Masterwork Project: Building a Period Computing Device from Scratch

Following on his acclaimed "Tweedle Glomping in Period" series, Maistor Justinos Tekton, called Justin, offers this detailed article on creating a period tablet computing device from scratch, using only tools and techniques available in the Middle Ages.


To begin, let us understand that this is a masterwork-level project, not to be undertaken by a beginner. Your humble author has over twenty-five years of experience in this field, and thousands of dollars in carefully-researched tools and equipment. If you are have not yet received your Laurel in Computing, you may wish to consider a less ambitious project. On the other hand, several of the sections of this project could, possibly, be undertaken as journeyman-level projects in their own right.

The Project Goal

It is not realistic, even at a masterwork level, to build one of the great cathedral computers of the High Renaissance at home. The sheer quantity of materials, not to mention the weight and storage requirements for the completed project, put such a work out of reach of any but a well-funded museum. Instead, we will focus on a much smaller and simpler device, of the sort that was commonly carried by clerks, exchequers, and tactical commanders in the Third Crusade. Examples of this portable device also were used aboard ship by pursers and captains, although such usage barely precedes the SCA late cutoff date of 1600 CE.

The device we have in mind is a tablet-shaped unit, approximately 40 cm wide, 25 cm deep, and 5 cm thick. Of course, our modern technology could make such a device much smaller, but we must stay within period dimensions. It will weigh approximately 4 kg, more or less, depending upon one's choice of materials.

Creating the Display

To begin, we will create the display surface. There were two types of these used in the Crusades. The Muslims used a device called "Al'gebra", which I believe is Arabic for "The Apple", while Christians insisted that only devices using stained glass Windows, a design adapted from the ancient Roman work of Minimus Flaccidus, were acceptable. So great was the rivalry between the two religions that Christians built their entire creation myth around the metaphorical "eating of an apple," that is, use of the wrong computing device, as an explanation for how humanity fell from divine grace. Some scholars argue that this computing dichotomy was the original reason for the hatred between Christians and Muslims. It should be noted that these were not the only computing factions of their day. Some of the Scandinavian Pagan cultures relied upon another device called the Ljynuks, a Finnish word meaning literally "Glass Sled," or colloquially, "Slide Along For Free."

Since we are building a Crusader device, we will use stained glass Windows for our display surface. It is beyond the scope of this article to describe the creation of stained glass panels, as ample references for this task can be found elsewhere. Rather, we shall focus on the mechanism by which they are utilized within our portable computing device. You will need at least two stained glass panels, each 38 cm by 23 cm in size, and unframed. The more panels you have, the more versatile your device can be. Again keeping with our Crusader theme, we recommend that the scenes on the panels be religious or martial in nature, perhaps combining both with such scenes as Saint Paul in full jousting armor skewering an Apple with a lance. Variety is crucial, else you will find using your finished computing device rather dull!

Obtain two pieces of good quality hardwood, preferably a very stable wood such as maple, close-grained and exceptionally straight, and having no checks or cracks. These should be closely matched to one another, and about 65 cm long each. Using a carving chisel, very carefully slot the entire length of each with a number of slots about 1 cm deep and about 0.5 mm wider than the thickness of the leading in your stained glass panels. Cut each diagonally at the 25 cm mark, leaving 40 cm, then cut the other ends of the resulting pieces diagonally. CAUTION: Be sure your diagonals point in the right direction, else you will find yourself starting over and uttering, as Shakespeare might say, "ye wordes most foul and vile." Those readers who have undertaken woodworking projects of this nature are altogether familiar with this situation and with the special linguistics of frustrated woodworkers.

Now, use period glue and pegs to assemble three sides of your frame, careful to exactly align the slots for the stained glass. In period, the side left open could be either one of the long sides or one of the short sides, but this author strongly recommends leaving the long side open (as was done in the later period) as this results in a more stable and usable design. Obtain a flat piece of the same hardwood as the frames, about 1 cm thick and exactly the size of the outer dimensions of the frame, and fasten the three-sided frame against this backing. If you cannot find a single piece of hardwood large enough, you may edge-glue several small pieces. This in fact is a more period method of construction (25 cm wide boards were not invented until 1658, which is outside our period of study), but the glued approach requires more effort.

You should now be able to slide several of the stained glass panels into the frame, and use the fourth board to keep them securely in place. A pair of simple metal latches, of the type used to secure helms, jewelry boxes, and other items, can easily be created using metalworking techniques of the day. Place one of these latches at each end of the fourth side of the frame. Voila! You have a completed display. Select the desired program by placing its stained glass in the foreground. Depending on the number of slots in your frame (in period, these were known as "cores" in some cultures and "tasks" or "processes" in others), you can place one or more additional panels into the background and rapidly switch between them. Other panels should be stored in a padded container, handled with the same care you would use for a modern hard disk drive, and for precisely the same reason.

More astute readers may note that the stained glass, against a solid wood backing plate, will be very dark and hard to read. This is unfortunate, but necessary for authenticity. It was not until 1723, with the advent of larger panels of clear glass, that the wooden backing plate was replaced with clear glass through which sunlight or candlelight could shine, a concept that came to be known as "backlighting" the display.

Adding A Mouse

Our modern "mouse" of plastic and electrons bears only a superficial resemblence to its medieval counterpart, but serves the same function, which is to say, entertaining your cat when you are away from the computing device. For our purposes, and the sake of portability, we will rely on a simple and small field mouse (the Spanish sometimes used gerbils for this, which is an acceptable substitute) rather than the larger and more ornate rats used by the monastic orders in their great cathedrals. You may be inclined to secure the tail of your mouse permanently to the display frame, but resist this simple approach! Your computing tablet could last much, much longer than the life of the typical mouse, so I recommend that you use a springy piece of brass or tin, about 1 cm wide and 6 cm long, fastened to the back of the display frame, to simply clamp down the tail. When your mouse dies of old age, you can then gently lift the clip (careful not to permanently bend it away from the frame) and replace the mouse with a new one.

Remember to feed your mouse often, or you will soon find its performance to be sluggish, and clean the mouse balls regularly, removing any traces of lint or dirt. Also, although a modern electronic mouse is an input device only, recall that an authentic medieval mouse possesses both input and output ports. In modern times, we use mouse pads primarily for decorative purposes, but with your medieval computing tablet, you will need the pad for its original practical purpose. A simple cloth of white wool, easily washable, will suffice if your persona is of merchant class, but if your persona is of the nobility, it is essential to keep up appearances by allowing your mouse to defecate upon a hand-blackworked linen or hand-embroidered silk pad, which is then meticulously cleansed by your servants each morning before dawn.

Connecting Your Computing Tablet

As we know from the modern world, a computing device is most useful for communicating with others, and this was certainly true in the Middle Ages as well. The next step, therefore, is to allow our computing tablet to connect with others of its kind. As in the modern world, this can be a process fraught with frustration, but be patient and see it through.

Begin with a rod of purest copper, as long and thin as you are able to obtain. In a piece of iron or (for those of late period) steel, drill or punch a hole just slightly smaller than your copper rod. Then next to it, place another just slightly smaller than that. Repeat, with smaller and smaller holes, until you have the smallest hole of just about 0.25 mm diameter.

Now, heat your copper rod until it softens but does not melt, and carefully use blacksmith's tongs (small) to draw the rod through the first hole. Move slowly and keep the metal at temperature. Repeat this process again and again, each time moving to a smaller hole so your copper becomes longer and thinner. If it should fracture or break due to impurity in the copper, you will need to start over with a new rod and the largest hole. Although you will lose several hours worth of tedious work, you should rejoice in enjoying the full period experience.

Once you have completed the drawing process, you have what the craftsmen of the day called a "wire". You will need a total of eight of these, so go back to the forge and get started. This is the most fun you could have in the Middle Ages without being hauled in front of an Inquisitor.

Take your eight wires, and carefully coat the entire length of each one with beeswax, ensuring that the coating is as uniform as possible and that there are absolutely no exposed bits of metal. Scrape the beeswax off the last 0.5 cm at each end of each wire.

Next, gather your eight wires into four pairs of two, and twist each pair carefully around one another. Lay the four twisted pairs side-by-side and carefully coat the entire assembly with more beeswax. Set aside this work to harden while you move to the next step.

Obtain two very small cubes (0.6 cm on each side) of granite (for noble personas) or limestone (for commoners) and carefully drill eight holes in one face of each cube, side-by-side, and almost but not quite all the way through the cube. Using the assembly of wires and beeswax you created earlier, insert the eight ends of the wires into the eight holes in a stone cube, repeating at each of the two ends of the assembly, and secure them by tamping molten pitch into the holes and around the wires near the ends. Be careful to keep the wires from touching during this, because the beeswax will assuredly melt off the wires for a centimeter or two.

When you are done, you now have a device that was believed to convey the essense of a person's speech through the Ether, and you are ready to attach it to your computing tablet.

Very carefully cut a slot in one edge of the frame of your computing tablet, such that one end of your Ether wires can be slipped into the slot. In northern Italy, one example of this device had a slot that was slightly keyhole-shaped so that the Ether wires were better retained; this is perfectly period and recommended unless you are doing a very early period persona. You might want to remove the stained glass panels during the slot-cutting operation to protect them from breakage.

Using the Finished Computing Tablet

Your finished tablet can be used in a variety of ways, from religious instruction to military command. In the case of the Crusades, which we are here re-creating, these were essentially one and the same, so your device is ideally suited.

In a well-lit area outdoors, insert the desired foreground and background panels into your display and hold it aloft for all to see. As you deliver your sermon, speech, or other diatribe, frequently replace the stained glass panels with different ones to add variety. You will note that this process involves a lot of sliding of panels in and out of the frame; this is the origin of our modern phrases such as "presentation slides" and "slide show." Remember to allow a period for questions at the end of your speech.

For communication to just one other person, for instance to convey secret military plans, you will need that Ether Wire and two of the computing tablets. Attach one end of the wire to each tablet by inserting the wire into the open slot. Note that the little stone cubes on the end keep it from slipping free as you pull the wire tight between the two tablets. Now, stretch the wire as tightly as you can without breaking it or pulling off the stone cubes. Keep the face of the stained glass flatly toward your face, and shout directly at the glass panel. The vibrations from your voice should be carried down the Ether wire, and the person at the other end should be able to very faintly hear you by placing their ear directly against the stained glass panel on their own computing tablet.

Congratulations! You have just carried on a private Ether conversation in exactly the way it was done in the Middle Ages! Furthermore, pressing a piece of cold glass to your face while one person shouts and the other strains to hear should give you a deep understanding of the inspiration of the aesthetics and function of the modern smartphone.

Closing Notes

Clearly, this is not a project for beginners, but I hope that you have found this tutorial helpful in your drive toward increasing authenticity.

It is worth noting that the development of portable computing devices continued and indeed expanded after the close of the SCA's period of study in the year 1600 CE. Pioneers such as Charles Babbage, whose Difference Engine took the concept of boat anchors to new heights, carried on the proud traditions of the Christians and Muslims from the Middle Ages. Furthermore, the Scandinavian Ljynuks devices, mentioned in passing earlier, continued to evolve, and some scholars actually consider these less-familiar works to be of superior craftsmanship compared to the works of western Europe that were based on the ancient Roman designs.

Frequently Asked Questions (FAQ)

  1. Is my modern Windows™ tablet period?
    Of course not. However, if you erase the operating system and install MS-DOS version 5.0 or earlier, then it is period. If you install CP/M-86, you can still get away with using it at SCA events, but technically it's too early for our time period.

  2. Is my modern iPad™ tablet period for my 1500s English persona?
    You didn't read the article, did you? Any device involving fruit, especially an apple, date, or grape, is only period if your persona is Middle Eastern. The iPad is not known to exist in England until the Elves brought it to the port town of Keebler, in the early 20th century.

  3. If I can prove that J.R.R. Tolkien used an iPad in England, then is it period?
    Oh, don't be daft! Yes, the Elves brought the iPad to Keebler, England, but Tolkien brought the Elves to England. You cannot use a single source -- even a primary source such as a signed first edition of The Hobbit -- to authenticate the provenance of itself.

  4. Is a modern tablet period if it runs COBOL and can accept punch cards?
    This is a complicated question. The strict answer is no, because COBOL and Hollerith cards were used only in the great cathedrals, and were not taken on the Crusades for use with tablets. There is, however, some debate among scholars suggesting that one deck of Hollerith cards containing a COBOL program was actually carried to the Field of Cloth of Gold by King Francis I of France, who according to one minstrel of the day, "Us'd it well upon the taunting of Kynge Henrie, then bespake a second time a taunt thereunto, and verily farteth in direction belike the Kynge's own way." So while the evidence for use of COBOL tablets is sketchy (pun intended) during our period of study, it is a reasonable argument that if they had COBOL tablets, they would have used them.

  5. Is Datamancer's steampunk laptop period?
    Who cares? If it gets you kicked out of the SCA, you've still got the most kickass laptop on the planet.

  6. Is an Etch-A-Sketch™ period?
    Yes. If you have one, please feel free to use it in Court at your next event.

About the Author

Maistor Justinos Tekton is an eleventh-century merchant from New Rome, known in western lands as Byzantium. He is currently traveling in western Europe with his lady wife, and as such he usually wears garb in the local style to avoid attracting attention as a foreigner.

The real-world person behind the above persona is the author of numerous authoritative treatises and monographs that have won worldwide academic acclaim, including:

  • "On a Method Whereby One May Utter Words and Pictures Most Efficaciously", in the Alder Leaf, April 1997.
  • "A Survey of Tweedle Glomping in Northern Italy, 1354 to 1357 CE", in the Journal of Tweedle Sciences, 1994.
  • "Tweedle Husbandry of the Burgundian Prairie Lands: An Asymmetrical Perspective", in the Proceedings of the North African Tweedle Society Annual Symposium, 1992.
  • "Tweedles and Needles: Glomping in the Textile Arts of Western Civilization", presented at the annual convention of the Textiles and Tweedles Society of Northumbria, UK, 1988.