lubuntu@lubuntu:~$ apt-cache policy casper casper: Installed: 1.438build1 Candidate: 1.438build1 Version table: *** 1.438build1 500 500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages 100 /var/lib/dpkg/status lubuntu@lubuntu:~$ cat /proc/cmdline BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/lubuntu.seed persistent --- lubuntu@lubuntu:~$ lsblk -fm /dev/sdc3 NAME FSTYPE LABEL UUID FSAVAIL FSUSE% MOUNTPOINT SIZE OWNER GROUP MODE sdc3 ext2 casper-rw c7b15f26-a266-4ec7-9efa-24d191d119be 12.3G 0% /media/lubuntu/casper-rw 13.3G root disk brw-rw---- lubuntu@lubuntu:~$ lsblk -fm /dev/sdc NAME FSTYPE LABEL UUID FSAVAIL FSUSE% MOUNTPOINT SIZE OWNER GROUP MODE sdc iso9660 Lubuntu 20.04 LTS amd64 2020-02-12-17-00-33-00 14.9G root disk brw-rw---- ├─sdc1 iso9660 Lubuntu 20.04 LTS amd64 2020-02-12-17-00-33-00 0 100% /cdrom 1.7G root disk brw-rw---- ├─sdc2 vfat Lubuntu 20.04 LTS amd64 0A8C-3858 3.9M root disk brw-rw---- └─sdc3 ext2 casper-rw c7b15f26-a266-4ec7-9efa-24d191d119be 12.3G 0% /media/lubuntu 13.3G root disk brw-rw---- lubuntu@lubuntu:~$ df -h Filesystem Size Used Avail Use% Mounted on udev 1.9G 0 1.9G 0% /dev tmpfs 382M 1.5M 381M 1% /run /dev/sdc1 1.7G 1.7G 0 100% /cdrom /dev/loop0 1.6G 1.6G 0 100% /rofs /cow 14G 59M 13G 1% / tmpfs 1.9G 0 1.9G 0% /dev/shm tmpfs 5.0M 4.0K 5.0M 1% /run/lock tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup tmpfs 1.9G 0 1.9G 0% /tmp tmpfs 382M 8.0K 382M 1% /run/user/999 /dev/sdd1 15G 1.7G 14G 12% /media/lubuntu/KEEP_ME /dev/sdc3 14G 59M 13G 1% /media/lubuntu/casper-rw lubuntu@lubuntu:~$