Large discs

[Diane Bruce]

On Fri, Jan 05, 2018 at 09:33:47PM +0000, Bill Gunshannon via cctalk wrote:
> Do they also guarantee there will be a device capable of reading it
> in 1000 years?

It was bad enough with the BBC Domesday project.

Paper. Paper is the only way.
acid free paper.

> 
> bill
> 
> ________________________________
> From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Mazzini Alessandro via cctalk <cctalk at classiccmp.org>
> Sent: Friday, January 5, 2018 4:01 PM
> To: 'Paul Koning'; 'General Discussion: On-Topic and Off-Topic Posts'
> Subject: R: Large discs
> 
> The M kind of dvd supports guarantee over 1000 years of retention, and
> resistance to acid/alien invasion/etc
> 
> -----Messaggio originale-----
> Da: cctalk [mailto:cctalk-bounces at classiccmp.org] Per conto di Paul Koning
> via cctalk
> Inviato: venerdì 5 gennaio 2018 21:45
> A: Warner Losh; General Discussion: On-Topic and Off-Topic Posts
> Oggetto: Re: Large discs
> 
> 
> 
> > On Jan 5, 2018, at 3:24 PM, Warner Losh via cctalk <cctalk at classiccmp.org>
> wrote:
> >
> > On Fri, Jan 5, 2018 at 1:13 PM, Fred Cisin via cctalk
> > <cctalk at classiccmp.org
> >> wrote:
> >
> >> On Fri, 5 Jan 2018, Mazzini Alessandro wrote:
> >>
> >>> I'm  not sure I would use SSD for long term "secure" storage, unless
> >>> maybe using enterprise level ones.
> >>> Consumer level SSD are, by specifics, guaranteed to retain data for
> >>> 6 months
> >>>
> >>
> > The JEDEC spec for Consumer grade SSDs is 1 year unpowered at 30C at
> > end of life.
> > The JEDEC spec for Enterprise grade SSDs is 90 days, unpowered at 30C
> > at end of life.
> 
> That's curious.  Then again, end of life for enterprise SSDs is many
> thousands of write passes over the full disk (or the same amount of writes
> to smaller address ranges thanks to remapping).  Under high but not insane
> loads that takes 5-7 years.  So presumably the retention while fairly new
> (not very worn) is much better.  Still it's surprising to see a number that
> small.
> 
> > As far as I've seen, all SATA and NVME drive vendors adhere to these
> > specs as a minimum, but there's also a new class of drive for 'cold
> storage'
> > which has high retention, but low endurance and longer data read times...
> 
> I don't know if the "cold storage" SSD stuff is going anywhere.  But in any
> case, it seems to aim at high density at the expense of low endurance.  I
> don't remember hearing retention discussed at all, higher or unchanged.
> 
> Having drives with limited retention seems quite problematic.  And
> "unpowered" suggests that leaving the power on would help -- but I don't see
> why that would be so.
> 
> As for writable DVDs and such, do they have any useful retention specs?
> 
>         paul
> 

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