*BSD News Article 75406


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From: j@uriah.heep.sax.de (J Wunsch)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: HP Colorado T4000s  Tape Drive error messages
Date: 3 Aug 1996 19:47:46 GMT
Organization: Private BSD site, Dresden
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dbrockus@cyberhall.com (David Brockus) wrote:

> cyber1# mt status
> Present Mode:   Density = 0x45         Blocksize = 512 bytes

I think this density value is too high for the `st' driver.  Have a
look into the driver source, it (stupidly) rejects densities > 0x17 or
so.  Simply remove this restriction and see if it would help.

> st0(ahc0:4:0): ILLEGAL REQUEST asc: 24,0 Invalid field in CDB
> st0: Cannot set selected mode
> 
> What is CDB?

The SCSI command descriptor block.

> Is there a device setup file where I specify the density and blocksize
> for each mode?

The SCSI code contains some `quirks' for some known tape drives, but
i'm pretty sure yours is not mentioned there.

> My problem is what do I do with this information?  In the man page for
> 'mt' that specific bit density is not supported, do I just pick the
> closest match?

Ah, no, you don't need to tell it to `mt'.  SCSI drives are addressed
in terms of blocks, so the underlying physics are largely irrelevant.
The only use of the different densities in `mt' is that you might
select one out of a few possible density values for those drives where
this is appropriate.  I assume your drive supports only a single
density value at all.

-- 
cheers, J"org

joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)