Firstly and most importantly, a cash register needs a power outlet. It is highly contestable that every single Western supermarket out there has a diesel generator down in the back / storage room that will kick in in an instant if a power outage begins.

Lest also forget the Crowdstrike drama where many supermarkets simply went dark, in some instances for nearly 24 hours, despite working communication links. But I digress.

Crowdstrike was an interesting one. Just as it was going down I went out to the supermarket and found half of the self checkouts had bluescreened. Then a few hours later they were all back and functioning again. The supermarket had remote management at a level below the OS that could restore the whole countries self checkouts rapidly.

I would not be surprised if they simply booted an image from the network. It would significantly simplify maintenance, as for any change you'd just need to update a single image and push it downstream to an in-store management server. The individual terminals essentially become disposable.

> It is highly contestable that every single Western supermarket out there has a diesel generator down in the back / storage room that will kick in in an instant if a power outage begins.

Literally true. However:

- If it takes them 10 minutes to fire up the generator, then 5 minutes to restart the network and registers, that is no big issue (in a many-hour outage)

- At least in my part of the USA, many supermarkets do have generators - because storm damage causes local outages relatively often, and they'd lose a lot of money if they couldn't keep their freezers and refrigerators powered. Since the power requirements of the lighting and registers are just (compared to the cooling equipment) a rounding error, those are also on generators.

Plus, there are backup-power lories and refrigerated trailers. If your shop doesn't have enough backup power for duration, you might see several of these pull into the carpark all at once. If not all of the chillers can be powered, shop's staff will schlep stuff to the refrigerated lories.

Seen it done in USA, for a Target next to a Kroger grocer. Kroger lost everything that needed cold after reserve either ran out or wouldn't start, but Target had a contingencies contract and lost no product.

Well,in my experience it was the case for the 2 largest supermarket chains. We lost electricity at 12:30pm and only got it back during the night at 3am.

But both major supermarkets nearby worked on diesel generators and payment by card worked flawlessly. I guess they had satellite connection.

It might have been more complicated in small villages but people living in rural areas ually still use a lot of cash.

In my local area of Spain/portugal, 2/3 supermarkets and 2/3 gas stations had generators up and running within a couple of hours. We’re pretty rural, though - I don’t know that urban areas faired as well

We're outside Mataro, had to make a trip into Barcelona yesterday. I'd say most gas stations north of Barcelona/Maresme area were 100% offline, some (we found only two, from 6 visited) gas stations still had operational pumps but huge queues and cash only. None of the TPVs seemed to work anywhere in the afternoon yesterday here, even the battery powered/mobile network ones.

That's true, I went shopping cca. 4-5 hours after the blackout started and had no issues, even card transactions worked. Whoever designed the retailer, they clearly had this scenario in mind. Even the "self-service" computer kiosks all worked.