.\" scsitape.1 Document Copyright 2001 Eric Lee Green .\" Copyright 2007-2008 by Robert Nelson .\" .\" This is free documentation; you can redistribute it and/or .\" modify it under the terms of the GNU General Public License as .\" published by the Free Software Foundation; either version 2 of .\" the License, or (at your option) any later version. .\" .\" The GNU General Public License's references to "object code" .\" and "executables" are to be interpreted as the output of any .\" document formatting or typesetting system, including .\" intermediate and printed output. .\" .\" This manual is distributed in the hope that it will be useful, .\" but WITHOUT ANY WARRANTY; without even the implied warranty of .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the .\" GNU General Public License for more details. .\" .\" You should have received a copy of the GNU General Public .\" License along with this manual; if not, write to the Free .\" Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, .\" USA. .\" .TH SCSITAPE 1 SCSITAPE1.0 .SH NAME scsitape \- control SCSI tape devices .SH SYNOPSIS scsitape [-f ] commands .SH DESCRIPTION The .B scsitape command controls SCSI tape drives in a platform-independent manner. As long as 'mtx' works on the platform, so does 'scsitape'. .P Note that 'scsitape' and your OS's native tape driver may stomp on each other. In particular, if you use 'setblk' and your OS's native tape driver has a different notion of the block size, you may get evil results. It is recommended to use 'scsitape' only for software where you've written your own low-level READ and WRITE routines that use the SCSI command set to directly talk to tape drives (i.e., you do not use the OS's native tape driver at all). .SH OPTIONS The first argument, given following .B -f , is the SCSI generic device corresponding to your tape drive. Consult your operating system's documentation for more information (for example, under Linux these are generally /dev/sg0 through /dev/sg15, under FreeBSD these are /dev/pass0 through /dev/passX. Under Solaris this is usually the same as your tape drive (Solaris has a SCSI passthrough ioctl). You can set the STAPE or TAPE environment variable rather than use -f. .P .SH COMMANDS .TP 10 .B setblk Set the tape drive's SCSI block size to bytes. (NOTE: if you are using your OS's native tape driver, THIS IS EVIL!). .TP 10 .B fsf Go forward by tapemarks. .TP 10 .B bsf Go to immediately previous the th previous tapemark. (WARNING: This probably doesn't do what you expect -- e.g. if you are immediately after a tapemark and type 'bfs 1', it moves to immediately *before* that tape mark, for a sum total of zero effective movement!). .TP 10 .B eod Go to end of data. .TP 10 .B rewind Rewind the tape drive. .TP 10 .B eject Eject the tape currently in the drive. .TP 10 .B erase Does a *short* erase (warning: does NOT work on all drives!). .TP 10 .B mark write filemarks ( 'mark 0' flushes the drive's buffers ). .TP 10 .B seek Seek to a logical position that was reported by a previous 'tapeinfo' command. .TP 10 .B write write blocks from stdin to the tape. Chunk the data into -sized chunks. *DOES NOT WRITE OUT A TAPEMARK!* (you will need to use a subsequent .B mark 1 command to write out a tape mark). .TP 10 .B read [] [ <#blocks/#bytes> ] read blocks from the tape, write them to stdout. If we are in variable block mode, should be zero (note: The maximum block size we currently support in variable block mode is 128K, MAX_READ_SIZE will need to be turned into a settable variable to allow bigger reads). If is omitted, we assume that we're in variable block mode, and that we are going to read from tape until we hit a tapemark or end of partition or end of tape. .SH AUTHORS This program was written by Eric Lee Green . Major portions of the 'mtxl.c' library used herein were written by Leonard Zubkoff. .P The SCSI read and write routines are based upon those that Richard Fish wrote for Enhanced Software Technology's BRU 16.1 product, substantially modified to work in our particular environment (in particular, all the variable block stuff is new since BRU only does fixed block reads and writes, and the BRU code uses bitmasks rather than bitfields for the various flags and such in return values, as well as the BRU code having a different SCSI API and having variable names considerably shorter than the rather sesquipedalian 'mtx' identifiers). As required by 'mtxl.c', these routines are licensed under the GNU General Public License. .SH HINTS Under Linux, .B cat /proc/scsi/scsi will tell you what SCSI devices you have. You can then refer to them as .B /dev/sga, .B /dev/sgb, etc. by the order they are reported. .P Under FreeBSD, .B camcontrol devlist will tell you what SCSI devices you have, along with which .B pass device controls them. .P Under Solaris 7 and 8, .B /usr/sbin/devfsadm -C will clean up your /devices directory. Then .B find /devices -name 'st@*' -print will return a list of all tape drives. /dev on Solaris is apparently only of historical interest. .SH BUGS AND LIMITATIONS for .B scsitape read 0 where you are doing variable-block-size reads and wish for bytes, it instead reads one and exactly one block from tape and prints that (no matter what its size). Use 'dd' on the output of scsitape if you want finer control. .P .B scsitape read 0 attempts reads of MAX_READ_SIZE, which is currently 128K. If blocks on tape are larger than 128K, only the first 128K will be read -- the remainder will be silently dumped in the toilet. .P This program does not interact well (or at all :-) with your OS's native tape driver. You will likely see weird things happen if you attempt to intermingle scsitape commands with native tape driver operations. Note that BRU 16.1 for Solaris (and possibly others, but Solaris I know about) will have a 'scsi' keyword to bypass the native tape driver and write via direct uscsi commands, so if you use 'scsitape' to bypass the flaws of the native Solaris driver, you can use BRU 16.1 to write your actual tape archives. (Assuming that BRU 16.1 has been released at the time that you read this). .SH AVAILABILITY This version of .B scsitape is currently being maintained by Robert Nelson as part of the 'mtx' suite of programs. The 'mtx' home page is http://mtx.sourceforge.net and the actual code is currently available there and via SVN from http://sourceforge.net/projects/mtx. .SH SEE ALSO .BR loaderinfo (1), tapeinfo (1), mtx (1)