Virtual machine isolation offers strong security boundaries, but traditional hypervisors carry heavy memory and boot overhead. Monolithic kernels, on the other hand, share a massive attack surface across every collocated container.
FTL introduces an alternative architecture by running the operating system as a library in userspace. Instead of delegating system calls to a monolithic kernel, each container hosts its own userspace OS implementing the virtual file system, process scheduling, and network stack. The underlying FTL kernel remains minimal, providing low-level hardware isolation and virtual CPU abstractions similar to a hypervisor.
Crucially, this design preserves complete compatibility with standard Linux binaries. Applications continue issuing regular Linux system calls, but those operations execute inside the container boundary without kernel privilege transitions.
Decoupling the OS implementation from kernel space could redefine multi-tenant container isolation in cloud infrastructure.



