Running bash before the system boots

[Thomas Bushnell BSG <tb@becket.net>]

Tollef Fog Heen <tfheen@err.no> writes:

> * Thomas Bushnell BSG 
> 
> | Now now, "ls" has been working for a long time.  We had bash running
> | before the system could even boot.  
> 
> Amazing.  How do you make bash run on a non-booted system?  It
> certainly sounds zen-ish to me.

The Hurd consists of many servers running on a microkernel. (The
microkernel is not part of the Hurd.)  We booted the microkernel (then
Mach) using the BSD-emulation server from CMU.  We could then run some
Hurd servers, enough for bash to work, without necessarily having
enough servers to bootstrap the whole Hurd.  As I recall, what was
really necessary was a filesystem server, the proc server, and the
exec server.  We didn't need authentication, or solid bootstrapping
support.

Thomas