Letter Re: Preserving a Digital Library

Monday, Sep 16, 2013

James,
Concerning the recent posts (all good) about a digital library:

I admit I didn't read every word, but as a fairly long time (23+ years) IT professional for the same company, I would be remiss to not identify the problems we have had.

First off understand, technology always marches on! And whiles many times I have successfully restored rewritten 20+ year old data, there have been many failures. As densities of storage medium grows the physical size of the actual stored information shrinks! So the actual stored magnetic 1's and 0's are written is in smaller and smaller spaces, becoming ever more susceptible to corruption. And this is but one of the dangers of data storage. Technological advances are probably even more troublesome.

During my 23 year tenure we have changed the backup medium at least 4 times and densities at least 3 times. Each requiring a different piece of hardware. Many requiring a re-reading from the old format and re-writing to the new format.  From 1/2" reel to reel type tape, to 1/4" cartridge tape, to low density 8 mm VCR type tape, to high density 8 mm tape, and now on to several different densities of the newer LTO format. We literally have several thousand tapes in our digital backups, but currently I can only read the last three generations. If you do not transfer your data to the current medium in a timely manner then your data stands at risk!

Optical technologies are a bit more stable, but I believe the DVD gold standard medium is only good for about 20 years. Assuming you have hardware that can read a DVD 20 years from now! And if the markets decides DVDs  (reference the old VHS or Laser-disc!) are no longer valid, then poof they are gone. These changes don't happen overnight, but rather in months to a year or so. You need to stay vigilant.

Understand that there is no guarantee that the IDE / USB drive you have backed up onto will be readable in the future. The old (late 1980's to mid 1990's) MFM interface (modified frequency modulation) drives are ancient and you would be lucky to find anyone who knows of them or to find a working interface for current PC's! The USB (2.0) 3.0 interface of today may well fall to the OMLITNNFIITW (Oh my Lord its the next new fastest interface in the world) syndrome. For example, there are few IDE interfaces available on the motherboards of today, most are SATA. Almost no serial ports to be found on the motherboards of today. A parallel port is a dinosaur. And it's next to impossible to find a floppy interface on today's motherboards, though you can still find USB floppy drives. For how long? Your guess is as good as mine!

The current SATA drive interface may last for decades, or just until they find something better. And the newer incredibly fast PCI-SATA interface is hitting the market as we speak. How long will either last? After 23 years the only thing I know is, is that change is constant!

In short computers are a dynamic and ever changing medium. As is your backup medium.

See you on the FALFiles, - Joe Ax


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