Can't get SureStore 12000e to Compress...

[Lenny Story]

Greetings,

I have a surestore 12000e Autoloader, and i cannot seem to get the compression to work.

I am writing a 1GB file which contains the repeated string :

This is a test of the emergency Broadcast system. 0123456789ABC
This is a test of the emergency Broadcast system. 0123456789ABC

I have enabled the compression using the command : mt -f /dev/nst0 datcompression 9.
The DC indication on the drives front panel is on. It is my guess that a file containing the same repeated value should compress to almost nothing.

The dip switches on the bottom of the drive are all on Except for 3 which is off.

My tests have consisted of rewinding the tape, and executing the command "tar -cvf /dev/nst0 gigfile.txt" with and without datcompression on. In both cases the "mt tell" command reports the same block location when finished. (104858).

Does anyone have a clue what im doing wrong ?

Thanks,
Lenny
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root@skunk:/home/catbert > cat /proc/scsi/scsi
Attached devices:
Host: scsi0 Channel: 00 Id: 02 Lun: 00
Vendor: HP Model: C1553A Rev: 9608
Type: Sequential-Access ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 02 Lun: 01
Vendor: HP Model: C1553A Rev: 9608
Type: Medium Changer ANSI SCSI revision: 02
root@skunk:/home/catbert >

---------------------------------------------------

root@skunk:/home/catbert > mt -f /dev/nst0 status
drive type = Generic SCSI-2 tape
drive status = 603990016
sense key error = 0
residue count = 0
file number = 1
block number = 0
Tape block size 10240 bytes. Density code 0x24 (DDS-2).
Soft error count since last status=0
General status bits on (81010000):
EOF ONLINE IM_REP_EN
root@skunk:/home/catbert >

---------------------------------------------------
root@skunk:/home/catbert > mtx -f /dev/nst0 inquiry
Vendor ID: 'HP ', Product ID: 'C1553A ', Revision: '9608'

---------------------------------------------------

root@skunk:/home/catbert > mtx -f /dev/nst0 status
Data Transfer Element: Full (Storage Element 1 Loaded)
Storage Element 1: Empty
Storage Element 2: Full
Storage Element 3: Full
Storage Element 4: Full
Storage Element 5: Full
Storage Element 6: Full
root@skunk:/home/catbert >

---------------------------------------------------

root@skunk:/home/catbert > cmtape


Device : /dev/nst0
Type : Generic SCSI-2 tape
---------------------------------------
Current File : 1
Current Block : 104858

Errors :
---------------------------------------
Sense Error : 0
Residue Count : 0
Software Errors : 0

Status : 24002800
---------------------------------------
Block Size : 10240 (0x2800)
Density : 36 (0x24)


General Status : 0x81010000
---------------------------------------
* End Of File
* Online
* Immediate Report Mode

[Tina Karasch]

nothing besides that the options you use....

tar cvf

just have the following meanings:

c
Create a new archive on the device.
v
Operate in verbose mode.
f
Specify the archive name explicitly.


And you tried to enable the compression using the command : mt -f /dev/nst0 datcompression 9

But the command to set compression on or off using GNU mt should be,

# mt -f /dev/st0 datcompression 0 # turns compression off

# mt -f /dev/st0 datcompression 2 # turns compression on

# mt -f /dev/st0 datcompression 1 # reports whether on or off Compression on.


Using mt-st,

# mt -f /dev/st0 compression 0 # turns compression off
# mt -f /dev/st0 compression 1 # turns compression on

or if all else fails....
the dip-swithches are set to use compression at power-up --> but give hostcontrol (SW/OS)
so you could set switch 2 to off to not give the os/sw the abillity to override the compression setting of the 12000e.

even though the status info of your drive looks ok besides the drv waiting for a write command; please check your dev config file.

A file-close on /dev/sti causes the tape drive to automatically rewind
the cartridge. For example, after a tar cf on /dev/st0, the drive head will be positioned at beginning of tape. A subsequent tar cf on the same device will overwrite the previous archive.

/dev/nsti is the no-rewind device. It can be used to create several
archives, one after the other, on a single Tape cartridge.
You can then select a particular archive to restore using the fsf and
bsf operations provided by the mt command. This will let you locate a particular archive by seeking to the correct filemark using high-speed locate.

Check if you already have the device-special files:
# ls -l /dev/*st?
crw-rw---- 1 root tape 9, 128 Sep 22 15:33 /dev/nst0
crw-rw---- 1 root tape 9, 129 Sep 22 15:33 /dev/nst1
crw-rw---- 1 root tape 9, 0 Sep 22 15:33 /dev/st0
crw-rw---- 1 root tape 9, 1 Sep 22 15:33 /dev/st1

If you donâ t see these files you can build them using the MAKEDEV script, using command construct:
# ./MAKEDEV st

You can make device-special files for up to eight SCSI tape drives, st0 through st7.

On some Linux distributions, you have to run MAKEDEV once for each
Drive, example:
# ./MAKEDEV st0

maybe also have a look at these urls ?

http://h20000.www2.hp.com/bizsupport/TechSupport/Home.jsp?locale=en_US&prodTypeId=12169&prodSeriesId=63992&submit.y=5&submit.x=10〈=en&cc=us

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=lpg51060&prodTypeId=12169&prodSeriesId=63992&locale=en_US

http://www.hp.com/cposupport/information_storage/support_doc/lpg51068.html

http://www.hp.com/cposupport/information_storage/support_doc/lpg51070.html


hope this helps you
@>'-;---