build a kernel and initrd to run Debian from RAM

 debirf (DEBian on Initial Ram Filesystem) is a set of tools designed
 to create and prepare a kernel and initial ram filesystem that can
 run a full-blown Debian environment entirely from RAM.
 .
 The kernel and initramfs pair created by debirf can be used for a
 myriad of purposes, from quick-and-easy system repair to diskless
 thin clients. The kernel and initrd can be placed in your system
 boot partition, burnt to read-only media, or supplied by a netboot
 server.
 .
 The debirf tools use a module architecture which allows you to
 customize debirf for any possible purpose by specifying what
 components are included in the generated image.