System Administration Commands                          disks(1M)

NAME
     disks - creates /dev entries for hard disks attached to  the
     system

SYNOPSIS
     /usr/sbin/disks [-C] [-r rootdir]

DESCRIPTION
     devfsadm(1M) is now  the  preferred  command  for  /dev  and
     should be used instead of disks.

     disks creates symbolic links in the /dev/dsk  and  /dev/rdsk
     directories pointing to the actual disk device special files
     under the /devices directory tree. It performs the following
     steps:

     1.  disks searches the kernel device tree to see  what  hard
         disks  are attached to the system. It notes the /devices
         pathnames for the slices on the drive and determines the
         physical  component  of  the  corresponding  /dev/dsk or
         /dev/rdsk name.


     2.  The /dev/dsk and /dev/rdsk directories are  checked  for
         disk entries - that is, symbolic links with names of the
         form cN[tN]dNsN, or cN[tN]dNpN,  where  N  represents  a
         decimal  number. cN is the logical controller number, an
         arbitrary number assigned by this program to designate a
         particular  disk  controller. The first controller found
         on the first occasion this program is run on  a  system,
         is  assigned number 0. tN is the bus-address number of a
         subsidiary controller attached to a peripheral bus  such
         as  SCSI  or  IPI  (the  target number for SCSI, and the
         facility number for IPI controllers). dN is  the  number
         of  the disk attached to the controller. sN is the slice
         number on the disk. pN is  the  FDISK  partition  number
         used by fdisk(1M). (x86 Only)


     3.  If only some of the disk entries are found  in  /dev/dsk
         for a disk that has been found under the /devices direc-
         tory tree, disks creates the missing symbolic links.  If
         none  of  the entries for a particular disk are found in
         /dev/dsk, disks checks to see if any entries  exist  for
         other  disks attached to the same controller, and if so,
         creates new entries using the same controller number  as
         used for other disks on the same controller. If no other
         /dev/dsk entries are found for slices of disks belonging
         to  the  same  physical  controller as the current disk,
         disks assigns the lowest-unused  controller  number  and
         creates  entries  for  the disk slices using this newly-
         assigned controller number.


     disks is run automatically each time a  reconfiguration-boot
     is  performed or when add_drv(1M) is executed. When invoking
     disks(1M) manually, first run drvconfig(1M) to ensure  /dev-
     ices is consistent with the current device configuration.

  Notice to Driver Writers
     disks  considers  all  devices   with   a   node   type   of
     DDI_NT_BLOCK, DDI_NT_BLOCK_CHAN, DDI_NT_CD, DDI_NT_BLOCK_WWN
     or DDI_NT_CD_CHAN to be disk devices. disks(1M) requires the
     minor name of disk devices obey the following format conven-
     tions.

     The minor name for block interfaces  consists  of  a  single
     lowercase  ASCII  character, a through u. The minor name for
     character (raw) interfaces consists of  a  single  lowercase
     ASCII character,  a through u, followed by ,raw.

     disks translates a through p to s0  through  s15,  while  it
     translates  q  through  u  to  p0  through p4. SPARC drivers
     should only use the first 8 slices: a through h,  while  x86
     drivers  can use a through u, with q through u corresponding
     to fdisk(1M) partitions. q represents the entire disk, while
     r, s, t, and  u represent up to 4 additional partitions.

     To prevent disks from attempting to  automatically  generate
     links for a device, drivers must specify a private node type
     and  refrain  from  using   a   node   type:   DDI_NT_BLOCK,
     DDI_NT_BLOCK_CHAN, DDI_NT_CD, or DDI_NT_CD_CHAN when calling
     ddi_create_minor_node(9F).

OPTIONS
     The following options are supported:

     -C              Causes disks to  remove  any  invalid  links
                     after adding any new entries to /dev/dsk and
                     /dev/rdsk. Invalid  links  are  links  which
                     refer  to  non-existent disk nodes that have
                     been removed, powered off, or are  otherwise
                     inaccessible.



     -r rootdir      Causes disks to presume that  the  /dev/dsk,
                     /dev/rdsk  and  /devices directory trees are
                     found under rootdir, not directly under /.



ERRORS
     If disks finds entries of a  particular  logical  controller
     linked to different physical controllers, it prints an error
     message and exits without making any  changes  to  the  /dev
     directory, since it cannot determine which of the two alter-
     native logical-to-physical mappings is correct.   The  links
     should  be  manually  corrected  or  removed  before another
     reconfiguration-boot is performed.

EXAMPLES
     Example 1: Creating Block and Character Minor Devices

     The following example demonstrates creating  the  block  and
     character  minor  devices  from  within  the xkdisk driver's
     attach(9E) function.


     #include    <sys/dkio.h>
     /*
      * Create the minor number by combining the instance number
      * with the slice number.
      */
     #define MINOR_NUM(i, s)   ((i) << 4 | (s))

     int
     xkdiskattach(dev_info_t *dip, ddi_attach_cmd_t cmd)
     {
         int instance, slice;
         char name[8];

             /* other stuff in attach... */

         instance = ddi_get_instance(dip);
         for (slice = 0; slice < V_NUMPAR; slice++) {
             /*
              * create block device interface
              */
             sprintf(name, "%c", slice + 'a');
             ddi_create_minor_node(dip, name, S_IFBLK,
                 MINOR_NUM(instance, slice), DDI_NT_BLOCK_CHAN, 0);

             /*
              * create the raw (character) device interface
              */
             sprintf(name,"%c,raw", slice + 'a');
             ddi_create_minor_node(dip, name, S_IFCHR,
                 MINOR_NUM(instance, slice), DDI_NT_BLOCK_CHAN, 0);
         }
     }



     Installing the  xkdisk disk driver on a Sun Fire 4800,  with
     the   driver  controlling a  SCSI disk (target 3 attached to
     an isp(7D) SCSI HBA) and performing  a  reconfiguration-boot
     (causing  disks  to  be  run)  creates the following special
     files in  /devices.

     # ls -l /devices/ssm@0,0/pci@18,700000/pci@1/SUNW,isptwo@4/
     brw-r-----   1 root sys   32, 16 Aug 29 00:02 xkdisk@3,0:a
     crw-r-----   1 root sys   32, 16 Aug 29 00:02 xkdisk@3,0:a,raw
     brw-r-----   1 root sys   32, 17 Aug 29 00:02 xkdisk@3,0:b
     crw-r-----   1 root sys   32, 17 Aug 29 00:02 xkdisk@3,0:b,raw
     brw-r-----   1 root sys   32, 18 Aug 29 00:02 xkdisk@3,0:c
     crw-r-----   1 root sys   32, 18 Aug 29 00:02 xkdisk@3,0:c,raw
     brw-r-----   1 root sys   32, 19 Aug 29 00:02 xkdisk@3,0:d
     crw-r-----   1 root sys   32, 19 Aug 29 00:02 xkdisk@3,0:d,raw
     brw-r-----   1 root sys   32, 20 Aug 29 00:02 xkdisk@3,0:e
     crw-r-----   1 root sys   32, 20 Aug 29 00:02 xkdisk@3,0:e,raw
     brw-r-----   1 root sys   32, 21 Aug 29 00:02 xkdisk@3,0:f
     crw-r-----   1 root sys   32, 21 Aug 29 00:02 xkdisk@3,0:f,raw
     brw-r-----   1 root sys   32, 22 Aug 29 00:02 xkdisk@3,0:g
     crw-r-----   1 root sys   32, 22 Aug 29 00:02 xkdisk@3,0:g,raw
     brw-r-----   1 root sys   32, 23 Aug 29 00:02 xkdisk@3,0:h
     crw-r-----   1 root sys   32, 23 Aug 29 00:02 xkdisk@3,0:h,raw



     /dev/dsk will contain the disk entries to the  block  device
     nodes in /devices


     # ls -l /dev/dsk
     /dev/dsk/c0t3d0s0 -> ../../devices/[...]/xkdisk@3,0:a
     /dev/dsk/c0t3d0s1 -> ../../devices/[...]/xkdisk@3,0:b
     /dev/dsk/c0t3d0s2 -> ../../devices/[...]/xkdisk@3,0:c
     /dev/dsk/c0t3d0s3 -> ../../devices/[...]/xkdisk@3,0:d
     /dev/dsk/c0t3d0s4 -> ../../devices/[...]/xkdisk@3,0:e
     /dev/dsk/c0t3d0s5 -> ../../devices/[...]/xkdisk@3,0:f
     /dev/dsk/c0t3d0s6 -> ../../devices/[...]/xkdisk@3,0:g
     /dev/dsk/c0t3d0s7 -> ../../devices/[...]/xkdisk@3,0:h



     and /dev/rdsk will contain the disk entries for the  charac-
     ter device nodes in /devices


     # ls -l /dev/rdsk
     /dev/rdsk/c0t3d0s0 -> ../../devices/[...]/xkdisk@3,0:a,raw
     /dev/rdsk/c0t3d0s1 -> ../../devices/[...]/xkdisk@3,0:b,raw
     /dev/rdsk/c0t3d0s2 -> ../../devices/[...]/xkdisk@3,0:c,raw
     /dev/rdsk/c0t3d0s3 -> ../../devices/[...]/xkdisk@3,0:d,raw
     /dev/rdsk/c0t3d0s4 -> ../../devices/[...]/xkdisk@3,0:e,raw
     /dev/rdsk/c0t3d0s5 -> ../../devices/[...]/xkdisk@3,0:f,raw
     /dev/rdsk/c0t3d0s6 -> ../../devices/[...]/xkdisk@3,0:g,raw
     /dev/rdsk/c0t3d0s7 -> ../../devices/[...]/xkdisk@3,0:h,raw



System Administration Commands                          disks(1M)



FILES
     /dev/dsk/*      Disk entries (block device interface)



     /dev/rdsk/*     Disk entries (character device interface)



     /devices/*      Device special files (minor device nodes)



ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWcsu                     |
    |_____________________________|_____________________________|


SEE ALSO
     add_drv(1M),   devfsadm(1M),    fdisk(1M),    attributes(5),
     isp(7D),       devfs(7FS),       dkio(7I),       attach(9E),
     ddi_create_minor_node(9F)

     Writing Device Drivers

BUGS
     disks silently ignores malformed minor device names.