The DLT7000 drive normally uses the DLTtape IV cartridge. This black plastic cartridge stores up to 35 GB of native (uncompressed) data, or 70 GB of compression mode data. The DLT7000 can also read and write the DLTtape IIIxt cartridge (15 GB native and 30 GB compressed), or the DLTtape III cartridge (10 GB native or 20 GB compressed).

The tape cartridges for the DLT2000XT drive are the white DLTtape IIIxt cartridges. The DLT2000XT drive stores and reads up to 15 GB native and 30 GB compressed data on each tape. Note that the DLT2000XT drive will not write more than this amount even if you use a higher capacity cartridge. Never use the DLTtape IV cartridge in a 2000XT drive.

The DLT7000 drive is capable of backward-format compatibility with previous generations of DLT tape cartridges, providing forward and backward data interchange with systems having older drives. For example, a system with a DLT2000 tape drive can interchange data with a system having a DLT7000 drive by using a CompacTape III cartridge.

Tape drives are not forward-compatible with respect to tape cartridges; for example, the DLT2000 tape drive cannot read DLTtape IV or DLTtape IIIxt cartridges.

To make tape cartridges last as long as possible, store them in a clean environment. Follow these guidelines for storing and using the tapes:

Observe the following precautions when handling or storing a tape:

The tape cartridge has a write-protect switch that functions as follows:

Figure 5-1 shows the write-protect switch and the indicator.

Figure 5-1. Tape Cartridge Write-Protect Switch

---

Note: Do not move the write-protect switch during tape operation.

---

The DLT tape drives have front-mounted LEDs that indicate the status of the unit. Figure 5-2 shows the front panel of the DLT20000XT and 7000 drives.

The DLT7000 front bezel has a density select button on the lower left that is not supported (and does not function) in Silicon Graphics systems. All DLT7000 density selection changes are made through software.

---

Note: For information on the power-on self test LED sequences, see “Using the Power-On Self-Test” in Chapter 3.

---

Figure 5-2. DLT2000XT and 7000 Front Panels

Table 5-1 summarizes front panel LEDs.

Table 5-2 summarizes middle front panel LEDs on the 2000XT.

After initialization, the drive is in one of the states shown in Table 5-3.

Load the tape cartridge as follows:

The green Operate Handle LED goes off and the yellow Tape in Use LED blinks to indicate that the tape is loading. When the tape is at the beginning-of-tape (BOT) marker, the yellow Tape in Use LED glows steadily. The tape is now ready for use.

When the tape is being read, written, or rewound, the yellow Tape in Use LED blinks (see Table 5-2).

Remove a tape cartridge as follows:

---

Note: The green Operate Handle LED must be on before you open the handle or remove a tape. Always remove the tape cartridge from the DLT before turning off power to the drive.

---

You can select compression from the host using the appropriate SCSI tape interface; see the tps reference page for more information. The default selection is the native tape density for the cartridge type you insert.

For interchange compatibility with earlier drives, the tape drive can write lower-capacity tape formats. On a write from BOT, the tape drive automatically reformats the tape cartridge to match the maximum native (uncompressed) capacity the drive can write on the cartridge. The drive automatically reads the media regardless of the format.

---

Note: After a bus reset, the tape drive responds within a bus selection timeout period. Although the system manager backup and restore tool may report the DLT drive as “unknown,” it works correctly.

---

The DLT drive default data block transfer size is 4KB (4096 bytes). To achieve better performance, adjust block size to 32K bytes or higher when using a fixed block device.

Depending on your particular applications, the fullest data transfer performance (throughput) can be obtained by specifying a variable block size during backups or other data transfer operations.

To use the variable setting when performing backups, use the v addition to the device identifier when specifying data for backup.

For example, the following command copies all files in the current directory to a DLT drive that is installed as SCSI unit 6 on controller 1:

% tar -cvf /dev/mt/tps1d6v * 

The v added at the end of the device identifier tps1d6 allows the system to vary the block transfer size to achieve the most efficient transfer of data.

The addition of the v can also provide variable block size transfers for use with other backup commands such as cpio, dd, dump, or restore. See the reference (man) page for a particular data transfer command for additional information on its use.

The hinv -c tape inquiry to a deskside or rackmount system provides information on every tape drive connected to that host. Use the command to determine if the DLT drive(s) you installed are recognized by the host.

%hinv -c tape
  Tape drive: unit 5 on SCSI controller 7: 8mm(8500) cartridge
  Tape drive: unit 6 on SCSI controller 6: DLT
  Tape drive: unit 5 on SCSI controller 6: DLT

---

Tip: If you installed a DLT drive, and the hinv list shows that the host system does not see it attached to any SCSI controller, read the next section “What to Do If hinv Does Not See the Tape Drive.” Also see Table 5-4 for additional solutions.

---

Table 5-4 lists general potential problems and possible solutions. If none of the offered solutions helps, consult your system administrator or service provider.

If none of the offered solutions helps, consult your system administrator or service provider.