When I connected a USB modem to my machine, it complained that /dev/sr1
does not exist. So, after a bit of Googling, I used the following commands to create this device.
ls -l /dev/sr*
brw-rw----+ 1 root cdrom 11, 0 Aug 16 08:05 /dev/sr0
sudo mknod /dev/sr1 b 11 0
sudo chown -v :cdrom /dev/sr1
sudo chmod -v g+w /dev/sr1
ls -l /dev/sr*
brw-rw----+ 1 root cdrom 11, 0 Aug 16 08:05 /dev/sr0
brw-rw-r--+ 1 root cdrom 11, 0 Aug 16 08:10 /dev/sr1
Then my modem worked without any problem. However, after a reboot, I find that the device has vanished, and I have to create the device again.
Please tell me,
- Why such a strange thing like a device vanishing is happening?
- How do I get rid of the situation?
I am using Ubuntu 15.04.
(As I am going to hit the Post button, I notice that creation date-time of /dev/sr0
coincides with the boot time this morning.
Are the devices being created at boot time?
Looks like the answer is, yes, indeed,
ls -l /dev/
total 0
lrwxrwxrwx 1 root root 7 Aug 16 08:14 atttyUSB1 -> ttyUSB1
crw------- 1 root root 10, 235 Aug 16 08:05 autofs
drwxr-xr-x 2 root root 640 Aug 16 08:14 block
drwxr-xr-x 2 root root 120 Aug 16 08:14 bsg
crw------- 1 root root 10, 234 Aug 16 08:05 btrfs-control
drwxr-xr-x 3 root root 60 Aug 16 2015 bus
lrwxrwxrwx 1 root root 3 Aug 16 08:14 cdrom -> sr0
lrwxrwxrwx 1 root root 3 Aug 16 08:14 cdrw -> sr0
drwxr-xr-x 2 root root 4300 Aug 16 08:14 char
crw------- 1 root root 5, 1 Aug 16 08:06 console
lrwxrwxrwx 1 root root 11 Aug 16 2015 core -> /proc/kc
<snipped>
So, if I ask, which list do I update to cause /dev/sr1
created at boot time?, can we move in the right direction?
)