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scu(8)								       scu(8)



NAME

  scu -	SCSI CAM Utility Program

SYNOPSIS

  /sbin/scu [-options ...] [command [keywords...]]

OPTIONS

  -c [cam-device]
      Specifies	the user agent path.

  -f [device-name]
      Specify the raw device pathname. You must	specify	a character device
      special file, for	example, /dev/rdisk/dsk10c.

      If the device name is not	specified on the command line, the program
      checks the environment variable SCU_DEVICE to define the device name.

  -n  Do not execute a startup script.

  -p  Enable pipe operation mode.

  -s startup-file
      Specify a	script startup file name.

DESCRIPTION

  The SCSI utility program, scu, interfaces with the CAM I/O subsystem and
  the peripherals attached to the SCSI buses.  Use this	program	to maintain
  and diagnose problems	with SCSI peripherals and the CAM I/O subsystem.

				    Warning

       Data corruption can occur when the write	back cache is enabled using
       scu. Compaq recommends that you do not enable the write back cache.

  The scu utility program has an extensive help	feature.  Log in as root and
  enter	/sbin/scu help at the command prompt to	view the help overview and
  enter	a ? at the topic>> prompt to view a list	of the utility's commands and
  conventions.

  The file /sbin/scu.hlp contains the help information used in the help
  feature.









COMMANDS

  The following	table summarizes the scu commands and their functions.	Refer
  to the help command for complete syntax and examples of use.

  _________________________________________________________________
  Command    Function
  _________________________________________________________________
  allow	     Allows media removal from a device
  change     Changes mode pages	for a device
  download   Downloads microcode to a device
  dump	     Dumps data	from a device
  eject	     Stops a CD-ROM and	then ejects its	caddy
  erase	     Performs erase operations on a device
  exit

	     Exit the scu program.  Ctrl/d can be used in interac-
	     tive operation.  An alias for exit	is quit.
  evaluate   Evaluates an expression
  format     Formats disk media
  help

	     Displays help on scu command elements
  mbad	     Produces hard and soft errors on disks
  mt	     Issues one	of the supported magnetic tape commands
  onerror    Controls program actions when an error occurs
  pause	     Pauses playing a CD-ROM audio disk
  play	     Plays tracks on a CD-ROM audio disk
  prevent    Prevents removal of media from a device
  read	     Performs read operations on a device
  reassign   Reassigns a defective block on a disk device
  release    Releases a	reserved device	or a frozen SIM	queue
  repeat     Defines a repeat count for	a series of commands
  reserve    Reserves a	device for exclusive use
  resume     Resumes playing a paused CD-ROM audio disk
  reset	     Resets a bus or device
  rezero     Issues a CAM Bus Reset CCB	command
  scan

	     Scans device media	or the CAM Equipment Device Table
	     (EDT)
  seek	     Seeks a logical block address
  set

	     Sets parameters for a device or the scu program
  shell	     Exits to shell program until you exit the shell
  show

	     Displays parameters for a device or the scu program
  sleep

	     Specifies the time	the scu	program	is to sleep
  source     Sources input from	an external command file
  start	     Starts a unit that	is stopped
  stop	     Stops a unit
  switch     Switches to another device
  system     Passes one	system command to the shell program
  test	     Performs tests on a controller
  time	     Times command sequences
  tur	     Issues a Test Unit	Ready command to a device
  usleep

	     Specifies the time	the scu	program	is to sleep (in
	     microseconds).
  verify     Performs verify operations	on a device
  write	     Performs write operations on a device
  xza	     Performs operations on the	KZMSA controller
  zero

	     Zeros device or scu program parameters
  _________________________________________________________________

RESTRICTIONS

  Commands that	modify device data or device parameters	require	write access
  to the device	entry.	Applications that change the volume level of the
  CD-ROM must open the device for write	access since a SCSI Mode Select	com-
  mand is used to modify the volume level.




EXIT STATUS

  0 (Zero)
      Success.

  1   Warning.

  -1  Failure.

ERRORS

  When a SCSI device error occurs, both	the sense key and the addition sense
  code or qualifier are	decoded	and displayed as follows:

       scu: Sense Key =	0x5 = ILLEGAL REQUEST -	Illegal	request	or CDB parameter,
	    Sense Code/Qualifier = (0x20, 0) = Invalid command operation code

  This error indicates that you	have issued a command that is not supported
  by the selected device.  This	can happen for optional	commands that are not
  supported by all devices.

EXAMPLES

   1.  To format an RX26 diskette at extra density, enter:
	    scu>> format	density	ED

   2.  To verify 1024 blocks starting at block 1000, enter:
	    scu>> verify	media starting 1000 length 1024

   3.  To display all changeable mode pages for	a device, enter:
	    scu>> show page pcf changeable

   4.  To display inquiry information for all devices on the first SCSI	bus
       at lun 0	in the Equipment Device	Table (EDT), enter:
	    scu>> show edt bus 0	lun 0 full



FILES

  /sbin/scu
      The SCSI Utility executable file.

  /dev/cam
      The device entry for the CAM User	Agent driver.

  /sbin/scu.hlp
      Contains the scu help information.

  /dev/rdisk
      Is the location of the raw device	special	files for hard disk devices.

SEE ALSO

  Commands: file(1), more(1)

  Functions: open(2), close(2),	ioctl(2), fopen(3), fgets(3), fputs(3),
  popen(3), pclose(3), malloc(3), printf(3), fprintf(3)

  American National Standard for Information Systems, Small Computer Systems
  Interface - 2	(SCSI -	2), X3.131-199X

  American National Standard for Information Systems, SCSI-2 Common Access
  Method: Transport and	SCSI Interface Module, working draft, X3T9.2/90-186