# /dev/tape ?

## trossachs

What is the device description for a scsi tape drive and how would I go about mounting this device? Can I automatically mount this in /etc/fstab, what options should I use?

Also, does anyone have any idea how I can use rsync to perform a one-off basic backup of my system onto tape, with periodic ones to follow? thx.

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## EvilTwinSkippy

SCSI tapes aren't generally mounted. You use them as a block device. Peer through your kernel logs to see if it mentions any tape devices.

They are usually at /dev/st(a|b|c...) or /dev/sg(a|b|c...)

To read from a tape: tar xf /dev/sta

To write to a tape: tar cf /dev/sta /foo

(I recommend you consult a handy backup howto.)

Make sure you grab the mtx tools to control the tape drive (rewind, eject, change tape, etc.)

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## trossachs

Which 'kernel logs' are you referring to? /var/log/messages? If so, I can see no mention of scsi or tape devices.

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## dogshu

Your first scsi tape drive should be /dev/st0, your second should be /dev/st1, etcetera.

You can see your kernel logs with the "dmesg" command.  Try running this to see what your scsi tape drive is called:

```
dmesg | grep st

```

Like EvilTwinSkippy said, you don't mount tape devices.  You access them with programs like "tar".

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## trossachs

After I run that command, this is what I see:

```

SCSI subsystem driver Revision: 1.00

kmod: failed to exec /sbin/modprobe -s -k scsi_hostadapter, errno = 2

```

Prob with my scsi adapter perhaps?

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## dogshu

Well, if you just do a "dmesg" you can look through the whole thing and see what it has to say about your SCSI adapter.

Here's what my kernel has to say about my SCSI adapter and my many SCSI devices:

```

Feb 29 19:13:19 delta-9 scsi0 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 6.2.36

Feb 29 19:13:19 delta-9 <Adaptec 3960D Ultra160 SCSI adapter>

Feb 29 19:13:19 delta-9 aic7899: Ultra160 Wide Channel A, SCSI Id=7, 32/253 SCBs

Feb 29 19:13:19 delta-9

Feb 29 19:13:19 delta-9 (scsi0:A:0): 40.000MB/s transfers (20.000MHz, offset 15, 16bit)

Feb 29 19:13:19 delta-9 (scsi0:A:3): 20.000MB/s transfers (20.000MHz, offset 16)

Feb 29 19:13:19 delta-9 (scsi0:A:6): 20.000MB/s transfers (20.000MHz, offset 16)

Feb 29 19:13:19 delta-9 (scsi0:A:6): 10.000MB/s transfers (10.000MHz, offset 16)

Feb 29 19:13:19 delta-9 (scsi0:A:9): 40.000MB/s transfers (20.000MHz, offset 32, 16bit)

Feb 29 19:13:19 delta-9 Vendor: SEAGATE   Model: ST39102LW         Rev: 0006

Feb 29 19:13:19 delta-9 Type:   Direct-Access                      ANSI SCSI revision: 02

Feb 29 19:13:19 delta-9 scsi0:A:0:0: Tagged Queuing enabled.  Depth 253

Feb 29 19:13:19 delta-9 Vendor: TOSHIBA   Model: DVD-ROM SD-M1401  Rev: 1010

Feb 29 19:13:19 delta-9 Type:   CD-ROM                             ANSI SCSI revision: 02

Feb 29 19:13:19 delta-9 Vendor: GENERIC   Model: CRD-BP5           Rev: 7.42

Feb 29 19:13:19 delta-9 Type:   CD-ROM                             ANSI SCSI revision: 02

Feb 29 19:13:19 delta-9 Vendor: SEAGATE   Model: DAT    06240-XXX  Rev: 8240

Feb 29 19:13:19 delta-9 Type:   Sequential-Access                  ANSI SCSI revision: 03

Feb 29 19:13:19 delta-9 scsi1 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 6.2.36

Feb 29 19:13:19 delta-9 <Adaptec 3960D Ultra160 SCSI adapter>

Feb 29 19:13:19 delta-9 aic7899: Ultra160 Wide Channel B, SCSI Id=7, 32/253 SCBs

Feb 29 19:13:19 delta-9

Feb 29 19:13:19 delta-9 (scsi1:A:0): 80.000MB/s transfers (40.000MHz, offset 31, 16bit)

Feb 29 19:13:19 delta-9 (scsi1:A:2): 160.000MB/s transfers (80.000MHz DT, offset 127, 16bit)

Feb 29 19:13:19 delta-9 Vendor: WDIGTL    Model: WDE18310 ULTRA2   Rev: 1.30

Feb 29 19:13:19 delta-9 Type:   Direct-Access                      ANSI SCSI revision: 02

Feb 29 19:13:19 delta-9 scsi1:A:0:0: Tagged Queuing enabled.  Depth 253

Feb 29 19:13:19 delta-9 Vendor: FUJITSU   Model: MAN3367MP         Rev: 2601

Feb 29 19:13:19 delta-9 Type:   Direct-Access                      ANSI SCSI revision: 03

Feb 29 19:13:19 delta-9 scsi1:A:2:0: Tagged Queuing enabled.  Depth 253

Feb 29 19:13:19 delta-9 st: Version 20040122, fixed bufsize 32768, s/g segs 256

Feb 29 19:13:19 delta-9 Attached scsi tape st0 at scsi0, channel 0, id 9, lun 0

Feb 29 19:13:19 delta-9 st0: try direct i/o: yes, max page reachable by HBA 1048575

Feb 29 19:13:19 delta-9 SCSI device sda: 17783240 512-byte hdwr sectors (9105 MB)

Feb 29 19:13:19 delta-9 SCSI device sda: drive cache: write back

Feb 29 19:13:19 delta-9 /dev/scsi/host0/bus0/target0/lun0: p1 p2

Feb 29 19:13:19 delta-9 Attached scsi disk sda at scsi0, channel 0, id 0, lun 0

Feb 29 19:13:19 delta-9 SCSI device sdb: 35761710 512-byte hdwr sectors (18310 MB)

Feb 29 19:13:19 delta-9 SCSI device sdb: drive cache: write back

Feb 29 19:13:19 delta-9 /dev/scsi/host1/bus0/target0/lun0: p1

Feb 29 19:13:19 delta-9 Attached scsi disk sdb at scsi1, channel 0, id 0, lun 0

Feb 29 19:13:19 delta-9 SCSI device sdc: 71771688 512-byte hdwr sectors (36747 MB)

Feb 29 19:13:19 delta-9 SCSI device sdc: drive cache: write back

Feb 29 19:13:19 delta-9 /dev/scsi/host1/bus0/target2/lun0: p1

Feb 29 19:13:19 delta-9 Attached scsi disk sdc at scsi1, channel 0, id 2, lun 0

Feb 29 19:13:19 delta-9 sr0: scsi3-mmc drive: 40x/40x cd/rw xa/form2 cdda tray

Feb 29 19:13:19 delta-9 Uniform CD-ROM driver Revision: 3.20

Feb 29 19:13:19 delta-9 Attached scsi CD-ROM sr0 at scsi0, channel 0, id 3, lun 0

Feb 29 19:13:19 delta-9 sr1: scsi3-mmc drive: 40x/40x writer cd/rw xa/form2 cdda tray

Feb 29 19:13:19 delta-9 Attached scsi CD-ROM sr1 at scsi0, channel 0, id 6, lun 0

Feb 29 19:13:19 delta-9 Attached scsi generic sg0 at scsi0, channel 0, id 0, lun 0,  type 0

Feb 29 19:13:19 delta-9 Attached scsi generic sg1 at scsi0, channel 0, id 3, lun 0,  type 5

Feb 29 19:13:19 delta-9 Attached scsi generic sg2 at scsi0, channel 0, id 6, lun 0,  type 5

Feb 29 19:13:19 delta-9 Attached scsi generic sg3 at scsi0, channel 0, id 9, lun 0,  type 1

Feb 29 19:13:19 delta-9 Attached scsi generic sg4 at scsi1, channel 0, id 0, lun 0,  type 0

Feb 29 19:13:19 delta-9 Attached scsi generic sg5 at scsi1, channel 0, id 2, lun 0,  type 0

```

As you can see, the kernel identifies my Adaptec SCSI adapter, then identifies each of the connected devices.  It sees my "SEAGATE DAT" tape drive, then attaches it to a device name (where it says "Attached scsi tape st0 at scsi0, channel 0, id 9, lun 0").

If you don't see any SCSI adapter related stuff in your kernel, you need to recompile your kernel with support for your SCSI adapter.  If you don't see anything about your SCSI tape drive in your kernel, you need to recompile your kernel with SCSI tape support.  Presuming there's nothing wrong with your hardware, of course (is everything plugged in, terminated, and turned on?)

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## trossachs

As I said in my previous post, I seem to have a prob with my Adaptec card as illustrated above. Will check to see whether or not support has been compiled into the kernel but I am sure it is.

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## trossachs

Have just booted the box and replaced both scsi card and cable with a set that I know works and still nothing. Have definately compiled all the info I need into the kernel, so cannot understand as to why this won't show up.

Is there any other clues I should be looking for?   :Confused: 

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## dogshu

well, I guess you can do a "/sbin/lspci" to see if the PCI bus even sees your SCSI card.  You need to "emerge pciutils" first.

Under Linux 2.6.3, there are 6 different drivers for various Adaptec SCSI cards, so maybe you should compile them all as modules, then try modprobing each driver one by one to see if any of them work for you.

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## trossachs

Well I have an Adaptec AHA-2940W/2940UW scsi adapter, but I cannot see a driver available within the compile kernel list. I've emerged pciutils, and have googled around, but I can see no website or instructions on how to use it!

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## dogshu

I'm pretty sure you use the same driver as me, the aic7xxx driver.  Try doing a "modprobe aic7xxx", if that doesn't work try enabling "Adaptec AIC7xxx Fast -> U160 support (New Driver)" under SCSI->SCSI- low-level drivers in your kernel.

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## trossachs

Will have to try this and see what's what. I am a bit concerned with the error I posted earlier, plus the fact that I have already compiled all references to AIC into the kernel.

The card and device deffinately work as I used them previously under another OS; thus I am quite at a loss.

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