Debian GNU/Linux (Buster) derivatives with a unique partitioning scheme crafted for maximizing the strength against filesystem corruption: the ISO9660 system partition is read-only by design at filesystem-level. The data persistence partition contains only the delta: system updates and your data lay there.
The data partition mounted on top of a read-only system partition makes the resulting operating system resistent to filesystem-corruption. Moreover, you can do complete system backups by just tar-ring only the files contained within that partition.
Both operating systems feature a liveng partioning scheme.