Feeds

The Bayeux Tapestry archiving model

A thousand year archive

Intelligent flash storage arrays

In the town of Bayeux in northern France you can see the world's oldest information archive based on a long ribbon of material, a very early example of what was to become tape media.

The 1000-year-old Bayeux Tapestry, actually an embroidery on a fine linen background, depicts a sequence of scenes telling the story of the events which led up to the Norman invasion of England in 1066 by William, the illegitimate son of Robert the Magnificent, Duke of Normandy, and his defeat of the perfidious British ruler Harold Godwinson, at the battle of Hastings. The historical accounts have it that Harold died from an arrow penetrating his eye, a fate said to be the appropriate one for people who break a sworn oath.

Death of Harold on Bayeux Tapestry

Death of King Harold - Harold Rex (Wikipedia).

William's half-brother, Bishop Odo, was involved in the events and apparently commissioned the tapestry to ornament Bayeux Cathedral, which he also commissioned. The supposed idea was to string the long tapestry around the nave of the cathedral at the time of its dedication, and so enable cathedral attendees to understand the sequence of events and the personalties involved in the Norman conquest of England.

It is not a tapestry created to glorify God and display religious themes. Instead it is an account in Latin and pictures - almost comic book in style although very serious - of a state campaign, a just war in which the French regained what was theirs by right, as they saw it. The English King, Edward the Confessor, having no heirs, sent Harold, then England's most powerful earl, to Normandy to tell William that he was Edward's appointed successor. Harold did so, swearing to the truth of this on relics. But when Edward died, Harold had himself crowned king of England.

Harold's story is different: it has been chronicled that he said he was shipwrecked in Normandy, and didn't realise he was swearing on relics.

Halley's comet appears, a portent of doom. William hears the news of Harold's coronation, builds a fleet of ships, crosses the English Channel with his army, and fought and won the Battle of Hastings a few days later on 14 October, 1066.

Bayeux Tapestry as an information archive

The Bayeux Tapestry, the victor's view of the events, was finished in 1077, ten years after it was begun, making it 934 years old. At 224.3ft long and 1.6ft wide the total surface area is 358.88sq ft.

Our understanding is that the Tapestry features 45 to 48 threads per inch which gives us a resolution approximating 47dpi with a colour depth of 8, ignoring later repairs. Thus, in information terms, the tapestry contains 2.429MB of information, assuming 1-bit per colour, 47dpi, and a 51,678.72 square inch surface area.

From the writing point of view it took ten years for English (Saxon) seamsters, seamstresses or embroiderers to write this 2.429MB of data, which must be some kind of record. Assuming an eight-hour, 350-day working period for these ten years, that implies a write bandwidth of 10.84 bytes/hour; a spectacularly slow data rate in information transfer terms.

What makes it worse is that there were multiple parallel write heads - seamsters or seamstresses - and we could envisage a team of five on average, meaning each write head in this theoretical Bayeux Tapestry archiving model wrote at a rate of 2.168 bytes/per hour (17.344 bits/min). A truly amazingly poor information write bandwidth from our IT viewpoint, but a blur of flickering needles and fingers seen from the embroiderers' seat.

If we think that needle rate is too high we can always increase the size of the embroidery team.

Bayeux Tapestry Boat

Boat pictured on Bayeux Tapestry (Wikipedia).

The read rate, going by the length of the taped commentary you hear as you walk along the length of the tapestry for 30 minutes, is 4.68MB/hour per person. Since more than one person can view the tapestry at a time we can estimate that 75 people could be reading parts of it simultaneously, giving us a real read rate of 351MB/hour.

From the endurance point of view the Tapestry has lasted almost 1000 years - an amazing record. The vegetable dyes used to colour the threads have kept their colour for nearly one hundred decades, and the woven cloth fabric has kept its structural integrity for the same time period despite several instances of mistreatment. Who says ribbons of "TAPEstry" are unreliable?

You can see the tapestry at the Musée de la Tapisserie de Bayeux. Bayeux Cathedral itself is not nearly so impressive although it has a fabulous soaring nave, transepts and vaulted ceilings constructed from Norman gothic columns, and some particularly fine stained glass windows where the long part of the nave meets the transepts. ®

Beginner's guide to SSL certificates

More from The Register

next story
The cloud that goes puff: Seagate Central home NAS woes
4TB of home storage is great, until you wake up to a dead device
Azure TITSUP caused by INFINITE LOOP
Fat fingered geo-block kept Aussies in the dark
You think the CLOUD's insecure? It's BETTER than UK.GOV's DATA CENTRES
We don't even know where some of them ARE – Maude
Intel offers ingenious piece of 10TB 3D NAND chippery
The race for next generation flash capacity now on
Want to STUFF Facebook with blatant ADVERTISING? Fine! But you must PAY
Pony up or push off, Zuck tells social marketeers
Oi, Europe! Tell US feds to GTFO of our servers, say Microsoft and pals
By writing a really angry letter about how it's harming our cloud business, ta
SAVE ME, NASA system builder, from my DEAD WORKSTATION
Anal-retentive hardware nerd in paws-on workstation crisis
prev story

Whitepapers

Choosing cloud Backup services
Demystify how you can address your data protection needs in your small- to medium-sized business and select the best online backup service to meet your needs.
Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Website security in corporate America
Find out how you rank among other IT managers testing your website's vulnerabilities.
Intelligent flash storage arrays
Tegile Intelligent Storage Arrays with IntelliFlash helps IT boost storage utilization and effciency while delivering unmatched storage savings and performance.