ri(7)							 Miscellaneous Information Manual						     ri(7)

NAME

       ri - I2O RAID disk interface

SYNOPSIS

       bus	       i2o0	  at pci2001   slot  4
       controller      i2o_bs0	  at i2o0      slot  18

DESCRIPTION

       The  ri	driver supports 32-bit and 64-bit PCI backplane RAID controllers with Intelligent I/O (I2O) host interface supporting backend SCSI
       channels.  I2O is an open architecture for developing device drivers that is independent of the operating system, processor  platform,  and
       system  I/O bus.  The communication model is based on a message-passing protocol reducing the number of driver interfaces needed.  A single
       driver called an Operating System Module(OSM) is provided to support all Block Storage class devices.  Any RAID system  that  supports  the
       I2O interface functions with this driver.  These devices are designated as ri to distinguish them from ra, re, and rz (SCSI) devices.

       The StorageWorks Command Console Utility (SWCC) is supported for online configuration and monitoring of I2O raid devices.

       The  following rules are used to determine the major and minor numbers that are associated with an ri type disk.  A dynamic major number is
       used to represent ri block devices, and is assigned during initial configuration.  The current major number can	be  determined	using  the
       following  command:  #  /sbin/devswmgr -getnum i2o_bs The preceding command displays the driver switch reservation list, showing the device
       instance and major number for the i2o_bs driver. An alternative method is: # /sbin/sysconfig -q i2o_bs

       The highest 14 bits of the 20-bit minor number represents a particular Block Storage device, while lowest six  bits  of	the  minor  number
       specify disk partitions (identified by the letters, a through h) on that device.

       The  device special file names associated with ri disks are based on conventions that are closely associated with the minor number assigned
       to the disk.  The standard device names begin with ri for block special files and rri for character (raw) special files. Following  the	ri
       is  the	unit  number and then a letter, a through h, that represents the partition.  Throughout this reference page, the question mark (?)
       character represents the unit number in the name of the device special file.  For example, ri?b could represent ri0b, ri1b, and so on.

       A disk can be accessed through either the block special file or the character special file.  The block special file accesses the disk using
       the file system's normal buffering mechanism.  Reads and writes to the block special file can specify any size.	This capability avoids the
       need to limit data transfers to the size of physical disk records and to calculate offsets within disk records.	The file system can  break
       up large read and write requests into smaller fixed size transfers to the disk.

       The  character special file provides a raw interface that allows for direct transmission between the disk and the user's read or write buf-
       fer.  A single read/write operation to the raw interface results in exactly one I/O operation.  Consequently, raw I/O may  be  considerably
       more efficient for large transfers.

       For  systems with ri disks, the first software boot after the system is powered on may take longer than expected.  This delay is normal and
       is caused by the software spinning up the ri disks.

   Disk Support
       The ri driver handles all disk drives that can be connected to the I2O RAID controller.	To determine which drives are supported  for  spe-
       cific CPU types and hardware configurations, see the hardware installation and configuration information for your I2O system.

       I2O  RAID Controllers are viewed in all cases as RI type disks.	There are some notable differences that should be taken into consideration
       when configuring a RAID device: Currently only sector sizes of 512 bytes are supported.	Logical Volume sizes are not fixed sizes  as  com-
       pared to other disk devices.  The size of the Logical Volume is configurable based on needs.  The dynamic nature of Logical Volume sizes is
       dealt with by defining RAID devices as DYNAMIC.	Only partitions a, b, c, and g are defined.  If necessary, the disklabel(8) command can be
       run to change and define partitions for RAID devices

       Usually,  the  ri?a partition is used for the root file system and the ri?b partition as a paging area.	The ri?c partition can be used for
       disk-to-disk copying because it maps the entire disk.

       The starting location and length (in 512 byte sectors) of the disk partitions of each drive are shown in the  following	table.	 Partition
       sizes can be changed by using the disklabel(8) command.

       I2O RAID partitions for systems
       based on the Alpha AXP architecture

	    disk start	   length

	    ri?a 0    131072	    ri?b 131072    262144	 ri?c 0    end	 of   media	   ri?d 0    0	     ri?e 0    0       ri?f 0	 0
	    ri?g 393216  end of media	   ri?h 0    0

FILES

       /dev/disk/ri???	/dev/disk/rri???

RELATED INFORMATION

       RAID(7), SCSI(7), tz(7), rz(7),disklabel(8), MAKEDEV(8), uerf(8) delim off

																	     ri(7)