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Data preservation on optical media for end-users ONLY


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#1 Wonko the Sane

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Posted 03 February 2013 - 04:14 PM

Let's talk of this here.
Spin-off from:
http://reboot.pro/to...se-of-isostick/
http://reboot.pro/to...stick/?p=166755
 
Particularly starting from this post:
http://reboot.pro/to...stick/?p=166797
 
Where basically ambralivio stated how DVD-RAM discs have longer life than other DVD formats:
 
 

In fact, while I agree with your remark on the maybe for the M-Disc solution, I think that its final usage, if any, is (will be) only limited to large organizations and istitutions. For a simple end-user, I think there are other, more friendly solutions, such as DVD-RAMs, even if they have been surprisingly abandoned in these last years (I have to admit I'm continuing to use them for archiving, until I'm able to find them on the market).
It should be clear that for making this solution to work in a safe way, it need to be complemented with other (more simple) ones.
 
Anyway, this topic is OT, but if Wonko agrees, we could open another specific thread and discuss about it.

 
 
After some back and forth about the availability of real data/research somehow stating the superiority (in terms of expected longevity) , ambralivio kindly supplied:
http://reboot.pro/to...stick/?p=166899
a link to this page (citing it as a reliable source):
http://dvddemystified.com/dvdfaq.html
 
Where you can read:
 
 
 

[3.12] How long do DVDs last?

DVDs are read by a laser, so they never wear out from being played since nothing touches the disc. Pressed discs (the kind that movies come on) will probably last longer than you will, anywhere from 50 to 300 years.

Expected longevity of dye-based DVD-R and DVD+R discs is anywhere from 20 to 250 years, about as long as CD-R discs. Some dye formulations (such as phthalocyanine and azo) are more stable and are expected to last longer, 100 years or more, compared to 20 or 30 years for less stable dyes. The phase-change erasable formats (DVD-RAM, DVD-RW, and DVD+RW) have an expected lifetime of 25 to 100 years.

In actuality DVDs often don't last as long as the above statistically-based longevity figures would lead you to expect. Longevity can be reduced by problems in manufacturing or recording and by poor quality material. Shoddy pressed DVDs may deteriorate within a few years and cheap recordable DVDs may produce errors when recording or may become unreadable after a while. (See 1.24.) In other words, you get what you pay for. If longevity is important, invest in high-quality media.

 
As expected the given ranges are totally unlike senceful, a range (very wide) is something like "2 to 3" or maybe "2 to 4", something like  "20 to 250" or "25 to 100" are not "ranges" they represent "random data" or "wild guesses".
However following the above statement:

  • DVD-R and DVD+R range from 20 to 250 years depending on the formulation of the dye
  • DVD-R and DVD+R with dye made out of phthalocyanine or azo are rated more than 100 years
  • DVD-RAM, DVD-RW, and DVD+RW (UNdistinguished) are rated for 25 to 100 years

 
The kind with the longest expected lifetime is evidently either DVD-R or DVD+R discs with phthalocyanine or azo dye (expected lifetime > 100 years).
There is nothing in the above confirming any kind of "superiority in expected lifetime" for the DVD-RAM format (25<expected lifetime < 100 years).
 
On the basis of the referenced, if you want to preserve data you should write them on DVD-R or DVD+R with phthalocyanine or azo dye.
 
The referenced page links to an interesting article (though possibly a bit dated, being from 2005), titled The Relative Stabilities of Optical Disc Formats:
http://www.uni-muens...loads/iraci.pdf
which unfortunately does not take specifically into consideration DVD-RAM.
 
The CD format (IMHO somehow connected with it's much lower density format) is a clear winner over *any* of the DVD types analyzed.
 
The article has however an interesting paragraph that perfectly reflects my personal opinion on the matter:
 

Current opinions
There are contradictory opinions in the sparse literature and research or from
individuals’ own experience when it comes to the longevity of optical discs. The
disc manufacturers have generated most of the longevity data presented in the lit-
erature. There are few independent studies and yet plenty of anecdotal evidence.
For example, some have claimed that CD-R discs have failed within five years.
On the other hand, some manufacturers claim lifetimes of 100 to 200 years. A
similar situation exists for other optical disc formats. Unfortunately, for those
considering the use of optical discs for archival storage of information, these
broad longevity ranges are not very useful.

 
We simply do not have valid (or valid enough) results/experiments/data. :(
 
From the little we have DVD-RAM seems not in any way a "better choice". :whistling:
 
:cheers:
Wonko

NOTE: THis thread is DUPLICATED from the one posted here:
http://reboot.pro/to...-optical-media/
that for *whatever* reason the "main recipient ambralivio CANNOT post into.


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#2 ambralivio

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Posted 03 February 2013 - 09:21 PM

Particularly starting from this post: http://reboot.pro/to...stick/?p=166797 Where basically ambralivio stated how DVD-RAM discs have longer life than other DVD formats:

 

Actually, things went in a different way.

Shortly, my advice about DVD-RAM was a simple, pragmatic alternative to M-Disc, as proposed by Wonko in the previous post :

 

http://reboot.pro/to...e-3#entry166778

Now, while I make my best in finding some references for DVD-RAMs (again, I've to admit it's really difficult finding articles/documentation on optical media reliability/lifetime), Wonko has only cited the new technology - M_DISC, a recent product from Millenniata.- without supplying any other link/documentation about it.

 

As a side note, just in the FAQ section of the DVD Demistified forum (which is given as a good reference in all the documentation/books/organizations about optical media), it is cited :

 

In 2009, Millenniata introduced M-ARC technology (also marketed by Cranberry as DiamonDisc), a DVD-compatible recordable format using an obsidian-like synthetic recording layer etched by a high-powered laser. The discs are expected to last hundreds of years. They require special, very expensive recorders, but the discs can be read by standard DVD readers. Because of the high recording costs, Cranberry offers an online service for uploading data to be burned

 

in some way, anticipating, the incompatibility of M-DISC with the actual burners.

 

Besides, the main question here is :

 

"What the heck on having an expected 300 years lifetime for M-DISC (supposing it is demonstrated) , when the obsolescence concern of software /hardware is taken into consideration (according to which it is absolutely not guaranteed that the actual software/hardware used for archiving will survive,  so that one can access and read again the archived documentation) ?

 

Another important point is that DVD-RAM really exist and they have had a valid story in the professional field; another thing is if Wonko did not have the opportunity to test and use them (maybe, even knowing them!!!).

 

ambralivio



#3 Wonko the Sane

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Posted 04 February 2013 - 10:26 AM

Wonko as a matter of fact, introduced the Millenniata explicitly specifying how the technology has not been reviewed/tested/whatever by third parties (to the best of his knowledge) and that the claim they made is based on a single experiment that (in Wonko's perverted mind) proves nothing about actual lifetime of the thingy:

http://reboot.pro/to...e-3#entry166778

Using history (and particularly Romans and their capabilities as builders) to provide an example of a suitable (thought time-taking :w00t:) testing method:

http://www.forensicf...553877/#6553877

 

In his simplicity Wonko also provided current prices of the actual drives (which are compatible with "normal" DVD's) the price of the two examples are not particularly high, most probably the referenced article took into consideration early models and it is a bit outdated.

See:

http://reboot.pro/to...e-4#entry166810

A cost between 25 and 80 dollars for the drive and 30 dollars for ten discs cannot be called "very expensive".

 

:cheers:

Wonko



#4 dog

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Posted 04 February 2013 - 02:31 PM

Having lost data on lots of CDRs and some DVDRs, I write nothing important on optical media any more. You need to read them every year or so to make sure they're still readable, and with any substantial quantity of data that's just a pain in the rear. Magnetic media for the win.



#5 Wonko the Sane

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Posted 04 February 2013 - 04:55 PM

Having lost data on lots of CDRs and some DVDRs, I write nothing important on optical media any more. You need to read them every year or so to make sure they're still readable, and with any substantial quantity of data that's just a pain in the rear. Magnetic media for the win.

Consider that when a CD (single item) fails, it fails with 650 Mb or 700 Mb of data, when the same happens to a DVD, it fails with 4.7 Gb or 9.4 Gb.

When (say :whistling:) a Seagate 7200.11 or 7200.12 1.5 Tb disk fails, it fails BIG.

With any "fluid bearing" drive, the risk of "stiction" after a long period of storage is quite high, from the little I know.

 

Personally till now (and obviously tomorrow disaster might happen :ph34r:) I haven't yet lost any meaningful data stored on CDR's (I started using DVD's too recently to have meaningful results yet), most ancient of them being dated 1994.

Though I do use a trick or two to have redundant data - hopefully a tidbit safer that "plain burning".

 

BUt anyway "reversing" on new media periodically is actually the approach currently used for data preservation :thumbsup: AFAIK.

 

:cheers:

Wonko



#6 ambralivio

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Posted 04 February 2013 - 09:52 PM

At first, I have honestly to admit that when Wonko cited, for the first time, the M-DISC solution he demonstrated to have some doubt (maybe).

And this is understandable.

But the point now is that I cannot comprehend how, a guy like Wonko, which usually goes deeply into the details (a talent I greatly appreciate), could propose (maybe) that media type as a a solution, without having a significative evidence about effective reliability, lifetime and convenience (in terms of availability on the market -single-source, no-compatibility with existing drive, cost of the drive).

 

Moreover, I could not see any comment from you on the question of the hardware/software obsoloscence (one of the most important topic in the data preservation topic), a point which was wisely and well commented by mscotgrover in the Forensic Focus thread.

As a side note, and just with reference to the 2 links (pointing to Millenniata site) you indicated in that thread (dated Aug, 2011), I realized that effectively, and strangely enough, they do not work anymore (who knows why ?) - even if I was able anyway to collect the report on the accelerated life cycle comparison, through Web Archive. 

 

Passing now to give a further step-on and a more constructive content to this thread, I'd say that in the data preservation, another important point is the "write quality" in the media, which can greatly affect the life-time.

From this viewpoint, the DVD-RAM has 2 features, not shared by other legacy optical media :

 

- random write (not sequential, like all the other optical media)

- write errors check, through the verification done in the hardware by the drive itself, so post-write verification by software is unnecessary

 

@ dog,

 

burning an optical media is a matter of the reliable triplet : media + burner + software.

And this complexity makes difficult a good comparison among optical media.

 

Anyway, I believe that Wonko is right with his comments on the media capacity (and related risks), but I'd appreciate how he is facing with redundant data, or said with a re-word, the tricks/strategy he is using.

Another important point to discuss in this thread, I guess.

 

ambralivio



#7 Wonko the Sane

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Posted 05 February 2013 - 09:24 AM

Well, the error check might be a point, but it is just - as I see it - a commodity, and in any case not a substitute of a "full verify" on the finalized disc.

The "random writes" are not a feature, on the contrary it is a "potential issue".

Sequential (or contiguous) data has always better chances of recovery if needed, on *any* media.

 

About the tricks "hinted", tools like DVDisaster (free/Open Source):

http://dvdisaster.net/en/index.html

or Accuburn (Commercial):

http://www.infinadyn...accuburn-r.html

are the only ones I trust when writing optical media aimed at storage.

 

And yes :thumbsup:,  the right coupling of hardware (burner) with media (make/model/factory) - which only sometimes is an issue with CD's - is of the uttermost relevance when it comes to DVD's.

 

:cheers:

Wonko



#8 ambralivio

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Posted 05 February 2013 - 11:12 PM

Well, the error check might be a point, but it is just - as I see it - a commodity, and in any case not a substitute of a "full verify" on the finalized disc

 

Naaah !!!!, with DVD-RAMs there is not only an error check but, additionally, a verification, and eventually a correction,  of the written data.
As a side note, the correction is possible only with random writes; in order to correct data in the case of a sequential write, you have to write again all the data stream.
Having said that, and in principle, if the write method permit to check & correct data, there is no need for a "full verify", even if it is convenient anyway, just to be on a safer side.

 

The "random writes" are not a feature, on the contrary it is a "potential issue". Sequential (or contiguous) data has always better chances of recovery if needed, on *any* media.



For a recovery I could agree, but here we are discussing of data preservation/archiving, not about their recovery.

In general, and just to clarify the two points above (error check and random data), we need to go back to the basic (sometime this is usefull)

You know, when you need to move or copy data (as in the case of preservation/archiving), basically you have to transmit them.


And you also know that every safe transmission system is based on the usage of some error check/verification and, possibly, a re-transmission if something fails; and, from this viewpoint, you should know that in most situations (I'd say always), the most effective way to make the error check is through a sequence/pattern of seek/write cycles.
Now this operational mode is possible (or, better said, more effective) by using a random write (which DVD-RAMs do permit, natively) rather than with a sequential writing (which is the mode used for all the other common optical media (CDs, DVDs, DVD±RWs).

Besides, for these last media, the only way to check data is only after having burned the media (wasting time and money).

About your proposed "tricks", what about the use of the tool DVDsig from Dariusz Stanislawek ?

http://members.ozema...eezip/freeware/

In some way, it could be used not only to validate data but also to ckeck for the data integrity preservation on the media ( wearing).

 

Personally, this is the tool I prefer, also due to its small size, which permits to be included, along its signature list, in the media.

A last point is about your storage strategy in terms of differentiating and spreading the archived data.

ambralivio



#9 Wonko the Sane

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Posted 06 February 2013 - 10:24 AM

Look, something that can be more easily recovered in case of need is inherently safer that something that is more difficult to.

 

The issues with optical media (unlike - generally speaking - the ones on hard disks that may fail "integrally") are more often than not about PARTIAL data loss.

 

Out of a number of files on a CD or DVD, even if the media is somehow compromised the failed readings tend to be only on some files (or if you prefer "sectors" or "areas") and more rarely to the whole media.

 

So, having an easier to recover format on disc or downright, as suggested, a redundant format does make the difference.

 

Verifying the media once written is - though wasting some time as you put it - a vital step of a data storing strategy, and, as a matter of fact, the media should be read/verified on ANOTHER device (NOT on the one that "burned" it) as this normally prevents the case of possible head misalignments of the drive.

 

Hashing the files (through the mentioned tools or with other ones) is "good practice", but for all it matters you can use FC as well.

The idea of hashing a file is connected (as you would say) to transmission of data.

You transmit the data and it's hash, the receiver re-calculates the hash and if it is the same (set apart the rare cases of collisions) the data arrived OK.

But when you "burn" something you are actually copying the data on another media, you have the original, you can directly compare the original to what was written. 

 

:cheers:

Wonko



#10 ambralivio

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Posted 06 February 2013 - 06:42 PM

something that can be more easily recovered in case of need is inherently safer that something that is more difficult to.

 

No doubt at all on the (relative) importance of recoverability.

But when you need for an overall evaluation of a process/technology/whatever, you must assign a weight (importance) to all the identified requirements and the inherent PROs & CONs.

Going to our specific topic of data preservation, the "recoverability" has a lower rank and it is at the bottom of the requirements list.

 

Verifying the media once written is - though wasting some time as you put it - a vital step of a data storing strategy, and, as a matter of fact, the media should be read/verified on ANOTHER device (NOT on the one that "burned" it) as this normally prevents the case of possible head misalignments of the drive.

 

Maybe this is not clear to you, yet.

I repeat, DVD-RAM technology was developed in order to have an operational "sectorized write verification" algorithm, per design.

So, in principle the "final verification" of what has been written (and already verified as having no errors) should be "almost" useless.

Nevertheless, and here I agree with you, a "final verification" by using another hardware (burner) is advisable, just to check or prevent for a potential drive head misalignments.

 

Hashing the files (through the mentioned tools or with other ones) is "good practice", but for all it matters you can use FC as well.

 

OK, but with a signature list (saved with the archived data) you do not need to have handy the "original ones", for making the FC (which, I'm supposing, you meant "File Compare").

 

:cheers:

ambralivio



#11 dog

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Posted 06 February 2013 - 08:53 PM

I reckon if you're worried about recovery then you don't have enough copies.

I probably did use to use cheap CDR media, but then I still use cheap HDs now.

The cheaper they are, the more point-in-time copies you can afford to keep, and the further you can scatter them around geographically.

 

If for some reason I had to use optical media, I'd try reduce the risks by making duplicate copies using different burners and different batches / brands of media. But for archiving, people usually go for tape.



#12 Wonko the Sane

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Posted 06 February 2013 - 09:14 PM

Maybe this is not clear to you, yet.

I repeat, DVD-RAM technology was developed in order to have an operational "sectorized write verification" algorithm, per design.

So, in principle the "final verification" of what has been written (and already verified as having no errors) should be "almost" useless.

Nevertheless, and here I agree with you, a "final verification" by using another hardware (burner) is advisable, just to check or prevent for a potential drive head misalignments.

It is crystal clear to me, rest assured, let's say that I weight that feature VERY differently from what you do.

 

It is "fine and dandy" until you take into account possible degradation of the media, BUT as it seems from the resources YOU provided DVD-RAM has a forecasted SHORTER lifespan, so this must be "weighted" carefully.

 

There are already (in all kind of optical media) "sectorized checks", why do you think that you have 2048 bytes sectors outs of the 2352 bytes a sector is actually made of? :unsure:

 

About hashing, as said it is "good practice", but not really *needed* at the time of verification just after burn (where a file compare - yes I meant FC.EXE as the more elementary form of file compare utility - is possible) and not really-really useful when re-accessing the data, the error control "implied" in optical media (the mentioned 2352/2048) and - in case of using one of the recommended  tool the redundant data they save are enough.

 

To be more clear, you save to a CD (say) 100 files.

After several years you try to access these files and you have a single sector error.

It is clear that that sector that gives an error is belonging to a given file.

If you hash the 100 files you got, and compare the hashes with the original ones, you can find that the error belongs (say) to file #37.

BUT in 99.99% if  a sector has a defect and the (implied) error correction data cannot correct it, you will have an error during the read (which will tell you which file has the error).

And still, you won't be able to recover that data.

 

In any case this approach with hashing is similar (if not exactly comparable) to "quality scans", whilst the idea is to use "read error tests" INSTEAD:

http://dvdisaster.net/en/index30.html

 

@dog

There is a whole range of issues with tapes, personally (and in my limited experience) I find them a nightmare :ph34r: when you actually need some data (but yes they are cheap, handy to use and widely used)

 

:cheers:

Wonko



#13 ambralivio

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Posted 06 February 2013 - 09:43 PM

The cheaper they are, the more point-in-time copies you can afford to keep, and the further you can scatter them around geographically.

 

This is a good point but it is clear that it can hide some ambiguity or even a false conclusion.

Infact, low price generally is associated to a low quality. So, it's true that a low price allows you for more copies, but each of them is affected by low quality, which will be reflected necessarily on a deeper maintenance....and  great annoyance !!!!!

 

But for archiving, people usually go for tape.

 

Surely, if the related drives could cost less.

I guess that today almost all the burners (a hardware commonly present on whatever desktop PC or that you can buy for 20-30 bucks today) are capable to manage DVD-RAMs - which, unfortunately, and as I said, are going to become rare !!!! but here it comes another their nice features, that is their ability to be re-used and re-written for many times/cycles (100,000 writes, against the only 1000 for DVDs, on average).

 

ambralivio



#14 Wonko the Sane

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Posted 06 February 2013 - 10:02 PM

but here it comes another their nice features, that is their ability to be re-used and re-written for many times/cycles (100,000 writes, against the only 1000 for DVDs, on average).

Which, again, is perfectly IRRELEVANT for data storage/preservation :frusty::, WORM technology is PERFECT for this. 

A blackboard (and chalk) have features that are VERY useful in (say) a classroom.

A message carved in stone appears as a much less suited for classroom use :whistling:, but much better to preserve data.

 

Or maybe only the Rosetta Stone was found ;).

 

:cheers:

Wonko



#15 ambralivio

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Posted 07 February 2013 - 11:37 PM

It is crystal clear to me, rest assured, let's say that I weight that feature VERY differently from what you do.

 

I see you continue on taking all the features separately, one-by-one, without considering the possible correlations among them and, it seems, never being successful to have an overall evaluation.

 

Let's start, then.

 

It is "fine and dandy" until you take into account possible degradation of the media, BUT as it seems from the resources YOU provided DVD-RAM has a forecasted SHORTER lifespan, so this must be "weighted" carefully.

 

As I said several time, but it seems in vane   :frusty:   :pressure:    , the importance of lifespan is significative but also limited, because the "obsolescence" constraint MUST BE TAKEN INTO CONSIDERATION.

 

Besides,

 

There are already (in all kind of optical media) "sectorized checks", why do you think that you have 2048 bytes sectors outs of the 2352 bytes a sector is actually made of?

 

I think it's time for you to read up and gain more knowledge on DVD-RAMs   :coffee: .

 

The DVD-RAM technology boasts :

 

  • 1 - a more sophisticated  ECC error correction scheme (with respect to all the other optical media)

  • 2 - a much more robust media defect sector management (DSM)

  • 3 - an improved use of the physical block addressing scheme

 

all of these, and PER DESIGN, being dependent by the inherent ability/feature to write/record also on the "lands", rather than only on "grooves".

 

And finally, your remark :

 

Which, again, is perfectly IRRELEVANT for data storage/preservation :frusty::, 

 

was completely out of place    :realmad:  :ranting2: , since my statement :

 

but here it comes another their nice features, that is their ability to be re-used and re-written for many times/cycles (100,000 writes, against the only 1000 for DVDs, on average).

 

should have been read/interpreted in the right context   :innocent:  of my remarks to dog's post, that is, considering the economical aspects (the reutilization of the rare-to-find DVD-RAM media) and without any reference to tha data preservation.

 

 

:cheers:

 

ambralivio



#16 Wonko the Sane

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Posted 08 February 2013 - 10:18 AM

Really, I am not following you. :dubbio:

 

We must have a completely different way to understand the concept of "data preservation". :w00t:

 

As always we have some examples in history: it was a common practice in the late Middle Age to erase existing manuscripts to re-use the (pricey) parchments to re-write over them "new", "better",  text.

This practice was exactly the contrary of data preservation (and contributed to loose forever a large part of the earlier literary production)

 

On the other hand, if we introduce the obsolescence (of the reading apparata) it makes even less sense to have a re-writable media, by the time you will need to reverse the data on new media (say holographic memory) because the readers won't be available anymore and last working items will become less and less, you won't have any use for re-usable media.

 

For "short term" backup purposes (and particularly "incremental" and "routine" backup) DVD-RAM is a very good choice, exactly for the reasons you mentioned, of course :).

 

:cheers:

Wonko



#17 ambralivio

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Posted 08 February 2013 - 10:27 PM

You know, life is tough, but what a better opportunity to confront each other when different viewpoints/understandings are on the table ?  :cheerleader:    ]

 

but from your last comments I see there is no undestanding at all   :confused1:    .

Never I stated to re-use the same media for storing/archiving other new data, therefore deleting/loosing important and precious data !!!!!

 

The only thing I said is : DVD-RAMs can be re-used a lot of times if necessary - eventually and if the case - without being too much anxious about the difficulty today to find them on the market.

 

As per your comments about the obsolescence, I'm seeing you easily switched from "1" (need for a long lifespan up to 300 years for the M-DISC) to "0" (short term storage),  so that I wonder if you are "digital" or, instead, "analog"   :ph34r:   ?

 

At the end, and considering that we are discussing about data preservation for  an end-user (or, simply, a human being) (this was my advice/assumption till the start of the discussion, and I'd like to be sure we are on the same page for this, at least  !!!!!), and not for large organizations working on the topic, we can consider that a lifespan of 30 years, for a storage media, is what one could look for; eventually, only few additional restore cycles will be necessary for covering  the today average life of humans.

 

Therefore, since this is the lifespan for DVD-RAMs, considering all the other their benefits/advantages, we can finally state that today and for the next 10 years to come,

 

DVD-RAMs, not only are the best media for backup, but today they represent the most convenient and suitable media storage

for the end-user data preservation

 

(Q.E.D.)

 

:cheers:

ambralivio



#18 Wonko the Sane

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Posted 09 February 2013 - 11:37 AM

The only thing I said is : DVD-RAMs can be re-used a lot of times if necessary - eventually and if the case - without being too much anxious about the difficulty today to find them on the market.

You do understand how this makes no sense whatsoever? :dubbio:

You find (today, on the market) 100 DVD-RAM's (and no more).

You use (write to them) as much as you need, let's say you write 50 of them.

You keep the other fifty in a cool, dry place, vertically stored, for future use.

When you need to write another one, you take it out of the 50 stored away (and 49 will remain available).

The very first time you re-use one of the first 50 you are outside the scope of data preservation, as the data that was originally written to that DVD-RAM won't be anymore preserved.

As said, DVD-RAM are a very good choice for backup (and for periodical backup and incremental backup).

In backup you may well overwrite media containing obsolete data and re-use the media.

In data preservation, by definition you never delete anything (your scope is to preserve) so you never have media available for re-use.

 

 

Anyway, I am really happy :) that:

  • you use DVD-RAMs
  • that you find them the best media for backup
  • that you find them the best media for end-user data preservation (please note how you introduced this not-so-trifling specification only lately)

But it is not that after you have babbled about their features (that have been regularly debunked by available data, or logically dismissed as irrelevant) you have actually demonstrated anything by centering a mere declaration in red and bold. 

You are just shouting your unsupported by data opinion.

 

Have fun demonstrating shouting your opinions on something else (and to someone else, I don't particularly like being shouted at). :bye:

 

:cheers:

Wonko



#19 ambralivio

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Posted 09 February 2013 - 07:26 PM

You do understand how this makes no sense whatsoever? :dubbio: You find (today, on the market) 100 DVD-RAM's (and no more). You use (write to them) as much as you need, let's say you write 50 of them. You keep the other fifty in a cool, dry place, vertically stored, for future use. When you need to write another one, you take it out of the 50 stored away (and 49 will remain available). The very first time you re-use one of the first 50 you are outside the scope of data preservation, as the data that was originally written to that DVD-RAM won't be anymore preserved.

 

All these statements above are useless, because you are freely assuming that only one media type is used (in this case the DVD-RAMs ), which is neither the general recommendation in data preservation, nor what I currently use in my archiving strategy.

Rule # 1 in digital preservation - Differentiating the storage media types (also based on different technologies)

Specifically, in my case, DVD-RAMs are only ONE of the media types I use.

 

In data preservation, by definition you never delete anything (your scope is to preserve) so you never have media available for re-use.

 

Can I ask you where you took that definition from ? or this is another of your free assumption ?

Have you never heard about archive refreshment ?

Rule # 2 in digital preservation - Refresh or transfer archive copies to new media at specified times.

 

 

Going forward :

 

that you find them the best media for end-user data preservation (please note how you introduced this not-so-trifling specification only lately)

 

This is not really true !!!

Please, see my old post from the "parent/original" thread : http://reboot.pro/to...e-3#entry166797

 

In fact, while I agree with your remark on the maybe for the M-Disc solution, I think that its final usage, if any, is (will be) only limited to large organizations and istitutions. For a simple end-user, I think there are other, more friendly solutions, such as DVD-RAMs, even if they have been surprisingly abandoned in these last years (I have to admit I'm continuing to use them for archiving, until I'm able to find them on the market).

,

 

which, I'm seeing now, it is also quoted in your initial post of this current thread. http://reboot.pro/to...ia/#entry167067

 

Really, I did thought that focusing on the end-user were a well established main boundary condition !!!!!

 

As per the "centering a mere declaration in red and bold" , please believe me, there was absolutely no intention to shout at you, at all.

 

On the other way, I did not know that centering & bolding text is meant to indicate shouting.

 

 

In conclusion, I do not understand how to interpret your final emoticon :bye: ?

 

Maybe, is it your final closing salutation to the thread ?  In this case, I'd be very regretful for that. :cheers:

 

:cheers:

ambralivio



#20 Wonko the Sane

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Posted 09 February 2013 - 08:11 PM

All these statements above are useless, because you are freely assuming that only one media type is used (in this case the DVD-RAMs ), which is neither the general recommendation in data preservation, nor what I currently use in my archiving strategy.
Rule # 1 in digital preservation - Differentiating the storage media types (also based on different technologies)
Specifically, in my case, DVD-RAMs are only ONE of the media types I use.

Good :), which is your "second choice"?
 

 
Can I ask you where you took that definition from ? or this is another of your free assumption ?
Have you never heard about archive refreshment ?
Rule # 2 in digital preservation - Refresh or transfer archive copies to new media at specified times.

 I took the definition from the Encyclopedia, you must have a different edition, that also contains the Rules you just posted (that you failed to read attentively, BTW):

 
Rule # 2 in digital preservation - Refresh or transfer archive copies to new media at specified times.

Rule #2 (in your own words) doesn't say to refresh or transfer archive-copies on re-writable, already written, media, making the "advantage" of more re-writes possible on DVD-RAM m00t (limited to this specific use)

 However:
http://www.dpconline...ns-and-concepts
 
 
 

Digital Archiving This term is used very differently within sectors.The library and archiving communities often use it interchangeably with digital preservation. Computing professionals tend to use digital archiving to mean the process of backup and ongoing maintenance as opposed to strategies for long-term digital preservation. It is this latter richer definition, as defined under digital preservation which has been used throughout this handbook.

 
 

 Digital Preservation Refers to the series of managed activities necessary to ensure continued access to digital materials for as long as necessary. Digital preservation is defined very broadly for the purposes of this study and refers to all of the actions required to maintain access to digital materials beyond the limits of media failure or technological change.

 
You probably think "digital archiving" while I think "digital preservation".
 

This is not really true !!!
....
Really, I did thought that focusing on the end-user were a well established main boundary condition !!!!!

Good :), then let me change the title of the thread, and forgive me for the misunderstanding :blush:.

If a DVD-RAM has (from the scarce data available and that BTW you yourself provided) an expected lifespan shorter than other solutions it is not a "better" solution in an absolute sense (and no, not even in the restricted field of "simple end-user").
And I really cannot see how "more friendly" it is than using different optical media, expecially since - again something I learned from you - that particular optical media is difficult to find/procure.  :dubbio:
 

As per the "centering a mere declaration in red and bold" , please believe me, there was absolutely no intention to shout at you, at all.
 
On the other way, I did not know that centering & bolding text is meant to indicate shouting.

Yes, bold/colour formatting is used to highlight words or parts of a sentence that you wish to draw other people particular attention to.


USING ALL CAPITALS or using bold and colour formatting - as well as non-left alignment - for whole sentences means plainly:

I AM SHOUTING!
 

I hope that you understand the differences between a mere declaration and a demonstration and how you simply won't make the first into the second by making it bold and red.
 

In conclusion, I do not understand how to interpret your final emoticon :bye: ?
 
Maybe, is it your final closing salutation to the thread ?  In this case, I'd be very regretful for that. :cheers:

I don't see why you should be regretful, you stated your stance, no matter the data against it being the "solution for data preservation for end-users" you not only insist on this, but effectively close the thread with your (only presumed) demonstration.

There is nothing else to say on this topic, you demonstrated your theory by stating it in red bold letters, that's all, no reply is possible to that.

 

tumblr_ll0qc6YBLl1qc7stfo1_400.jpg


:cheers:
Wonko


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#21 ambralivio

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Posted 09 February 2013 - 10:30 PM

Wonko,

 

I think that most of the misunderstandings in the discussion came out from the common, defective & risky habit (nowadays) not to read carefully and with the necessary accurate way.

 

The following :

 

This is not really true !!! Please, see my old post from the "parent/original" thread : http://reboot.pro/to...e-3#entry166797

 

and this :

 

Good :), then let me change the title of the thread, and forgive me for the misunderstanding :blush:.

 

are just few examples.

 

Can you well understand and recognize how many ambiguities and doubts may arise (and really it happened in our case) due to this (important for me, as stated) point ?

 

Going forward. By saying :

 

If a DVD-RAM has (from the scarce data available and that BTW you yourself provided) an expected lifespan shorter than other solutions it is not a "better" solution in an absolute sense (and no, not even in the restricted field of "simple end-user").

 

again, you are making the same mistake to consider all the features on a one-by-one basis. Globally (that is, taking into account all the important (weighted) features) I stated that DVD-RAM is the best (but not the sole possible solution).

 

As per centering/bolding/colouring text, I think there is nothing to add, since I did not know that. Now I have also this refined taste/knowledge, thanks.  :thumbsup:

 

And finally :

 

I don't see why you should be regretful, you stated your stance, no matter the data against it being the "solution for data preservation for end-users" you not only insist on this, but effectively close the thread with your (only presumed) demonstration. There is nothing else to say on this topic, you demonstrated your theory by stating it in red bold letters, that's all, no reply is possible to that.

 

I am really regretful because I did not think that only by fixing the best (which does not necessarily means the unique to be used)  media should have concluded the thread !!!!!

 

And what about other suitable media, and (more importantly) possible strategies

 

A last point is about your storage strategy in terms of differentiating and spreading the archived data.

 

and tools for checking the data/media integrity/life ?

 

:cheers:

ambralivio



#22 Wonko the Sane

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Posted 10 February 2013 - 11:53 AM

again, you are making the same mistake to consider all the features on a one-by-one basis. Globally (that is, taking into account all the important (weighted) features) I stated that DVD-RAM is the best (but not the sole possible solution).

Not really.

I am making NO mistakes whatever (at least about this) in my perverted mind.

You think I am making a mistake, this is different.

And you use as a truism your personal opinion (not backed up by available data) and your particular "weighting method", as if it was the only possible one.

It is not.

My weighting method is different, which does not mean that it is wrong (and it doesn't mean that it is right, either), it is simply different.

 

By repeating a mere statement over and over (and over) you are not making it become the one and only truth.

 

We are now at this:

ambralivio recommends using primarily (rare to find) DVD-RAM's (which can be re-written many times) and have - assertedly - better error correction when writing as optical media for data preservation and defines this as "most user-friendly" method.

 

Wonko (the Sane) recommends INSTEAD the use of:

  • DVD-R or DVD+R discs with phthalocyanine or azo dye (WORM technology) or - even better - if compatible with amount of data, CD media
  • NEVER RW media, and only write data to new, pristine, write once media
  • a dedicated program to write to the media redundant information AND careful verification of compatibility between media and writer

 

BTW Wonko  does not see how this is in any way less "user-friendly" than the preceding, and in any case, he gives not a d@mn about user-friendliness (real or supposed), as the scope is preserving data, not "being nice to the end-user".

 

End users reading this thread will hopefully do whatever they see fit, possibly in a more informed way than before :).

 

There is nothing to add, see you in 50 years time, to compare results of the two different approaches. :bye:

 

 

:cheers:

Wonko



#23 ambralivio

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Posted 10 February 2013 - 09:27 PM

Well, whar I can say at the end ?

 

Only the members, which will read this thread, can have the due diligence for judging how this thread, started & closed by yourself, has been conducted.

 

The only thing, of which I am very glad, is that you finally changed your opinion, switching from the initial M-Disc (which was a real gamble) to DVD-R or DVD+R discs with phthalocyanine or azo dye, and this is good :good:  ......because you made some progress along the way !!!!!

 

 

:bye: :bye: & see you at the next gamble  :juggler: 

 

ambralivio

 

 

P.S. - However, ambralivio is still available to continue this thread in case someone else feels it is worth and/or interesting.



#24 Wonko the Sane

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Posted 10 February 2013 - 09:54 PM

I never actually promoted in any way the M-Disc I only provided the info about that technology,  EXPRESSLY STATING how I DID NOT believe to the claim about their durability based on a single test, which in my perverted mind makes NO SENSE whatsoever and provides NO MEANINGFUL comparison data.

 

You stated (falsely/lacking evidently either the information or the will to search for it) how the M-DISC was an expensive technology.

 

I posted actual data to debunk your statement, showing how the technology (which I DO NOT ENDORSE IN ANY WAY, DIRECTLY OR INDIRECTLY) is NOT particularly expensive and perfectly comparable to other optical media based data preservation strategies.

 

Since most people won't have the patience to look on the other thread, this is what I posted initially:

 

 

@bblauw
JFYI, CD/DVD's are NOT considered a valid long term storage media, digital preservation is becoming a branch of IT/Science:
http://en.wikipedia....al_preservation
 
BUT (maybe, and I would like to remark the maybe) we have now a solution, meet the M-DISC:
http://www.forensicf...ewtopic/t=8026/
http://www.mdisc.com/

 

 

If from the above and from the CLEAR skepticism coming from the original post on forensicfocus you managed to derive that I had an opinion favouring the M-DISC technology, you have more serious problems in understanding me than I thought. :dubbio:

 

:cheers:

Wonko






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