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Technical Note

Two competing tape technologies dominate the enterprise backup segment, LTO and SDLT. The current top 2 drive technologies are LTO3 and SDLT600 respectively. Both products represent evolution from a previous generation rather than complete new products. This is preferable as it ensures compatibility with a large range of existing tape libraries and provides backward read compatibility with the previous generation of product. Both factors offer continued protection of investment.

The LT03 significantly raises the bar, both in capacity per tape and with significantly higher drive transfer rates. To obtain the maximum performance from these new drives it will be important to use a back-up server equipped with the appropriate newer generation of high speed interface cards (see SCSI Information). Typically these servers will utilise PCI-X interface technology which provides internal bus speeds capable of supporting these data rates. [Functional Software has conducted testing with these higher performance drives and can ensure you get the most from your implementation of LT03 based libraries.]

DLT tape has been the other tape standard for enterprise use for many years. There are thousands of companies around the world that rely on this well proven technology to protect their data. The SDLT600 is read compatible with the SDLT320 but utilises a new cartridge, Super DLTtape II, to obtain its 300Gbyte native (600Gbyte compressed) capacity. The previous generation product, the SDLT 320, used the same Super DLTtape I cartridges as the SDLT 220 and is backward read compatible with DLTtape IV media, preserving investments in previous DLT technologies. For this reason alone DLT will continue to be a player in the tape market.

In the comparison table below the HP Ultrium LTO2 product specs have been used. The HP drive incorporates Adaptive Tape Speed which dynamically matches the transfer rates of slower hosts (from 10 MB/s upwards), which increases performance, reduces mechanical wear on the drive and extends tape life.

Comparison Chart

HP Ultrium 960
HP Ultrium 460
Native Capacity (GB) 400 300 200 160
Compressed Capacity (GB) 800 600 400 320
Media Type MP² AMP¹ MP² AMP¹
Drive LT03 Ultrium SDLT600 LT02 Ultrium SDLT320
Drive Transfer Rate (Native) (MB/s) 80 36 30 16
Drive Transfer Rate (Native) (GB/h) 288 133 108 57
Drive Transfer Rate (Comp.) (MB/s) 160 72 60 32
Interfaces Available LVD ULTRA, 320 SCSI,
2 GB Fibre Channel
2 GB Fibre Channel
LVD Ultra-3 SCSI,
2 GB Fibre Channel
Ultra 2 LVD and
Cartridge Memory LTO-CM No LTO-CM No
Compression Technology ALDC (2 : 1) DLZ (2 : 1) ALDC (2 : 1) DLZ (2 : 1)
MTBF - hours 250,000 250,000 250,000 250,000
Form Factor 5.25inches 5.25inches 5.25inches 5.25inches
Backward Read Compatible? Read and write
compatible with LTO2.
Read compatible with LT01
Read and write
compatibility with SDLT320.
See notes below
Read and write
compatible with LTO1
1st generation.
Read compatibility
with dual-head design.
See notes below
Backward Write Compatible? Read and write
compatible with LTO2
No Read and write
compatible with LTO1

¹ AMP : Advanced Metal Particle

² MP : Metal Particle

  • SDLT600 is backward compatible with Super DLTtape II 300 GB - READ AND WRITE native capacity, Super DLTtape I 160 GB - READ ONLY native capacity and DLTtape VS1 80 GB - READ ONLY native capacity.
  • SDLT 320 is backward-read and -write compatible with the SDLT 220, and backward-read compatible with the DLT 8000, DLT 7000, DLT 4000, DLT VS80, and DLT1 using DLTtape IV media.