Installation:

Copy pseudo.h into the kernel 'include/sys' directory as well as the system
/usr/include/sys directory.
Put pseudo.c into the kernel 'kernel/blk_drv' directory.
Apply the kernel.diff patch in your kernel directory.

Recompile kernel and reboot.

mknod /dev/psm0 b 12 0
mknod /dev/pss0 b 11 0

Type make to make the ramdisk and file device drivers.
type 
ram /dev/pss0 1000 &
mkfs /dev/pss0 1000
mount /dev/pss0 /tmp

Your /tmp directory is now mounted on a userspace ramdisk.
Or copy your root disk into a file and type
file /dev/pss0 [file name] &
mount /dev/pss0 /mnt
ls -al /mnt

You have just mounted a file as /mnt

There can be upto 16 pseudo devices running (minor numbers 0-15).

A simple interface is provided in pseudo_lib.c (take a look at ram.c
to see how its used). If a definite block size is needed filter.c can
provide block size conversions.

As soon as the TCP/IP code is running it would be trivial to make
code to remotely mount a disk.

WARNING:
 This is a test version and the "nice" shutdown code for a device
 doesn't work yet. Changing from one device driver to another on
 the same minor device may do strange things since old pages may
 still be in the disk cache.
 I have also had some lock up trouble when running multiple device
 drivers at the same time,