scu(8) System Manager's Manual scu(8)
NAME
scu - SCSI CAM Utility Program
SYNOPSIS
/sbin/scu [-options ...] [command [keywords...]]
OPTIONS
Specifies the user agent path. 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. Do not execute a startup script. Enable pipe operation mode. 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.
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Command Function
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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 interactive
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
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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 command is used to modify the volume level.
EXIT STATUS
Success. Warning. 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
To format an RX26 diskette at extra density, enter: scu> format density ED To verify 1024 blocks starting at block 1000, enter: scu> verify
media starting 1000 length 1024 To display all changeable mode pages for a device, enter: scu> show page pcf changeable 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
The SCSI Utility executable file. The device entry for the CAM User Agent driver. Contains the scu help information. 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
scu(8)