So the main team of characters is traveling back in time from "modern day" to medieval Europe, arriving around the 1300s.

Assumptions: They Know they are going, they have space and time to prepare, the team consists of 10 people in their mid-20s with a variety of skills. They are not returning to modern times. They are staying in the past.

They are taking back information in a variety of forms. The goal is to get to a stable system for reading from their SSDs and computer drives. What would be the quickest and most reasonable way to be able to read and have this reference material available?

Other materials will be brought along. Books, microfiche, and other reference material. The Travelers have a limited Volume (10M cube, 1000 cubic meters)to bring along. So the obvious desire is to keep information in the densest form. So what information would need to be available before the SSDs to get to them?

  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – L.Dutch
    Apr 2, 2019 at 9:54
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    $\begingroup$ 1000 cubic meters can store a lot of items. Is putting in a small computer and solarpanel array an option? $\endgroup$
    – Mast
    Apr 2, 2019 at 10:33
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    $\begingroup$ There are now micro sd cards that go up to 1 terabyte... why not bring a bunch of those and a smartphone? (Plus solar panels, of course) $\endgroup$
    – ChatterOne
    Apr 2, 2019 at 13:43

12 Answers 12


If they are just bringing the drives, and not the attached computer, this is pretty much impossible. The infrastructure simple isn't there in 1300 to refine anything to the necessary purities to even begin manufacturing microprocessors. See this answer to get an idea of how hard this is to do: How long would it take to create a Windows 1.0 capable machine from complete scratch? .

If they can bring their laptops, they only need to worry about a power supply. By far the easiest way they could do this would be to bring some small solar panels, a turbine they could hook up to a water wheel, or a bicycle powered generator.

If they have to make their own power supply, they will have to get /make a bunch of copper wire and some permanent magnets and make their own generators to attach to a turbine of some sort (water wheel probably). This won't be easy. See these two related questions:

I was thrown into the middle ages, how do I power my time machine?

How hard is it to build a generator if you've jumped to the distant past?

Basically this will be hard unless you bring everything you need. In which case look for guides for "living off the grid" to get a more thorough idea of what you need.

  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – L.Dutch
    Apr 3, 2019 at 3:03

Quite obviously, the only way to read SSDs in the 14th century is to bring a computer. Or, actually, several computers. With great care, the computers will last for some twenty years, in which time one could hope, with an extraordinary amount of good luck, to push technological progress up to the 17th century -- you know, printing presses, telescopes, logarithms, basic algebra, some calculus, laws of motion, half-decent cannon, basic knowledge on the strength of materials. Use the time to transcribe the most important social and scientific principles of the modern world; then the computers will die, and everything in their memory will die with them.

Since questions like this appear from time to time, I thought it would be a good idea to set things straight. First of all, one cannot make an electronic computer in medieval Europe; what one can try is accelerate the technical and scientific progress to the point where making an electronic computer is possible: but, quite obviously, when reaching that point one will no longer be in medieval Europe. Technical and scientific progress cannot be decoupled from social evolution; a world which has the technology to build electronic computers is not a medieval world.

Why do I say that a world which has the technology to make electronic computers cannot possible resemble medieval Europe? For two obvious reasons: first, in a world with advanced technology there are lots and lots of literate people and lots and lots of books; and second, a world with advanced technology must by necessity be based on some sort of modern economy, either a Soviet-style planned economy, or a free market economy, but in any case nothing like the sluggish medieval economy. When a civilization reaches the point where the vast majority of people are literate and numerate and where most people work for a wage that civilization is way past feudalism.

When thinking of modern technology one must always keep in mind that it is but the top of vast mountain of work and knowledge; for the engineers who design and make, let's say, microprocessors rely on many other people to run the factories, and to make the wafers, and to design and make the photoengraving machines, and the measurement devices, and the artificial light sources, and the office buildings, and the vehicles, and the electric power grid, and the transportation networks and so on and so forth.

For a gentle introduction to the modern technological pyramid one is strongly urged to read Leonard Read's 1958 essay I, Pencil, in which the pencil, speaking in the first person, "details the complexity of its own creation, listing its components (cedar, lacquer, graphite, ferrule, factice, pumice, wax, glue) and the numerous people involved, down to the sweeper in the factory and the lighthouse keeper guiding the shipment into port" (Wikipedia). It's a short but definitely illuminating piece, and, moreover, it's available on line from multiple sources:

I, Pencil, simple though I appear to be, merit your wonder and awe, a claim I shall attempt to prove. In fact, if you can understand me—no, that's too much to ask of anyone—if you can become aware of the miraculousness which I symbolize, you can help save the freedom mankind is so unhappily losing. I have a profound lesson to teach. And I can teach this lesson better than can an automobile or an airplane or a mechanical dishwasher because—well, because I am seemingly so simple.

Simple? Yet, not a single person on the face of this earth knows how to make me. This sounds fantastic, doesn't it? Especially when it is realized that there are about one and one-half billion of my kind produced in the U. S. A. each year.

On to the practicalities.

The practicalities are of two kinds: practicalities related to the development of the story, and practicalities related to the verisimilitude of the world.

When developing the story it is very helpful to be aware of similar stories which have already been told. It is simply a good use of the author's time to read similar stories, so that they can benefit from the work of previous authors who worked in the field. The field in question is a subgenre of alternate history, characterized by describing the changes brought about by one or more modern people who find themselves in a pre-modern world.

  • It all begins with L. Sprague de Camp and his 1939 novel Lest Darkness Fall. American archaeologist Martin Padway is transported to Rome in the year 535 CE. One thing leads to another and he finds himself ruling Ostrogothic Italy. In a remarkable scene, the novel addresses the clash between modern economic expectation and the sad reality of the early Middle Ages. The hero coaxes an artisan to make a crude printing press and starts printing a newspaper; in the 6th century there was no paper in Europe, so the newspaper was naturally printed on vellum. The first issue goes out, but when the hero want to print a second issue his vellum suppliers inform him that he has used all the vellum available in central Italy, and he must wait at least half a year to get more from distant suppliers.

  • A necessary step are the entertaining (if maybe sexist, insensitive, and, possibly, quite badly written) adventures of Leo Frankowski's hero, Conrad Stargard, The Cross-Time Engineer (1986). A Polish engineer (from the People's Republic of Poland, no less!) is sent back in time to 13th century Poland, where he kick-starts an industrial revolution of sorts, becomes a powerful nobleman and generally messes up historical lines. The series is notable for the attempt to establish a plausible sequence of technological developments; the above-mentioned defects start to crowd out the good parts as the series progresses, so by Lord Conrad's Lady one is advised to skim and concentrate only on the technical aspects.

  • Eric Flint and many others put a lot, and I mean a lot, of effort into developing the Ring of Fire shared universe. A mid-size American town is transported from 1990s West Virginia to war-ravaged 1632 Thuringia. They immediately proceed to meddle in the Thirty Years' War, and to introduce great social and technological change. This shared universe is remarkable for the vast amount of research, with Eric Flint and his many many co-authors trying to make sure that each and every step in technological development was indeed possible, or at least not utterly impossible. One is well-advised to read the books and spend some time in the forum dedicated to the exploration of technologies.

  • Then there are many other more-or-less well-known works in this subgenre; I will only add S. M. Stirling's Nantucket series, beginning with Island on the Sea of Time (1998). Modern day Nantucket is transported in the 2nd millennium before the common era, and the inhabitants proceed to do their best to uplift the world around them, both socially and technologically. The plausibility of the developments is well-maintained, even if not raising to the high standards of 1632 and its sequels.

When plotting out the technological developments which go from the point of departure, be it the 2nd millennium BCE, or the 6th century CE, or the 14th century, or the 17th, up to something resembling the modern world, one must always remember that the modern world lives in the age of machines. To make the machines which make the stuff available in the modern world one first needs to make the machines which made the machines, and the machines which made the machines which made the machines, and so on up to many layers deep.

To concentrate on a specific example, let's consider the USB cable which connects the SSD device to the computer. The cable. Quoting from the standard describing USB cables and connectors (USB CabCon Workgroup, Universal Serial Bus 3.1 Legacy Connectors and Cable AssembliesCompliance Document, version 1.1, 2018):

  • Low Level Contact Resistance: 30 mΩ maximum initial for the Power (VBUS) and Ground (GND) contacts and 50 mΩ maximum initial for all other contacts when measured at 20 mV maximum open circuit at 100 mA.

  • Dielectric Withstanding Voltage: The dielectric must withstand 100 VAC (RMS) for one minute at sea level after the environmental stress defined in EIA 364-1000.01.

  • Cable Assembly Voltage Drop: At 900mA: 225mV max drop across power pair (VBUS and GND) from pin to pin (mated cable assembly).

  • Contact Capacitance: 2 pF maximum unmated, per contact. D+/D- contacts only.

  • Propagation Delay: 10ns maximum for a cable assembly attached with one or two Micro connectors and 26ns maximum for a cable assembly attached with no Micro connector. 200 ps rise time. D+/D-lines only.

  • Propagation Delay Intra-pair Skew: 100 ps Maximum. Test condition: 200 ps rise time. D+/D-lines only.

If you don't hit those specifications, the cable won't work. You must achieve the specs. There is no loophole.

Let's select the propagation delay. In order to make an USB cable one needs to be able to measure time with an accuracy of at least 10 ps. In 10 picoseconds light travels 3 mm, about one eighth of an inch. How does one approach the problem of designing and making a device which is able to measure the time in which light travels 3 millimeters? I have no idea; there are no more than two or maybe three people in a million who have a working acquaintance with designing and making such devices; and those rare people have no idea how make the wires, or the pins; or how to program the microcontrollers; etc.

How fast could technological development be pushed? That is to say, in real history the world took some seven hundred years to progress from the fourteenth century to the age of smartphones; how quickly can one imagine that this journey can be made? I'd say that with a lot of luck and dedication, and with quasi-divine guidance, it could be shortened to maybe three to four hundred years if all pitfalls are magically avoided. The reasoning is simple:

  • The last hundred years or so cannot be shortened; from the early twentieth century onwards technology progressed at breakneck pace, and there is no reasonable way to make it go faster. Remember that when the first people set foot on the Moon there were people alive, even in developed countries, which had been born before Edison invented his lightbulb. When Apple introduced the iPhone, there were people alive, even in developed countries, who had been born at a time when the shortest time to cross the Atlantic was measured in days.

  • The 19th century might be condensed in 75 years; to condense it further would stretch the societal evolution beyond breaking point. The 19th century began with Napoleon conquering Europe on horseback and ended with telegraph lines circling the globe; it began with the U.S.A. issuing letters of marque to privateers in their War of 1812 with the United Kingdom, and ended with global trade networks; it began with all European powers attempting to suppress the French Republic and ended well on the way towards universal suffrage in most civilized countries. That's some 175 years up to this point.

  • The 18th century might be condensed in 50 years, but not more. In real history, the 18th century saw tremendous advances in mathematics and in physics. Luminaries such as Leonhard Euler, Pierre-Simon Laplace, and the Bernouillis were pushing mathematics forward at the maximum speed human mind is capable of; going more than two times faster is inconceivable. That's 225 years up to this point.

  • The 17th century saw the transition from not having any physics to speak of to having decent physics. Maybe it could be condensed in 75 years, maybe not, but definitely not less. Remember that in real history the 17th century saw the discovery of calculus and the laws of motion, analytic geometry, and logarithms. The entire idea of a computable universe was born in the 17th century. That's 300 years already.

And then one must necessarily add some time to allow for developing the printing press, and introducing basic algebra, and printing enough books to lift people from the absolute darkness of the Middle Ages to the first lights of dawn...

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    $\begingroup$ "If you don't hit those specifications, the cable won't work. You must achieve the specs. There is no loophole." -> Many devices work with a bad cable (albeit maybe at reduced speed). I experimented with a DIY extender cable, chained with 3 more extenders. $\endgroup$
    – Vi.
    Mar 31, 2019 at 4:45
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    $\begingroup$ "The last hundred years or so cannot be shortened" - I think that progress runs faster and faster because more people are involved in advances and information is exchanged faster. So, by uniting people under one power, and spending more money on science, and especially on knowledge sharing, you can do it faster. And reduce consumption to a minimum, shifting all the money to tech & science. $\endgroup$
    – Bulat
    Mar 31, 2019 at 12:18
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    $\begingroup$ @Bulat: No, not really. Each invention and each discovery needs to be put in production and taught in schools, so that successive generations can build upon them. You can't just throw money into math and physics and chemistry and engineering; you must also account for the speed of teaching, learning and applying new knowledge. I would even say that we are now running faster than what's healthy and sustainable; a large part of ultra-modern technology is really understood and know by very few people. Look how key pieces of tech are concentrated in one or two or three factories worldwide. $\endgroup$
    – AlexP
    Mar 31, 2019 at 14:10
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    $\begingroup$ But, @AlexP, it just works. I attribute exponential technology growth exactly to growth of the population (more people are doing research) and speeding up knowledge exchange. And USSR/North Korea are good examples of underdeveloped countries which nevertheless made fast progress in fundamental science/tech because they concentrated their resources there. The same approach worked for western countries when they were involved in WWII. $\endgroup$
    – Bulat
    Mar 31, 2019 at 14:25
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    $\begingroup$ @Bulat: Excellent examples! How many fundamental discoveries and truly new technologies were made or invented in the USSR during its 70-odd years of existence, compared with Germany or the USA? (And please take into consideration that I was born, raised and educated in one of the countries blessed by the fraternal care and guidance of the USSR, so I know what I'm talking about.) Did the USSR invent the transistor? Television? Computers? Integrated circuits? Jet aircraft? True, the USSR was not a desert bereft of scientific and technological progress, but too little compared with its resources. $\endgroup$
    – AlexP
    Mar 31, 2019 at 14:44

They cannot "just bring SSDs" - they need something to read it with. The simpler, the sturdier, the less energy-hungry, the better. Actually they don't need SSDs, they need memory.

The main things they have to worry about are, roughly in order:

  • theft and confiscation. They have no guild, no home, no patron. They have no servants or guards. For the standards of the time, they're a band of vagrants, surely up to no good.
  • weather and accidents.
  • power supply (easily fixed: solar panels. This doubles the risks above).
  • wear and tear.

Assuming they have prepared, their first step is to become invaluable to some powerful patron by exploiting their future knowledge of history and politics.

I would suggest several redundant tablets (you get the most capability density per volume) and smaller emergency smartphones [obviously in airplane mode ;-D ], at least some disguised somehow - maybe inside wooden slats. Batteries, lots of them.

On that note, tablets have the advantage that getting 5V DC is pretty easy using large and inefficient chemical batteries - it could be done in ancient Sumer if you knew how, and they do. Zinc, copper, iron and oil of vitriol, you don't need much else (of course a voltage regulator and a multimeter will come in very handy - I expect them to bring along a good half dozen of the latter, and a packet of the former).

Laptops, on the other hand, require special chargers that are driven by 110V or 220V AC. Or you need to feed them 12V at a much higher amperage (I think it's now usually 65W, five times a cheapo charger and thirteen times its power).

Then, the memories they can bring back, again redundantly, sewed inside clothes or otherwise hidden, using micro SDHC cards. They're way sturdier than hard disks and even SSDs, and you can get them in the hundreds of gigabytes sizes.

They probably shall have to balance carefully the need of being on the front line (perhaps not metaphorically), in order to continue earning protection, and the need to teach and train. 1348 is the year of the Black Death; their knowledge of contagion, disinfectants and sterilization procedures would be enough to protect, say, a castle or monastery or small fortified city.

(On that note -- they might bring back cultures for streptomycin and the necessary to treat a large number of people (as well as a small reserve of short-lived plague vaccine for themselves). The antibiotic they might produce would never been really refined, but people would have jumped on a 80% chance of recovering from the plague, even at the cost of some loss of hearing). Once established as doctors and wise men from the far-away land of Presbyter Johannes, their problems would mostly be over.

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    $\begingroup$ @VolkerSiegel, getting electricity is easy. Getting enough controlled electricity to run a laptop isn't. If you had consistent year-round access to lemons (their regular cultivation in Italy didn't occur until the 1400s), you'd still not be able to run a laptop for more than a few minutes no matter how you chain the lemons together (too much intrinsic resistance). If the travelers had the lacquer tech from Japan they might create rudimentary water turbines - maybe. (and then there's the need for regulators and limiters... ugh.) $\endgroup$
    – JBH
    Mar 30, 2019 at 22:53
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    $\begingroup$ @VolkerSiegel, You're talking to an EE. Salt water makes for an amazingly weak battery. Putting batteries in parallel will reduce the intrinsic resistance (and increase the available amperage at the induced voltage), but it's uncontrolled. and it takes a lot of lemons (and even more salt water) to create a battery that would run a laptop for more than minutes. If you don't believe me, give it a try. $\endgroup$
    – JBH
    Mar 31, 2019 at 0:05
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    $\begingroup$ @VolkerSiegel, modern electronics draws electricity (amperage) dynamically. The power supply is designed to compensate for those changes in demand by regulating the voltage (to keep it stable). It requires transistors. Without that control circuitry, the dynamic draws will cause the voltage of the "batteries" to change - shutting the laptop down in the best case, damaging the laptop in the worst case. $\endgroup$
    – JBH
    Mar 31, 2019 at 2:51
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    $\begingroup$ @VolkerSiegel Modern laptops are not transistor radios, they can be damaged by uncontrolled low voltage (modern electronics expect the power to be on or off, not something in between). And we're not talking about alkaline batteries (which will void your warranty), we're talking about lemons and sea water. It's like being told by someone who's read a book about trapeze that if a trapeze artist can make it through one show without a net, the nets aren't needed. My end of this conversation is over. $\endgroup$
    – JBH
    Mar 31, 2019 at 7:47
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    $\begingroup$ @reirab People don't just wait patiently while you murder them with advanced weaponry. Those are warriors, not random civilians. Modern weapons make you very dangerous on a battlefield (if you have the training), but they will not prevent other people from killing (or detaining) you. Why do people always imagine the spearmen in Civilization killing the tank by running all the way to the tank and striking with their spear? You don't attack where the enemy is strong :) $\endgroup$
    – Luaan
    Apr 1, 2019 at 12:19

The real question is what do the travelers really need. They don't need to access a SSD. They need something. They have information they need to be able to access.

From the fact that we are bringing along microfische, it is already clear that they can easily bring more than a dozen people could read in a lifetime. Thus this isn't a "we need this information to survive" thing. It's a "We don't know what we're doing, so we're bringing it all!"

As others have pointed out SSDs are simply too complicated. SSDs are typically connected via either SATA or USB or Thunderbolt, all of which are very advanced high speed interfaces. Even making high enough quality wires for these is almost certainly out of the capabilities of the 13th century, much less actually handling the data.

If I may recommend an alternative: micro SD cards!


Micro SD cards have an astonishingly high density. As pointed out in the XKCD link above, a milk jug of them can store 1.6 petabytes. Personally, I'd recommend using the larger SD cards, to make wiring easier, but if volume is at a premium, a jug full of micro SD cards (and perhaps a few micro SD to SD converters for convenience) will take care of your needs.

More importantly, SD cards can communicate using SPI. This is a slow interface, so they typically switch over to the faster SD interface, but SPI is always there. How slow is it? Well.... as slow as we like it, actually.

SPI is clocked by the master (usually the computer). The master says when the slave gets to transmit data, one bit at a time. Usually we try to push SPI as fast as we possibly can, but SPI can theoretically go all the way down to DC. This means you could have a human being manually putting bits on the wire, and reading them out with a galvometer!

And now we know what goes on the microfiche. The microfiche are an index of all of the contents on the SD cards, so that we don't have to waste all sorts of time reading bits we didn't need!

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    $\begingroup$ Good point about SPI! $\endgroup$ Mar 31, 2019 at 18:30
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    $\begingroup$ You would need stable power, and maybe some way to debounce the clock and data switches, also a good supply of frogs for the galvos. Were I doing it I would probably design something bespoke rather then going SD with a small solar panel and pile of flash chips embedded in epoxy with an led and touch switch, then teach everyone who needs to drive the thing morse code. No IO, no mechanical interfaces, put it in the sunlight and tap out queries. Dress the thing up right (and make the interface default to Latin) and you can probably get the local religious order to manage it for you. $\endgroup$
    – Dan Mills
    Mar 31, 2019 at 21:05
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    $\begingroup$ And you need a reason that the SD cards are easier to use than paper. $\endgroup$
    – user253751
    Mar 31, 2019 at 21:32
  • $\begingroup$ You could bring Arduinos or similar to read from the micro-sd cards (with a display and even a serial thermal printer to print out longer portions). Arduinos are a lot more resilient to fluctuating power than computers. One can bring a bunch of pre-programmed boards, and spares for displays and printers (maybe lots of paper too). $\endgroup$
    – States
    Apr 1, 2019 at 11:34
  • $\begingroup$ @States True. I bet that, were we to know how the information was intended to be used, that we'd find your approach is likely very effective. One thing I don't know is the powered-off lifespan comparison between SD cards and Arduinos. Might the Arduinos die first? $\endgroup$
    – Cort Ammon
    Apr 1, 2019 at 15:03

This sounds like an XY problem.

As the others have said, you absolutely need a computer to read SSDs.

If your goal is to have information available with low-tech means, print it all on microfiche. You will not have data compression, searches will be long, and it will be bulkier, but you will be able to read them with only a very reasonable upgrade in technology.

  • $\begingroup$ A step back from microfiche is small print on thin paper, such as the compact version of the Oxford English Dictionary. That can get a lot of information into a small space, and only needs a magnifying glass to read it. $\endgroup$ Mar 31, 2019 at 19:08
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    $\begingroup$ @PatriciaShanahan True! A bit more fragile though. Microfiche can be read by magnifying glass, but maybe it depends on the reduction. $\endgroup$
    – Law29
    Mar 31, 2019 at 20:55

I think you're overvaluing the importance of information, and undervaluing the importance of infrastructure. rather than bringing computers, bring books. books can be copied with period infrastructure. not any books, though. there's a few concepts of what books to bring (ex: linky).

EDIT: microfiche contents can be copied to books with period infrastructure--so that is probably also a good plan. but microfiche itself is also more fragile, so multiple copies is probably a good idea.

focus on things like crop rotation/agriculture, metallurgy (how to make steel en-masse is of primary importance), chemistry (gunpowder, smokeless powder, etc), physics, medicine, etc.

but that won't take up all that much space. you're bringing 1000 m^3. in that space, you could bring a decent quantity of rifles and ammunition, medicine, etc. that seems far more important in 1300AD than a computer and whatever your computer could do.

in fact, the most useful thing i could imagine for a computer in 1300 is managing a country's finances (i'm not sure how realistic something like an income tax would be without computers)... so it might still be worth bringing a few.

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    $\begingroup$ "I think you're overvaluing the importance of information, and undervaluing the importance of infrastructure." Definitely. It's like taking your taking your Macbook Pro on wilderness survival training. $\endgroup$ Apr 2, 2019 at 0:32

I think there is an implicit assumption that if a computer were to be sent back in time, it would be a commercial, off the shelf version. I say that because you mention SSD. It is quite likely that it would be built to specifications with unique chips and energy technologies. It also couldn't really be repaired without bringing spare parts.

Unfortunately, you didn't say why they needed a computer if they were not returning. Most reference material would be worthless, even to people with doctorates in their fields. A computer sent back in time should be rugged, should be built to the narrow purpose of its mission meeting only the minimum requirements that must happen, should use very low power settings rather than standard commercial settings, should use DC power, and should have a power source dependent on the local environment. It could be powered by steam from a wood burning stove in the right area of Europe.

The information they need will depend on the information they are carrying inside their heads. Trig tables would matter, but there is no need for a calculator if you could carry a slide rule. A metal slide rules would be vastly superior to a computer with the correct set of tables for things such as integration.

The 1300s are an unfortunate time to return to. The world was in upheaval. Climate change had cooled places and many places would be overcast quite a bit in Europe. The Black Plague killed an average of one in three persons, but in some places killed every single person and in others, none at all. There were frequent huge storms and floods, so you need to be waterproof.

In Europe, there was a massive religious response to mass death. A Christian in the year 1000 might barely recognize the Christianity of 1400 outside the liturgies. Outside Europe, there was a massive deconversion from Christianity. Between 1200 and 1500, two-thirds of all Christian churches closed worldwide. Almost none of it was due to persecution, children just joined other religions. Had you lived in the year 1100 in Ireland, you could have traveled to Tokyo to hear the liturgy sung and never missed a Sunday service along the way. This was also true in the reverse direction. It was a massive collapse of an important global social network.

Churches that had been open since the apostles founded them closed forever. Europe was the primary holdout for Christianity, but it survived from Syria to India while collapsing in most of Africa except Egypt and the Sudan. It vanished from China, Japan, Mongolia and almost entirely in Persia.

At this time, the penalty for minor theft such as a loaf of bread was to be plowed to death. You were buried up to your chest and plows would be driven through you.

I bring this up because a computer should be built for a purpose and not just to be brought along. Until a few decades ago, people just committed facts to memory and learned how to do things. Many standard technologies, such as glass making was just being rediscovered so you won't be able to make medicines generally. Europe also had low grade metal making compared to other periods in time.

You need a power source, you need a rugged design, you need something that can be powered by local energy sources, you need something that is easily repaired, but more than anything else, it needs to be built exactly to mission. There can't be a video game on it. They are costly in terms of robust design. It is why they sell game PCs. Finally, it shouldn't carry anything the mind can carry or which is robustly needed so should be in a book. A trig table should be in a book. Every American school child learned to use a slide rule. It shouldn't be a substitute calculator.

Finally, you should read, "I, Pencil" to understand the distributed information problem. It is at https://fee.org/resources/i-pencil/

I bring it up because my first reaction was that the use of a computer is a puzzling use of space for people who will die in the 14th century.

One final note, you probably would not use SSD in such a computer. It isn't a robust technology compared to many others. You wouldn't bring a Lexus, you would bring a Model T. It was designed to break. It was designed for a world that didn't yet have roads except for dirt paths. It was designed to a minimum of parts so there were fewer single points of failure. Ask instead, if I built a computer to do the following things, and it had to survive N years even if hit with a sword, what do I need to do?


I think it is possible, assuming they have the following:

  • a (stable) power source, a lemon battery will probably do just fine
  • wires, or anything that can be used as such
  • a way to solder on the memory chip inside the SSD
  • a way to measure volts or at least detect if a digital signal is 1 or 0 (a led maybe?)
  • a good knowledge of SSD internals and the SPI protocol

The thing is, you can't reasonably expect them to be able to use the SATA port without a microcontroler, but the data you want to read is stored inside chips that are much more generic.

Those memory chips are used inside all sort of devices, like cellphones, usb thumb drive, SD cards, embedded systems and so on.

They talk multiple protocols, some are fast and complex, some are really basic. One of those is the SPI protocol.

SPI requires basically 3 wires to work: a clock, an input and an output. In SPI mode the microcontroller is the one that decide the communication speed with the clock signal.

In theory you can "bitbang" the clock and input signal making contact with a couple of wires, or 2 push buttons if you have them. To read the output you'll need a detector on the output line, it will detect one bit at a time. It can be a voltmeter, a led, or anything that can help you distinguish from 1 to 0.

The difficulty here is to solder on the tiny pin inside an SSD.

For the sake of completeness I have to point out that an SD card is much more compact and easy to work with. You don't have to solder and you can use much ticker wires. The wiring is the following:

SD card SPI wiring

SS is an enabler. It can be tied to ground and ignored for this answer.

Now, bitbanging the clock and the input by hand is tedious and error prone. A more advanced method may be to replace the 2 buttons / wire contacts with a perforated cardboard.

You take a strip of cardboard and trace 2 columns, one per sigal. On one column you drill an hole every even or odd row, it doesn't matter as long as you are consistent. This is your clock.

On the other column you drill an hole every time your input signal needs to be 1.

At this point you need to setup the contacts of the input and clock signal so that you can slide the cardboard between the contacts and have them open and close when the drillholes pass trought them.

This method will ensure 2 things:

  • you can check your input on the cardboard before sending it
  • you can send you input way faster and precisely, minimizing the mistakes.

Now, you have to write down the output signal on a piece of paper, every ones and zeroes, and start decoding it. It will take a long time, depending on the encoding, but that's it.

The data encoded on the card may be stored in a filesystem like FAT or EXT4, and that will require a very good knowledge of the filesystem structure, but they can also be stored in a raw format, for example plain ASCII codes starting from the first byte of the first block of memory. That will be much much easier to read.

  • 1
    $\begingroup$ Indeed the SD card is a much better choice. Among other reasons, the clock can be arbitrarily slow. I tested one with a one second clock and it worked just fine. $\endgroup$
    – Joshua
    Apr 1, 2019 at 16:31

Probably bring a couple dozen Raspberry Pi 2+ units, screens, a few keyboards and mice (or go with all touch screens), several solar rechargers, and several rechargeable 5V 0.5-1.0A power sources. These units are designed to run on micro-usb power, but that means there is less power to allocate to other peripherals. They'll probably need a couple SATA II/III to USB 2/3 cables if the SSD is required. Otherwise, maybe go with micro-SD cards plugged into USB adapters. Of course, they could bring one of each item if they're in a gambling mood.

If their goal is to kick-start certain tech early, it may help to include this video from Jeri Ellsworth. However, I would recommend the entire video libraries of Jeri, Applied Science, NurdRage, and other similar channels.


Others have addressed the very real issues of power supply. I would like to mention a few aspects of sheer practicality. I am lucky if a computer lasts me 10 years, and that is in a clean climate controlled environment with a good power supply, it is cleaned regularly, etc.

Temperature variations are a huge problem. Components expand and contract with heat, which over time can result in cracks and mechanical failure. Temperature swings are caused by turning a computer on and then off again; by intense calculations that heat up the CPU; and by ambient climate conditions. We mitigate the effects of temperature by air-cooling or water-cooling, both of which require fans. Fans wear out in a few years, and once they are gone, the computer will quickly overheat and become unusable, if it is not destroyed. This often happens before anyone realizes the problem, which is why we keep backups. You won't just have to replace the fan, you'll likely need to replace the entire motherboard.

Very low power computers do not require mechanical cooling; but even cell phones heat up.

Speaking of mechanical failure, computers have lots of cables and connectors. These can work loose due to physical stresses of temperature or moving. Dirt on the contacts of a single plug can cause a whole system to stop working. The insulation on the wires becomes brittle over time and loses its flexibility.

Cell phones and tablets are likely to be the most robust solution, but they rely on high tech batteries that last a few years at the longest. Your iphone is disposable, as the battery is non-replaceable. The best bet here is a cheap phone with a replaceable battery, and a crate of spare batteries. Even then, the chemicals in batteries can degrade over time (measured in years), so the crate may just be a toxic paperweight after a couple of decades. Of course a phone is a very limited computer, with a slow CPU, not much memory, very limited apps, and an awkward interface. I'd hate to have to enter data on one.

Even solid state components wear out. Temperature variations cause mechanical strain and failure. Circuit boards grow tin whiskers after a number of years. Fans stop working. USB plugs get so loose they stop working, or break loose from circuit boards. Random accidents crack flat screens. Rats and cats chew through cables. Power surges destroy delicate circuits. Brownouts destroy data. Chips and power supplies mysteriously fail for no discernable reason.... one day you try to turn on the computer, and it simply doesn't turn on. Even the ink in inkjet printers and in DVD-ROMS will fade over a period of years until it becomes unusable.

Computers these days are disposable. We deal with it by redundancy (backups) and continuous replacement. Redundancy and replacement depends on ready availability of cheap commodity hardware. Lacking that you are going to want small warehouse of spare parts... every conceivable spare part since you can't predict what will fail.

Electronic data storage is very fragile. Long term, you can only preserve data if you actively copy it from medium to replacement medium. Forget to copy a CD-ROM for 10 years and it may become unreadable. Magnetic media has a long life but requires mechanical devices (hard or floppy drives) to read it. Electronic media is susceptible to electromagnetic radiation and discharges (static, lightning). A properly produced non-writeable ROM is probably the most durable, if shielded from radiation; writeable solid state media such as SSDs or flash memory has a limited number of writes, and I don't know how long it can be read.

A lifetime is a long time to keep all this running for a 20-something. They'll want a clean safe space where they are secure and never have to move this stuff around. They'll need "leisure" time to make use of it; medieval farmers or servants likely won't have time or energy for computers to be interesting. That means wealth, but the wealth will have to not be noticeable. If they have to move their computers around, or of a warband decides to trash the place, both will make it hard to keep things running.

If they are hoping to leave a record for future generations, I think it should probably be in the form of carefully stored books, since I doubt that electronic media are going to survive hundreds of years with data intact, buried in the ground or locked in a church vault. A hard drive might survive, if nobody touches it, and it is sealed so moisture doesn't destroy it.

On the other hand if it is just for personal use, and only needs to last 20 years or so, it should be do-able given care and some spare parts.

I think I would suggest low power industrial computers, such as 8-bit or 16-bit systems like are used in embedded systems. These are simpler and more robust and more likely to last a long time, and are designed for dirty, extreme conditions. Older components may be more robust (i.e. cruder with loose tolerances) but will be more power hungry, bulkier and heavier. Modern components are low power and tiny and fast, but delicate. It's a tradeoff. It shouldn't be difficult for engineers to rig up hardware and software to make an SSD usable for such a device; anyone well-heeled enough to time travel back to the 1300s can probably afford some custom engineering.

Electronic paper (yes it exists) might make a good low-power display device, better than a flatscreen. I have no idea of its durability or longevity, but it would be readable by lamp light. A lot of power is used to make a screen produce light.

Bring several keyboards, since those do wear out. A capacitance based touch keyboard is slow and awkward to use but might have the longest durability. (Not one of those plastic membrane keyboards; those do wear out due to mechanical failure!)

I think wet cell batteries, like car batteries, are very heavy but provide a lot of power and are more rechargeable than lithium batteries. I don't know a lot about batteries though.


Why not build your own reader device using a raspberry pi zero and some off the shelf additions?

  1. As many [Raspberry Pi zero]'s as you can take along. Their dimensions are 65 mm by 30 mm, so you can take a LOT of them along without using up too much space.
  2. As many [7.5" E-Ink Displays] as you can take along.
  3. As many [Cellphone Power Banks] as you can take along or need. At least 3 for every device you want to have continuously in use. A 6000mah power bank should run a rpi 0 with e-ink display for about a day of continuous use, assuming reading documents with images.
  4. A USB keyboard, or simple button navigation device (what is the nature of the data on the SSDs?) Maybe get a [mini usb keyboard] or a [micro usb keyboard].
  5. As many micro USB cables as you can take with, Probably no more than about 40 per device you want to have simultaneously powered. Get good quality cables with decent physical protection. Look for something like the [Rugged Geek Micro USB Charging Cable]
  6. AS many [USB Cellphone Solar Chargers] as you can take with, at least 3 for every device you want to have in continuous use. Perhaps look at getting something like this: [10000mAh Solar Power Bank - Sweet Orange]
  7. If you will not (always) have access to the sun, you will want to take a few [emergency solar hand crank cell phone chargers]. Be sure to test the ones you take with first - many do not work as advertised.
  8. various electronic components, depending on your choice of keyboard and storage solution.
  9. If a member of your group is skilled at electronics, then be sure to take through a variety of capacitors, resistors, leaded solder, a butane soldering iron with as many cans of butane as you can take.

You should get a few of your group to play around with assembling these. Everything you will be making is field serviceable and field replaceable.

The low power rpi and e-ink displays mean that your batteries should last a really long time.


I'd start like this:

A location on a large continent in moderate or hot climate with no humans using the land regularly, but humans who are used to work hard for others nearby, at a large river with no flooding issues and bordering the ocean through a calm bay or sea. The position should be defensible (on a hill with no mountains nearby) and with lots of wood and potential farmland around. Having the right materials nearby (coal, iron, other metals, limestone for concrete and so on) would also be helpful.

They will need to bring along weapons to defend against nearby criminals, adventurers, power hungry lords, and so on. And the tools to quickly set up defenses where 10 people can defend the core parts first against nearby lords and later against revolts, and loyal locals can quickly be enabled to defend against any army the middle ages can possibly muster.

A popular ideology with loyalty testing and such can help secure following among locals and further away.

Seeds brought along will quickly boost the population, offsetting losses due to the plague and other diseases. Some of them will be kept under wraps as long as possible. Similar to a few modern breeds of milk cows, pigs, chicken, sheep, and so on. Cotton and other useful seeds are brought along to boost the economy.

So we get an inner tower where only the 10 time travelers are allowed in, and a few of them have to keep watch at all times. It's surrounded by an inner castle with a limestone mine and oven, a printing press, a paper mill, and other primary industries, run and protected by the most loyal locals. Then comes the outer castle with a large market, a savings bank, a hospital and other cash generators, access to the harbor (which also makes money), towers for defense, factories for goods to sell in the market and so on. A wharf produces ships to quickly get all needed resources from far and wide. Another factory produces horse carriages which are a few centuries ahead of their time to connect the land routes. Trade unions are set up with purposes like building roads, extending the harbor and so on.

Modern surveillance technology brought along helps make sure the loyal people are truly loyal. Modern management methods ensure loyalty and productivity, too. Competition ensures avoidance of wasteful practices and best factor allocation.

There are two kinds of factories: The ones to mass produce stuff to sell all over the world for currency and resources, like easy to produce medicines, textiles, and so on. And the ones for the colonists local needs, like ammunition and tools, which are usually kept from view of any but the most trusted people.

Local crafts are used and improved - glass makers for laboratory equipment, brewers for fermentation and other tanks, wineries for barrels and other wood work, smiths for tools and so on.

Each new factory is able to expand to cover the whole world demand if possible, to keep competition low, and brings a new ability to the time travelers. Difficult to copy tags ensure very little copying and help popularise the colony.

Prospectors are trained to find needed resources and teach the locals how to mine them. The approximate locations should be known by the time travelers. Traders are trained to identify the different materials and sort them into the correct stores for the factories.

Talented people from all over the world get attracted with high wages, trained to get the necessary skills and help further development. Our 10 time migrants let others do the work and are mostly just in contact with a few of the most trusted, to help speed up progress through them.

Something like a dominant trading power comparable to the Netherlands 400 years ago should be easily possible within a decade. By then, our 10 people should have chemical factories, an iron and other metal industries, medical and technology labs, and so on - 17th century level with a few 19th and 20th century elements and tricks.

Once the basics are there - a trade network for the resources and the exports, a known brand people all over the world try to get their hands at, and an industrial base - the rest should go faster.

Intermediate technologies like land line phones can be left out completely. Such stuff is only produced as prototypes to simplify the step to the next technology and to have testing equipment. Once photographic options and all the needed chemicals are there, our labs go directly to fiddling with lithographic electronics design until they get rudimentary chips useful for simple phone switches and automation. The saved workforce is retrained for newer products. Once a chip production is running, it will be easy to build a small processor, which will mostly be useful to find skilled programmers and electronic engineers all over the world. Once sizable and sufficiently dense chips can be produced, simple versions of modern chip architectures can be built and the aging and partly defect devices of the 10 can be replaced with slow but new equipment. And simple versions brought to the masses, to keep outside competition at bay.

With all the advantages of hindsight and equipment brought along, the level of the 1970s in some core technologies should be possible in 20 years, similar to how some industries developed out of nothing in some developing countries in the 1950s and 1960s. Another 10 years to get to the year 2000 - which is where we should be able to make any device of today work partially (enough to read the data if it's not encrypted, as we have the specs and know how to use them). After that, it gets tricky, because only some more modern technology is easily available. Modern chip design software and other such trade secrets are difficult to get and need to be reinvented. Metallurgy is a lot of fiddling - where we need to figure out the fine details for the most current technologies (older stuff can be improvised more easily). And so on. As we have a much smaller population base, fewer highly talented people will be possible to find for that. Progress will slow down to less than what we have now as soon as most technologies are 2 or 3 years behind ours today.

  • $\begingroup$ An excellent answer to the question how should they progress to do a tech reboot, but unfortunately that's not the question the originator asked. +1 for effort as a new contributor, but that's why you are getting the -1s, if you are curious $\endgroup$ Apr 1, 2019 at 20:57
  • 1
    $\begingroup$ I think it's the only answer yet which actually fits the question. There are primitive technical solutions which require manually writing down billions of bits - which is unrealistic. There are people saying it takes centuries. Mine seems to be the only fairly plausible one (also supported by how a few countries managed to develop a modern infrastructure from nothing) in the last 100 years. $\endgroup$ Apr 1, 2019 at 21:16
  • $\begingroup$ I think this answer underestimates the amount of research work done since WW2. Getting from '70s to today requires the modern world with billions of population base. Even if you have godlike powers to rule over all people, it will take several generations to have enough people with the basics of what is needed to work with modern technology. The time travellers can't do everything themselves, their "1st tier" students can't do it, neither can 2nd or 3rd tier. You need millions of engineers and scientists to make things progress fast enough. It'll take generations. Still, cool plan. $\endgroup$
    – hyde
    Apr 2, 2019 at 9:17
  • $\begingroup$ If I look at countries like Taiwan or Korea, it seems possible with fewer people. Not to mention Singapore or an average New England state. Also, with all the knowledge already there - we can assume that the 10M3 are filled with professional literature to the brim - it's more the workers than the scientists who are needed. The only area where I see serious issues are metallurgy and such - it takes years of fiddling to get what sounds easy in theory. While other things can be done much more easily. $\endgroup$ Apr 2, 2019 at 18:02

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