Why bother? I see two possibilities: - Two separate address spaces, one volatile (RAM) and one persistent (SSD). "Writing" to persistent storage is as simple

Why bother? I see two possibilities: - Two separate address spaces, one volatile (RAM) and one persistent (SSD). "Writing" to persistent storage is as simple as "mov [src],[dst]". - One global address space, with a page attribute of "volatile" (true/false). Writing is just as simple as above. At that point the OS and userspace are free to create whatever abstractions are necessary on top. They don't necessarily need to be filesystems or files per se.