[NTLUG:Discuss] SCSI tape setup - beyond just /dev/st0

[Richard]

I have googled until my fingers are cramping.  I don't know what I'm
looking for at this point.  My ultimate goal is to issue a SCSI command to
my Python tape drive to turn off hardware compression.  I COULD do it with
jumper settings
(http://www.certance.com/download/userguides/user_guide_cdl432xx_en.pdf)
but I think controlling it via software is better.


(http://www.certance.com/download/productmanuals/prod_man_stdlx2401lw_en.pdf)
has instructions for DEC Unix that talks about how one can configure the
SCSI Cam driver.

<snippet>
With Version 4.0 of the Digital UNIX operating system, DEC introduced a
new method of configuring the CAM SCSI driver. Modify the file
/etc./ddr.dbase as follows:
1. Look through the file and locate the database entry for the DEC TLZ07
DAT drive
2. Copy this entry and paste it later in the file, taking care to maintain
the file syntax.
3. Modify this new entry as shown below....
</snippet>

then.. then there are modifications that allow one to set "CompressionCode
= 0x0".

So the questions are....

How does one pass scsi parameters to a scsi device?  I assume MT is for
passing parameters, but what about at load time?

Is there a configuration file for scsi devices?  Kernel parameters?

Some *nixes appent '.5' to the end of a scsi device to signify 'Use this
device without compression'.  How are those '.5 devices' made?--is it with
mknod and some parameter?

I don't know what I need to search on at this point.

HELP!!!


-- 
Richard