The DLT7000 and 2000XT tape drives are high-performance, high-capacity, 1/2-inch streaming cartridge tape products designed and configured for use in Silicon Graphics high-performance servers and graphics systems. The tape medium can endure 500,000 passes and has an estimated shelf life of 30 years. Chapter 5, “DLT Drive Operation and Troubleshooting,” contains details on tape cartridges for the DLT drives.
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The DLT7000 tape drive features a native formatted capacity of 35 GB and a sustained user data transfer rate of up to 5 megabytes per second (MBps) uncompressed. Operating in compressed mode, a 70 GB capacity and 10 MBps transfer rate is possible. The DLT7000 tape drive design, a 5.25-inch form factor, includes a dual-channel read/write head, Lempel-Ziv (LZ) high-efficiency data compression, and tape mark directory to maximize data throughput and minimize data access time.
The DLT7000 drive uses the black DLTtape™ IV cartridges that have a capacity of 35.0 GB (native) or 70.0 GB (compressed). Built-in data compression increases cartridge capacity and drive transfer rate by a factor of 2 to 2.5. Actual amounts of data stored in compression mode are dependent on data type. You must use the DLTtape IV cartridge to achieve the data capacity and transfer rates listed.
The DLT2000XT tape drive features a native formatted capacity of 15 GB and a sustained user data transfer rate of up to 1.25 MBps A capacity of 30 GB, and data transfer rates of up to 2.5 MBps are possible using compressed mode. The DLT2000XT tape drive design, a 5.25-inch form factor, includes a dual-channel read/write head, Lempel-Ziv (LZ) high-efficiency data compression, and tape mark directory to maximize data throughput and minimize data access time.
The DLT2000XT drive uses white DLTtape IIIxt tape cartridges that have a capacity of 15.0 GB (native) or 30.0 GB (compressed). Built-in data compression increases cartridge capacity and drive transfer rate by a factor of 2 to 2.5.
For unattended backups or archiving, the DLT2000XT drive allows you to back up a high data-capacity system at a high speed. In noncompressed mode, the 2000XT has a maximum transfer rate of 1.25 MBps; in compressed mode, the maximum transfer rate is 2.5 MBps on writes and 3.0 MBps on reads. The compaction features of the DLT2000XT include a read/write cache of 2.0 MB; this working space enables maximum use of available tape space.
Table 1-1 summarizes supported DLT drive versions for various chassis.
Table 1-1. DLT Drive Configurations in Silicon Graphics Chassis
Chassis | DLT7000 | DLT2000XT | Maximum Number of Drives |
|---|---|---|---|
Origin2000 deskside | X | X | No internal DLTs; up to 4 external drives |
Origin2000 rackmount | X | X | Four |
Onyx2 deskside | X | X | No internal DLTs; up to 4 external drives |
Onyx2 rackmount | X | X | One |
Origin Vault | X | X | One |
Origin200 | X | X | One internal; up to 3 external drives using optional SCSI PCI boards |
As shown in Figure 1-1, the DLT drive uses a lift-handle to load and unload the tape cartridge. The drive has a green “operate handle” LED that indicates when operation of the handle is allowed. This LED is located below or to the right of the handle depending on drive orientation.
 | Caution: Never turn off an active DLT drive until after you have removed the tape cartridge, and properly halted the host system. Turning off the drive while it is in active use by the host is likely to result in data loss. |
Figure 1-2 shows the DLT2000XT carrier-mounted drive.
Each Origin Vault comes with two SCSI interface cables for connection to the host system. The internal-mount DLT drives install directly into the vault or Origin200, and do not require termination procedures. See Chapter 2 for configuration information on the drives. Always use the SCSI cable supplied with your Origin Vault or desktop DLT.
Pinouts for a host system's 68-pin single-ended SCSI connector are in Appendix A, “Hardware Specifications.”
The deskside Origin2000 and Onyx2 products come with only one external single-ended SCSI connector as a standard preconnected feature from the factory. The desktop version of the DLT7000 drive requires a differential SCSI connection which must be ordered and installed as part of the DLT7000 option.
Additional external SCSI connectors must be ordered as an optional XIO board and connected and configured by a trained field installer during or after the installation of the deskside host system.
The Origin200 deskside system uses a PCI based SCSI option board that may be installed by the end user.
| Caution: Installation of an optional external XIO SCSI board is not considered an end-user task on Origin2000 and Onyx2 systems. Opening of the XIO I/O panels by anyone other than a trained and qualified service person may violate safety agency requirements and regulations. |
Streaming tape drives such as the DLT drive require sustained data throughput from the system and host SCSI bus. To guarantee SCSI bus throughput for sustaining streaming operation of the drive, configure the DLT as the only device on an individual SCSI bus. Performance can be adversely affected when the DLT drive shares the bus with other devices. Sharing the bus with low-utilization devices such as a CD-ROM drive or a 4-mm DAT or 8-mm tape unit can allow acceptable performance.