cloneToSda allows one to clone the core of a live Freeduc system to the local machine's hard disk. All
data on the hard disk will be erased, four partitions will be created on the hard disk
/dev/sda1
The first partition (which weighs some gigabytes) contains a bootable iso-9660 filesystem, so the
core of Freeduc is in read-only mode.
/dev/sda2
The second partition is a hidden NTFS partition, inside the iso-9660 partition, to feature iso-hybrid
boot properties. This partition contains necessary files to boot in EFI mode.
/dev/sda3
A vestigial vfat partition. For pluggable disks, it does make sense to provide a vfat partition,
which can contain files reachable from Windows and Mac machines. When the same system is used on a
hard drive, allocating disk resource to this partition does not make sense.
/dev/sda4
This partition bears a EXT4 filesystem. It is called the "persistence" partition, and some of its
directories are mounted in overlay mode: that means that every changes to the original system are
written there.
If one erases the directory rw/ near the root of this partition, all persistence data are removed.
One important file must be kept in its root directory: "persistence.conf" defines how overlays are
mounted. By default, this file defines one single overlay for all the system.