Tandberg Data SLR7-140 PROGRAMMER, Руководство пользователя

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Tandberg Data Log Sense
13-31 Tandberg SLR Product Line SCSI Functional Specifications
Remaining Capacity
Counter - Partition 0
When the drive operates in write mode this counter
counts/presents remaining physical native capacity of
partition 0, scaled in KBytes. When the drive operates
in read mode this counter reflects the potential amount
of data stored from the current tape position to the end
of the partition and not the actual remaining storage
capacity of the partition. If the drive operates on
another partition than partition 0, this counter will be
equal to Maximum Capacity of partition 0.
Note that the capacity indicated is the capacity up to
the logical early warning marker.
This counter is not designed for use as an absolute
count of remaining capacity at any arbitrary moment, but
as a means to calculate approximate fraction of tape
usage during backup or restore operations.
Any attempt by initiator to alter this counters value
will be ignored.
Note: The Remaining Capacity counter presents an
approximate amount of native physical data which can be
written to the current tape partition. This count can be
related to logical user data only if the tape drive is
used in an optimal way. A high number of underruns
during write (due to a tape of poor quality, not
favorable system settings, low host transfer rate and/or
writing of a small amount of data per session) or
excessive use of forced streaming might reduce the
actual remaining capacity significantly. In addition,
the counter does not reflect any impact of a possible
use of data compression. The Remaining Capacity counter
is controlled by processes on the tape side of the data
buffer and is thus not fully synchronized with the data
stream on the SCSI-bus.