smt(1)

NAME

smt - magnetic tape control

SYNOPSIS

smt [ -f tapename ] command [ count ]

DESCRIPTION

The smt program sends commands to a local or a remote mag

netic tape drive.

The count operand specifies the number of times the re

quested command is to be performed. If count is omitted, the val

ue of count defaults to one.

OPTIONS

-help Prints a summary of the options for smt(1) and ex

its.

-version

Prints the smt version number string and exists.

-debug print additional debug messages.

-f tapename

-t tapename

Set the raw tape device to use, otherwise smt uses

a system specific default for the rtape device. If smt is in

stalled suid root or if it has been called by root, tapename may

be in remote syntax: user@host:filename as in rcp(1) even if in

voked by non root users. See SUID NOTES for more information.

To make a file local although it includes a colon

(:), the filename must start with: '/', './' or '../'

Note that if smt talks to an old rmt remote tape

server that does not support symbolic open modes, it does not

open a remote tape with the O_CREAT open flag because this would

be extremely dangerous. If the rmt server on the other side is

the rmt server that comes with star or the GNU rmt server, smt

may use the symbolic mode for the open flags. Only the symbolic

open modes allow to send all possible open modes in a portable

way to remote tape servers.

It is recommended to use the rmt server that comes

with star. It is the only rmt server that gives platform inde

pendent compatibility with BSD, Sun and GNU rmt clients and it

includes security features that may be set up in /etc/de

fault/rmt.

See ENVIRONMENT section for information on how to

use ssh(1) to create a remote tape server connection.

-wready

Wait for the tape drive to become ready before exe

cuting the command.

COMMANDS

The following commands are supported:

eof

weof Write count EOF (FILE) marks at the current

position on the tape.

This command may be run remotely with any BSD

compliant old rmt server.

fsf Forward skip over count FILE marks. The tape

is positioned on the first block of the file.

This command may be run remotely with any BSD

compliant old rmt server.

bsf Backward skip count FILE marks. The tape is

positioned on side of the FILE mark that is closer to the begin

ning of the tape.

This command may be run remotely with any BSD

compliant old rmt server.

asf Absolute FILE mark positioning to file number

count. This is equivalent to a rewind followed by a fsf count.

A RMT version 1 server is needed to run this

command on a remote tape drive.

fsr Forward skip count tape records.

This command may be run remotely with any BSD

compliant old rmt server.

bsr Backward skip count tape records.

This command may be run remotely with any BSD

compliant old rmt server.

rewind Rewind the tape.

This command may be run remotely with any BSD

compliant old rmt server.

offline

rewoffl Rewind the tape. If the specified tape drive

allows to take the drive off-line or to unload the tape, a off

line or unload operation is performed in addition.

This command may be run remotely with any BSD

compliant old rmt server.

status Retrieve and print status information for the

tape drive.

A RMT version 1 server is needed to get cor

rect status information on a remote tape drive.

nop No operation. If you only like to wait for

the tape drive to become ready, call smt -wready nop.

This command may be run remotely with any BSD

compliant old rmt server.

retension Retension the tape. This only makes sende with

cartridge tape drives.

A RMT version 1 server is needed to run this

command on a remote tape drive.

erase Erase the entire tape. This may take a long

time (up to several hours) depending on the tape drive and the

medium.

A RMT version 1 server is needed to run this

command on a remote tape drive.

eom Position the tape to the end of the recorded

media. This allows to append data to previously written tapes.

A RMT version 1 server is needed to run this

command on a remote tape drive.

nbsf Backward skip count FILE marks. The tape is

positioned on side of the FILE mark that is closer to the end of

the tape. This is before the first block of the file. The nbsf

command is equivalent to count+1 bsf's followed by one fsf.

A RMT version 1 server is needed to run this

command on a remote tape drive.

load If the specified tape drive allows to take the

drive on-line or to load the tape, a on-line or load operation is

performed. in addition. For remote tape drives, this command

only works if the remote tape server supports symbolic open modes

as the command needs the O_NDELAY flag to succeed.

A RMT version 1 server is needed to run this

command on a remote tape drive.

EXAMPLES ENVIRONMENT

RSH If the RSH environment is present, the remote con

nection will not be created via rcmd(3) but by calling the pro

gram pointed to by RSH. Use e.g. RSH=/usr/bin/ssh to create a

secure shell connection.

Note that this forces smt to create a pipe to the

rsh(1) program and disallows smt to directly access the network

socket to the remote server. This makes it impossible to set up

performance parameters and slows down the connection compared to

a root initiated rcmd(3) connection.

RMT If the RMT environment is present, the remote tape

server will not be the program /etc/rmt but the program pointed

to by RMT. Note that the remote tape server program name will be

ignored if you log in using an account that has been created with

a remote tape server program as login shell.

TAPE In case no -f option pas been specified, the de

fault tape name is taken from the TAPE environment.

FILES SEE ALSO

spax(1), suntar(1), scpio(1), tar(1), cpio(1), pax(1),

rcp(1), mt(1), rmt(1), match(1), dd(1), sdd(1), rsh(1), ssh(1),

star(1), star(4/5), rcmd(3),

DIAGNOSTICS NOTES

If the remote tape server is running Linux and the remote

tape server on such a system is not the rmt server that comes

with star(1), then completely unexpected results (including unex

pectedly erased tapes) may occur. This is because Linux ignores

the numbering values for the magnetic tape op codes and only the

rmt server from star(1) maps to standard values. The standard

rmt server on Linux for this reason may not be called BSD compli

ant.

BUGS AUTHOR

Joerg Schilling
Seestr. 110
D-13353 Berlin
Germany

Mail bugs and suggestions to:

schilling@fokus.fraunhofer.de or js@cs.tu-berlin.de or

joerg@schily.isdn.cs.tu-berlin.de

Joerg Schilling 04/09/26

SMT(1)