
a) In /etc/lilo.conf, insert:

	append " ramdisk_size=16384"

   for the default kernel.  This will cause the kernel to allocate a
   max of 16M per ramdisk in use.  Could also do this via insmod param

   In /etc/fstab, append:

   /dev/ram /mnt/xdphys_disk ext2 rw,user,noauto,sync 0 0 
   /dev/ram2 /mnt/xdphys_disk ext2 rw,user,noauto,sync 0 0 

   Note that /dev/ram is a link to /dev/ram1

   so that any user can mount/umount the ramdisk, and we don't have to
   make anything suid root. We do three so that we can have a choice
   about which to use, in case

   Also do:

   chmod a+rwx /dev/ram /dev/ram1 /dev/ram2

   So that the user can do whatever he wants to it.

   You must also add the following sudo priviledges for every user who
   wants to use this:

	Cmd_Alias UMOUNT_RAM = "/bin/umount /mnt/xdphys_disk"

	<user> ALL=NOPASSWD: UMOUNT_RAM

	... this so they can unmount other user's ram disks.

b) If RAM disk use is desired, user must set "use_ramdisk" to 1 in Parms,
   and restart xdphys, xdphys will perhaps tell them that they might need
   to do so when they change that setting (callback?).

c) Then, at start, xdphys calls an external script (perl, suid root?) to

	1) determine whether the RAM disk is currently mounted or unmounted
	   (use a known name for this)
    2) if it is mounted, remove any files that are there (maybe ask first).
    3) If it is not mounted, then zero it out, make a file system, and
	   mount it, making the mount point if necessary (perl snippet):

		# First grep ~/.xdphysrc/config.xdphys for ramdisk size
		# G
		mke2fs -vm0 /dev/ram 
		# grep output of mke2fs for filesystem size, and print it
		mount /dev/ram

d) The mount point will be a known, fairly unique mountpoint,
   e.g. /mnt/xdphys_disk; possibly allow another svar, "ramdisk_device" 
   (defaulting to /dev/ram), in case something else takes 
   our preferred ramdisk device.

e) xdphys svars:

	use_ramdisk:         boolean, default to '1'
         needs callback to indicate this will take effect the next time
		 xdphys is started.
	Also include?
	ramdisk_size:        string, default to '/dev/ram'
         needs callback to indicate this will take effect the next time
		 xdphys is started. A

		This one is tough: if the user wants to increase the RAM disk size
		beyond what is specified in /etc/lilo.conf ... I guess he shouldn't
		be able to.  It should give a message indicating what should be done
		to lilo.conf
		
f) xdphys should perhaps always write to the same filename when writing
   to the RAM disk, for simplicity.  Then move it to the real file, later.
