Quantum DLTtape SDLT 220, User Manual

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CHAPTER 3: Drive Specifications SDLT 220 and SDLT 320 Product Manual
3-4 March 2004 81-85002-01
3.1.6 Maximum Data Transfer Rate
The maximum sustained (and burst) data transfer rates for SDLT drives are shown in
Table 3-4 .
N
OTE
: Cable lengths and cable type can limit attainable transfer
rate; for details, refer to a separate document,
SDLT 220 and SDLT 320 Design and Integration Guide,
81-81148-01.
3.1.7 Head Life and MTBF
Mean time between failures (MTBF) for the overall tape system is projected to be
250,000 hours, not including the heads. Head life is a minimum of 30,000 tape
motion hours and an average of 50,000 tape motion hours.
Table 3-4. Maximum Data Transfer Rates
SDLT 220
Sustained
SDLT 220
Burst
Max*
SDLT 320
Sustained
SDLT 320
Burst
Max*
Config-
uration
Native
Com-
pressed‡
Native
Com-
pressed‡
HVD
(Ultra 1
SCSI)
Narrow 11 MB/sec 20 MB/sec 20 MB/sec 16 MB/sec 20 MB/sec 20 MB/sec
Wide 11 MB/sec 22 MB/sec 40 MB/sec 16 MB/sec 32 MB/sec 40 MB/sec
LVD
(Ultra 2
SCSI)
Narrow 11 MB/sec 22 MB/sec 40 MB/sec 16 MB/sec 32 MB/sec 40 MB/sec
Wide 11 MB/sec 22 MB/sec 80 MB/sec 16 MB/sec 32 MB/sec 80 MB/sec
* Burst speeds are limited by the SCSI bus itself, not the design of SDLT 220/320 or Super DLTtape media.
‡ The compression rates shown assume an industry standard 2:1 compression ratio. Actual compression ratios
achieved depend on the redundancy of data files being recorded. For non-compressible (expanding) data, this
results in a reduction in capacity and transfer rate for the data. Fully random data is the worst case for
compressibility.