A question about finding your optical drive in Linux :)

Hello,
I've searched around quite a bit, but can't find a definitive answer. I'm looking for specifically my DVD-RW drive to burn data discs with, using growisofs (I prefer the commandline ).
In kubuntu, I was able to find the device listed as /dev/scd1, but in ubuntu that didn't work, I had to use /dev/dvdrw. My question is, how do I find, definitively, where my optical drive is, preferably through the commandline?
Thanks.

 

I believe /dev/dvdrw is a symlink automatically created by the installation scripts or perhaps recreated at each boot. It points to the real device.

There should be no difference between Ubuntu and Kubuntu regarding how the devices are named. Ubuntu and Kubuntu differ only as to which default desktop is installed. Device naming operates at a lower level than that.

 

I know, that's the strange part. I tried it, but /dvdrw would not work in kubuntu, likewise, /scd1 would not work in ubuntu.
That's why I asked. Isn't there some terminal command to bring up the true device symlink?

 

This is a bit late, but you might want to look at the man page for udev.

Here's the discriptor:

Code:

NAME
       udev - dynamic device management

DESCRIPTION
       udev provides a dynamic device directory containing only the files for
       actually present devices. It creates or removes device node files in
       the /dev directory, or it renames network interfaces.

       Usually udev runs as udevd(8) and receives uevents directly from the
       kernel if a device is added or removed from the system.

       If udev receives a device event, it matches its configured rules
       against the available device attributes provided in sysfs to identify
       the device. Rules that match may provide additional device information
       or specify a device node name and multiple symlink names and instruct
       udev to run additional programs as part of the device event handling.

 

the easiest way to get the device name is:

Code:

loki@galileo:~$ grep /dev /etc/fstab
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto,exec 0       0
loki@galileo:~$

now you can simply do:

Code:

loki@galileo:~$ ls -l /dev/scd0
brw-rw----+ 1 root cdrom 11, 0 2008-08-04 06:23 /dev/scd0
loki@galileo:~$ 

now take note of the block indicator at the beginning which corresponds to major-block 11 which you can further confirm by tracking down the module with:

Code:

loki@galileo:~$ lsmod | grep cdrom
cdrom                  37408  1 sr_mod
loki@galileo:~$

which you can use for:

Code:

loki@galileo:~$ modprobe -c | grep sr_mod
alias block-major-11-* sr_mod
loki@galileo:~$

which now reaffirms everything back up to /etc/fstab. if you need more information about the drive itself you can use:

Code:

loki@galileo:~$ hdparm -i /dev/sr0

/dev/sr0:

 Model=MAT****A DVD+/-RW UJ-857G               , FwRev=Z111    , SerialNo=
 Config={ Fixed Removeable DTR<=5Mbs DTR>10Mbs nonMagnetic }
 RawCHS=0/0/0, TrkSize=0, SectSize=0, ECCbytes=0
 BuffType=unknown, BuffSize=0kB, MaxMultSect=0
 (maybe): CurCHS=0/0/0, CurSects=0, LBA=yes, LBAsects=0
 IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio1 pio2 pio3 pio4
 DMA modes:  sdma0 sdma1 sdma2 mdma0 mdma1 mdma2
 UDMA modes: udma0 udma1 *udma2
 AdvancedPM=no
 Drive conforms to: Unspecified:  ATA/ATAPI-3,4,5,6,7

 * signifies the current active mode

loki@galileo:~$

 

Thanks szandor! Just what I was looking for!
Just a question if you may know. Why is it then, that in kubuntu /dev/scd1 worked, but in ubuntu, I have to use /dev/dvdrw?