Quantum tape drive

[Dan Nelson]

In the last episode (Jan 28), Jaime said:
> On Wed, Jan 28, 2009 at 3:23 PM, Dan Nelson <dnelson at allantgroup.com> wrote:
> >
> > In the last episode (Jan 28), Jaime said:
> >> /usr/bin/tar -cvpX /usr/local/etc/backups/skiplist-relative.txt -f /dev/sa0 -C / .
> >
> > If nothing else, I suggest bumping up your blocksize.  The default for
> > tar (10k) is pretty small for modern tape drives.  Try -b 128 (for a 64k
> > block size).  Another optimization would be to put a buffering program
> > in between tar and your tape drive to decouple disk reads from tape
> > writes.  misc/team, misc/buffer, and misc/cstream in ports are good for
> > this.
> 
> Thanks.  Would this decrease the ability of other Unixes being able to
> read the tape?  For example, using pax (which can read tar archives)
> or GNU's tar?

It shouldn't.  At worst you may have to specify a matching blocksize
argument when reading.

> Sadly, I forgot to mention something in my last message.  Sorry.
> 
> When reading from the tape using tar (bsdtar from FreeBSD 6.2 -- and,
> yes, I'm preparing a cvsup as I write this :) ) the tape drive's Alarm
> and Fault LEDs are lit up and then camcontrol devlist no longer shows
> the tape drive.

According to
http://downloads.quantum.com/dlt_v4/DLT-V4_Product_Manual_81-81422-03_A01.pdf#page=67
, there is no alarm LED on a DLT-V4 drive, just Ready, Fault, Clean, and
Media.  If the Fault light is lit solid, it says that's an "Internal
firmware error".  If Fault and Clean are blinking slowly, you may have a bad
tape or may need to put a cleaning tape in.
 
> After I wrote to the tape via a quick boot into Knoppix, I found that
> FreeBSD's tar command could list the files on the tape.  So maybe that is
> in the past now.  Maybe not.  I should have mentioned it earlier.  Sorry.
> 
> Any other thoughts before I try to OS update and the larger block size?

-- 
	Dan Nelson
	dnelson at allantgroup.com