had to connect to their OUTBOUND wifi, she just opted to return it. So, a lost sale AND the cost of a return.

Young people seem to find nothing odd about RENTING -- anything! Wanna listen to some music? You can RENT it, one song at a time! Wanna access the internet using free WiFi *inside* a business? The idea that they are leaking information never crosses their mind. They *deserve* to discover that some actuary has noted a correlation between people who shop at XYZCo and alcoholism. Or, inability to pay their debts. Or, cannabis use. Or... whatever the Big Data tells *them*.

Like the driver who complained that his CAR was revealing his driving behavior through OnStar to credit agencies and their subscribers (insurance companies) were using that to determine the risk he represented.

But IP and MAC masquerading are trivial exercises. And, don't require a human participant to interact with the target (i.e., they can be automated).

I have voice access to the services in my home. I don't rely on the CID information provided as it can be forged. But, I *do* require the *voice* match one of a few known voiceprints -- along with other conditions for access (e.g., if I am known to be HOME, then anyone calling with my voice is obviously an imposter; likewise, if someone "authorized" calls and passes the authentication procedure, they are limited in what they can do -- like, maybe close my garage door if I happened to leave it open and it is now after midnight). And, recording a phrase (uttered by that person) only works if you know what I am going to ASK you; anything that relies on your own personal knowledge can't be emulated, even by an AI!

No need for apps or appliances -- you could technically use a "payphone" (if such things still existed) or an office phone in some business.

I have a "cordless phone" in the car that lets me talk to the house from a range of 1/2 mile, without relying on cell phone service. I can't send video over the link -- but, I can ask "Did I remember to close the garage door?" Or, "Did I forget to turn off the tea kettle?" as I drive away.

No, you just have to rely on other mechanisms for authentication.

I have a friend who manages a datafarm at a large multinational bank. When he is here, he uses my internet connection -- which is "foreign" as far as the financial institution is concerned -- with no problems. But, he carries a time-varying "token" with him that ensures he has the correct credentials for any ~2 minute slice of time!

I rely on biometrics, backed with "shared secrets" ("Hi Jane! How's Tom doing?" "Hmmm, I don't know anyone by the name of Tom") because I don't want to have to carry a physical key (and don't want the other folks with access to have to do so, either)

And, most folks don't really need remote access to the things that are offering that access. Why do I need to check the state of my oven/stove WHEN I AM NOT AT HOME? (Why the hell would I leave it ON when the house is empty???) There are refrigerators that take a photo of the contents of the frig each time you close the door. Do I care if the photo on my phone is of the state of the refrigerator when I was last IN PROXIMITY OF IT vs. it's most recent state? Do I need to access my thermostat "online" vs. via SMS? Or voice?

Ok that doesn't surprise me. I'd want to be sure that the requirement is always met even when the 12V connector is in a position where it isn't sure whether it's connected or not. Or rapid and repeated connect/disconnect of 12V doesn't cause any issue.

I'd have trouble here with no wifi access. I can restrict outbound with a firewall as necessary.

That's why most tor exit nodes and home user vpn services are blocked. I don't allow unauthenticated access to anything (except web sites). I prefer to keep authentication simple and drop packets from countries and places who have no business connecting. Granted a multinational bank may need a different approach since their customers could be anywhere. If I were a multinational bank I'd be employing people to watch where the packets come from and decide which ones the firewall should drop.

I have 25 general purpose drops, here. So, you can be in any room, front/back porch -- even the ROOF -- and get connected.

When I *need* wifi, I have to turn on one of the radios in the ceiling, temporarily. (they are there as convenience features for visiting guests; they are blocked from all of the wired connections in the house)

The internal network isn't routed. So, the only machines to worry about are this one (used only for email/news/web) and a laptop that is only used for ecommerce.

I have an out-facing server that operates in stealth mode and won't appear on probes (only used to source my work to colleagues). The goal is not to look "interesting".

The structure of the house's fabric allows me to treat any individual node as being directly connected to the ISP while isolating the rest of the nodes. I.e., if you bring a laptop loaded with malware into the house, you can't infect anything (or even know that there are other hosts, here); it's as if you had a dedicated connection to the Internet with no other devices "nearby".

They can type code. Rust is supposed to be safe.

We considered the brownout case. The MAX809 handles that.

This supply will also tolerate +24v input, in case someone grabs the wrong wart. Or connects the power backwards.

My son asked me to explain how Government works. So I told him. They hire a guy, give him a FLIR, and bundle both with their product as an in-situ prognostic solution.

Danke,

I doubt it's safe from the programmer who implemented my humidifier like this:

if humidity < setting { fan_on(); } else { fan_off(); }

I have wired LAN to every room too but it's not only me who uses wifi so wifi can't be turned off.

My LAN is more like a small/medium size business with all workstations, servers and devices behind a firewall and able to communicate both with each other and online as necessary. I wouldn't want to give online security advice to others without doing it myself.

Not sure what you mean by that. Given what gets thrown at my firewall I think you could maybe look more interesting than you think.

I wouldn't bother. I'd just not connect it to wifi or wired if I thought there was a risk. It's been a while since I had to clean a malware infested PC.

Someone still needs to provide DDNS.

Yes, UPNP has been a thing for several generations of routers now. but browswers have become fussier about port numbers too. also some customers are on Carrier Grade NAT, I don't think that UPNP can traverse that. IPV6 however can avoid the CGNAT problem.

It's an ease of use vs quality of service problem.

I have 72 drops in the office and 240 throughout the rest of the house (though the vast majority of those are for dedicated "appliances")... about 2.5 miles of CAT5.

I have no desire to waste any time installing the latest OS & AV updates, keeping an IDS operationally effective, etc. My business is designing devices so my uses reflect that -- and nothing else.

"Patch Tuesday?" What's that?? Why would I *want* to play that game?

The advice I give to others is to only leave "exposed" what you absolutely MUST leave exposed. Most of my colleagues have adopted similar strategies to keep their intellectual property secure; it's a small inconvenience to (physically) move to a routed workstation when one needs to check email or chase down a resource online.

Nothing on my side "answers" connection attempts. To the rest of the world, it looks like a cable dangling in air...

So, you'd have to *police* all such connections. What do you do with hundreds of drops on a factory floor? Or, scattered throughout a business? Can you prevent any "foreign" devices from being connected -- even if IN PLACE OF a legitimate device? (after all, it is a trivial matter to unplug a network cable from one "approved" PC and plug it into a "foreign import")

My current project relies heavily on internetworking for interprocessor communication. So, has to be designed to tolerate (and survive) a hostile actor being directly connected TO that fabric -- because that is a likely occurrence, "in the wild".

Imagine someone being able to open your PC and alter the internals... and be expected to continue to operate as if this had not occurred!

Must be a big house.

You could ping me if you knew my IP address.

What I mean by that is I'd clean it without it being connected. The Avira boot CD used to be useful but I forget how many years ago.

Devices on a LAN should be secure just like Internet facing devices.

That's fine if the failure is clearly in the equipment itself, but what if it is in the way it interacts with something outside it, some unpredictable or unrecognised input codition? It works perfectly on the bench, only to fail when put into service ...again and again.

The ocassional beeping is a low battery alert.

RL