BDXL 100GB disc *actual* capacity

Discussion in 'PC Hardware' started by x86, Jun 16, 2018.

  1. x86

    x86 MDL Addicted

    Jul 8, 2011
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    Can someone (preferably) who owns a Verbatim BDXL 100GB (M-disc) - share with me how much actual data can you fit in that disc?

    I am not talking the advertised "100" gigs, nor a conversion from online conversion tools. I know that manufacturer perceive disk space differently, but what I m looking here is an actual size (e.g. in bytes) of how much usable data can you actually fit in one of those discs. That's total clean, usage size - minus any restrictions imposed/reserved by the disc.

    For example, in a 4.7GB DVD disc, I remember I could fit 4482MB of actual data. But what about that particular Verbatim BDXL disc?
     
  2. Michaela Joy

    Michaela Joy MDL Crazy Lady

    Jul 26, 2012
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    Just going by linear scaling (not 100% accurate, but close enough for gubment' work)

    4.7 - 4.482 = .218

    We're looking at a 25x scale up. (Once again: roughly)

    .218 * 25 = 5.45

    Or roughly 5 1/2 gb.

    Of course that's probably worse case. :)

    I hope this is somewhat helpful.
     
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  3. lewcass

    lewcass MDL Senior Member

    Mar 10, 2018
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    This is apples and oranges but,,,,,

    A 32gb usb key is 29.xxGB once formatted. 3 x 32 = 96. 3 x 29 = 87. allow for the extra 4gb then you are going to get at least 90gb usable. Compared to the usable 4.3gb i get from a single layer dvd. Even a worst case scenario i would accept anything over 80 usable gb. Go for a good name brand and the best disc they offer and dont even worry about it.
     
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  4. GezoeSloog

    GezoeSloog MDL Addicted

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    #4 GezoeSloog, Jun 16, 2018
    Last edited: Jun 16, 2018
    Why do you think that there will be something different but not "standard" 7% loss (10^9/2^30)?

    add: $170 per 1TB :thumbdown:
     
  5. John Sutherland

    John Sutherland MDL Addicted

    Oct 15, 2014
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    The problem stems from hardware manufacturers defining a kilobit as 1000 bits(10^3), whereas any binary based operating system sees a kilobit as 1024 bits(2^10). GezoeSloog has the right answer, but if your calculator (either hand-held or built-in) can't handle 10^9 or 2^30, there is an easier way. Using a 4.7GB DVD as an example:

    4.7 GB * 1000 = 4700MB capacity according to the OEM's.

    4700MB / (1.024 * 1.024) = 4482.27MB capacity according to your OS.

    Applying the same technique to 100GB gives you 95367.74MB true capacity as defined by an OS.
     
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  6. WindowsGeek

    WindowsGeek MDL Senior Member

    Jun 30, 2015
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    For sure u never really get what u pay for if the drive is 100GB once formatted is something like 90 to 92 GIGSo_O in todays storage time 100GB is nothing.
     
  7. x86

    x86 MDL Addicted

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    Indeed, but you may still be looking at this if the only thing of concern is archival longevity. Which is superior compared to any magnetic-based medium.

    That's a bit less than the '7% loss' mentioned earlier. Is that guideline true for all types of media? Just read someone posting a comment on Amazon, according to which they could only managed to fit 91.8GB
    (95367.74MB is 93.1GB)
    That's why I asked if anyone has got their hand on them 100GB discs, so that they can confirm...
     
  8. Joe C

    Joe C MDL Guru

    Jan 12, 2012
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    hard to buy a 100gb M disk because you can buy a 1tb platter drive for less, heck you can even get a 120 ssd for less. I do know about data rot but it's really gotta be something very valuable to cough up that much for those m-disks
     
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  9. John Sutherland

    John Sutherland MDL Addicted

    Oct 15, 2014
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    Hello @x86 - O.K. My claim of 95367.74MB is based on the media being in an unformatted state, or "RAW" in Windows terminology. Once you partition and format a RAW volume as a NTFS volume in order to store data on it, you lose a small percentage of it to NTFS file system overhead. The files $Volume, $MFT, $MFTMirr, $Bitmap, $UsnJrnl, $LogFile, $AttrDef, $Boot, $BadClus, $Secure, $Upcase, and $Extend are all NTFS metadata files that exist on your Windows C:\ system partition, or any other NTFS partition being used by Windows. They are all hidden from the user and for good reason: modifying or deleting certain ones, like $MFT or $MFTMirr, could result in all of the data on the partition becoming unreadable and/or unrecoverable.

    I'm not sure exactly what percentage of the disc's capacity is lost when you format it, but it might explain why the person on Amazon could only fit 91.8GB of data on a 93.1GB disc.
     
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  10. x86

    x86 MDL Addicted

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    I also tried to get a hint from Verbatim themselves - and their response was that "the 100GB M-Disc can store approximately 93GB of data"
    And I m thinking 'approximately'? :confused: If the people who make the actual thing can't provide an actual figure, then who can? Jeez
     
  11. x86

    x86 MDL Addicted

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    Think I found something. I used 7z, which (thankfully) has pre-defined templates for some common media for it's "split to volumes..." option. So I created some for checking the actual size:

    DVD (4.7GB) 4,37 GB (4.697.620.480 bytes)
    DVD-DL (8128MB) 7,93 GB (8.522.825.728 bytes)
    Bluray (25GB) 22,5 GB (24.159.191.040 bytes)

    So my question now is - if the 25GB BD disc is 22,5 GB (24.159.191.040 bytes) is it safe to assume that x4 of that makes the 100GB M-DISC? Probably not - as it turns out to be 90 GB (96.636.764.160 bytes), whilst people report they could fit 91/93GB.
     
  12. GezoeSloog

    GezoeSloog MDL Addicted

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