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fordman

UDF Volume Label truncated at 32 characters in Windows XP

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I wrote a DVD and the UDF volume label was 34 characters in the UDF field (well within the 126 character limit), but I removed two characters in the ISO9660 field to limit it to the max of 32 characters.

 

Well, I can tell that Windows XP is displaying the UDF label as expected since it's the "preferred" file system, because the volume label is in mixed case as I entered it in the UDF field, and it has one of the characters I removed for the ISO9660 field. However, the last two characters do not show, either in Windows explorer or when issuing a DIR of the DVD from a command prompt.

 

I can see in ISOBuster that all 34 characters were written to the volume lable for the UDF file system, so why is windows ignorning anything past 32 characters?

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Probably because it considers it too long to display!

 

OK, perhaps I wasn't specific enough with my question, so here goes: If Windows XP supports the UDF file system, and volume labels up to 126 characters are valid in that file system, why does Windows XP not display the volume label properly?

 

I could swear that I have burned discs in the past that DID show more than 32 characters under windows, whether in windows explorer or from a command prompt. If that is true, then something has changed since then - either ImgBurn or something that affects the UDF file system under windows. I don't believe it's ImgBurn, though I was indeed using an older version back then, because ISOBuster shows all the characters I entered. So, I wonder if there could be something (say an upper or lower filter for the device) that could be "dumbing down" the windows UDF support?

 

However, if I'm wrong in my recollection about it display more than 32 characters before, then I suppose that means that Windows doesn't fully support the UDF file system.

Edited by fordman

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I knew what you meant the first time!

 

I'm just saying that perhaps Microsoft made the decision that 32 characters is more than enough to display for the volume label of a disc - even though a filesystem on the disc may actually support more than that.

 

Filter drivers should only change the low level stuff (i.e. when reading a given sector). If that's the case, all programs would read the UDF volume label as being 32 chars in length.

IsoBuster and DVD Dec can both confirm it's longer than that. Programs that use the normal API calls to get the volume label will all display the one windows does.

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In other words, it ain't gonna matter because Microsoft crippled Windows Explorer to only display 32 characters, regardless. I've made many complaints about this before during my ceaseless dedication to testing Label functions. :D

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