HP 35480 DAT questions

HP 35480 DAT questions

Post by Richard W. Ko » Thu, 05 Dec 1996 04:00:00



Hi there Linux dudes,

Just purchased an HP 35480 DAT drive to use for Linux 2.0.24,
and was wondering if I could get some recommendations on the
dip switch settings on the bottom. I am planning to run GNU
dump and GNU tar as my backup programs, but I was wondering
what the best setup is for the 8 dip switches.

These are two settings that I have been given

1-8 ON (Compression enabled, host control)
1,3-8 ON and  2 OFF (Compression enabled, NO host control)

Do you users use GNU mt to set the compression, does it work
first off? Or do you recommend the second setting and just
allow the drive to do the copmression on its own without
user/host intervention?

Thanx,
Rich

 
 
 

HP 35480 DAT questions

Post by G. de Freita » Fri, 06 Dec 1996 04:00:00



> Hi there Linux dudes,

> Just purchased an HP 35480 DAT drive to use for Linux 2.0.24,

I have been using mine for 2yrs+, no problems.
=/dev/st0
mine = 1-8 ON (Compression enabled, host control)

Quote:> and was wondering if I could get some recommendations on the
> dip switch settings on the bottom. I am planning to run GNU
> dump and GNU tar as my backup programs, but I was wondering

===================;-)
I suggest "dds2tar", 90M tape, 60 seconds to access _ANY_ file from
index, INDEX written by -R option (man tar)

Quote:> what the best setup is for the 8 dip switches.

> These are two settings that I have been given

> 1-8 ON (Compression enabled, host control)
> 1,3-8 ON and  2 OFF (Compression enabled, NO host control)

> Do you users use GNU mt to set the compression, does it work
> first off? Or do you recommend the second setting and just
> allow the drive to do the copmression on its own without
> user/host intervention?

> Thanx,
> Rich

Your'e welcome, Hope I've helped.
Ciao4Now,
G.

 
 
 

HP 35480 DAT questions

Post by Al Slat » Fri, 06 Dec 1996 04:00:00



: Hi there Linux dudes,

: Just purchased an HP 35480 DAT drive to use for Linux 2.0.24,
: and was wondering if I could get some recommendations on the
: dip switch settings on the bottom. I am planning to run GNU
: dump and GNU tar as my backup programs, but I was wondering
: what the best setup is for the 8 dip switches.

: These are two settings that I have been given

: 1-8 ON (Compression enabled, host control)
: 1,3-8 ON and  2 OFF (Compression enabled, NO host control)

: Do you users use GNU mt to set the compression, does it work
: first off? Or do you recommend the second setting and just
: allow the drive to do the copmression on its own without
: user/host intervention?

11011111 for anything on a PC loosely speaking.

1-2 do DC control thus:

00      DC off by default, DC control by host disallowed
01      DC off by default, DC control by host allowed
10      DC on by default, DC control by host disallowed
11      DC on by default, DC control by host allowed

If GNU mt does DC control by mode page, then it quite probably
works, if it does by density code, then no it won't unless you
fiddle the switches on the underside to allow it.

Unless the tape driver explicitly turns DC off on initial
mount/open then you'll get DC on by default with 1 and 2
on. I don't recall Linux's st.c doing this.

To see how GNU mt does compress, see what ioctl it
throws for it and look in the st.c source to see if
it uses mode select of page 0x0f...

cheers,
al
(not speaking for HP..)

 
 
 

HP 35480 DAT questions

Post by Kai M{kisar » Sat, 07 Dec 1996 04:00:00


...

Quote:> Unless the tape driver explicitly turns DC off on initial
> mount/open then you'll get DC on by default with 1 and 2
> on. I don't recall Linux's st.c doing this.

Correct.

Quote:> To see how GNU mt does compress, see what ioctl it
> throws for it and look in the st.c source to see if
> it uses mode select of page 0x0f...

st.c uses mode page 0x0f to control compression in the MTIOCTOP
function MTCOMPRESSION. I don't know about GNU mt but the mt from
mt-st-0.4.tar.gz does support this ioctl (mt compression).

        Kai

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