qr-backup

qr-backup is a program to back up digital documents to physical paper. Restore is done with a webcam, video camera, or scanner. Someday smart phone cameras will work.

I’ve been making some progress on qr-backup v1.1. So far I’ve added:

  • --restore, which does a one-step restore for you, instead of needing a bash one-line restore process
  • --encrypt provides password-based encryption
  • An automatic restore check that checks the generated PDF. This is mostly useful for me while maintaining qr-backup, but it also provides peace-of-mind to users.
  • --instructions to give more fine-tuned control over printing instructions. There’s a “plain english” explanation of how qr-backup works that you can attach to the backup.
  • --note for adding an arbitrary message to every sheet
  • Base-64 encoding is now per-QR code, each QR is self-contained.
  • Codes are labeled N01/50 instead of 01/50, to support more code types in the future.
  • Code cleanup of QR generation process.
  • Several bugfixes.

v1.1 will be released when I make qr-backup feature complete:

  • Erasure coding, so you only need 70% of the QRs to do a restore.
  • Improve webcam restore slightly.

v1.2 will focus on adding a GUI and support for Windows, Mac, and Android. Switching off zbar is a requirement to allow multi-platform support, and will likely improve storage density.

USB Flash Longevity Testing – Year 2

Year 0 – I filled 10 32-GB Kingston flash drives with random data.
Year 1 – Tested drive 1, zero bit rot. Re-wrote the drive with the same data.
Year 2 – Re-tested drive 1, zero bit rot. Tested drive 2, zero bit rot. Re-wrote both with the same data.

They have been stored in a box on my shelf, with a 1-month period in a moving van (probably below freezing) this year.

Will report back in 1 more year when I test the third 🙂

FAQs:

  • Q: Why didn’t you test more kinds of drives?
    A: Because I don’t have unlimited energy, time and money :). I encourage you to!
  • Q: You know you powered the drive by reading it, right?
    A: Yes, that’s why I wrote 10 drives to begin with. We want to see how something works if left unpowered for 1 year, 2 years, etc.
  • Q: What drive model is this?
    A: The drive tested was “Kingston Digital DataTraveler SE9 32GB USB 2.0 Flash Drive (DTSE9H/32GBZ)” from Amazon, model DTSE9H/32GBZ, barcode 740617206432, WO# 8463411X001, ID 2364, bl 1933, serial id 206432TWUS008463411X001005. It was not used for anything previously–I bought it just for this test.
  • Q: Which flash type is this model?
    A: We don’t know. If you do know, please tell me.
  • Q: What data are you testing with?
    A: (Repeatable) randomly generated bits
  • Q: What filesystem are you using? / Doesn’t the filesystem do error correction?
    A: I’m writing data directly to the drive using Linux’s block devices.