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HTG Explains: Live File System vs. Mastered Disc Formats in Windows

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When burning a CD or DVD with Windows, you’ll be asked whether you want to use a Live File System or a Mastered disc format. Each has its own advantages and disadvantages.

Windows 7 refers to this as “Like a USB flash drive” or “With a CD/DVD player.” But how exactly can a non-rewritable disc function like a USB flash drive?

Disc-Burning Basics

A standard writable CD or DVD can only be written to once. When you write data to an area of the disc, that data will be present on the disc forever. You can’t erase this data, except by physically destroying the disc itself.

Rewriteable discs work differently, allowing you to “reset” the disc back to its original state and burn to it again.

shiny-disc

Image Credit: John Liu

Mastered Disc Format

The Mastered disc format is the one most people will be familiar with, as it’s been around for much longer. When you use the Mastered disc format, you can only burn to a disc once. This is ideal if you’re filling a disc up with files or burning an ISO image to it.

However, the single-burn restriction applies no matter how many files you’re burning. For example, if you use the Mastered disc format and burn 50 MB of files to a disc, you can’t go back and add more files later. Once a non-rewritable disc is burned with a Mastered format, its state is final. The hundreds of megabytes you could have used are lost – one burn is the limit.

However, the Mastered disc format is more compatible. You can use Mastered discs with versions of Windows earlier than Windows XP and other types of devices, such as DVD players and CD players. These devices don’t usually support Live File System discs.

When using the Mastered disc format with rewritable discs, you’ll have to use an “Erase” operation that wipes the entire disc to delete files. You can’t simply delete individual files from a disc to recover space.

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Live File System

The Live File System works differently. Instead of only burning to the disc once, you can burn to the disc multiple times after formatting it with a Live File System. For example, you can have a disc inserted in your disc drive and add files to it regularly. Each file will be burned to the disc as you add it. With a Mastered disc, files you add enter a sort of staging area – they’re not burned to the disc until you click the burn button.

When you want to use the disc with another computer, you can close the session by ejecting the disc. This writes some data to the disc, so you should close the session as few times as possible.

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You can later open a new session and burn more files to the disc, creating a new session. However, if you’re using a non-rewritable disc, you can still only write to every area of the disc once. For example, if you burn a 50 MB file to the disc, then delete it later and burn another 50 MB file to the disc, the total space used on the disc is still 100 MB. The original 50 MB you burned to the disc is still present, although it’s been marked as deleted and won’t be shown when you use the disc.

If you’re using a rewritable disc with the Live File System, space used by deleted files will be erased immediately and the space will be reclaimed. This is a big advantage for rewritable discs – you can write to them and delete files as if you were writing to a USB flash drive, without having to perform a clunky full-disc erase operation every time you want to erase some files.

However, Live File System isn’t as compatible as the Mastered disc format. It will work on computers running Windows XP and newer versions of Windows, but many other types of devices won’t work with a Live File System disc.


Ultimately, there’s no one right choice – there’s a more compatible option and a more convenient option. The option you choose should depend on how you want to burn files to the disc and what devices you want to use the resulting disc with.

Chris Hoffman is a technology writer and all-around computer geek. He's as at home using the Linux terminal as he is digging into the Windows registry. Connect with him on Google+.

  • Published 10/13/12

Comments (19)

  1. mgo

    Thank you for the Disc-Burning Basics article. Clearly written and helpful. Another keeper for future reference.

  2. Craig Cochrane

    Great article, thanks HTG!

  3. Sam

    Excellent article and very well written. Kind of declutters the minefield of new processes and capabilities of new Tech Products hitting people everyday.

  4. Ushindi

    Thanks very much – I had no idea I could add ANYTHING extra to a non-rewritable disc. I always wondered why my idiot computer would ask me if I wanted to use the disc as a flash drive – I guess maybe it wasn’t my computer that was the idiot. :-)

  5. Doh

    @USHINDI Nope! Hahaha. J/k.

    Seriously, I would like to hear who still uses discs, and if so, for what application. The only reason I still use a burner is for archiving to M-DISC (Write Once and Read Forever™) only to be tucked away at an offsite storage facility.

    Removable USB drives have become the standard. You can install and/or run many OS’s from them. Windows 8 needs the removable bit flipped to make it a fixed disk. I wish either Microsoft pulled their heads out of their arses or the USB drive manufacturers were a little more cooperative in releasing bit flip tools.

  6. Steven

    @Doh

    Discs are still good for back up data and are slightly less harder to lose.

  7. Zinc64

    @Doh

    People still use discs because they still use DVD/BD players.

    Convincing my parents to buy a new Blu-ray player just to get a USB port or network jack is a lot harder than just giving them movies on burned DVDs.

    Plus at about $1 per GB…USB pen drives are pretty pricey.
    External USB drives are another thing altogether.

  8. MMSDave

    Echo Zinc64. Good info. Some of us don’t live in a “Gotta have the Latest Greatest” world, and make do with what we got.I believe the school system here has advanced to Vista.

  9. Bud Vitoff

    @Steven

    I think we have a “double negative” situation here.

    Don’t you mean that discs are harder (or less easy) to lose?

  10. DOH

    @Steven I disagree. Most run of the mill CD/DVD use dye. Hence why I use M-Disc which uses a metal layer instead of dye. You need a special burner for them. Most dye based discs have a storage shelf life of only 1-4 years. Hell, I’ve had backups become non readable after just 6 months with regular discs. I would rather carry 1 thumb drive than 13 DVD cases around with me. I’d be more prone to losing a DVD out of that stack than losing my thumb drive.

    So keeping that in mind, if regular CD/DVD are not to be trusted as archival media, then I ask again. What good are they?

    @Zinc64 OK, you seem to have a legitimate use for them (burning your movies to give to your parents). Most people I know just stream movies to their TV as most of them have network capability now. I on the other hand, use my TV as a second monitor, which works out great.
    Also, I just bought a 64GB thumb drive for 20$.

    @MMSDave Are you kidding? XP and Vista are quite capable of handling USB drives. USB drives have been around since the 90′s. By your logic we should all be driving Edsels!

    So, other than using them to give movies to our technologically handicapped parents, or for long term archival, I still see no need for them anymore.

    Now, Holographic Discs are another story! aka “HVD”

  11. Scott

    I burn CDs with mp3 files that I ripped from a CD audio book. I get 10-12 CDs compressed down to one 700 mb mp3 CD.
    I can get more on my mp3 player, but if I put it on a CD, I can leave it in my home or car stereo and use all the energy sources and controls in those devices.
    I always pick the CD\DVD option, because I have memory of things not working correctly when I picked the USB version, but I could be fuzzy on that. This works for my needs, but I’m glad to know details.
    thanks,

  12. TylerCPU

    “However, the single-burn restriction applies no matter how many files you’re burning. For example, if you use the Mastered disc format and burn 50 MB of files to a disc, you can’t go back and add more files later. Once a non-rewritable disc is burned with a Mastered format, its state is final. The hundreds of megabytes you could have used are lost – one burn is the limit.”

    This is not true. I can add files to the “Mastered CD” later. It works fine. Its not one burn only and can’t write more files.

  13. TylerCPU

    But still a nice write up.

  14. Epale Pues

    I presume the author, while well intentioned, has never heard of cd packet writing. Easy CD Creator, Nero, and many of the old standard cd burning applications supported one proprietary version or another and were often incompatible with future versions of the same software, let alone other company products. In terms of mastering a disc, I presume this includes what is commonly referred to as disc finalization. Because you can master a disc with multiple tracks and not finalize it, though this reduces compatibility with devices, the issue is that many devices will indicate that a disc burned this way is empty when it really has data on it. Have you ever burned a coaster, tried to read it and had the computer indicate that there was no data on the disc? Don’t think it is always empty, there is usually some data that made it successfully onto the disc. Which is why ISOBUSTER is so awesome for recovering data from bad discs. It tries to read a disc every possible way.

    Thank you Apple for dumbing down everyone so that no one bothers to understand why things work the way they do and everyone only expects things to work one way. Now even Microsoft is chasing this strategy in the hopes of retaining their market share. Can you say Windows 8??? Maybe there really is a reason they are giving it away for $15 dollars.

  15. m2k1981

    In use the discs get scratched. And data can’t be read. This goes in favour of pen/thumb drive.

  16. DaveyHo69

    I’ve got several dead thumb drives from 8Gb to 16Gb, presumably died after numerous “eject”, “safely remove” & attempts to “stop” the drive from the taskbar utility. Lots of times all efforts fail, even though there are no open apps using the drive, none visible anyway. Please avoid the obvious retorts, no newbie here…

  17. Z

    I did “treat like a usb flash drive” and drug a 113mb file over. After that I checked properties and it says i used 535 Mb and only have 117MB remaining? I tried 2 brand new cd’s and the same thing happened?I did a re-install of Windows 7 the other day-not sure if that has anything to do with it?

  18. MMSDave

    @DOH Just saying… We use what we have on hand rather than throwing more food dollars at something ’cause it’s shiny. We have a Prius in this county that SITS for 1/2 to 2/3s of the year because it won’t handle the weather. They drive their “EDSEL” most of the time because it gets the job done!

  19. Srinivas

    Thanx chris..gr8 explanation

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