Dear Jon
Since you found out anyway, I give up lying; I gonna tell you frankly:
I don't know exactly what I have.
'dmesg' says: st18: <HP DDS-3 4mm DAT loader>
'inquire' says: [email protected]:HP C1557A U709|Tape, /dev/rmt/0mbn
I did believe that this is similar to a Surestore 12000e.
Also I remember that somewhere it said the 'b' (berkley) option was a good
idea for amanda.
The '72-144 Gbyte 4mm DDS-3 Autoloader Installation and User's Guide' says
that a DDS-3 125m tape would hold 72GB uncompressed and 144GB compressed.
The tape itselfes says: 12GB native Capacity.
There is no switch inside the drive to enable/disable compression, so I assume
when not using the 'c,u' option, it wont compress.
Then there is the density switch (l,m,h) for low, medium and high. I don't
think this has to do with compression. I believe this depends on the made
of the tape? (I am not using any)
Sorry about the 'n' option. That was a lie ;-)
Cheers
Urs
>On Fri, Feb 28, 2003 at 11:06:56AM +0100, forster AT bluemail DOT ch wrote:
>> Here is what I put to config.
>> I have no idea what that filemark is. So if its wrong, I am not lying
;)
>>
>> define tapetype SURESTORE-1200E {
>> comment "HP AutoLoader"
>> length 12000 mbytes
>> filemark 100 kbytes
>> speed 500 kbytes
>> }
>
>Actually I suspect you have been lying in a number of places and ways.
>Perhaps unintentionally :))
>
>What tape drive do you really have?
>
>If I recall correctly, the SureStore-1200 is a DDS2 (DAT-2) changer
>and you were using a reasonable (3.9GB) tapetype definition for that.
>
>But you were using 125M tapes, DDS3 tapes that should not work in a
>DDS2 drive. Actually, has anyone ever tried that?
>
>And for sure, even using a 5M longer DDS3 tape with a DDS2 drive, I
>don't think would not get anywhere near the 8GB capacity you seem to
>be getting.
>
>Unless you can write to DDS3 formula tapes in a DDS2 drive AND we
>consider your other lie :)
>
>>> 4.) is hardwarecompression active in your tapedrive?
>> No, disabled by using device /dev/rmt/0bn
>> (b= berkley mode n= no compression)
>
>Based on device name I'm guessing this is a Solaris or HP system.
>In either case, "n" refers to No Rewind, not no compression.
>
>By chosing the 0 device with no density modifier (like "l", "m", ...),
>you have elected default compression, which generally is on.
>
>So maybe, if you are using a DDS2 drive, a DDS3 tape, no software
>compression, and hardware compression, you can get 8+GB of data written.
>
>What are you actually doing?
>
>BTW using the Berkeley drive options is not recommended.
>
>--
>Jon H. LaBadie jon AT jgcomp DOT com
> JG Computing
> 4455 Province Line Road (609) 252-0159
> Princeton, NJ 08540-4322 (609) 683-7220 (fax)
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