tl;dr: FTL is a new OS for cloud workloads that implements most OS concepts (processes, VFS, TCP/IP) as a userspace shared library per container, while a minimal kernel provides hypervisor-like isolation using hardware user mode. It's Linux-binary compatible, aiming to combine microkernel flexibility/security with monolithic kernel performance, and lets developers extend kernel-like features without eBPF or kernel programming. Current releases run simple Rust HTTP servers and async Rust apps, with filesystem, Node.js/Go, and SMP/ARM64 support planned through early 2027.