DOTS: human-readable digital storage

Reading digital files require a computer, OS and app, which will all be different in 100 years. Why not store human-readable files instead? Now we can.

Digital files are dependent on apps to let us to read them. So even if the raw data is perfect - which it won't be -  we may not be able to read many digital files 100 years from now.

But what if we stored human-readable document/photo/video copies? That is the premise of DOTS – the Digital Optical Technology System – that I learned about at the 2013 Creative Storage conference in LA Tuesday.

DOTS technology was developed by Kodak and ignored. In 2011, Group 47 acquired all DOTS patents and tech documentation from Kodak.

Group 47 plans to license the DOTS technology, and is also working to extend the DOTS patent portfolio with improvements and new techniques of leveraging the technology.

What is DOTS?
G47 says that DOTS is:

  • Archival for no less than 100 years
  • Non-magnetic
  • Chemically inert
  • Immune from electromagnetic fields including electromagnetic pulse (EMP)
  • Stable in temperatures ranging from 15º - 150º F and humidity from 5% - 85%.

DOTS can survive almost anywhere humans would choose to live.

How does DOTS store an image?
DOTS stores data optically on a specially formulated, write-once tape in 15 micron-wide tracks:



These dots can store binary - machine-readable - data directly as the absence or presence of a dot represents one bit. But it can also store tiny human readable high-res photos or movie frames.



By breaking each frame into RGB - Red, Blue, Green - components, and each component into 8, 10 or 12 bit planes, a 4k image can be stored on a DOTS tape.

A camera can read each plane, combine them optically, and recreate the original movie frame. Since the data is read with a camera and not a computer, there is no dependence on exotic file formats or specialized editing apps.

Computer image file formats are highly compressed - losslessly or not - to save space. But the compression that makes them efficient also makes them sensitive to bit flips in a digital file.

G47 took 24 frames of 4K JPEG 2000 Digital Cinema Initiative compliant images, and randomly flipped 13 bits of each of the JPEG images, a 0.001% error rate. Six of the 24 frames couldn't be opened and five of the frames had visual damage.

Since bit flips are endemic in magnetic storage, it clearly isn't suitable for 100 or even 50 year archives. DOTS solves that problem.

G47 plans to deliver DOTS media and devices in LTO tape compliant form factors so current tape robots can use it. The optical images read by the tape drives will be converted to digital formats for computer use, but they can also be "read" by a camera and used without a computer.

Each LTO-sized cartridge can store 1.2TB and can be read at a faster than HDD 250MB/sec. And since it is optical, faster 2nd gen readers will be able to read 1st gen DOTS at 2nd gen speeds. Try that with magnetic tape!

The Storage Bits take
Optical storage is attractive because we understand how to manipulate light better than magnetism. DOTS is especially attractive because the data is human readable, dispensing with the entire computer data stack.

Since DOTS doesn't compress images its capacity requirements will be quite large compared to modern compressed images. But if media cost is low enough the ease of long-term storage will make it a bargain compared to magnetic tape.

But less efficient capacity will be a small price to pay for long-term human-readable data storage. Our digital civilization needs something more robust than simply copying digital data to new media every 3-5 years.

DOTS is the best answer yet to this critical problem.

Comments welcome, as always. I'm readying a review of another promising archive medium, the 1,000 year DVD . Images courtesy of Group 47.