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  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 con-
	   troller 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 /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(1M) 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. The minor name for character (raw) inter-
       faces 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 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)

       Writing Device Drivers

BUGS

       disks silently ignores malformed minor device names.

SunOS 5.10							    7 Nov 2002								 disks(1M)