Quantum DLTtape DLT 2000, Руководство пользователя

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DEMYSTIFYING TAPE DRIVE SPECS 6.2
which ones you can ignore. Figure 6-1 includes the most impor-
tant specifications for the DLTtape drives.
Capacity and Data Compression
Some manufacturers specify capacity in native mode. Others list
capacity with an asterisk, and a footnote that says something like
“assumes 2:1 compression.” Sometimes you might see a figure
without an asterisk, but that figure could still very well assume
compression of three or four to one.
Compression is the result of applying a compression algorithm to
the data before it is written to the tape. For a lot of applications,
compression is standard operating procedure. However, compres-
sion is only relevant if you actually compress your data, which you
may or may not want to do. Big blocks of text can be squeezed down
Figure 6-1 DLTtape Drives
are the performance and reliability targets for all
others on the market today. This chart shows some of the important specifications
for DLTtape drives.
Native Capacity 20GB 35GB 40GB 40GB 110GB
Compressed 40GB 70GB 80GB 80GB 220GB
Capacity (2:1)
Native 1.5MB/s 5MB/s 3MB/s 6MB/s 11MB/s
Transfer Rate
Compressed 3MB/s 10MB/s 6MB/s 12MB/s 22MB/s
Transfer Rate
Drive MTBF (hrs) at 200,000 200,000 200,000 250,000 250,000
100% Duty Cycle
Head Life (hrs) 10,000 30,000 30,000 50,000 50,000
Tape Life (yrs) 30 30 30 30 30
Media Passes 1 million 1 million 1 million 1 million 1 million
Uncorrected Bit 1 per 10
17
1 per 10
17
1 per 10
17
1 per 10
17
1 per 10
17
Error Rate
Warranty (yrs) 3 3 3 3 3
DLT
4000 DLT
7000 DLT1 DLT
8000 SDLT
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