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.TH SCUZZ 8

.SH NAME

scuzz \- SCSI target control

.SH SYNOPSIS

.B scuzz

[

.B -6eq

] [

.B -m

.I max-xfer

] [

[

.B -r

]

.I sddev

]

.SH DESCRIPTION

.I Scuzz

is an interactive program for exercising

raw SCSI devices.

Its intended purpose is to investigate and manipulate

odd devices without the effort of writing a special driver,

such as shuffling the media around on an optical jukebox.

It reads commands from standard input and applies them to a SCSI target

(other devices accessed through the

.IR sd (3)

interface,

such as ATA(PI) devices,

may also work).

If

.I sddev

is given on the command line, an

.B open

(see below)

is immediately applied to the target.

On successful completion of a command,

.BI ok " n

is printed, where

.I n

is the number of bytes transferred to/from the target;

the

.B -q

command line option suppresses the

.B ok

message.

.LP

The

.B -6

forces the use of 6-byte SCSI commands rather than 10-byte ones.

Some older devices require this, though

.I scuzz

attempts to adapt automatically.

The

.B -e

makes

.I scuzz

more willing to retry I/O errors but less tolerant of other errors

and implies

.BR -6 .

This option is often needed to read Exabyte 8mm tapes.

The

.B -m

option sets the maximum I/O transfer size to

.IR max-xfer .

Exabyte drives often require this to be 1024 or the exact tape block size

and some 4mm drives require this to be the exact tape block size or larger.

.SS Commands

.TF "inquiry"

.PD

.TP

.BI help " command

.B Help

is rudimentary and prints a one line synopsis for the named

.IR command ,

or for all commands if no argument is given.

.TP

.B probe

.B Probe

attempts an

.B inquiry

command on all SCSI units,

and prints the result preceded by the name of those

targets which respond.

.LP

The

.B help

and

.B probe

commands may be given at any time.

.TF "inquiry"

.PD

.TP

.BI open\ [ -r ] sddev

.B Open

must be given before any of the remaining commands will be accepted.

Internally,

unless the

.B -r

option is given,

.B open

issues

.B ready

then

.BR inquiry ,

followed by a device class-specific command to determine the

logical block size of the target.

.I Sddev

is an

.IR sd (3)

device directory like

.IR /dev/sdC0 .

.TP

.B close

.B Close

need only be given if another target is to be opened in the current

session.

.LP

The remaining commands are in rough groups,

intended for specific classes of device.

With the exception of the

.BR read ,

.BR write ,

and

.B space

commands,

all arguments are in the style of ANSI-C integer constants.

.TF "inquiry"

.PD

.TP

.B ready

Test Unit Ready

checks if the unit is powered up and ready to do

.B read

and

.B write

commands.

.TP

.B rezero

Rezero

Unit requests that a disk be brought to a known state,

usually by seeking to track zero.

.TP

.B rewind

.B Rewind

positions a tape at the beginning of current partition

(there is usually only one partition, the beginning of tape).

.TP

.B reqsense

Request Sense retrieves Sense Data concerning an error or

other condition and is usually issued following the completion of a command

that had check-condition status.

.I Scuzz

automatically issues a

.B reqsense

in response to a check-condition status and prints the result.

.TP

.B format

Format

Unit performs a ``low level'' format of a disk.

.TP

.B rblimits

Read Block Limits

reports the possible block lengths for the logical unit. Tapes only.

.TP

.BI read " file nbytes

.B Read

transfers data from the target to the host.

A missing

.I nbytes

causes the entire device to be read.

.TP

.BI write " file nbytes

.B Write

transfers data from the host to the target.

A missing

.I nbytes

causes the entire input file to be transferred.

.IP

The first argument to the

.BR read

and

.BR write

commands specifies a source

.RB ( write )

or destination

.RB ( read )

for the I/O.

The argument is either a plain file name or

.B |

followed by a command to be executed by

.IR rc (1).

The argument may be quoted in the style of

.IR rc (1).

.TP

.BI seek " offset whence

.B Seek

requests the target to seek to a position on a disk,

arguments being in the style of

.IR seek (2);

.I whence

is 0 by default.

.IP

.I Scuzz

maintains an internal notion of where the current target

is positioned.

The

.BR seek ,

.BR read ,

.BR write ,

.BR rewind ,

.BR rezero ,

and

.B wtrack

commands all manipulate the internal offset.

.TP

.BI filemark " howmany

Write Filemarks

writes one (default) or more filemarks on a tape.

.TP

.BI space\ [ -b ]\ [ -f ]\ [[ "--\fP]\fIhowmany\fP]"

.B Space

positions a tape forwards or backwards.

The arguments

specify logical block

.RB ( -b )

or

filemark

.RB ( -f )

spacing;

default is

.BR -b .

If

.I howmany

is negative

it specifies spacing backwards,

and should be preceded by

.B --

to turn off any further

option processing.

Default is 1.

.TP

.B inquiry

.B Inquiry

is issued to determine the device type of a particular target,

and to determine some basic information about the implemented options and

the product name.

.TP

.BI modeselect bytes...

.TP

.BI modeselect6 bytes...

Mode

Select

is issued to set variable parameters in the target.

.I Bytes

given as arguments comprise all the data for the target;

see an appropriate manual for the format.

The default is the 10-byte form of the command;

modeselect6 is the 6-byte version.

.TP

.BI modesense\ [ page [ nbytes ]]

.TP

.BI modesense6\ [ page [ nbytes ]]

Mode

Sense

reports variable and fixed parameters from the target.

If no

.I page

is given,

all pages are returned.

.I Nbytes

specifies how many bytes should be returned.

The default is the 10-byte form of the command;

modesense6 is the 6-byte version.

.TP

.BI start\ [ code ]

.TP

.BI stop\ [ code ]

.TP

.BI eject\ [ code ]

.TP

.BI ingest\ [ code ]

.BR Start ,

.BR stop ,

.BR eject ,

and

.B ingest

are synonyms for Start/Stop Unit with different default values of

.IR code .

Start/Stop Unit is typically used to spin up and spin down a rotating

disk drive.

.I Code

is 0 to stop,

1 to start and

3 to eject (if the device supports ejection of the medium).

.TP

.B capacity

Read Capacity reports the number of blocks and the block

size of a disk.

.LP

The following commands are specific to CD and CD-R/RW devices.

A brief description of each is given; see the SCSI-3

Multimedia Commands (MMC) Specification for details of arguments

and interpretation of the results.

.TF "inquiry"

.PD

.TP

.BI blank\ [ track/LBA [ type ]]

Erase a CD-RW disk.

Type identifies the method and coverage of the blanking.

.TP

.BI rtoc\ [ track/session-number [ ses ]]

The Read TOC/PMA command transfers data from one of the tables of contents

(TOC or PMA) on the CD medium.

.TP

.B rdiscinfo

(Note the spelling.)

Provides information about disks, including incomplete CD-R/RW.

.TP

.BI rtrackinfo\ [ track ]

Provides information about a track, regardless of its status.

.TP

.B cdpause

.TP

.B cdresume

Pause/resume playback.

.TP

.B cdstop

Stop playback.

.TP

.BI cdplay\ [ track-number ]\ or\ [ -r [ "LBA\fP[\fIlength\fP]]]"

Play audio.

With no arguments, starts at the beginning of the medium.

If a track number is given, the table of contents is read

to find the playback start point.

If the

.B -r

option is given, block addressing is used to find the

playback start point.

.TP

.BI cdload\ [ slot ]

.TP

.BI cdunload\ [ slot ]

Load/unload a disk from a changer.

.TP

.B cdstatus

Read the mechanism status.

.LP

The following commands are specific to Media Changer devices.

A brief description of each is given; see the SCSI-3

Medium Changer Commands (SMC) Specification for details of arguments.

.TF "inquiry"

.PD

.TP

.B einit

Initialize element status.

.TP

.BI "estatus " "type " [ length ]

Report the status of the internal elements.

Type 0 reports all element types.

.TP

.BI "mmove " transport\ source\ destination [ invert ]

Move medium.

.SH FILES

.TF /dev/sdXX/raw

.TP

.B /dev/\fIsdXX\fP/raw

raw SCSI interface for command, I/O, and status.

.SH SOURCE

.B /sys/src/cmd/scuzz

.SH "SEE ALSO"

.IR sd (3)

.br

.IR "Small Computer System Interface - 2 (X3T9.2/86-109)" ,

Global Engineering Documents

.br

.IR "SCSI Bench Reference" ,

ENDL Publications

.br

.IR "SCSI-3 Multimedia Commands (MMC) Specification" ,

www.t10.org

.br

.IR "SCSI-3 Medium Changer Commands (SMC) Specification" ,

www.t10.org

.SH BUGS

Only a limited subset of SCSI commands has been implemented (as needed).

.LP

Only one target can be open at a time.

.LP

LUNs other than 0 are not supported.

.LP

No way to force 10-byte commands, though they are the default.

.LP

Should be recoded to use

.IR scsi (2)

in order to get more complete sense code descriptions.

.LP

.I Scuzz

betrays its origins by spelling

.B rdiscinfo

with a

.B c

even though the devices it manipulates are spelled with a

.BR k .

.LP

The

.I max-xfer

value is currently limited to 245760

to limit kernel memory consumption.

.LP

It may be necessary to set

.I max-xfer

to exactly the block size used to write a tape

in order to read it on some drives.