i2o_bs(7D)

NAME

     i2o_bs - Block Storage OSM for I2O

SYNOPSIS

     disk@local target id#:a through u
     disk@local target id#:a through u raw

DESCRIPTION

     The I2O Block Storage OSM abstraction (BSA,  which  also  is
     referred  to  as  block  storage class) layer is the primary
     interface that Solaris operating environments use to  access
     block  storage devices. A block storage device provides ran-
     dom access to a permanent storage medium.  The i2o_bs device
     driver uses I2O Block Storage class messages to control  the
     block device; and provides the same  functionality  (ioctls,
     for  example)  that  is present in the Solaris device driver
     like 'cmdk, dadk' on x86 for disk.  The  maximum  size  disk
     supported by i2o_bs is the same as what is available on x86.

     The i2o_bs is currently implemented version 1.5 of  Intelli-
     gent IO specification.

     The block files access the disk using  the  system's  normal
     buffering  mechanism and are read and written without regard
     to physical disk records.  There is also a  "raw"  interface
     that  provides  for direct transmission between the disk and
     the user's read or write buffer.  A single  read   or  write
     call usually results in one I/O operation; raw I/O is there-
     fore  considerably  more  efficient   when  many  bytes  are
     transmitted.  The  names  of  the  block  files are found in
     /dev/dsk; the names of the raw files are found in /dev/rdsk.

     I2O associates each block storage device with  a  unique  ID
     called  a  local target id that is assigned by I2O hardware.
     This information can be acquired by the  block  storage  OSM
     through  I2O Block Storage class messages. For Block Storage
     OSM, nodes are created in /devices/pci#/pci#  which  include
     the local target ID as one component of device name that the
     node refers to.  However the /dev names  and  the  names  in
     /dev/dsk  and /dev/rdsk do not encode the local target id in
     any part of the name.

      For example, you might have the following:

     /devices/                                       /dev/dsk name
     ---------------------------------------------------------------
     /devices/pci@0,0/pci101e,0@10,1/disk@10:a       /dev/dsk/c1d0s0

      I/O requests to the disk must have an offset  and  transfer
     length that is a multiple of 512 bytes or the driver returns
     an EINVAL error.

      Slice 0 is normally used for the  root  file  system  on  a
     disk,  slice 1 is used as a paging area (for example, swap),
     and slice 2 for backing up  the entire  fdisk partition  for
     Solaris software. Other slices may be used for usr file sys-
     tems or system reserved area.

      Fdisk partition 0 is to access the entire disk and is  gen-
     erally used by the fdisk(1M)  program.

FILES

     /dev/dsk/cndn[s|p]n
            block device

     /dev/rdsk/cndn[s|p]n
           raw device

           where:

           cn    controller n

           dn    instance number

           sn    UNIX system slice n (0-15)

           pn    fdisk partition (0)

     /kernel/drv/i2o_bs
            i2o_bs driver

     /kernel/drv/i2o_bs.conf
           Configuration file

ATTRIBUTES

     See attributes(5)
      for descriptions of the following attributes:

     ____________________________________________________________
    | ATTRIBUTE  TYPE             | ATTRIBUTE                   |ALUE
    |_____________________________|_____________________________|
    | Architecture                | x86                         |
    |_____________________________|_____________________________|

SEE ALSO

     fdisk(1M), format(1M)mount(1M),lseek(2), read(2),  write(2),
     readdir(3C), vfstab(4), acct(3HEAD), attributes(5), dkio(7I)