MT.1
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上传日期:2007-01-18
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- .TH MT 1
- .SH NAME
- mt - magnetic tape control
- .SH SYNOPSIS
- .B mt
- .RB [ -f
- .IR device ]
- .RI [ count ]
- .SH DESCRIPTION
- .B Mt
- is a user interface to the magnetic tape commands described in
- .BR mtio (4).
- It allows one to space a tape forwards or backwards, write end of file
- markers, etc.
- .PP
- With the
- .B -f
- option a tape device can be named, otherwise the environment variable
- .B TAPE
- is used if set, otherwise the default device
- .B /dev/nrst4
- is assumed. Standard input is used if the tape name is a dash (-). The
- .I count
- argument is used to tell how many blocks or files to space or how many file
- markers to write. It may be a C-style decimal, octal or hexadecimal constant,
- by default "1".
- .PP
- .I Command
- is the action to perform, it may be one of the following, or any
- unambiguous prefix (like
- .B st
- for
- .BR status ):
- .TP 15
- .B eof, weof
- Write
- .I count
- end-of-file markers.
- .TP
- .B fsf
- Forward space
- .I count
- file markers.
- .TP
- .B fsr
- Forward space
- .I count
- records. (The size of a record depends on the tape, and may even be
- variable, depending on the size of the writes.)
- .TP
- .B bsf
- Backwards space
- .I count
- files. The count may be zero to backspace to the start of the current file.
- (A tape device need not support backwards movement, or may be very slow
- doing it. Rewinding and forward spacing may be better.)
- .TP
- .B bsr
- Backwards space
- .I count
- records. The tape is positioned after the last block of the previous file
- if you hit a filemark when spacing backwards. The block count is set to -1
- to indicate that the driver has no idea where it is on the previous file.
- .TP
- .B eom
- Forward space to the end of media.
- .TP
- .B rewind
- Rewind the tape.
- .TP
- .B offline, rewoffl
- Rewind and take offline. This may cause some drives to eject the tape.
- .TP
- .B status
- Shows the status of the drive, the sense key of the last SCSI error,
- current file number, current record number, residual count if the last
- command that encountered end-of-file, and the current block size.
- .TP
- .B retension
- Removes tape tension by winding and rewinding the tape completely.
- .TP
- .B erase
- Erases the tape completely and rewinds it.
- .TP
- .B density
- Sets the density code to read or write the tape to
- .IR count .
- Density codes supported depend on the drive. This command need not be
- used if the drive senses the proper density on read and can only write
- one density.
- .TP
- .B blksize, blocksize
- Sets the block size used to read or write the tape to
- .IR count .
- This command may be used to select a fixed block size for a variable block
- size tape. This will speed up I/O for small block sizes. Use a zero
- .I count
- to use variable sized blocks again.
- .SH ENVIRONMENT
- .TP 15n
- .B TAPE
- Tape drive to use if set.
- .SH FILES
- .TP 15n
- .B /dev/nrst4
- Default tape device.
- .SH "SEE ALSO"
- .BR mtio (4),
- .BR st (4).
- .SH AUTHOR
- Kees J. Bot (kjb@cs.vu.nl)