	ident	"@(#)README	1.5	94/05/19 SMI"

DRIVER NAME:
	ramdisk -- pseudo-device to support file system I/O to kernel 
		   memory heap.

ARCHITECTURES:
	x86 and SPARC

DESCRIPTION OF DRIVER:
	This simple sample driver demonstrates DDI/DKI driver principles
	by providing a disk-like interface to a dedicated chunk of system
	memory (i.e., a "RAM disk"). The driver is NOT intended
	to be a shippable product--there are many better ways of using memory!
	This driver works for both SPARC and Intel machines.

CAVEATS AND CONSTRAINTS:
	This driver demonstrates how DDI/DKI interfaces can be used to
	put together a driver; it's not recommended that this driver be
	used for anything other than demonstration purposes.

COMPILING/LOADING:
	Use the Makefile in the ramdisk directory to compile the driver.
	The Makefile determines the architecture (x86 or sparc) of the 
	build machine and sets a preprocessor variable (i386 or sparc)
	accordingly. The object files are placed in an appropriate
	architecture-specific subdirectory of the pio directory.

	To install:

	1. Copy the module (ramdisk) from the appropriate 
	   architecture-specific subdirectory (i386 or sparc) and config file
	   (ramdisk.conf) from the ramdisk directory into /usr/kernel/drv.

	2. Run add_drv(1M).

	Note: you need to run add_drv only the very first time you introduce
	    the driver to the system. Thereafter you can use modunload, and
	    just access the driver to reload it.
	Note: Modload/unload won't call the probe/attach routines. 
	    If you want to repeat the whole thing, run rem_drv(1M) and 
	    then add_drv again.

	To use the ramdisk with the default ramsize below do:

	# mkfs -F ufs -o nsect=8,ntrack=8,free=5 /devices/pseudo/ramdisk@0:c,raw 1024
	# mount -F ufs /devices/pseudo/ramdisk@0:c /mount-point

	By appending entries to the /etc/devlink.tab file, you can
	make several ramdisks appear, all with the same geometry.

REFERENCES:
        SunOS 5.4 Writing Device Drivers
