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+   Linux Driver for Mylex DAC960/AcceleRAID/eXtremeRAID PCI RAID Controllers
+
+                        Version 2.2.11 for Linux 2.2.19
+                        Version 2.4.11 for Linux 2.4.12
+
+                              PRODUCTION RELEASE
+
+                                11 October 2001
+
+                               Leonard N. Zubkoff
+                               Dandelion Digital
+                               lnz@dandelion.com
+
+         Copyright 1998-2001 by Leonard N. Zubkoff <lnz@dandelion.com>
+
+
+                                 INTRODUCTION
+
+Mylex, Inc. designs and manufactures a variety of high performance PCI RAID
+controllers.  Mylex Corporation is located at 34551 Ardenwood Blvd., Fremont,
+California 94555, USA and can be reached at 510.796.6100 or on the World Wide
+Web at http://www.mylex.com.  Mylex Technical Support can be reached by
+electronic mail at mylexsup@us.ibm.com, by voice at 510.608.2400, or by FAX at
+510.745.7715.  Contact information for offices in Europe and Japan is available
+on their Web site.
+
+The latest information on Linux support for DAC960 PCI RAID Controllers, as
+well as the most recent release of this driver, will always be available from
+my Linux Home Page at URL "http://www.dandelion.com/Linux/".  The Linux DAC960
+driver supports all current Mylex PCI RAID controllers including the new
+eXtremeRAID 2000/3000 and AcceleRAID 352/170/160 models which have an entirely
+new firmware interface from the older eXtremeRAID 1100, AcceleRAID 150/200/250,
+and DAC960PJ/PG/PU/PD/PL.  See below for a complete controller list as well as
+minimum firmware version requirements.  For simplicity, in most places this
+documentation refers to DAC960 generically rather than explicitly listing all
+the supported models.
+
+Driver bug reports should be sent via electronic mail to "lnz@dandelion.com".
+Please include with the bug report the complete configuration messages reported
+by the driver at startup, along with any subsequent system messages relevant to
+the controller's operation, and a detailed description of your system's
+hardware configuration.  Driver bugs are actually quite rare; if you encounter
+problems with disks being marked offline, for example, please contact Mylex
+Technical Support as the problem is related to the hardware configuration
+rather than the Linux driver.
+
+Please consult the RAID controller documentation for detailed information
+regarding installation and configuration of the controllers.  This document
+primarily provides information specific to the Linux support.
+
+
+                                DRIVER FEATURES
+
+The DAC960 RAID controllers are supported solely as high performance RAID
+controllers, not as interfaces to arbitrary SCSI devices.  The Linux DAC960
+driver operates at the block device level, the same level as the SCSI and IDE
+drivers.  Unlike other RAID controllers currently supported on Linux, the
+DAC960 driver is not dependent on the SCSI subsystem, and hence avoids all the
+complexity and unnecessary code that would be associated with an implementation
+as a SCSI driver.  The DAC960 driver is designed for as high a performance as
+possible with no compromises or extra code for compatibility with lower
+performance devices.  The DAC960 driver includes extensive error logging and
+online configuration management capabilities.  Except for initial configuration
+of the controller and adding new disk drives, most everything can be handled
+from Linux while the system is operational.
+
+The DAC960 driver is architected to support up to 8 controllers per system.
+Each DAC960 parallel SCSI controller can support up to 15 disk drives per
+channel, for a maximum of 60 drives on a four channel controller; the fibre
+channel eXtremeRAID 3000 controller supports up to 125 disk drives per loop for
+a total of 250 drives.  The drives installed on a controller are divided into
+one or more "Drive Groups", and then each Drive Group is subdivided further
+into 1 to 32 "Logical Drives".  Each Logical Drive has a specific RAID Level
+and caching policy associated with it, and it appears to Linux as a single
+block device.  Logical Drives are further subdivided into up to 7 partitions
+through the normal Linux and PC disk partitioning schemes.  Logical Drives are
+also known as "System Drives", and Drive Groups are also called "Packs".  Both
+terms are in use in the Mylex documentation; I have chosen to standardize on
+the more generic "Logical Drive" and "Drive Group".
+
+DAC960 RAID disk devices are named in the style of the obsolete Device File
+System (DEVFS).  The device corresponding to Logical Drive D on Controller C
+is referred to as /dev/rd/cCdD, and the partitions are called /dev/rd/cCdDp1
+through /dev/rd/cCdDp7.  For example, partition 3 of Logical Drive 5 on
+Controller 2 is referred to as /dev/rd/c2d5p3.  Note that unlike with SCSI
+disks the device names will not change in the event of a disk drive failure.
+The DAC960 driver is assigned major numbers 48 - 55 with one major number per
+controller.  The 8 bits of minor number are divided into 5 bits for the Logical
+Drive and 3 bits for the partition.
+
+
+          SUPPORTED DAC960/AcceleRAID/eXtremeRAID PCI RAID CONTROLLERS
+
+The following list comprises the supported DAC960, AcceleRAID, and eXtremeRAID
+PCI RAID Controllers as of the date of this document.  It is recommended that
+anyone purchasing a Mylex PCI RAID Controller not in the following table
+contact the author beforehand to verify that it is or will be supported.
+
+eXtremeRAID 3000
+            1 Wide Ultra-2/LVD SCSI channel
+            2 External Fibre FC-AL channels
+            233MHz StrongARM SA 110 Processor
+            64 Bit 33MHz PCI (backward compatible with 32 Bit PCI slots)
+            32MB/64MB ECC SDRAM Memory
+
+eXtremeRAID 2000
+            4 Wide Ultra-160 LVD SCSI channels
+            233MHz StrongARM SA 110 Processor
+            64 Bit 33MHz PCI (backward compatible with 32 Bit PCI slots)
+            32MB/64MB ECC SDRAM Memory
+
+AcceleRAID 352
+            2 Wide Ultra-160 LVD SCSI channels
+            100MHz Intel i960RN RISC Processor
+            64 Bit 33MHz PCI (backward compatible with 32 Bit PCI slots)
+            32MB/64MB ECC SDRAM Memory
+
+AcceleRAID 170
+            1 Wide Ultra-160 LVD SCSI channel
+            100MHz Intel i960RM RISC Processor
+            16MB/32MB/64MB ECC SDRAM Memory
+
+AcceleRAID 160 (AcceleRAID 170LP)
+            1 Wide Ultra-160 LVD SCSI channel
+            100MHz Intel i960RS RISC Processor
+            Built in 16M ECC SDRAM Memory
+            PCI Low Profile Form Factor - fit for 2U height
+
+eXtremeRAID 1100 (DAC1164P)
+            3 Wide Ultra-2/LVD SCSI channels
+            233MHz StrongARM SA 110 Processor
+            64 Bit 33MHz PCI (backward compatible with 32 Bit PCI slots)
+            16MB/32MB/64MB Parity SDRAM Memory with Battery Backup
+
+AcceleRAID 250 (DAC960PTL1)
+            Uses onboard Symbios SCSI chips on certain motherboards
+            Also includes one onboard Wide Ultra-2/LVD SCSI Channel
+            66MHz Intel i960RD RISC Processor
+            4MB/8MB/16MB/32MB/64MB/128MB ECC EDO Memory
+
+AcceleRAID 200 (DAC960PTL0)
+            Uses onboard Symbios SCSI chips on certain motherboards
+            Includes no onboard SCSI Channels
+            66MHz Intel i960RD RISC Processor
+            4MB/8MB/16MB/32MB/64MB/128MB ECC EDO Memory
+
+AcceleRAID 150 (DAC960PRL)
+            Uses onboard Symbios SCSI chips on certain motherboards
+            Also includes one onboard Wide Ultra-2/LVD SCSI Channel
+            33MHz Intel i960RP RISC Processor
+            4MB Parity EDO Memory
+
+DAC960PJ    1/2/3 Wide Ultra SCSI-3 Channels
+            66MHz Intel i960RD RISC Processor
+            4MB/8MB/16MB/32MB/64MB/128MB ECC EDO Memory
+
+DAC960PG    1/2/3 Wide Ultra SCSI-3 Channels
+            33MHz Intel i960RP RISC Processor
+            4MB/8MB ECC EDO Memory
+
+DAC960PU    1/2/3 Wide Ultra SCSI-3 Channels
+            Intel i960CF RISC Processor
+            4MB/8MB EDRAM or 2MB/4MB/8MB/16MB/32MB DRAM Memory
+
+DAC960PD    1/2/3 Wide Fast SCSI-2 Channels
+            Intel i960CF RISC Processor
+            4MB/8MB EDRAM or 2MB/4MB/8MB/16MB/32MB DRAM Memory
+
+DAC960PL    1/2/3 Wide Fast SCSI-2 Channels
+            Intel i960 RISC Processor
+            2MB/4MB/8MB/16MB/32MB DRAM Memory
+
+DAC960P     1/2/3 Wide Fast SCSI-2 Channels
+            Intel i960 RISC Processor
+            2MB/4MB/8MB/16MB/32MB DRAM Memory
+
+For the eXtremeRAID 2000/3000 and AcceleRAID 352/170/160, firmware version
+6.00-01 or above is required.
+
+For the eXtremeRAID 1100, firmware version 5.06-0-52 or above is required.
+
+For the AcceleRAID 250, 200, and 150, firmware version 4.06-0-57 or above is
+required.
+
+For the DAC960PJ and DAC960PG, firmware version 4.06-0-00 or above is required.
+
+For the DAC960PU, DAC960PD, DAC960PL, and DAC960P, either firmware version
+3.51-0-04 or above is required (for dual Flash ROM controllers), or firmware
+version 2.73-0-00 or above is required (for single Flash ROM controllers)
+
+Please note that not all SCSI disk drives are suitable for use with DAC960
+controllers, and only particular firmware versions of any given model may
+actually function correctly.  Similarly, not all motherboards have a BIOS that
+properly initializes the AcceleRAID 250, AcceleRAID 200, AcceleRAID 150,
+DAC960PJ, and DAC960PG because the Intel i960RD/RP is a multi-function device.
+If in doubt, contact Mylex RAID Technical Support (mylexsup@us.ibm.com) to
+verify compatibility.  Mylex makes available a hard disk compatibility list at
+http://www.mylex.com/support/hdcomp/hd-lists.html.
+
+
+                              DRIVER INSTALLATION
+
+This distribution was prepared for Linux kernel version 2.2.19 or 2.4.12.
+
+To install the DAC960 RAID driver, you may use the following commands,
+replacing "/usr/src" with wherever you keep your Linux kernel source tree:
+
+  cd /usr/src
+  tar -xvzf DAC960-2.2.11.tar.gz (or DAC960-2.4.11.tar.gz)
+  mv README.DAC960 linux/Documentation
+  mv DAC960.[ch] linux/drivers/block
+  patch -p0 < DAC960.patch (if DAC960.patch is included)
+  cd linux
+  make config
+  make bzImage (or zImage)
+
+Then install "arch/i386/boot/bzImage" or "arch/i386/boot/zImage" as your
+standard kernel, run lilo if appropriate, and reboot.
+
+To create the necessary devices in /dev, the "make_rd" script included in
+"DAC960-Utilities.tar.gz" from http://www.dandelion.com/Linux/ may be used.
+LILO 21 and FDISK v2.9 include DAC960 support; also included in this archive
+are patches to LILO 20 and FDISK v2.8 that add DAC960 support, along with
+statically linked executables of LILO and FDISK.  This modified version of LILO
+will allow booting from a DAC960 controller and/or mounting the root file
+system from a DAC960.
+
+Red Hat Linux 6.0 and SuSE Linux 6.1 include support for Mylex PCI RAID
+controllers.  Installing directly onto a DAC960 may be problematic from other
+Linux distributions until their installation utilities are updated.
+
+
+                              INSTALLATION NOTES
+
+Before installing Linux or adding DAC960 logical drives to an existing Linux
+system, the controller must first be configured to provide one or more logical
+drives using the BIOS Configuration Utility or DACCF.  Please note that since
+there are only at most 6 usable partitions on each logical drive, systems
+requiring more partitions should subdivide a drive group into multiple logical
+drives, each of which can have up to 6 usable partitions.  Also, note that with
+large disk arrays it is advisable to enable the 8GB BIOS Geometry (255/63)
+rather than accepting the default 2GB BIOS Geometry (128/32); failing to so do
+will cause the logical drive geometry to have more than 65535 cylinders which
+will make it impossible for FDISK to be used properly.  The 8GB BIOS Geometry
+can be enabled by configuring the DAC960 BIOS, which is accessible via Alt-M
+during the BIOS initialization sequence.
+
+For maximum performance and the most efficient E2FSCK performance, it is
+recommended that EXT2 file systems be built with a 4KB block size and 16 block
+stride to match the DAC960 controller's 64KB default stripe size.  The command
+"mke2fs -b 4096 -R stride=16 <device>" is appropriate.  Unless there will be a
+large number of small files on the file systems, it is also beneficial to add
+the "-i 16384" option to increase the bytes per inode parameter thereby
+reducing the file system metadata.  Finally, on systems that will only be run
+with Linux 2.2 or later kernels it is beneficial to enable sparse superblocks
+with the "-s 1" option.
+
+
+                      DAC960 ANNOUNCEMENTS MAILING LIST
+
+The DAC960 Announcements Mailing List provides a forum for informing Linux
+users of new driver releases and other announcements regarding Linux support
+for DAC960 PCI RAID Controllers.  To join the mailing list, send a message to
+"dac960-announce-request@dandelion.com" with the line "subscribe" in the
+message body.
+
+
+                CONTROLLER CONFIGURATION AND STATUS MONITORING
+
+The DAC960 RAID controllers running firmware 4.06 or above include a Background
+Initialization facility so that system downtime is minimized both for initial
+installation and subsequent configuration of additional storage.  The BIOS
+Configuration Utility (accessible via Alt-R during the BIOS initialization
+sequence) is used to quickly configure the controller, and then the logical
+drives that have been created are available for immediate use even while they
+are still being initialized by the controller.  The primary need for online
+configuration and status monitoring is then to avoid system downtime when disk
+drives fail and must be replaced.  Mylex's online monitoring and configuration
+utilities are being ported to Linux and will become available at some point in
+the future.  Note that with a SAF-TE (SCSI Accessed Fault-Tolerant Enclosure)
+enclosure, the controller is able to rebuild failed drives automatically as
+soon as a drive replacement is made available.
+
+The primary interfaces for controller configuration and status monitoring are
+special files created in the /proc/rd/... hierarchy along with the normal
+system console logging mechanism.  Whenever the system is operating, the DAC960
+driver queries each controller for status information every 10 seconds, and
+checks for additional conditions every 60 seconds.  The initial status of each
+controller is always available for controller N in /proc/rd/cN/initial_status,
+and the current status as of the last status monitoring query is available in
+/proc/rd/cN/current_status.  In addition, status changes are also logged by the
+driver to the system console and will appear in the log files maintained by
+syslog.  The progress of asynchronous rebuild or consistency check operations
+is also available in /proc/rd/cN/current_status, and progress messages are
+logged to the system console at most every 60 seconds.
+
+Starting with the 2.2.3/2.0.3 versions of the driver, the status information
+available in /proc/rd/cN/initial_status and /proc/rd/cN/current_status has been
+augmented to include the vendor, model, revision, and serial number (if
+available) for each physical device found connected to the controller:
+
+***** DAC960 RAID Driver Version 2.2.3 of 19 August 1999 *****
+Copyright 1998-1999 by Leonard N. Zubkoff <lnz@dandelion.com>
+Configuring Mylex DAC960PRL PCI RAID Controller
+  Firmware Version: 4.07-0-07, Channels: 1, Memory Size: 16MB
+  PCI Bus: 1, Device: 4, Function: 1, I/O Address: Unassigned
+  PCI Address: 0xFE300000 mapped at 0xA0800000, IRQ Channel: 21
+  Controller Queue Depth: 128, Maximum Blocks per Command: 128
+  Driver Queue Depth: 127, Maximum Scatter/Gather Segments: 33
+  Stripe Size: 64KB, Segment Size: 8KB, BIOS Geometry: 255/63
+  SAF-TE Enclosure Management Enabled
+  Physical Devices:
+    0:0  Vendor: IBM       Model: DRVS09D           Revision: 0270
+         Serial Number:       68016775HA
+         Disk Status: Online, 17928192 blocks
+    0:1  Vendor: IBM       Model: DRVS09D           Revision: 0270
+         Serial Number:       68004E53HA
+         Disk Status: Online, 17928192 blocks
+    0:2  Vendor: IBM       Model: DRVS09D           Revision: 0270
+         Serial Number:       13013935HA
+         Disk Status: Online, 17928192 blocks
+    0:3  Vendor: IBM       Model: DRVS09D           Revision: 0270
+         Serial Number:       13016897HA
+         Disk Status: Online, 17928192 blocks
+    0:4  Vendor: IBM       Model: DRVS09D           Revision: 0270
+         Serial Number:       68019905HA
+         Disk Status: Online, 17928192 blocks
+    0:5  Vendor: IBM       Model: DRVS09D           Revision: 0270
+         Serial Number:       68012753HA
+         Disk Status: Online, 17928192 blocks
+    0:6  Vendor: ESG-SHV   Model: SCA HSBP M6       Revision: 0.61
+  Logical Drives:
+    /dev/rd/c0d0: RAID-5, Online, 89640960 blocks, Write Thru
+  No Rebuild or Consistency Check in Progress
+
+To simplify the monitoring process for custom software, the special file
+/proc/rd/status returns "OK" when all DAC960 controllers in the system are
+operating normally and no failures have occurred, or "ALERT" if any logical
+drives are offline or critical or any non-standby physical drives are dead.
+
+Configuration commands for controller N are available via the special file
+/proc/rd/cN/user_command.  A human readable command can be written to this
+special file to initiate a configuration operation, and the results of the
+operation can then be read back from the special file in addition to being
+logged to the system console.  The shell command sequence
+
+  echo "<configuration-command>" > /proc/rd/c0/user_command
+  cat /proc/rd/c0/user_command
+
+is typically used to execute configuration commands.  The configuration
+commands are:
+
+  flush-cache
+
+    The "flush-cache" command flushes the controller's cache.  The system
+    automatically flushes the cache at shutdown or if the driver module is
+    unloaded, so this command is only needed to be certain a write back cache
+    is flushed to disk before the system is powered off by a command to a UPS.
+    Note that the flush-cache command also stops an asynchronous rebuild or
+    consistency check, so it should not be used except when the system is being
+    halted.
+
+  kill <channel>:<target-id>
+
+    The "kill" command marks the physical drive <channel>:<target-id> as DEAD.
+    This command is provided primarily for testing, and should not be used
+    during normal system operation.
+
+  make-online <channel>:<target-id>
+
+    The "make-online" command changes the physical drive <channel>:<target-id>
+    from status DEAD to status ONLINE.  In cases where multiple physical drives
+    have been killed simultaneously, this command may be used to bring all but
+    one of them back online, after which a rebuild to the final drive is
+    necessary.
+
+    Warning: make-online should only be used on a dead physical drive that is
+    an active part of a drive group, never on a standby drive.  The command
+    should never be used on a dead drive that is part of a critical logical
+    drive; rebuild should be used if only a single drive is dead.
+
+  make-standby <channel>:<target-id>
+
+    The "make-standby" command changes physical drive <channel>:<target-id>
+    from status DEAD to status STANDBY.  It should only be used in cases where
+    a dead drive was replaced after an automatic rebuild was performed onto a
+    standby drive.  It cannot be used to add a standby drive to the controller
+    configuration if one was not created initially; the BIOS Configuration
+    Utility must be used for that currently.
+
+  rebuild <channel>:<target-id>
+
+    The "rebuild" command initiates an asynchronous rebuild onto physical drive
+    <channel>:<target-id>.  It should only be used when a dead drive has been
+    replaced.
+
+  check-consistency <logical-drive-number>
+
+    The "check-consistency" command initiates an asynchronous consistency check
+    of <logical-drive-number> with automatic restoration.  It can be used
+    whenever it is desired to verify the consistency of the redundancy
+    information.
+
+  cancel-rebuild
+  cancel-consistency-check
+
+    The "cancel-rebuild" and "cancel-consistency-check" commands cancel any
+    rebuild or consistency check operations previously initiated.
+
+
+               EXAMPLE I - DRIVE FAILURE WITHOUT A STANDBY DRIVE
+
+The following annotated logs demonstrate the controller configuration and and
+online status monitoring capabilities of the Linux DAC960 Driver.  The test
+configuration comprises 6 1GB Quantum Atlas I disk drives on two channels of a
+DAC960PJ controller.  The physical drives are configured into a single drive
+group without a standby drive, and the drive group has been configured into two
+logical drives, one RAID-5 and one RAID-6.  Note that these logs are from an
+earlier version of the driver and the messages have changed somewhat with newer
+releases, but the functionality remains similar.  First, here is the current
+status of the RAID configuration:
+
+gwynedd:/u/lnz# cat /proc/rd/c0/current_status
+***** DAC960 RAID Driver Version 2.0.0 of 23 March 1999 *****
+Copyright 1998-1999 by Leonard N. Zubkoff <lnz@dandelion.com>
+Configuring Mylex DAC960PJ PCI RAID Controller
+  Firmware Version: 4.06-0-08, Channels: 3, Memory Size: 8MB
+  PCI Bus: 0, Device: 19, Function: 1, I/O Address: Unassigned
+  PCI Address: 0xFD4FC000 mapped at 0x8807000, IRQ Channel: 9
+  Controller Queue Depth: 128, Maximum Blocks per Command: 128
+  Driver Queue Depth: 127, Maximum Scatter/Gather Segments: 33
+  Stripe Size: 64KB, Segment Size: 8KB, BIOS Geometry: 255/63
+  Physical Devices:
+    0:1 - Disk: Online, 2201600 blocks
+    0:2 - Disk: Online, 2201600 blocks
+    0:3 - Disk: Online, 2201600 blocks
+    1:1 - Disk: Online, 2201600 blocks
+    1:2 - Disk: Online, 2201600 blocks
+    1:3 - Disk: Online, 2201600 blocks
+  Logical Drives:
+    /dev/rd/c0d0: RAID-5, Online, 5498880 blocks, Write Thru
+    /dev/rd/c0d1: RAID-6, Online, 3305472 blocks, Write Thru
+  No Rebuild or Consistency Check in Progress
+
+gwynedd:/u/lnz# cat /proc/rd/status
+OK
+
+The above messages indicate that everything is healthy, and /proc/rd/status
+returns "OK" indicating that there are no problems with any DAC960 controller
+in the system.  For demonstration purposes, while I/O is active Physical Drive
+1:1 is now disconnected, simulating a drive failure.  The failure is noted by
+the driver within 10 seconds of the controller's having detected it, and the
+driver logs the following console status messages indicating that Logical
+Drives 0 and 1 are now CRITICAL as a result of Physical Drive 1:1 being DEAD:
+
+DAC960#0: Physical Drive 1:2 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02
+DAC960#0: Physical Drive 1:3 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02
+DAC960#0: Physical Drive 1:1 killed because of timeout on SCSI command
+DAC960#0: Physical Drive 1:1 is now DEAD
+DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now CRITICAL
+DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now CRITICAL
+
+The Sense Keys logged here are just Check Condition / Unit Attention conditions
+arising from a SCSI bus reset that is forced by the controller during its error
+recovery procedures.  Concurrently with the above, the driver status available
+from /proc/rd also reflects the drive failure.  The status message in
+/proc/rd/status has changed from "OK" to "ALERT":
+
+gwynedd:/u/lnz# cat /proc/rd/status
+ALERT
+
+and /proc/rd/c0/current_status has been updated:
+
+gwynedd:/u/lnz# cat /proc/rd/c0/current_status
+  ...
+  Physical Devices:
+    0:1 - Disk: Online, 2201600 blocks
+    0:2 - Disk: Online, 2201600 blocks
+    0:3 - Disk: Online, 2201600 blocks
+    1:1 - Disk: Dead, 2201600 blocks
+    1:2 - Disk: Online, 2201600 blocks
+    1:3 - Disk: Online, 2201600 blocks
+  Logical Drives:
+    /dev/rd/c0d0: RAID-5, Critical, 5498880 blocks, Write Thru
+    /dev/rd/c0d1: RAID-6, Critical, 3305472 blocks, Write Thru
+  No Rebuild or Consistency Check in Progress
+
+Since there are no standby drives configured, the system can continue to access
+the logical drives in a performance degraded mode until the failed drive is
+replaced and a rebuild operation completed to restore the redundancy of the
+logical drives.  Once Physical Drive 1:1 is replaced with a properly
+functioning drive, or if the physical drive was killed without having failed
+(e.g., due to electrical problems on the SCSI bus), the user can instruct the
+controller to initiate a rebuild operation onto the newly replaced drive:
+
+gwynedd:/u/lnz# echo "rebuild 1:1" > /proc/rd/c0/user_command
+gwynedd:/u/lnz# cat /proc/rd/c0/user_command
+Rebuild of Physical Drive 1:1 Initiated
+
+The echo command instructs the controller to initiate an asynchronous rebuild
+operation onto Physical Drive 1:1, and the status message that results from the
+operation is then available for reading from /proc/rd/c0/user_command, as well
+as being logged to the console by the driver.
+
+Within 10 seconds of this command the driver logs the initiation of the
+asynchronous rebuild operation:
+
+DAC960#0: Rebuild of Physical Drive 1:1 Initiated
+DAC960#0: Physical Drive 1:1 Error Log: Sense Key = 6, ASC = 29, ASCQ = 01
+DAC960#0: Physical Drive 1:1 is now WRITE-ONLY
+DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 1% completed
+
+and /proc/rd/c0/current_status is updated:
+
+gwynedd:/u/lnz# cat /proc/rd/c0/current_status
+  ...
+  Physical Devices:
+    0:1 - Disk: Online, 2201600 blocks
+    0:2 - Disk: Online, 2201600 blocks
+    0:3 - Disk: Online, 2201600 blocks
+    1:1 - Disk: Write-Only, 2201600 blocks
+    1:2 - Disk: Online, 2201600 blocks
+    1:3 - Disk: Online, 2201600 blocks
+  Logical Drives:
+    /dev/rd/c0d0: RAID-5, Critical, 5498880 blocks, Write Thru
+    /dev/rd/c0d1: RAID-6, Critical, 3305472 blocks, Write Thru
+  Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 6% completed
+
+As the rebuild progresses, the current status in /proc/rd/c0/current_status is
+updated every 10 seconds:
+
+gwynedd:/u/lnz# cat /proc/rd/c0/current_status
+  ...
+  Physical Devices:
+    0:1 - Disk: Online, 2201600 blocks
+    0:2 - Disk: Online, 2201600 blocks
+    0:3 - Disk: Online, 2201600 blocks
+    1:1 - Disk: Write-Only, 2201600 blocks
+    1:2 - Disk: Online, 2201600 blocks
+    1:3 - Disk: Online, 2201600 blocks
+  Logical Drives:
+    /dev/rd/c0d0: RAID-5, Critical, 5498880 blocks, Write Thru
+    /dev/rd/c0d1: RAID-6, Critical, 3305472 blocks, Write Thru
+  Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 15% completed
+
+and every minute a progress message is logged to the console by the driver:
+
+DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 32% completed
+DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 63% completed
+DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 94% completed
+DAC960#0: Rebuild in Progress: Logical Drive 1 (/dev/rd/c0d1) 94% completed
+
+Finally, the rebuild completes successfully.  The driver logs the status of the 
+logical and physical drives and the rebuild completion:
+
+DAC960#0: Rebuild Completed Successfully
+DAC960#0: Physical Drive 1:1 is now ONLINE
+DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now ONLINE
+DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now ONLINE
+
+/proc/rd/c0/current_status is updated:
+
+gwynedd:/u/lnz# cat /proc/rd/c0/current_status
+  ...
+  Physical Devices:
+    0:1 - Disk: Online, 2201600 blocks
+    0:2 - Disk: Online, 2201600 blocks
+    0:3 - Disk: Online, 2201600 blocks
+    1:1 - Disk: Online, 2201600 blocks
+    1:2 - Disk: Online, 2201600 blocks
+    1:3 - Disk: Online, 2201600 blocks
+  Logical Drives:
+    /dev/rd/c0d0: RAID-5, Online, 5498880 blocks, Write Thru
+    /dev/rd/c0d1: RAID-6, Online, 3305472 blocks, Write Thru
+  Rebuild Completed Successfully
+
+and /proc/rd/status indicates that everything is healthy once again:
+
+gwynedd:/u/lnz# cat /proc/rd/status
+OK
+
+
+                EXAMPLE II - DRIVE FAILURE WITH A STANDBY DRIVE
+
+The following annotated logs demonstrate the controller configuration and and
+online status monitoring capabilities of the Linux DAC960 Driver.  The test
+configuration comprises 6 1GB Quantum Atlas I disk drives on two channels of a
+DAC960PJ controller.  The physical drives are configured into a single drive
+group with a standby drive, and the drive group has been configured into two
+logical drives, one RAID-5 and one RAID-6.  Note that these logs are from an
+earlier version of the driver and the messages have changed somewhat with newer
+releases, but the functionality remains similar.  First, here is the current
+status of the RAID configuration:
+
+gwynedd:/u/lnz# cat /proc/rd/c0/current_status
+***** DAC960 RAID Driver Version 2.0.0 of 23 March 1999 *****
+Copyright 1998-1999 by Leonard N. Zubkoff <lnz@dandelion.com>
+Configuring Mylex DAC960PJ PCI RAID Controller
+  Firmware Version: 4.06-0-08, Channels: 3, Memory Size: 8MB
+  PCI Bus: 0, Device: 19, Function: 1, I/O Address: Unassigned
+  PCI Address: 0xFD4FC000 mapped at 0x8807000, IRQ Channel: 9
+  Controller Queue Depth: 128, Maximum Blocks per Command: 128
+  Driver Queue Depth: 127, Maximum Scatter/Gather Segments: 33
+  Stripe Size: 64KB, Segment Size: 8KB, BIOS Geometry: 255/63
+  Physical Devices:
+    0:1 - Disk: Online, 2201600 blocks
+    0:2 - Disk: Online, 2201600 blocks
+    0:3 - Disk: Online, 2201600 blocks
+    1:1 - Disk: Online, 2201600 blocks
+    1:2 - Disk: Online, 2201600 blocks
+    1:3 - Disk: Standby, 2201600 blocks
+  Logical Drives:
+    /dev/rd/c0d0: RAID-5, Online, 4399104 blocks, Write Thru
+    /dev/rd/c0d1: RAID-6, Online, 2754560 blocks, Write Thru
+  No Rebuild or Consistency Check in Progress
+
+gwynedd:/u/lnz# cat /proc/rd/status
+OK
+
+The above messages indicate that everything is healthy, and /proc/rd/status
+returns "OK" indicating that there are no problems with any DAC960 controller
+in the system.  For demonstration purposes, while I/O is active Physical Drive
+1:2 is now disconnected, simulating a drive failure.  The failure is noted by
+the driver within 10 seconds of the controller's having detected it, and the
+driver logs the following console status messages:
+
+DAC960#0: Physical Drive 1:1 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02
+DAC960#0: Physical Drive 1:3 Error Log: Sense Key = 6, ASC = 29, ASCQ = 02
+DAC960#0: Physical Drive 1:2 killed because of timeout on SCSI command
+DAC960#0: Physical Drive 1:2 is now DEAD
+DAC960#0: Physical Drive 1:2 killed because it was removed
+DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now CRITICAL
+DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now CRITICAL
+
+Since a standby drive is configured, the controller automatically begins
+rebuilding onto the standby drive:
+
+DAC960#0: Physical Drive 1:3 is now WRITE-ONLY
+DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 4% completed
+
+Concurrently with the above, the driver status available from /proc/rd also
+reflects the drive failure and automatic rebuild.  The status message in
+/proc/rd/status has changed from "OK" to "ALERT":
+
+gwynedd:/u/lnz# cat /proc/rd/status
+ALERT
+
+and /proc/rd/c0/current_status has been updated:
+
+gwynedd:/u/lnz# cat /proc/rd/c0/current_status
+  ...
+  Physical Devices:
+    0:1 - Disk: Online, 2201600 blocks
+    0:2 - Disk: Online, 2201600 blocks
+    0:3 - Disk: Online, 2201600 blocks
+    1:1 - Disk: Online, 2201600 blocks
+    1:2 - Disk: Dead, 2201600 blocks
+    1:3 - Disk: Write-Only, 2201600 blocks
+  Logical Drives:
+    /dev/rd/c0d0: RAID-5, Critical, 4399104 blocks, Write Thru
+    /dev/rd/c0d1: RAID-6, Critical, 2754560 blocks, Write Thru
+  Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 4% completed
+
+As the rebuild progresses, the current status in /proc/rd/c0/current_status is
+updated every 10 seconds:
+
+gwynedd:/u/lnz# cat /proc/rd/c0/current_status
+  ...
+  Physical Devices:
+    0:1 - Disk: Online, 2201600 blocks
+    0:2 - Disk: Online, 2201600 blocks
+    0:3 - Disk: Online, 2201600 blocks
+    1:1 - Disk: Online, 2201600 blocks
+    1:2 - Disk: Dead, 2201600 blocks
+    1:3 - Disk: Write-Only, 2201600 blocks
+  Logical Drives:
+    /dev/rd/c0d0: RAID-5, Critical, 4399104 blocks, Write Thru
+    /dev/rd/c0d1: RAID-6, Critical, 2754560 blocks, Write Thru
+  Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 40% completed
+
+and every minute a progress message is logged on the console by the driver:
+
+DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 40% completed
+DAC960#0: Rebuild in Progress: Logical Drive 0 (/dev/rd/c0d0) 76% completed
+DAC960#0: Rebuild in Progress: Logical Drive 1 (/dev/rd/c0d1) 66% completed
+DAC960#0: Rebuild in Progress: Logical Drive 1 (/dev/rd/c0d1) 84% completed
+
+Finally, the rebuild completes successfully.  The driver logs the status of the 
+logical and physical drives and the rebuild completion:
+
+DAC960#0: Rebuild Completed Successfully
+DAC960#0: Physical Drive 1:3 is now ONLINE
+DAC960#0: Logical Drive 0 (/dev/rd/c0d0) is now ONLINE
+DAC960#0: Logical Drive 1 (/dev/rd/c0d1) is now ONLINE
+
+/proc/rd/c0/current_status is updated:
+
+***** DAC960 RAID Driver Version 2.0.0 of 23 March 1999 *****
+Copyright 1998-1999 by Leonard N. Zubkoff <lnz@dandelion.com>
+Configuring Mylex DAC960PJ PCI RAID Controller
+  Firmware Version: 4.06-0-08, Channels: 3, Memory Size: 8MB
+  PCI Bus: 0, Device: 19, Function: 1, I/O Address: Unassigned
+  PCI Address: 0xFD4FC000 mapped at 0x8807000, IRQ Channel: 9
+  Controller Queue Depth: 128, Maximum Blocks per Command: 128
+  Driver Queue Depth: 127, Maximum Scatter/Gather Segments: 33
+  Stripe Size: 64KB, Segment Size: 8KB, BIOS Geometry: 255/63
+  Physical Devices:
+    0:1 - Disk: Online, 2201600 blocks
+    0:2 - Disk: Online, 2201600 blocks
+    0:3 - Disk: Online, 2201600 blocks
+    1:1 - Disk: Online, 2201600 blocks
+    1:2 - Disk: Dead, 2201600 blocks
+    1:3 - Disk: Online, 2201600 blocks
+  Logical Drives:
+    /dev/rd/c0d0: RAID-5, Online, 4399104 blocks, Write Thru
+    /dev/rd/c0d1: RAID-6, Online, 2754560 blocks, Write Thru
+  Rebuild Completed Successfully
+
+and /proc/rd/status indicates that everything is healthy once again:
+
+gwynedd:/u/lnz# cat /proc/rd/status
+OK
+
+Note that the absence of a viable standby drive does not create an "ALERT"
+status.  Once dead Physical Drive 1:2 has been replaced, the controller must be
+told that this has occurred and that the newly replaced drive should become the
+new standby drive:
+
+gwynedd:/u/lnz# echo "make-standby 1:2" > /proc/rd/c0/user_command
+gwynedd:/u/lnz# cat /proc/rd/c0/user_command
+Make Standby of Physical Drive 1:2 Succeeded
+
+The echo command instructs the controller to make Physical Drive 1:2 into a
+standby drive, and the status message that results from the operation is then
+available for reading from /proc/rd/c0/user_command, as well as being logged to
+the console by the driver.  Within 60 seconds of this command the driver logs:
+
+DAC960#0: Physical Drive 1:2 Error Log: Sense Key = 6, ASC = 29, ASCQ = 01
+DAC960#0: Physical Drive 1:2 is now STANDBY
+DAC960#0: Make Standby of Physical Drive 1:2 Succeeded
+
+and /proc/rd/c0/current_status is updated:
+
+gwynedd:/u/lnz# cat /proc/rd/c0/current_status
+  ...
+  Physical Devices:
+    0:1 - Disk: Online, 2201600 blocks
+    0:2 - Disk: Online, 2201600 blocks
+    0:3 - Disk: Online, 2201600 blocks
+    1:1 - Disk: Online, 2201600 blocks
+    1:2 - Disk: Standby, 2201600 blocks
+    1:3 - Disk: Online, 2201600 blocks
+  Logical Drives:
+    /dev/rd/c0d0: RAID-5, Online, 4399104 blocks, Write Thru
+    /dev/rd/c0d1: RAID-6, Online, 2754560 blocks, Write Thru
+  Rebuild Completed Successfully