MTX Frequently Asked Questions
Finding the Correct Device
Links:
Compatibility
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Q: Why does this command not work??
# mtx -f /dev/st0 inquiry
In /var/log/messages I see:
st0: Write not multiple of tape block size.A: Note that mtx 1.2 and above use the SCSI GENERIC interface on Linux, FreeBSD, and Solaris (at least). They do NOT use the tape device node. Please read the man page for directions. -
Q: When I do 'mtx -f /dev/sga inquiry' it shows
Product Type: Tape Drive
Vendor Id: HP
Product ID: C1553A
But when I do a 'mtx -f /dev/sga status' it fails. Why?!A: You're trying to send a robotics command to a tape drive. You need to send robotics commands to robotics devices, not to tape drives. Look in /proc/scsi/scsi (Linux) or camcontrol (FreeBSD) to find out what the robotics device is. It will be reported as a 'Medium Changer', not a 'Sequential Access' or 'Tape Drive'. -
Q: When I do 'cat /proc/scsi/scsi' it shows only one device, the tape device! A: You are using a DAT autochanger that has one SCSI ID but two LUN's, LUN 0 and LUN 1. You need to compile a new kernel with SCAN SCSI LUNS enabled or add this line to your /etc/lilo.conf (then run /sbin/lilo and reboot): append="max_scsi_luns=2" -
Q: I'm tired of typing '-f /dev/sgc' all the time. How do I set a default device that 'mtx' looks at? A: Set the CHANGER environment variable. For example, with 'bash': export CHANGER=/dev/sgc -
Q: I get
modprobe: can't locate module char-major-21
syslog messages being squirreled away into a file on our syslog host, and mtx doesn't work. What's the problem?A: You need to compile SCSI generic support into your kernel (or as a module). -
Q: When I installed mtx, a message showed up on the console stating that a scsi changer was found at dev sgr. However, I have no device /dev/sgr. A: On Linux, do 'mknod /dev/sgr c 21 19' to create a device node. By default only 16 SCSI generic nodes are created, which might not be enough if you have multiple SCSI controllers with lots of devices.
| Maintained by Robert Nelson | Date Changed: | Changed By: |
