Provided by: sg-utils_1.02-1_i386 bug

NAME

       sg_map - displays mapping between sg and other SCSI devices

SYNOPSIS

       sg_map [-a] [-n] [-scd] [-sd] [-sr] [-st] [-x]

DESCRIPTION

       Sometimes  it  is  difficult to determine which SCSI device a sg device
       name (e.g. /dev/sg0) refers to.  This  command  loops  through  the  sg
       devices  and  finds  the  corresponding SCSI disk, cdrom or tape device
       name (if any). Scanners are an example of SCSI  devices  that  have  no
       alternate SCSI device name apart from their sg device name.

       -a     assume  the  sg  devices have alphabetical device names and loop
              through /dev/sga, /dev/sgb, etc. Default is numeric scan

       -n     assume the sg devices have numeric device names and loop through
              /dev/sg0, /dev/sg1, etc. Default is numeric scan

       -sd    display mappings to SCSI disk device names

       -scd   display  mappings  to  SCSI  cdrom  device  names  of  the  form
              /dev/scd0, /dev/scd1 etc

       -sr    display  mappings  to  SCSI  cdrom  device  names  of  the  form
              /dev/sr0, /dev/sr1 etc

       -st    display mappings to SCSI tape device names

       -x     after  each  active  sg  device name is displayed there are five
              digits: <host_number> <bus> <scsi_id> <lun> <scsi_type>

       If no options starting with "-s" are given then the mapping to all SCSI
       disk, cdrom and tape device names is shown.

       If  the  device  file  system  (devfs) is present a line noting this is
       output. The  "native"  devfs  scsi  hierarchy  makes  the  relationship
       between  a  sg  device  name  and any corresponding disk, cdrom or tape
       device name easy to establish. This replaces the need for this command.
       However  many  applications will continue to look for Linux SCSI device
       names in their traditional  places.  [Devfs  supplies  a  compatibility
       daemon  called  devfsd  whose default configuration adds back the Linux
       device names in their traditional positions.

       Quite often the mapping information can be  derived  by  observing  the
       output  of the command: "cat /proc/scsi/scsi".  However if devices have
       been added since boot this can be deceptive.

EXAMPLES

       My system has a SCSI disk, a cd writer and a dvd player:
          $ sg_map
          # Note: the devfs pseudo file system is present
          /dev/sg0  /dev/sda
          /dev/sg1  /dev/sr0
          /dev/sg2  /dev/sr1

       In order to find which sg device name corresponds to the disk:
          $ sg_map -sd
          # Note: the devfs pseudo file system is present
          /dev/sg0  /dev/sda
          /dev/sg1
          /dev/sg2

       The "-x" option gives the following output:
          sg_map -x
          # Note: the devfs pseudo file system is present
          /dev/sg0  1 0 1 0  0  /dev/sda
          /dev/sg1  2 0 4 0  5  /dev/sr0
          /dev/sg2  2 0 6 0  5  /dev/sr1

       When a SCSI scanner is added the output becomes:
          $ sg_map
          # Note: the devfs pseudo file system is present
          /dev/sg0  /dev/sda
          /dev/sg1  /dev/sr0
          /dev/sg2  /dev/sr1
          /dev/sg3

       By process of elimination /dev/sg3 must be the scanner.

AUTHOR

       Written by Doug Gilbert

REPORTING BUGS

       Report bugs to <dgilbert@interlog.com>.

COPYRIGHT

       Copyright © 2000 Douglas Gilbert
       This software is distributed under the  GPL  version  2.  There  is  NO
       warranty;  not  even  for  MERCHANTABILITY  or FITNESS FOR A PARTICULAR
       PURPOSE.

SEE ALSO

       scsi_info(8) , scsidev(8) , devfsd(8)