[Fwd: Re: Secure logging - explained]

From: Robert Rapplean <robert_at_rapplean_dot_net>
Date: Thu Nov 11 2004 - 10:07:31 CST

Now that Fred mentions the archival quality and reliability of CD media,

I have to agree. Your typical CD has a shelf life of five to ten years,
and this drops to about six months to two years if you put any kind of
adhesive label on them.

Also, in the experience of myself and my friends, the typical CD has
roughly a 20-50% failure to burn rate. I'm very much in the habit of
throwing away every other CD because they don't burn correctly. This is
partially because of borderline shoddy CD production, and partially
because of the inherent inaccuracy of the typical mass-market $50 CD
burner. The price you quote for DVD burners is for the low-end,
low-quality DVD burner. I haven't purchased an extensive collection of
DVD burners, but if they're anything like CD burners then the low end
will not be a reliable solution. I had to spend four to five times the
base CD burner price in order to purchase a CD burner which didn't waste
every other CD I tried to burn, or need to be replaced after about a
year of occasional use.

In order to get production quality (and reliably auditable) CD burning,
you would have to spend something like $150 per burner, and purchase
archive quality CD's at roughly $1.60/pop, and even then you'd run into
the issue of a temperature sensitive process. Any CD burner that is
sitting near a door that opens a lot on a cold day WILL fail its burn.

All things said and done, I think that we should more seriously consider
good old fashioned ink-on-continuous-tape, maybe with a running vertical
barcode if we can manage it. A machine readable paper tape would
significantly reduce wear and tear from human handling.


Fred McLain wrote:

>Hi Jim,
>I'd strongly call into question your belief that CDR would be more
>reliable then a register tape. I believe that some (most?) bank
>machines also uses these sorts of tapes for their audit logs. Thermal
>printers should not be used because they are susceptible to erasure
>though heat but ink based printer output can last for decades and even
>longer with the right type of paper.
>CDs have recently been shown to have a far shorter shelf life then
>originally imagined due to oxidation of the underling aluminum foil.
>They start pitting after time and can be quickly made entirely
>unreadable. A small scratch on the top side of a CD (where the foil is)
>will kill the entire CD whereas a mark on a strip of paper only obscures
>what is under the mark. Recordable multi session CDs are usually only
>"reliable" on the drive that recorded them, another issue. Also think
>about the number of recordable CDs that turn out to be "spoiled" -
>hardly the medium for a real time log.
> -Fred-

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Received on Tue Nov 30 23:17:27 2004

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