There has been a huge solar event (or something, the flare is only a plot device), and the electricity in your area is gone. Some places people manage to recover their electricity, other places they do not. Your hard-drive is wiped too. Not a big loss, your data is backed up in the clou... wait, their hard-drives are wiped too. In fact, everyone's hard-drive is gone.

A lot of software should survive though, your Ubuntu CD is still there, and so is your grandfather's helloWorld program on punch cards, as optical and physical storage media is not affected. But where can you run the software? Every CPU in the world is fried, and that is a huge problem because it is difficult to make new ones to replace them. CPUs are no longer handmade, and the machines and controllers to make them require computers. So basically, we need new computers first, before we can make new computers...

This looks like a huge technological setback, but how large is it actually? And what steps are needed in order to recover the current technological level?

Sent from my Babbage device


Just to make it clear, the fact that most CPUs would not fail is besides the point. The flare is just a device to accomplish this, and the important point is that every CPU and magnetic drive is destroyed. I am not asking what consequences a complete computer failure has for society, just how we can get them up and running again.

Rebuilding of the software and compiler chain is already answered here, but actually lacking the hardware, and the hardware to re-build the hardware is not covered. I feel that difference is large enough to not be a duplicate.

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    $\begingroup$ I swear there's a related/duplicate question in the history, but I can't seem to find it. That being said, frying CPUs that are off, and frying CPUs that are hardened is really hard. Would you rather the "solar event' be treated as magic, or see answers that question whether humanity can survive the effects of such a massive event in the first place? It may be that the only way to generate those massive voltage gradients could be if the sun went nova. $\endgroup$
    – Cort Ammon
    Jun 2, 2016 at 6:07
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    $\begingroup$ @CortAmmon The flare is somewhat magical in the sense that all CPUs are gone, regardless off hardening, without the event also frying brains. $\endgroup$ Jun 2, 2016 at 6:11
  • $\begingroup$ I wasn't aware that flares damaged CPU's. Are you certain that this is a reasonable prediction, or is this besides the point and it's a non-negotiable element of your premise? $\endgroup$ Jun 2, 2016 at 6:56
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    $\begingroup$ @Hohmannfan I recommend you re-type the question because what you ask is about a magic event that specifically targets only one specific type of electronics, and of those electronics, only those that in a very particular context. And this magic somehow also targets two specific types of storage media (tape and disk), but then leave everything else untouched. And then you also say "Ignoring all other aspects of this of this magic event — like that society collapses around us — how do we deal with this one singular aspect of this magic event"? How do you expect an answer to this, hm? $\endgroup$
    – MichaelK
    Jun 2, 2016 at 8:51
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    $\begingroup$ @Hohmannfan In short you are asking: "How do we deal with cleaning the sea water out of all the carpets on the Titanic? No no, the hole in the side is just a device to get the carpets wet, the ship doesn't sink". $\endgroup$
    – MichaelK
    Jun 2, 2016 at 8:55

4 Answers 4


Edit after question clarification

In short you are asking the equivalent of:

"How do we deal with cleaning the sea water out of all the carpets on the Titanic if it runs aground on a sand bank? Iceberg? No no, that is not important, the grounding of the ship is just a plot device to get all the carpets wet; the ship does not sink. And nothing else on board the ship gets wet either. So, about those carpets...".

I think you can see now why you are not getting the answers you expected: the question relies on the wrong kind of plot device event in order to reach a specific scenario; a scenario that is entirely unrealistic and requires magic in order to happen; where you then hand-wave away all the primary consequences of this event in order to explore a secondary — or even less important — consequence.

Original answer follows...

That is not how it happens.

A geomagnetic storm does not cause an Electromagnetic Pulse in the same way that a high-altitude nuclear detonation does. An EMP causes a very fast spike in the magnetic field, while a storm causes relatively slow, but huge fluctuations in the field. These are very different when it comes to the damage they do.

What happens is that the power-grid soaks up the fluctuations in the magnetic field, and through induction this will cause massive direct currents in the power grids, which will wreak havoc on the grid and may cause damage. Any very long conductor (such as power-lines and pipelines) will be affected by this, and this in turn will affect anything that is connected to these long conductors. Transformers and high voltage power control equipment will be at risk. But computers are too small to be affected by the fluctuations directly, and they are too far away from the high voltage power grids.

If(!) what you really want is a plot device to knock out all computers all around the world, well then you are in for a bit of trouble. It would mean that you need to blanket all the inhabited parts of planet Earth with nuclear detonations.

But assuming this is somehow achieved, do remember that 90-95% of all CPUs in the world are not in computers... they are other electronic equipment. Even your credit card has a small CPU. So the problem will be that all our infrastructure is shot to pieces, because we rely on CPUs, micro-controllers and other such chips to make the stuff we take for granted every day — electricity, food, petrol, heat, cold, water — reach us. The only things that will really survive are the huge old industries, like power plants (and yes, this includes nuclear plants, they avoid reliance on electronics for precisely these reasons), forges, smelting plants and such. That is the real problem, not lack of computers.

How do we bootstrap all this? Well, do remember that CPUs have not been around very long. Modern CPUs have not been around for much more than 30 years. If we need to bootstrap all this, it will take us much less than that. The big problem will not be to start up manufacturing again for lack of information, but for lack of infrastructure to support it. Logistics will be shot because of this event.

Your question is a valid one but I am afraid it is The Smaller Problem™. We will be very busy worrying about other things, such as food, fuel, water, sewage, power, healthcare and so on.

Oh, and hard-drives will not be wiped by this by the way, nor will magnetic tape.

EDIT: What is the difference between an EMP and a geomagnetic storm?

The EMP causes a fast but very short-lived voltage spike. It is like you shuffled your feet on a carpet and then poked at your CPU. The "zap" is tiny, but it is likely to damage the CPU and put it out of commission. The EMP will cause such a "zap" in pretty much everything it reaches. The power grid-will also be affected by it but with the right safety equipment it can soak up the short-lived currents that this spike causes.

The geomagnetic storm by contrast causes large and long-lived direct currents. The voltage is small compared to the EMP but it is as if someone put a huge Earth-sized battery onto every power grid. Tiny things like CPUs will not notice this but the power-grid goes haywire because of this direct current, it is not equipped to deal with it.

  • $\begingroup$ How does this answer my question? The solar flare is only a plot device to achieve the the conditions described. Other effects on society, or the impossibility of the scenario is besides the point. $\endgroup$ Jun 2, 2016 at 8:17
  • $\begingroup$ Then post the question as such: "computers — only computers — and all storage media are suddenly wiped, by magic. All other CPUs, microcontrollers and integrated circuitry remain untouched because this magic is very particular about what it wipes". The answer to this is still the same though because without information on storage media our infrastructure goes to poops. Our biggest problem will be to get the infrastructure going again... not to rebuild computers. The second biggest problem will be to rebuild the financial systems because you essentially wiped out all the world's money. $\endgroup$
    – MichaelK
    Jun 2, 2016 at 8:23

Total financial chaos

What's that got to do with it?

It's been a long time since the money was real and held in your hand or written on paper. The money now exists only in the computer, being sent from one computer to another as a number. You've just wiped the whole lot. Ownership of general stuff is probably known, but all the people who own things through lawyers and shell companies around the world probably can't track half of it. Pay the rent? With what, to whom, and how?

The problem isn't that you've lost your desktop computer and there's no point going to work (How were you planning to get there anyway? Better start walking), the problem is that everyone has lost everything. We're so dependent on computers now that this loss of data would mean you might as well set up a forge and start beating ploughshares into swords.

Practicalities of restarting a global economy

Assuming someone actually has the specs on paper and can start some sort of manufacturing process.

Computer chips don't have a high calorie content, nor do promissory notes. Your former staff are going to be more interested in how to feed their families for the next 24 hours than in coming to work. Full blown government intervention will be required to maintain a food supply. Oppressive regimes will probably do better at this than the western democracies as it's going to require hundreds of people used to desk jobs to be sent to the fields for hard manual labour that used to be automated.

I'm not even close to being qualified to plan from there, but someone has to deal with planes potentially falling out of the sky, ships lost at sea, panicking city residents, total collapse of infrastructure and communications.


Losing all the computers and all the data is effectively the end of our civilisation. We'd need to start again. Millions would die, more in formerly richer countries than poorer ones.

  • $\begingroup$ Note that I am not asking about the consequences for society, just the views on how far the technical setback is. Economic collapse is irrelevant. $\endgroup$ Jun 2, 2016 at 7:55
  • $\begingroup$ @Hohmannfan, I see what you mean but economic collapse is critical, how much you lose is dependent on how fast you get the economy running again. If you're knocked back to subsistence farming for a generation then you lose almost everything. The sooner you're back up and running the more you save. $\endgroup$
    – Separatrix
    Jun 2, 2016 at 8:55
  • $\begingroup$ Fifty years ago we did not do things by computer. None any of the other 100 000 years ago humans have been around. Strangely enough: we survived that. Erasing records of ownership and money does not collapse the world, nor make people suddenly starve. The farms are still there. The mines are still there. Everything substantial still exist, even if we wipe out records about who owns it. $\endgroup$
    – MichaelK
    Sep 17, 2017 at 21:05
  • $\begingroup$ @MichaelK, but what society runs on now is not substantial. Most people who see this make their living pushing numbers around a computer, not working in the fields. We live in a very different place from 30 years ago, even 15 years ago the NHS still ran on paper, thousands will die just from the loss of those records. $\endgroup$
    – Separatrix
    Sep 18, 2017 at 7:29
  • $\begingroup$ Society does not "run on" computers. The society is us... people. We are the society. We run on food. Food does not disappear just because the fiction that is money disappear. It will disappear because the computers that are use to grow, harvest and distribute the food go away in this magic event. $\endgroup$
    – MichaelK
    Sep 18, 2017 at 7:41

I think we could get up and running pretty quickly. I think logistics would be the biggest challenge.

We still make chips using older fabrication methods because it's cheaper, and we still have research fabs (like those at Universities) where things are not too overly automated. Most likely somebody would have a fab that is up and running enough to make some old chip, like an 8080. We still have the masks for that chip. We also will almost certainly have some very high quality silicon wafers lying around because someone will be just starting a production run when the solar flare hits.

I would expect the setbacks of having to bootstrap out fabs again would be far outweighed by the setbacks caused by all of our computers suddenly dying without any warning.


Sorry for short and brutal answer, but I'll post it anyway.

There would be no "we" after that event

If all CPUs are fried, even the ones not connected and stored in steel warehouses, or in transit in steel intermodal containers, then it means event was probably of neutron nature, not electric one. And after neutron event on such a scale, most DNA on earth would be broken beyond repair. Organ failure in minutes, hours, days at best.

Even if you would blanked whole world in nuclear explosions, humanity would still have plenty computers. Ones in military bases and on warships. These can resist EMP from nuclear weapon and even some neutron problems pretty reliably, as it is what they are expected to encounter.


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