VS160 tape drive compression (not)

[David Nixon]

Hello,
I've been testing an QUANTUM DLT VS160 tape drive
under HP-UX 11.11; using the /dev/rmt/c#t#d0BEST raw mag.tape device.
However compression for this device is not enabled.

Thus far I have only been able to write 77GB of data
to one tape. Could it be the case that the SCSI tape driver (stape)
does not yet support this type of drive?

Thanks for any pointers,

DavidN.

[Chris Moore]

Yes, it's likely that stape doesn't recognize the drive.
What is the SCSI model string reported by the drive? You
can get that from an ioscan. stape recognizes Quantum
DLT2*, DLT4*, DLT7*, DLT8*, SuperDLT1*, and SDLT320*. However,
if stape doesn't recognize the drive it should then check
the density setting of the device and be able to figure out
it's a DLT.

If you know the density value that the drive uses (the actual
code sent in the SCSI command) you can create a device file
that uses that code. Check out the stape section of the man
page for mksf. The -b option can be followed by a decimal number
which is to be sent to the drive for the density code.

Chris Moore




David Nixon wrote: Hello, I've been testing an QUANTUM DLT VS160 tape drive under HP-UX 11.11; using the /dev/rmt/c#t#d0BEST raw mag.tape device. However compression for this device is not enabled.

[David Nixon]

> Yes, it's likely that stape doesn't recognize the drive. What is the SCSI model string reported by the drive? You can get that from an ioscan. stape recognizes Quantum DLT2*, DLT4*, DLT7*, DLT8*, SuperDLT1*, and SDLT320*. However, if stape doesn't recognize the drive it should then check the density setting of the device and be able to figure out it's a DLT.
Hello Chris,

My tape drive reports itself as a QUANTUM DLT VS160.
If you know the density value that the drive uses (the actual code sent in the SCSI command) you can create a device file that uses that code. Check out the stape section of the man page for mksf. The -b option can be followed by a decimal number which is to be sent to the drive for the density code.

According to the specs. 0x99 is the code for VS160 compression. I
couldn't get 'mksf' to accept that value, so created my own tape device
using 'mknod':

crw-rw-rw- 1 bin bin 205 0x002000 Mar 29 12:54 c0t2d0D153C

With this I will try to 'vxdump' an 130GB files system but, after
reading the PHKL_29899 (11.11 SCSI Tape cumulative) patch documentation,
I'm not optimistic that stape will use my density value.

DaveN.
Chris Moore