WARNING: CD_Rs can go bad suddenly

When you can buy CD-R disks for less than $0.50 Canadian, you have to question Quality and Quality control. I have used lots that the manufacturer is not proud enough of to even stamp with any identification. They are made in just about every semi-industrialized nation on earth. Get good , brand name disks and you are relatively safe. The cheap stuff?? You pay your money, and you take your chances. So far I have had no delamination failures and only 1 or 2 infant mortalities.

maybe the software was burned on CD-R(?), if they were avail then.

i mis-spoke about the data location on CD-Rs, it is in a dye layer that is applied to the top of the bottom disc. the metal is applied over it. further reading reveals the dye will last after being burned but has less than 5 years shelf life before being written.

more speculation now, maybe the dye layer is very delicate and the low-end producers are simply forced to do the very least they can to get a working product. thus no overspray, no top lamination, and the label _is_ the foil top surface. --Loren

Don't know if anybody has mentioned it, but there is an article on the web about this problem. I haven't read it yet, but it showed up in a web-based news letter I subscribe to.

What was the nature of the infant mortalities? I've been using the cheap ones and have had exactly one failure.

Ted

I had one I could not record to - period, and one that said it recorded, but was totally unreadable from the get-go. This is when running Nero. With the older burning software under-runs etc made a LOT of coasters.

I just measured and destroyed a few dics. All were between .042 and .047" thick. The cdr and CDRW had single layer polycarbonate with thin foil and "paint" top surface. Real CDs were laminated with the "foil" virtually centered between plastic layers.Virtually impossible to separate the layers. My Sony CDRW are made in Austria. My Verbatim CDRW in Ireland. I also have Verbatim Datalife Plus CDRW made in Singapore and Taiwan HP Sure-Stor CDR were Japanese. Then there are the no-names with no record of who they were made by and where.

Ted started a very interesting thread. i have changed the title and offer a few observations.

the urls offered so far are great reads and reveal a product that is really still under development. in the computer world, "backup data" is an entire industry, and often "beta" products are adopted by 2nd/3rd tier players.

so, what to do? we are stuck with large files now. i want to invite experience and speculation from anyone who has real world stories and has read thru this thread and some of the url's. my cheapies are made in Taiwan and recommend: NO labels, low humidity/heat, soft-point _oil_ based markers.

let me start:

2) cheapie disks have no/little protection for the foil layer and this layer is subject to defects at the perimeters (inner&outer)

4) the metal foil bonding is the real issue for catistrophic/sudden failure and the perimeter seams are the most vunerable (discounting mechanical abuse)

6) when/if marking the disk, avoid marking over the foil perimeters.

this is just a quick effort, and now i am wondering about "sleeves", there are many of these "wallets" sold now that offer more compact storage than the hard shells. the sleeve or wallet material would be the question.

my thanks to Ted and everyone who has contributed here, so far. --Loren

......following left for context..........

By strange coincidence, this is discussed in the most recent issue of the "LangaList" newsletter. Fred Langa has an article about it at

This is a nice summary of CD-R problems and can happen. I've collected a lot of information over the years and came to many of the same conclusions, but to have it in one post is good.

We are stuck with the technology for now, waiting for the next good thing to come along. I would really like to go to DVD, but until my relatives and friends have compatible equipment, I have to hold off. It's the bane of any new product. At what time does it cross the critical mass threshold?

I use two wallets that hold 80 and 88 CDs each. One by Fellows and one by Case Logic. I have noticed some scratching on the CDs but since the CD may have been in either case, I can't say which one or both may have caused it. It's a very light scratch that I don't think would cause a problem. Carrying 160 CDs in even the thin jewel cases is impractical, so I'll stick with the wallets. Space in an RV is at a premium.

In the meantime, my policy of making multiple backups on media from different manufacturers will continue. That's as good as I can do now.

Earle Rich Mont Vernon, NH

And how are recordable DVDs constructed??? Same as CD-R??? If so, no advantage other than you lose more data at a time when they go bad.

With 4.7 G on a single disk, it's more likely you have another recent backup to go to. I can store my whole My Documents folder on a single disk with about 1G to spare. Beats using half a dozen CD-Rs every time.

It might not reach really stellar consumer volumes until the capacity doubles or so, so that commercial DVD movies can be backed up/stolen. Most of the pressed commercial ones are double-layer and are more like

DVDs seem a bit more sensitive to problems than CDR's- and when an expensive Gamecube game goes TU (they use a proprietary mini-DVD format) it hurts. AFAIK, those games can't be backed up, BTW, even on mini-DVD-R because Nintendo used a proprietary format which so far has protected them against the copying going on in PS2 and X-box games.

Best regards, Spehro Pefhany

Sure enough. Perhaps the technology will improve enough to bypass the learning curve we've had to go through with CD-R. We can hope.

Earle Rich Mont Vernon, NH

...>

one advantage of a wallet or just the sleeves: protection while searching for a disk. i have often dropped a disk or case w/disk while looking thru them. you could also label the sleeve. many data backup discs will never be used again, compact protected storage is attractive.

sleeves could be reorganized safely and as easily as cases. this does not address the longer term storage needs, like decades, the plastic sleeve material would be a real concern unless it came from proven materials (photographic industry?). --Loren

On Tue, 04 Nov 2003 13:44:10 GMT, Spehro Pefhany wrote something ......and in reply I say!:

But as I have (just) found out, Win 98 and Me only read the _FIRST_ session on a DVD. Not the last. Not the most recent! BAH!

Sorry. it pissed me off.....

remove ns from my header address to reply via email

!!

I don't bother adding sessions to CDRs or DVDs. BTW, there's another limitation with DVDs on some O/S's- no more than 8 directory levels deep.

Best regards, Spehro Pefhany

...>>

...>>

Spehro touches on something i have been trying to understand, and i believe he adds some context. first, let me say i have worked in the computer industry for some 40yrs, but much of what i do with the newer stuff (especially WinTel offerings) is almost by "feel". i have very recently been recording MP3 voice and ISO9660 data files at home. these are not compatible in some way (as i am sure many know), but my software somehow can "convert" the format, either way, several times.

this is a mystery to me, but since these are CD-R discs, there must be some reserved format areas on the disk that have space for updates. like blanking out a header file and writing a new one just after. so what is my point? well, the "shelf" life of CD-Rs is limited, and if you add to, or change formats at some future date....????, you risk writting on a disk that is no longer viable for writing.

this leads to another question, why do read errors, however bad, make the disk unusable. it must be this "format" area, or call it header data, that can be deleted then re-written into a reserved area, is the critical "failure" point. add this to our receipt for sudden/fatal errors... my first guess is that these areas are close to one of the foil perimiters. just more speculation. --Loren

Hum - DVD are created thusly (via Technology Review (try

DVD's are much the same except DVD-R(+R) and DVD-Ram are different in definition.

DVD read only - once written. Translucent or opaque spot for 1/0 'detent'. label protective layer (thick) reflective layer recording layer reflection (not written) = 0 protective layer (now under the bottom) :-)

DVD-RW - xtal structure - aligned or distorted array for 1/0 'detent'. label protective layer (thinner) reflective layer dielectric layer recording layer dark spot (distorted array = 1) dielectric layer protective layer (now under the bottom) :-)

Martin

Another item is black disks can't be read in normal DVD play or recorders. The wrong absorbent colors... CD's can read them.

Martin

What I mostly know is I have to have both kinds in the office.

Use DVD-R on my computer and DVD+R on my Video burner.

I got the impression that the +R (cheaper of the two) has multi- save area each under menu area.

The -R's I've only dumped a restore dump (takes a long time) to them.

Martin ( come to think - the Video burner takes a movie length of time to burn and then it must be finalized or another movie to add and then finalize.)