HP Integrity NonStop H-Series - Manual (Page 24)

Chapter Four - Tape Cartridges
Tandem 5142-xSE Rackmount Tape Subsystems User Guide 1 4
4.2 Selecting a Tape Cartridge
The 5142-xSE uses data-quality removable, rewriteable 4mm DAT cartridges. The following table
shows tape cartridge capacity.
Cartridge Type Drive Type Native
Capacity Compressed
Capacity*
60m cartridge DDS-1 1.3GB 2.6GB
90m cartridge DDS-1 2.0GB 4.0GB
120m cartridge DDS-2 4.0GB 8.0GB
125m cartridge DDS-3 12.0GB 24.0GB
*assumes 2:1 data compression
Table 7 Tape capacities
4.3 Write-Protecting a Tape Cartridge
The tape cartridge (See Figure 10 has a write-protect switch that protects data cartridges from being
overwritten. To protect the cartridge, slide the switch all the way to the left (the hole will be visible).
Data can then be read from the tape but not written to it. Slide the switch to the right (covering the
hole) to write-enable the cartridge. Data can then be written to and read from the tape.
Write Protected
White Switch to the Left
Digital
Data
Storag
Label Side Up
Write Enabled
White Switch to the Right
Digital
Data
Storag
Label Side Up
Cartridge to be Loaded
in this Orientation
Cartridge to be Loaded
in this Orientation
Figure 10 Write-protecting a cartridge
Caution The tape log, which contains a history of usage of the tape, will not be updated when the
cartridge is write-protected. It follows that the tape log becomes inaccurate if a cartridge is
used when write-protected.
4.4 Labeled and Unlabeled Tapes
The 5142-xSE can use both labeled and unlabeled cartridge tapes. A tape label is a record at the
beginning of a tape that identifies the tape volume and the files it contains. An expiration date protects
labeled-tape information from being accidentally overwritten. A scratch tape is a labeled tape with an
expiration data that has passed. If a tape has no standard label, it is considered unlabeled. Tandem
systems support two standard tape-label formats: (1) ANSI and (2) IBM-MVS.
Note: Because they can be cataloged and offer security features for protecting data, labeled tapes should be
used with the 5142-1SE and 5142-2SE tape subsystems.