Tape Drives

Tape drives are used primarily to store data offline, often as a backup.

Once a new tape drive is connected to the system and booted properly, the tape drive is ready for use. Unlike disk drives, tape drives do not need to be formatted, labeled, or prepared in any special way.

Once the tape device is installed and the operating system is running, you refer to the tape device by the logical device name as described in the Table 3-1 below. For more information on logical device names refer to Appendix A, SCSI Addressing.

Table 3-1 Address and Logical Device Names for Tape Drives

Tape Drive	SCSI Address Switch or Jumper Setting (Target ID)	Primary Logical Device Name	Additional Logical Device Names
First tape drive	4*	/dev/rmt/0	/dev/rmt/0n   /dev/rmt/0h   /dev/rmt/0c   /dev/rmt/0ubn
Second tape drive	5*	/dev/rmt/1	/dev/rmt/1n   /dev/rmt/1h   /dev/rmt/1c /dev/rmt/1ubn

*Can be any unique address on the bus.

For most tape operations you should use the primary logical device name because the tape drive will use its optimum default characteristics. However, if you want to specify a particular tape drive behavior, append a letter to the appropriate logical device name as follows:

• Append a letter to the drive number to specify a tape density where h is high, m is medium, l is low, c is compressed, and u is ultra. Not all tape drives support all densities. If you are in doubt, do not specify a density. The tape drive should default to the optimum setting.

• Append a b to the drive number to specify BSD behavior. This means that when reading past an end-of-file mark, it returns the first record of the next file. This is desirable if the tape is going to be read on a BSD UNIX system.

• Append an n to the drive number to specify no rewind operation, otherwise the tape will rewind when the tape operation is complete.

Valid tape names are shown in the table below. If you are working with the second tape drive use a 1 instead of 0.

0n   0b   0bn

0c   0cb   0cbn   0cn

0h 0hb 0hbn 0hbn

0m   0mb   0mbn   0mn

0l   0lb   0lbn   0ln

0u   0ub   0ubn   0un

To Add a Tape Drive

1. Shut down your system.

   See "Shut Down the System".

2. Check that the address switch for the tape drive has been set correctly.

   The SCSI address switch for tape drives is typically preset by the factory to SCSI target ID 4. If you have more than one tape drive, you must set the SCSI address switch of the second tape drive to an address other than SCSI target ID 4 or any other target ID present on the bus.

   Refer to the documentation that came with your new tape device and to Appendix A, SCSI Addressing".

   ---

   Note -

   Connecting more than four tape drives to a single SCSI bus can cause slower system performance.

   ---

   ---

   Caution -

   Each tape drive must have a unique SCSI target ID setting. The SCSI address switches on your tape drives may need to be set to different numbers than those shown in Table 3-1. For further information on device addresses, see the System Administration Guide.

   ---

3. Install the tape drive.

   For installation information, refer to the documentation that accompanies your hardware.

4. Turn the power on to the system and all the peripheral devices.

   In most cases, this will cause the system to automatically boot. If the /reconfigure file is present (as described in "To Prepare the System"" in Chapter 1), then the operating system will automatically assign a logical device name and initialize the appropriate device drivers for the new device. If the /reconfigure file does not exist, you can achieve the same effect by performing a boot -r. See Appendix B, Booting Your System" for more information.

   Your new tape drive is ready for use.