IBM F50 RS/6000 7025 - Manual (Page 49)

Operating in Harsh Environments
The 8-mm tape drive is ideally suited to streaming operations, as opposed to tape
movement operations involving multiple stop/starts and random searches. When the
tape is used for frequent stop and start operations, streaming movement is beneficial
and should be used whenever possible. This can be accomplished by ensuring that
any save or restore operation is the only active operation performed by a device
connected to this SCSI I/O controller.
Any tape that has been used outside the ranges specified in the table on 2-22 for an
extended period of time (50 passes in 40 hours of nonstop operation) should not be
used as an archival tape. Exposure to the environment will deteriorate the magnetic
and physical strength of the tape. Do not store important data on a tape that has
been used outside the specified ranges; transfer the data to a new tape for reliable
archiving.
8-mm Data Cartridge Erasure
Most bulk eraser devices do not have the capability to erase 8-mm data cartridges.
To properly erase an 8-mm data cartridge with a bulk eraser device, the erasure
rating must be at least 1500 oersted.
The 2.3GB and the 5.0GB 8-mm tape drives erase residual data before writing new
data on the data tape.
Tape Cartridge Data Efficiency
The 8-mm tape cartridge efficiency is defined as the amount of data that can be
stored on the cartridge. The following variables affect the amount of data that can be
stored on a tape cartridge:
Size of the data file
Number of file marks per file
File mark size used
Compatibility mode (2.3GB or 5.0GB)
Media rewrites.
Chapter 2. Using the System Unit 2-23