# UDF support

## mathfeel

I wanted to try UDF as a filesystem to share data between Linux and Windows. This gets around the 32GB limit of FAT and NTFS-3g is pretty slow for me.

According to Wikipedia: http://en.wikipedia.org/wiki/Universal_Disk_Format

Linux supports UDF up to version 2.60. (my kernel is Gentoo-sources-3.2.9).

So I formatted a usb flash drive in Windows 7 with this option:

```
format /fs:udf /r:2.50 d:
```

But the file system cannot be mounted under Linux:

```
[174.683223] UDF-fs: error (device sdb): __udf_read_inode: (ino 4294967295) failed !bh

[  174.683235] UDF-fs: warning (device sdb): udf_find_metadata_inode_efe: metadata inode efe not found

[  174.683289] UDF-fs: error (device sdb): __udf_read_inode: (ino 4294967295) failed !bh

[  174.683299] UDF-fs: warning (device sdb): udf_find_metadata_inode_efe: metadata inode efe not found

[  174.683304] UDF-fs: error (device sdb): udf_load_metadata_files: Both metadata and mirror metadata inode efe can not found

[  174.683313] UDF-fs: error (device sdb): udf_load_partdesc: error loading MetaData partition map 1

[  174.689553] UDF-fs: error (device sdb): __udf_read_inode: (ino 4294967295) failed !bh

[  174.689564] UDF-fs: warning (device sdb): udf_find_metadata_inode_efe: metadata inode efe not found

[  174.689602] UDF-fs: error (device sdb): __udf_read_inode: (ino 4294967295) failed !bh

[  174.689610] UDF-fs: warning (device sdb): udf_find_metadata_inode_efe: metadata inode efe not found

[  174.689615] UDF-fs: error (device sdb): udf_load_metadata_files: Both metadata and mirror metadata inode efe can not found

[  174.689622] UDF-fs: error (device sdb): udf_load_partdesc: error loading MetaData partition map 1

[  174.710068] UDF-fs: warning (device sdb): udf_load_vrs: No anchor found

[  174.710078] UDF-fs: Rescanning with blocksize 2048

[  174.734076] UDF-fs: warning (device sdb): udf_load_vrs: No anchor found

[  174.734087] UDF-fs: warning (device sdb): udf_fill_super: No partition found (1)
```

If I remove the /r:2.50 option, letting format default to 2.0.1, then Both Windows and Linux can mount it.

Also, Windows cannot read udf created in Linux using mkudffs no matter what options I try.

So the questions are what's up with the 2.50 support? Is Windows messing up or Linux?

----------

## DaggyStyle

why not use ext3?

see this: http://robertbeal.com/528/mount-ext3-in-windows-7-x64

----------

## Aquous

Or ext4: http://www.ext2fsd.com/

----------

## chithanh

Linux UDF support is has not received much attention in recent time. Is there a reason why you need UDF 2.50 features? Even though reading all versions of UDF should be supported (and if not, report a bug) there is no write support for >UDF 2.01.

Regarding ext2fsd/ext2ifs, I have not found them very reliable.

----------

## Ant P.

If you want reliable UDF, use mkudffs instead of a microsoft tool.

----------

## mathfeel

 *chithanh wrote:*   

> Linux UDF support is has not received much attention in recent time. Is there a reason why you need UDF 2.50 features? Even though reading all versions of UDF should be supported (and if not, report a bug) there is no write support for >UDF 2.01.
> 
> Regarding ext2fsd/ext2ifs, I have not found them very reliable.

 

No reason why 2.50. Just that wiki suggests Linux supports it and it's one of those case of high-version-number-mentality. For >32GB partition, UDF seems like a good choice. I find that writing to NTFS using ntfs-3g is often slow.

 *Ant P. wrote:*   

> If you want reliable UDF, use mkudffs instead of a microsoft tool.

 

I can't get Windows to recognize the fs made with mkudffs, but I can get Linux to recognized the Windows formatted one.

----------

## Jaglover

There is a 32 GiB limit with FAT32?   :Shocked: 

----------

## mathfeel

 *Jaglover wrote:*   

> There is a 32 GiB limit with FAT32?  

 

And a 4GB per file limit. Given certain HD Video files today, that's unacceptable.

----------

## Chiitoo

I do think I have had larger volumes than 32 with FAT32...

In fact, is it not 2TB or TiB or well, around that?

Reference:Comparison of file systems - Limits @ Wikipedia, the free encyclopediaNow that I think of it, I do remember, faintly, such a limit from somewhere.

Aha!  Looking closer at the Wikki, there is a citing:

 *Wikipedia @ Comparison of file systems wrote:*   

> ^ While FAT32 partitions this large work fine once created, some software won't allow creation of FAT32 partitions larger than 32 GB. This includes, notoriously, the Windows XP installation program and the Disk Management console in Windows 2000, XP, 2003 and Vista. Use FDISK from a Windows ME Emergency Boot Disk to avoid. [2]~»

 

Blubb.

----------

