How does Windows report a CD as 7TB of size and explain under the hook for me?

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What method Windows use to detect size of a CD? Does it depends on the data type of that CD (give it Audio CD, SVCD, data, etc...)? I guess yes. What mechanism used there, and how I can make a CD like that? (for study purpose).

I've got a CD for quite a long time and the 1st day I put it into CD drive, it displays 7TB?!.. That day, I just thought maybe there's error or something else and ignore it, but I always curious about how or why it appears that way. Recently I found out that CD and take a check, it's still weird like that.

Some screenshot might be easier for conversation:

Ctrl+A all files and folders, total size ~659 MB Properties window (Alt+enter) CD media volume ~ 7.45TB?! Track details by ImgBurn (I don't really get anything out of it, but if useful info for anyone else... UltraISO report CD directory ~700MB but the same time, displays 961MB in total

  • Ctrl+A all files and folders, total size ~659 MB
  • Properties window (Alt+enter) CD media volume ~ 7.45TB?!
  • Tracks info by ImgBurn (I don't really get anything out of it, but if useful info for anyone else...
  • UltraISO report CD directory ~700MB but the same time, displays 961MB in total

So what's going on in this CD, and why? Please explain as good as you can (and the more detail, the better). Feel free suggest other method to get specified info of that disc or any other application might be useful in the case.

About size of CD volume, I heard there's some kind structure of folder or something similar they can create in other OS, or say about some setup disc has got hardlink or similar things which share between folders so the real data is bigger than the volume size. And when put that disc to PC running Windows OS, it displays the difference between volume size and total size of file+folders but this's not the case, is it? (the volume size appears to be bigger than total data?! and ridiculous big number, it looks like bug or some error related to the way Windows detect volume size??)

Edward

Posted 2014-11-11T16:49:34.650

Reputation: 251

Answers

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Simply because it's using hardlinks. If there are many files with the same content in various directories, they can just be stored in one place and then pointed by different links in those directories.

In the old times it's very common for discs that contain multiple versions of Windows installation in one because those sources typically contain a lot of duplicated files. The windows files properties dialog is counting the size of each link while disk properties only display the total space used on the disc, that's why the difference

phuclv

Posted 2014-11-11T16:49:34.650

Reputation: 14 930

But this's not the case. Did you really read the question? Anyway thanks for answer.

The files/folder properties display size less than volume. And there isn't visible hardlink in the given CD. Can you ensure your answer about this "simply using hardlink"? because it's not simply does. And no hint of hardlink in the CD at all.

And the volume size of those Windows installations only smaller than the total files/folders due to using hardlink, not bigger. – Edward – 2014-11-11T17:46:11.373

e.g Hardlink doesn't make volume CD size grown over its specified limitation, if a 700MB CD is full of 1000000 hardlinks of 600MB, the total files/folders size is 600MB*1000000, but volume size in windows properties still 700MB. Check again with all install volume you got. – Edward – 2014-11-11T17:53:39.193

Asked: 2014-11-11T16:49:34.650

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Active: 2014-11-11T17:41:40.833