Same reason website's are remote controllable. There's someone who's job it is, is to make sure the fridge is up and running, 24/7 and for the same reason that website operators/SREs don't live at each POP/DC, that fridge operator wants to remotely be able to flip some relays off and on to fix the problem without having to drive onsite, if possible. Additional, a single person/fewer people can then also be responsible for multiple/more sites.
replyThat’s exactly right. There all all sorts of read-only architectures where the device can be monitored without every directly accessing it:
reply- The device’s control has a radio transmitter that emits its readings, but no receiver. Listen for those messages to monitor it but there’s not a physical path to reply to it.
- The device’s controller writes a database or message queue. Its code never reads from that source. Monitors listen to those messages.
And many, many similar methods with the same core concept: the item transmits its status but doesn’t have a method to receive replies. You just have to commit to using any one of those thousands of mechanisms.
The fridges are cheaper to make because they don't need a bunch of knobs and switches and temperature displays - just an app on employee phones.
replyHow is a button more expensive than a computer with network access?
replyRead-only access is mostly an illusion that itself can be hacked to gain control.
replyI have a read only temperature sensor in my old-school non-computerized refrigerator and freezer. Hack until the cows come home but it still can't turn off my freezer.
replyGood. You've got a read-only widget that monitors your freezer.
replyIf it were hacked to start delivering temperature readings that were dangerously-high while you were out of town, then: Would you keep the food, or discard it?
1) you'd wonder what broke
2) you'd wonder why it fixed itself
3) you'd check the ice cream when you got home
4) ice cream is fine, must have been a bug in the temperature reporting.
replyOff topic but "hack until the cows come home" put a smile on my face.
replyAir-gapping, network segregation, data diodes, etc. are all real things. It's possible to make a read-only refrigerator that is "unhackable". I have a temperature monitor in my refrigerator right now. Hack that monitor and it doesn't affect my refrigerator at all.
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replynot in this case where a thermosensor can do nothing but monitor a temperature.
replyYeah? We had an old Unix server that printed its logs in realtime to a dot matrix printer. How are you going to gain control of that?
replyRead-only is a strong control with lots of solid implementations.
Depending on the make and model, send a reverse feed code and then overwrite with block characters. You will know that something bad happened, but you won't know what.
replyThat makes it inconvenient to read, not impossible. E.g. use transmitted instead of reflected light (shine a bright light behind the paper) to see how much ink is in each place.
replybecause you might not want to send a technician to every single one of them once a firmware update is needed
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