Linux 8.0 - scsi tape drive

[Cokey de Percin]

On Thu, 2004-03-25 at 22:12, Mayur Patel wrote:
> HI...
> 
> This is my first posting so not sure if posting in correct place or not. Please advise if not.
> 
> I want to use HP DAT 24X6 SCSI tape drive with Linux 8.0. I've attached the tape drive with linux but getting following error.
> 
> can someone please educate how the scsi tape drive installation works in linux ?
> 
> can someone please classified below output with his/her suggestion/comments ?
> 
> Thanks in advance for your help. I'd follow up if i need to provide any more information.
> 
> thanks again. please help.
> 
> 
> [BDC root]# mt -f /dev/st0 status
> SCSI 2 tape drive:
> File number=-1, block number=-1, partition=0.
> Tape block size 0 bytes. Density code 0x0 (default).
> Soft error count since last status=0
> General status bits on (50000):
> DR_OPEN IM_REP_EN
> 
> [BDC root]# more /proc/scsi/scsi
> Attached devices:
> Host: scsi0 Channel: 00 Id: 03 Lun: 00
>  Vendor: HP Model: C1557A Rev: U812
>  Type: Sequential-Access ANSI SCSI
> revision: 02
> Host: scsi0 Channel: 00 Id: 03 Lun: 01
>  Vendor: HP Model: C1557A Rev: U812
>  Type: Medium Changer ANSI SCSI
> revision: 02
> [BDC root]# uname -r
> 2.4.18-14
> [BDC root]# tar cvf /dev/st0 /etc
> tar: Removing leading `/' from member names
> etc/
> etc/sysconfig/
> etc/sysconfig/network-scripts/
> etc/sysconfig/network-scripts/ifup-aliases
> tar: /dev/st0: Wrote only 0 of 10240 bytes
> tar: Error is not recoverable: exiting now
> 
> [BDC root]# mt -f /dev/nst0 status
> SCSI 2 tape drive:
> File number=-1, block number=-1, partition=0.
> Tape block size 0 bytes. Density code 0x0 (default).
> Soft error count since last status=0
> General status bits on (50000):
> DR_OPEN IM_REP_EN
> 
> [BDC root]# mt -f /dev/nst1 status
> /dev/nst1: No such device or address
> 
> [BDC root]# mt -f /dev/nst0 status
> SCSI 2 tape drive:
> File number=-1, block number=-1, partition=0.
> Tape block size 0 bytes. Density code 0x0 (default).
> Soft error count since last status=0
> General status bits on (50000):
> DR_OPEN IM_REP_EN
> ****
> File number=-1, block number=-1 <<<<<<< those are negative -1
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> - File online. File on time.

Well, looks to me like either you don't have a tape in the drive or it
doesn't know there's a tape there.  Did you actually 'load' a tape?  I
don't mean put tapes in the cart. and load the cart. into the changer, I
mean cause the changer to load a tape in the actual tape drive.  If
there is a tape in the drive (as opposed to the changer) you should get
this:

gandolf:/# mt -f /dev/nst0 status
SCSI 2 tape drive:
File number=-1, block number=-1, partition=0.
Tape block size 0 bytes. Density code 0x25 (DDS-3).  <<< notice this
Soft error count since last status=0
General status bits on (1010000):
 ONLINE IM_REP_EN                                    <<< notice this

In order to 'load' a tape from the changer cart. you need to use the mtx
command (mtx-1.2.16-2 for 7.3) and in order to use it, you need to know
the sg# for the drive & changer.  

I use 'sgcheck' (scsi-1.7.... ) which will give you something like this:

gandolf:/# sgcheck

Assignment of generic SCSI devices,
device host/channel/ID/LUN type(numeric type) vendor model:

/dev/sg0 0/0/0/0 Direct-Access SEAGATE ST34501W
/dev/sg1 1/0/4/0 Sequential-Access HP C1557A
/dev/sg2 1/0/4/1 Medium Changer HP C1557A
/dev/sg3 1/0/5/0 CD-ROM YAMAHA CRW8824S
/dev/sg4 1/0/6/0 CD-ROM TOSHIBA DVD-ROM SD-M1401
/dev/sg5 2/0/1/0 Processor HP C2520A

Note that the drive and the changer have the same scsi id, but different
luns.  The changer is usually 1 while the drive is 0.

The syntax to load a tape with mtx is (for my situation):

mtx -f /dev/sg2 load 1 0; this loads the first tape from the           
			  changer into the drive

mtx -f /dev/sg2 status  ; gives a status, this:

gandolf:/# mtx -f /dev/sg2 status
  Storage Changer /dev/sg2:1 Drives, 6 Slots ( 0 Import/Export )
Data Transfer Element 0:Full (Storage Element 1 Loaded)
      Storage Element 1:Empty
      Storage Element 2:Full
      Storage Element 3:Full
      Storage Element 4:Full
      Storage Element 5:Full
      Storage Element 6:Full

Now that there's a tape in the actual drive, you cat tar to it in the
normal way.

mtx -f /dev/sg2 unload  ; put the tape back

Best

Cokey

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F. 'Cokey' de Percin, DBA       Email:
CSC                              Work - cdeperci at csc.com
Columbia, South Carolina         Home - fdepercin at sc.rr.com


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