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I just burned a CD-R but I did not use all the data/space in it. I left about 2 minutes of music unused. After burning, I checked the CD-R and found that it was full. When I tried to burn to it, it says:

Please insert a blank CD-R.

What happened to all the data/space on the CD-R that I had not used?

Giacomo1968
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Adam
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  • You keep on using the phrase "data" when what you're talking about is simply empty space. There is no data on empty space. It's just simply empty space. – Giacomo1968 Mar 11 '15 at 18:33

2 Answers2

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When you start recording a CD-R you open a session and when the recording ends, the disc is "closed" meaning no more data can be added to the CD-R. The unused space is unavailable and "invisible" for the player.

Your burner software must have a "multisession" option that let you record a session and keep the unused space available for a new session.

During the late 90s and early 2000s, some record labels sold multisession CDs, one having the audio tracks and other with video and multimedia content.

jcbermu
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  • How about the unused data on the physical CD. Does it tell the CD player that no data is there or does it physically destroy the data? – Adam Mar 11 '15 at 13:39
  • @Adam Based on the physical appearance and time required to close discs on my old writer (like 2002 old) I'd say it actually makes the remainder of the disc non-writable by putting garbage on it. – Logarr Mar 11 '15 at 13:49
  • @Logarr in my experience (with a different writer/software) it keeps the blank mirror sheen – ratchet freak Mar 11 '15 at 13:51
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    Each "session" has a "lead-in" area with a capacity of about 9 MB and inside it there is a Table of Contents (**TOC**) that contains the total length of the recording session, a list of tracks and their starting addresses and some other information. The CD player reads the TOC and knows the size of the used area, ignoring everthing else. Usually the recorder doesn't touch the reminder area keeping it as it came from factory. – jcbermu Mar 11 '15 at 14:04
  • @Logarr I have never heard of an optical disc burner that adds garbage data to unused space. Every optical disc burn I have ever made has left a clear area where data was burned and then the rest of the disc was simply left untouched. The way you can physically see this is to look at the disc before you burn it and it’s all shiny. Then burn data on it and look again; the area “burned” is not as reflective and looks “rougher” while the untouched area is simply shiny. – Giacomo1968 Mar 11 '15 at 18:47
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Yes, you can see the written parts of the disc if you put it under dimmer light. Being that the laser writes from the inner to the outer edge, you will see that a written disc of say,680megs of data will then change visually as a slightly darker color of the disc. ( green,red,blue cd-r's exists) That outer "non written" sliver will be seen with your eye if you rotate the disc just so. The next question is: With all of those half written discs that you've done over the years,... would there exist at this point, a program that could just make a non iso standard disc that re-uses all of those discs by writing another table of contents and additional data to the empty part... the part that could still take a burning laser. Just saying... ( per the environmental guy in me)

mas
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