# No /dev/dvd or /dev/cdrw

## Fred Krogh

I'm guessing it has to do with /etc/udev/rules.d/70-persistent-cd.rules, but that file is missing.  So if that is the problem where to I get it or what do I do to create it?  I do have /dev/cdrom pointing to /dev/sr0, which works, but that is supposed to work as a RW drive as well.  I think I have everything that should be needed in the kernel configuration, and all necessary use flags set.  Creating a symlink to point /dev/dvd to /dev/sr0 does not let me write to the disk. Thanks,

Fred

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## Jaglover

You have to be a member of cdrom group. Then you can write to sr0. Symlinks are not used any more.

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## Fred Krogh

I am a member of the cdrom group and the cdrw group.  The problem may be with the dvd's I've tried.  I'll post later when I have dvd's that I have more reason to think might work.  Thanks,

Fred

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## VoidMage

Those symlinks were created by udev, but it stopped creating them (except for a single /dev/cdrom) a few versions ago.

You could write your own rule, but what do you really need them for ?

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## PaulBredbury

Here's an example rule to add symlinks:

```
ACTION=="add", SUBSYSTEM=="block", ATTRS{model}=="BDDVDRW CT10N", SYMLINK+="cdrom cdrw dvd", MODE="0664", GROUP="cdrom"
```

To get the model info:

```
udevadm info -a --name /dev/sr0
```

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## Fred Krogh

I've tried starting with a unused dvd RW disk.  I've tried dvd+rw-format -force /dev/dvd, and after it gets up to about 29% is starts a counter over and stops with: * formatting 0.4-|.  This looks suspicious to me as nothing else seems to work.

Also tried dvdformat and it gets up to about 22% and then end with:  *Quote:*   

> * 4.7GB DVD+RW media detected.
> 
> * formatting 0.4|-
> 
> mke2fs 1.42.7 (21-Jan-2013)
> ...

 After a "y" *Quote:*   

> Filesystem label=
> 
> OS type: Linux
> 
> Block size=4096 (log=2)
> ...

 It hung there for awhile, and after it finished I tried "mount /mnt/dvd, which gave *Quote:*   

> mount: wrong fs type, bad option, bad superblock on /dev/sr0,
> 
>        missing codepage or helper program, or other error
> 
>        In some cases useful info is found in syslog - try
> ...

 dmesg has errors like *Quote:*   

> [81681.466972] EXT3-fs (sr0): error: can't find ext3 filesystem on dev sr0.
> 
> [81681.481846] EXT2-fs (sr0): error: can't find an ext2 filesystem on dev sr0.
> 
> [81681.497149] EXT4-fs (sr0): VFS: Can't find ext4 filesystem
> ...

 

So does it look like a defective disk, a defective device, or a defective user?  Thanks,

Fred

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