"If I execute: mount /dev/sr0 /media/cdrom0"
one problem may be:
overdefined! If fstab is working fine just say
mount /dev/sr0
That's it! Now mount must work.
other problem can be:
EXT4-fs (sr0): unable to read superblock
you probably do NOT have ext4 on the CD! I'm not aware this exists.
This means not to type the type in the CLI is striking back.
Look at the man page to name the type. Most probably a
-t iso9660
will do the job.
Type in the type and it will work on CLI.
For modern SD-cards look out for exfat support. Something like
install exfat-utils
And for DVD-RAM you need UDFtools.
DVD-RAM is very old so there is no new info. Old and underestimated. DVD-RAM on Ubuntu Linux is easy. I use Ubuntu 16.10 with XFCE4 but that does not matter at all.
Why DVD-RAM? Because it is more reliable and more stable archiving data. See Wikipedia for details on DVD-RAM.
However, DVD-RAM is rather an external drive than a DVD to write on. Not all drives can write and read. However, most modern Laptop and Computer optical drives can.
Careful: DVD-RAM is slow by modern means. Don't force the mount and umount to break.
We have to format it as UDF file system. This is the appropriate FS for the DVD-RAM (I do not quote the details here, use duckduckgo.com)
Know your CD-Writer: Mount a CD, with „mount“ watch out for the name. Like /dev/sr0.
Take the DVD-RAM out of the cartridge if necessary, put it in your drive and reboot.
Prepare:
sudo apt-get install udftools
sudo apt-get install dvd+rw-tools
Make a mount point:
sudo mkdir /mnt/dvdram0
and adapt the user rights etc. You need to adapt the rights again for the mounted DVD-RAM (different than vfat floppy or external drive).
Adapt the fstab:
sudo vim /etc/fstab
For automatic mount enter a new line like
/dev/sr0 /mnt/dvdram0 auto user,users,rw,auto,exec,utf8 0 0
The first auto may better be "udf". The second auto depends on you: Try noauto if the boot process hangs.
Format the DVD-RAM:
sudo mkudffs --media-type=dvdram /dev/sr0
The default options for mkudffs probably match your needs. Otherwise: man mkudffs !
Mount the DVD-RAM:
mount /dev/sr0
should do it, otherwise use as sudo mount /dev/sr0. With the fstab entry it will be found.
When you ask your CLI now with mount it should answer something like:
/dev/sr0 on /mnt/dvdram0 type udf (rw,nosuid,nodev,relatime,utf8,user=myname)
Now again adapt the access rights for the mounted(!) drive:
sudo chown myname /mnt/dvdram0
sudo chmod u+rwx /mnt/dvdram0
Test your access rights:
mkdir /mnt/dvdram0/mydirectory
without sudo it should work. Otherwise check the rights.
Do a reboot now or restart all relevant services.
So now we have
installed the tools
prepared to mount
formatted the DVD-RAM
mounted it in the file system
adapted the user access
It shall be available in the file manager like a normal drive. Watch out for /mnt/dvdram0 (and in Nemo create a bookmark).
Unmounting takes time because of write completion. It is done from CLI or try to find a way in your browser.
What did I forget? What was wromng?
Better way to unmount??
Best Answer
RAM drive
If there is enough RAM in your computer, it should be possible to detach the DVD disk, if you add the boot option toram, because it means that the system will write the content of the DVD disk into RAM, and use that image instead of reading files from the disk.
A. When you boot with syslinux you can add boot options like this:
As the CD boots, the user can gain access to the advanced page and its options by pressing any key when the small logo appears at the bottom of your screen.
After selecting language you arrive at the main menu of the installer.
Select 'Try Ubuntu without installing'
Press F6.
A menu with a number of options appears. The option toram is not there, so press Escape to close the list.
Now a string of options is visible, often with 'quiet' or 'quiet splash ---' at the end. Add toram to the string surrounded by spaces before the dashes.
Press return, and booting the live session 'Try Ubuntu' continues ...
See this link for more details, Syslinux boot options
B. When you boot with grub you can add boot options like this:
When a live drive boots to grub, you will see the grub menu (white text on black background). 'Try Ubuntu without installing' is selected, and should be used in this case.
The automatic countdown may be stopped by pressing any key other than the ENTER key.
Press the 'e' key to reveal the selection's settings.
Use the UP/DN/Left/Right cursor keys to navigate to the desired point for editing. Do not use ENTER to move between lines.
Move the cursor to the space before the dashes at the end of the 'linux' line. Add toram to the line surrounded by spaces before the dashes.
When editing is complete, Press CTRL-x or F10 - and booting continues.
See this link for more details, Editing the GRUB 2 Menu During Boot
-o-
Workarounds
Boot from DVD, write to a USB pendrive or memory card.
Boot from USB pendrive or memory card, write to a DVD disk.