Memory-resident Unix system?

[Doug Gwyn <gwyn>]

> Is there a version of Unix that provides minimal functionality?  We would
> like to hook an existing driver to an existing application program and get
> it to run on a special-purpose board.  Essentially, we would like to use
> just enough Unix-glue so that the driver has the functions it expects, and
> the application sees enough of the "system calls" so that it is happy,
> and eliminate the portion of Unix that would be unneeded.

AT&T UNIXes come with a "stand-alone" system that is used to build
versions of dd, cat, etc. for use under the "stand-alone shell".
The "scc" utility compiles for this environment, using run-time
support from lib2.a.  This looks like it might be close to what you want.