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+              README FOR LINUX SONY CDU-535/531 DRIVER
+              ========================================
+
+This is the Sony CDU-535 (and 531) driver version 0.7 for Linux.
+I do not think I have the documentation to add features like DMA support
+so if anyone else wants to pursue it or help me with it, please do.
+(I need to see what was done for the CDU-31A driver -- perhaps I can
+steal some of that code.)
+
+This is a Linux device driver for the Sony CDU-535 CDROM drive.  This is
+one of the older Sony drives with its own interface card (Sony bus).
+The DOS driver for this drive is named SONY_CDU.SYS - when you boot DOS
+your drive should be identified as a SONY CDU-535.  The driver works
+with a CDU-531 also.  One user reported that the driver worked on drives
+OEM'ed by Procomm, drive and interface board were labelled Procomm.
+
+The Linux driver is based on Corey Minyard's sonycd 0.3 driver for
+the CDU-31A.  Ron Jeppesen just changed the commands that were sent
+to the drive to correspond to the CDU-535 commands and registers.
+There were enough changes to let bugs creep in but it seems to be stable.
+Ron was able to tar an entire CDROM (should read all blocks) and built
+ghostview and xfig off Walnut Creek's X11R5/GNU CDROM.  xcdplayer and
+workman work with the driver.  Others have used the driver without
+problems except those dealing with wait loops (fixed in third release).
+Like Minyard's original driver this one uses a polled interface (this
+is also the default setup for the DOS driver).  It has not been tried
+with interrupts or DMA enabled on the board.
+
+REQUIREMENTS
+============
+
+	- Sony CDU-535 drive, preferably without interrupts and DMA 
+	  enabled on the card.
+
+	- Drive must be set up as unit 1.  Only the first unit will be 
+	  recognized
+
+	- You must enter your interface address into 
+          /usr/src/linux/drivers/cdrom/sonycd535.h and build the
+          appropriate kernel or use the "kernel command line" parameter
+                sonycd535=0x320
+          with the correct interface address.
+
+NOTES:
+======
+
+1) The drive MUST be turned on when booting or it will not be recognized!
+   (but see comments on modularized version below)
+
+2) when the cdrom device is opened the eject button is disabled to keep the
+   user from ejecting a mounted disk and replacing it with another.
+   Unfortunately xcdplayer and workman also open the cdrom device so you
+   have to use the eject button in the software.  Keep this in mind if your
+   cdrom player refuses to give up its disk -- exit workman or xcdplayer, or
+   umount the drive if it has been mounted.
+
+THANKS
+======
+
+Many thanks to Ron Jeppesen (ronj.an@site007.saic.com) for getting
+this project off the ground.  He wrote the initial release
+and the first two patches to this driver (0.1, 0.2, and 0.3).
+Thanks also to Eberhard Moenkeberg (emoenke@gwdg.de) for prodding
+me to place this code into the mainstream Linux source tree
+(as of Linux version 1.1.91), as well as some patches to make
+it a better device citizen.  Further thanks to Joel Katz
+<joelkatz@webchat.org> for his MODULE patches (see details below),
+Porfiri Claudio <C.Porfiri@nisms.tei.ericsson.se> for patches
+to make the driver work with the older CDU-510/515 series, and
+Heiko Eissfeldt <heiko@colossus.escape.de> for pointing out that
+the verify_area() checks were ignoring the results of said checks.
+
+(Acknowledgments from Ron Jeppesen in the 0.3 release:)
+Thanks to Corey Minyard who wrote the original CDU-31A driver on which
+this driver is based.  Thanks to Ken Pizzini and Bob Blair who provided 
+patches and feedback on the first release of this driver.
+
+Ken Pizzini
+ken@halcyon.com
+
+------------------------------------------------------------------------------
+(The following is from Joel Katz <joelkatz@webchat.org>.)
+
+	To build a version of sony535.o that can be installed as a module,
+use the following command:
+
+gcc -c -D__KERNEL__ -DMODULE -O2 sonycd535.c -o sonycd535.o
+
+	To install the module, simply type:
+
+insmod sony535.o
+	or
+insmod sony535.o sonycd535=<address>
+
+	And to remove it:
+
+rmmod sony535
+
+	The code checks to see if MODULE is defined and behaves as it used
+to if MODULE is not defined. That means your patched file should behave
+exactly as it used to if compiled into the kernel.
+
+	I have an external drive, and I usually leave it powered off. I used
+to have to reboot if I needed to use the CDROM drive. Now I don't.
+
+	Even if you have an internal drive, why waste the 96K of memory
+(unswappable) that the driver uses if you use your CD-ROM drive infrequently?
+
+	This driver will not install (whether compiled in or loaded as a
+module) if the CDROM drive is not available during its initialization. This
+means that you can have the driver compiled into the kernel and still load
+the module later (assuming the driver doesn't install itself during
+power-on). This only wastes 12K when you boot with the CDROM drive off.
+
+	This is what I usually do; I leave the driver compiled into the
+kernel, but load it as a module if I powered the system up with the drive
+off and then later decided to use the CDROM drive.
+
+	Since the driver only uses a single page to point to the chunks,
+attempting to set the buffer cache to more than 2 Megabytes would be very
+bad; don't do that.