Live data from Hacker News

The Reliability of Optical Disks

blog.ligos.net

21–30 of 116 posts

Re: The Reliability of Optical Disks

#23

I have many degraded CDs and DVDs from 2000-2010. No drive would read them. Most from reputable brands. Most non-RW. All stored in dark places, indoors.

Did you enable the "Try Really Hard" option? Can't remember the name of the software with it. Nero, maybe?

Re: The Reliability of Optical Disks

#25

Aside from the author dismissing tape because "drives are expensive" and then concluding that the primary disadvantage to optical is "the discs are expensive" (wow, big surprise...) and then he doesn't bother to actually calculate the costs of either... ...and not describing how they tested for errors... ...and not having particularly rigorous testing methodology (the DVD was apparently left for three months before h…

> I don't understand how the author possibly could be reading ten year old CD-Rs.

The cyanine dye CD-Rs were the most unreliable but the later phthalocyanine and azo discs are more robust. Mine all readback fine so long as they have been stored well without sunlight exposure.

Re: The Reliability of Optical Disks

#26
post #24

Worth looking into Millennium Disc or M-DISC[0]. Apparently it's media that can last 1000 years. Thinking of buying two 50GB disks and putting some backup files on them when I have a few coins to drop. [0] https://en.wikipedia.org/wiki/M-DISC

The article covers m-disc extensively, not sure why you’re linking Wikipedia here?

Re: The Reliability of Optical Disks

#27
post #24

Worth looking into Millennium Disc or M-DISC[0]. Apparently it's media that can last 1000 years. Thinking of buying two 50GB disks and putting some backup files on them when I have a few coins to drop. [0] https://en.wikipedia.org/wiki/M-DISC

The author explicitly notes that he is testing M-Discs; in fact, for heat, he only tests M-Discs.

Re: The Reliability of Optical Disks

#28

I have many degraded CDs and DVDs from 2000-2010. No drive would read them. Most from reputable brands. Most non-RW. All stored in dark places, indoors.

Did you enable the "Try Really Hard" option? Can't remember the name of the software with it. Nero, maybe?

Many disk imaging programs have similar features. I'm partial to GNU ddrescue.

https://en.wikipedia.org/wiki/Ddrescue

Re: The Reliability of Optical Disks

#29
post #24

Worth looking into Millennium Disc or M-DISC[0]. Apparently it's media that can last 1000 years. Thinking of buying two 50GB disks and putting some backup files on them when I have a few coins to drop. [0] https://en.wikipedia.org/wiki/M-DISC

BD M-disc is the same as a normal BD-R. The DVD M-disc is the only one worth considering for long time archival storage.

Re: The Reliability of Optical Disks

#30
If I am looking at a ~100 years timescale for preservation of documents, there are exactly two choices that I would consider. At the hundreds of years timescale, exactly one.

Those are, in order:

1. Microfilm/microfiche

2. Ink on 100% cotton paper, or ink on vellum

The properties of microfilm have been well studied. It requires no technology other than a magnifying glass to read, has a well over 500 year lifespan in studies, and has exemplars that have survived more than 150 years.

Ink on paper, on the other hand, we have exemplars that are almost 1000 year old, with ink on vellum more than 2000 years old. It requires no tools whatsoever to read, and we have been working and understanding how it is best preserved for hundreds of years.

Post reply on HN