Long Term Archive IX

What media will you use to store your everlasting data? We have discussed the issues with keeping the spinning brown
stuff (Disks) going due to mechanical issues. We have also mentioned the chemical decomposition and coercivity decay of magnetic tape over time. I have admitted my predilection for physical records that do not require fancy technology to recover so I like rock paintings, engravings and ink on paper. It is difficult however to balance the convenience of storing a terabyte of data on a half kilo, two hundred dollar disk drive with the mountain of paper required for the equivalent in written pages. (Approximately five hundred million pages)

Back in the nineteen nineties some guy tried to market a system which converted data to a 2-D barcode which could be printed on any printer. It could be photocopied or faxed and it could be input as data again by a simple scanner and some software. It stored 4MB on one A4 page. That’s about the same as two thousand typewritten pages. I really liked this but it never caught on. Even so, you would need two hundred and fifty thousand such encoded pages to match the aforementioned hard disk. (1TB)

This brings me to the optical disk. CDs, DVDs and Blu-Ray have tiny physical pits which are read by a laser and although the players might be obsolete or just worn out in the future, the pits should still be there even if the Martians have to read them bit by bit through a microscope. Of course the encoding is digital and it is not just zeroes and ones but a special code (Atkinson code) to eliminate strings of the same bit. Someone could work it out.

You may have heard of CD rot or the discolouration of early CD plastic due to oxygen getting in. The gold CDs were less vulnerable to this than the polished aluminium substrate examples but it has all been solved with an epoxy edge layer. Anyway, it only applied to pre-pressed commercial CDs and DVDs such as music and movies. Your own data goes on CD/DVD-R or -RW which use dyes and the manufacturers assure us they will last for 100 years.

Still, 100 years is not that much. Imagine if the oldest recorded history we had was news articles on the Wright brothers flight or ‘House Rule’ being accepted for Ireland or turning of the first sod for Canberra. I’m still waiting for the next breakthrough technology in long term storage.

cheers
Spike

Sources:
http://web.archive.org/web/20081022212501/http://www.slais.ubc.ca/PEOPLE/students/student-projects/C_Hill/hill_libr516/print.htm

http://prov.vic.gov.au/wp-content/uploads/2012/01/Mgmt_Electron_Records.pdf

http://www.jamesshuggins.com/h/tek1/how-big.htm

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