Drawbridge
The "picoprocess" here seems very similar to Linux's "seccomp" mechanism for restricting the kernel API surface.  Current sandboxing mechanisms on Linux (such as Chrome's various sandboxes) use seccomp to restrict almost all syscalls, and their APIs come from IPC to more privileged processes.<p>Two notable differences:<p>On the one hand, seccomp provides much more flexibility about the subset of kernel API offered to the process, rather than just saying "here's 45 syscalls".<p>On the other hand, Drawbridge claims to run unmodified Windows applications; they may have an efficient mechanism for trapping NT "syscalls" and redirecting them to their "user-mode NT kernel" ntoskrnl.dll.  However, this might just mean that they run unmodified applications making Win32 library calls, and the libraries have been modified, in which case programs making NT kernel syscalls would not run unmodified.<p>I'd really like to see a standard mechanism on Linux, similar to the "personality" mechanism, that augments seccomp with an efficient process for defining a new "syscall" layer.  That would make sandboxing much simpler and more efficient.