On Tuesday 18 February 2003 05:44 am, Paul Bijnens wrote:
>Joshua Baker-LePain wrote:
>>On Mon, 17 Feb 2003 at 11:27pm, marc.bigler AT day DOT com wrote
>>
>>>I am using an Exabyte Eliant 820 tape drive on Linux kernel
>>> 2.4.18 and would like to make sure the hardware compression is
>>> disabled. Does anyone know how I can check that ?
>>
>>For that drive, compression is controlled via density.  0x15 is
>>uncompressed.
>
>The latest amtapetype from amanda 2.4.4b1 includes an heuristic
> test to check if the tapedrive really has hardware compression
> disabled (it could be on because dipswitches were set to force it
> on or off regardless of software commands).
>Run it as "amtapetype -c ..." to do the compression detection test
> only (the tape contents are lost; use a scratch tape!).
>
>Paul

There is also a util called tapeinfo which I believe is part of the 
current mtx package.  It reports on the complete device, 
non-destructively.

To use it, you give it the 'sg' address of the drive in the changer, 
like this:

[amanda@coyote everything]$ tapeinfo -f /dev/sg0
Product Type: Tape Drive
Vendor ID: 'ARCHIVE '
Product ID: '4586XX 28887-XXX'
Revision: '0420'
Attached Changer: No
SerialNumber: 'DT014WP'
MinBlock:1
MaxBlock:16777215
SCSI ID: 6
SCSI LUN: 0
Ready: yes
BufferedMode: yes
Medium Type: 0x32
Density Code: 0x24
BlockSize: 512
DataCompEnabled: no
DataCompCapable: yes
DataDeCompEnabled: yes
CompType: 0x0
DeCompType: 0x0
Block Position: 64
------------------
I have no idea why it says there is no attached changer, because it 
has one at LUN=1.  But the data is otherwise accurate.

-- 
Cheers, Gene
AMD K6-III@500mhz 320M
Athlon1600XP@1400mhz  512M
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