What role does filsesystem.squashfs play in the Ubuntu boot disk?

Question

linux

If you make a bootable flash drive with custom settings, then the instructions indicate how to work with this file, you can pull out the whole system from it, why it is, how it affects the boot, and maybe someone will explain in a popular language about squashfs, otherwise I’m not used to seeing file systems that need to be unpacked

Answer 1

SquashFS is a FS image packed as much as possible, not only files are compressed in it, but also their allocation table, free space is removed from sparse files, deduplication is used, etc. The image is read-only and cannot be modified without unpacking and repackaging. Since the LiveCD still needs to write something to the disk, this issue is solved with the help of a cascade-mounted file system, which uses a temporary directory in RAM to write.

Answer 2

This is the distribution. Approximately as ISO

Answer 3

This is a compressed image of the system, which runs in LiveCD mode.