disks(1M)						  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 directory  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 num-
		  ber  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 manually,
       first run drvconfig(1M) to ensure /devices 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 requires the minor name of disk devices obey the following format conventions.

       The  minor  name  for block interfaces consists of a single lowercase ASCII character, a through u, representing the slices and the primary
       partitions. The minor name for logical drive block interfaces consists of the strings p5 through p36. The minor name  for  character  (raw)
       interfaces  consists  of a single lowercase ASCII character, a through a, followed by the string ,raw, representing the slices and the pri-
       mary partitions. The minor name for logical drive character (raw) interfaces consists of the string p5 through p36 followed by ,raw.

       disks performs the following translations:

	   o	  a through p to s0 through s15

	   o	  q through u to p0 through p4

	   o	  p5 through p36 to p5 through p36

       SPARC drivers should only use the first eight slices: a through h, while x86 drivers can use a through u, with q through u corresponding to
       fdisk(1M)  primary  partitions.	q represents the entire disk, while r, s, t, and u represent up to four additional primary partitions. For
       logical drives, p5 to p36 correspond to the 32 logical drives that are supported. The device nodes for logical drives change dynamically as
       and when they are created or deleted.

       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 alternative 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 character 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

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 attributes:

       +-----------------------------+-----------------------------+
       |      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)

BUGS

       disks silently ignores malformed minor device names.

SunOS 5.11							    31 Oct 2008 							 disks(1M)