CFHT archive manual - tapes and tape devices Tapes and Tape Devices CFHT Tape Devices UNIX Tape Devices Tape Handling Guidelines Compression and Density ... Reading and Writing Tapes Types of CFHT Tape Devices Type
Native Capacity
Compressed Capacity
Where
Transfer Rate
dds2 dat
kuanalu
0.4M/sec
dds3 dat
onohi, mahina
2.23M/sec dds4 dat druid, umi 5.5M/sec exabyte onohi, mahina, hoku, kuanalu 0.5M/sec exabyte-mammoth kuanalu 3.0M/sec dlt 7000 hoku, onohi, mahina, manao, kou, kapu, druid 5.0M/sec sdlt manao 10.0M/sec DDS or DAT tapes are 4mm cartridges. The media is very compact and relatively inexpensive. Because of the compact size of the tape, DAT tapes are more susceptible to breakage and short shelf life than other form factors. They are primarily used for applications where space is an issue like personal backups or collections of data where a lot of tapes are to be kept in an accessible and convenient location. Exabyte tapes are all 8mm cartridges. The media is bigger than a DAT but still relatively compact. It is more reliable and slightly more expensive. Almost all tape drives in this format are manufactured by Exabyte Corp. and so compatibility is usually good though using older type tapes in newer drives can cause problems. For example using a 5gb (black) exabyte tape in a "mammoth" drive that uses 20gb (tan) tapes renders the drive inoperable until it is cleaned. UNIX Tape Devices n non rewinding c compressed h high density m medium density l low density (or uncompressed) u ultra density Note that not all of these options are available for all types of tape drive and that they don't always mean the same thing for all tape drives. In many cases for example, the drive may only be able to write at less than four densities or compression may be on or off by default for the unmodified device file. For more info on tape compression below. Normally the default device and and non-rewinding device are the only tape device files you will need. | |
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