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CD-R shows zero content
#42328 10/26/16 08:43 PM
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(I hope this is in the right place.)

This seems very strange. I'll try to be brief.

Every week we burn a CD with PDFs of our finished pages, which the courier collects and then prints our publication. Every week I get the CD back, I store them in archives (now going back years) in case I need them again.

Today I got out two previously burned CDs to extract the PDFs for a customer who wanted them: easier than PDF-ing the pages again. (with me so far? good)

I put the CD into this Mac. CD loaded. It said zero content. I tried another. Same result. How can that be, when the CD is burned?

Our printer (the company, not the device) also use Macs. Seems to me they load our CD, print from it, put the CD back in the case, return it to me, right? So how can the returned CD have zero content?

What am I missing here? Even if they swipe (copy) the PDFs onto their desktop, the originals would still be on the hard CD? confused

Last edited by cyn; 10/27/16 05:26 AM. Reason: Topic moved from the "Peripherals" forum to the "Audio, Video, Photography" forum.
Re: CD-R shows zero content
Bensheim #42329 10/26/16 09:08 PM
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Media does go bad; how old are the CDs, not that it necessarily makes a difference?

And brand may also make a diffrence.


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Re: CD-R shows zero content
artie505 #42331 10/27/16 12:16 AM
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Artie has already mentioned CDs going bad and the fact that brand can make a difference, and there are several other things that can happen with burned CDs. Basically they are not as reliable as many of us would like to believe. While your experience is not particularly common it is not rare for many reasons.

Commercial CDs and DVDs are not burned they are mechanically stamped creating microscopic pits on the drive surface that are read by the "read" lasers in the drive. Burned CDs/DVDs simulate the microscopic pits using a dye layer on the disc whose color is changed by the "burn" lasers and about 80% of the time the "read" lasers on a different drive will read the dye color changes the same as if they were the pits of a stamped disk. How effective this is depends on...
  • The strength and precise frequency of the "burn" lasers
  • The chemical makeup of dyes in the specific media
  • The reflectivity of the aluminum reflecting layer of the medai. (Air infiltration will over time oxidize the aluminum reflective layer making it less reflecive layer and either making the disc unreadable or causing read errors)
  • the precise frequency of the read lasers
  • Different brands and even different product lines within the same brand may use different dyes and different reflective media which can effect the read and/or write performance in different drives.
  • dust on the lasers and/or the mirrors and/or the sensors in a drive can effect the read/write performance of a given drive.
  • NOTE: in each superdrive there are different read and write lasers for CD-R, CD-RW, D-RAM, DVD-R, DVD+R, DVD-RW, DVD+RW, DVD-R DL, DVD+R DL
  • any one of these lasers can fail while the rest remain good which next to media compatibility issues is probably the most common type of failure and can be difficult to diagnose.
After reading all that it sometimes seems a wonder that optical media drives work as well and as often as they do. At one time, I would have said Superdrive failures were the most common hardware failure on Apple computers, but Apple solved that with their decision to not include Superdrives on new Macs, so now the most common hardware failure is more likely hard disk drives.


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Re: CD-R shows zero content
joemikeb #42332 10/27/16 12:24 AM
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Great post...much new (to me) info...Thanks!


The new Great Equalizer is the SEND button.

In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire
Re: CD-R shows zero content
artie505 #42341 10/27/16 10:49 AM
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MANY thanks for the replies. Further investigations reveal that it's not the media (the disks).

I phoned the printers, who said that always happens at their end - they put our burned disk in and get no contents - they are now in the habit of putting it straight into an external drive (an LG DVD writer/reader) and proceed from there. They also commented that we are not the only customer with whom this happens.

Our of curiosity, I put one of those CDs into the Mac which created the burn, and it COULD read it ok.

However, IMO that doesn't mean that this Mac which I'm typing on, has a malfunctioning CD/DVD drive: only recently I put a music CD in there and successfully pulled off tracks for my iPod.

Hmmmm......

Re: CD-R shows zero content
Bensheim #42342 10/27/16 11:18 AM
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Originally Posted By: Bensheim
MANY thanks for the replies. Further investigations reveal that it's not the media (the disks).

I phoned the printers, who said that always happens at their end - they put our burned disk in and get no contents - they are now in the habit of putting it straight into an external drive (an LG DVD writer/reader) and proceed from there. They also commented that we are not the only customer with whom this happens.


What brand of blank CDs are you using?

There is a BIG difference between different brands of blanks! Every manufacturer uses their own custom, proprietary organic dyes in their blank CDs. I have encountered many brands of blanks, most notably Memorex blanks, that can not be read on standard CD-ROM players, only on some brands of burners. (Memorex blanks are so unreliable, I once had someone offer me a case of them for free and I said no.)


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Re: CD-R shows zero content
Bensheim #42456 11/02/16 12:55 PM
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maybe also you are not closing the session, and when you put it in it's opening a new empty session? (check your desktop for more than one new device to mount when you insert the cd, or check in disk utility)

If the CD had say, 10 sessions on it before it was closed, it would pop up 10 different disks on the desktop when it was inserted.


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