DLT 40/80 hardware compression

[Brinkmann_1]

I am using a Compaq 40/80 drive and have recently noticed the the compression lights on the right hand side are off. When I try to select a compression ratio nothing happens. "no lights". And all backs that run are 1:1 ratio.

[Kurt Beyers. · Accepted solution]

And how are you taking backups?

Choose the correct hardware path to the tape drive, eg. tape0:0:0C instead of tape0:0:0. The 'C' at the end of the hardware path means that there is hardware compression.

best regards,

Kurt

[Brinkmann_1]

I using veritas 9.1 Backup Exec. This is the only device on that system.

[Brinkmann_1]

Maybe I didn't explain this very well. When I press the compression button on the left side of the drive I get no lights/compression selection.

Thanks again for the help.

[Brinkmann_1]

Ok Here is an update; I just ran HPtools Compression Test and the final results stated....
"Hardware compression may be switched off!"

Is there a way to physically turn on hardware Compression on he drive it's self (jumper, dipswitch)???

[Kurt Beyers.]

Hello,

No there are no DIP switches to enable/disable hardware compression. So it looks like a hardware problem.

Here is a copy/paste of the section about compression:

"The DLT80 drive reads and writes both uncompressed (native) and Digital Lempel-Div (DLZ) compressed data. The DLT80 drive features a native formatted capacity of 40 GB and a sustained native data transfer of 6.0 MB/s.

When operating in compressed mode, data capacity is affected by how much the data can be compressed. Most data can be compressed at an approximate 2:1 ratio.
This would provide the DLT80 drive with a compressed capacity of 80 GB and a compressed data transfer up to 12 MB/s.
The DLT80 drive ships from the factory with data compression enabled for writing. In this mode, data is always compressed when writing to the tape, but the drive is capable of reading both compressed and uncompressed tapes. For the drive to write uncompressed data, the data compression setting must be changed through the software. To change it, consult the backup application software documentation for the data compression enabling and disabling procedure. Using the Density Select button on the front panel can also disable/enable data compression but is only effective per session. See "Front Panel LEDs and Buttons" in Chapter 5 for more information."

You find the reference guide at http://h200002.www2.hp.com/bc/docs/support/UCR/SupportManual/TPM_185292e4/TPM_185292e4.pdf

best regards,

Kurt

[Brinkmann_1]

Thanks for all the help that link helped a lot!

[Brinkmann_1]

EUREKA!!!!
I found out what the issue was.. Just a small Hardware issue. I spoke with a coworker, that use to build these drives (back in the day). He sugessted to remove the front panel and resit the connectors from the button to the drive... OOOOOOHHH! That was it!!! I've got hardware compression again... I hope this information helps anyone that has the same problem.