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+Channel attached Tape device driver
+This driver is considered to be EXPERIMENTAL. Do NOT use it in
+production environments. Feel free to test it and report problems back to us.
+The LINUX for zSeries tape device driver manages channel attached tape drives
+which are compatible to IBM 3480 or IBM 3490 magnetic tape subsystems. This
+includes various models of these devices (for example the 3490E).
+Tape driver features
+The device driver supports a maximum of 128 tape devices.
+No official LINUX device major number is assigned to the zSeries tape device
+driver. It allocates major numbers dynamically and reports them on system
+Typically it will get major number 254 for both the character device front-end
+and the block device front-end.
+The tape device driver needs no kernel parameters. All supported devices
+present are detected on driver initialization at system startup or module load.
+The devices detected are ordered by their subchannel numbers. The device with
+the lowest subchannel number becomes device 0, the next one will be device 1
+and so on.
+Tape character device front-end
+The usual way to read or write to the tape device is through the character
+device front-end. The zSeries tape device driver provides two character devices
+for each physical device -- the first of these will rewind automatically when
+it is closed, the second will not rewind automatically.
+The character device nodes are named /dev/rtibm0 (rewinding) and /dev/ntibm0
+(non-rewinding) for the first device, /dev/rtibm1 and /dev/ntibm1 for the
+second, and so on.
+The character device front-end can be used as any other LINUX tape device. You
+can write to it and read from it using LINUX facilities such as GNU tar. The
+tool mt can be used to perform control operations, such as rewinding the tape
+or skipping a file.
+Most LINUX tape software should work with either tape character device.
+Tape block device front-end
+The tape device may also be accessed as a block device in read-only mode.
+This could be used for software installation in the same way as it is used with
+other operation systems on the zSeries platform (and most LINUX
+distributions are shipped on compact disk using ISO9660 filesystems).
+One block device node is provided for each physical device. These are named
+/dev/btibm0 for the first device, /dev/btibm1 for the second and so on.
+You should only use the ISO9660 filesystem on LINUX for zSeries tapes because
+the physical tape devices cannot perform fast seeks and the ISO9660 system is
+optimized for this situation.
+Tape block device example
+In this example a tape with an ISO9660 filesystem is created using the first
+tape device. ISO9660 filesystem support must be built into your system kernel
+The mt command is used to issue tape commands and the mkisofs command to
+create an ISO9660 filesystem:
+- create a LINUX directory (somedir) with the contents of the filesystem
+ mkdir somedir
+ cp contents somedir
+- insert a tape
+- ensure the tape is at the beginning
+ mt -f /dev/ntibm0 rewind
+- set the blocksize of the character driver. The blocksize 2048 bytes
+ is commonly used on ISO9660 CD-Roms
+ mt -f /dev/ntibm0 setblk 2048
+- write the filesystem to the character device driver
+ mkisofs -o /dev/ntibm0 somedir
+- rewind the tape again
+ mt -f /dev/ntibm0 rewind
+- Now you can mount your new filesystem as a block device:
+ mount -t iso9660 -o ro,block=2048 /dev/btibm0 /mnt
+ - Driver has to be stabilized still
+This driver is considered BETA, which means some weaknesses may still
+be in it.
+If an error occurs which cannot be handled by the code you will get a
+sense-data dump.In that case please do the following:
+1. set the tape driver debug level to maximum:
+ echo 6 >/proc/s390dbf/tape/level
+2. re-perform the actions which produced the bug. (Hopefully the bug will
+3. get a snapshot from the debug-feature:
+ cat /proc/s390dbf/tape/hex_ascii >somefile
+4. Now put the snapshot together with a detailed description of the situation
+ that led to the bug:
+ - Which tool did you use?
+ - Which hardware do you have?
+ - Was your tape unit online?
+ - Is it a shared tape unit?
+5. Send an email with your bug report to: