Sun Microsystems StorageTek T9840, Руководство пользователя

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Mixed Media Management
34 T9840 User’s Reference Manual • September 2008 Revision YA • 95739
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The T9840D tape drive cannot correct or cause an invalid MIR on a T9840A/B
written data cartridge. A T9840A/B MIR can only become invalid during a mount
on a T9840A/B drive.
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If a T9840C or T9840A/B written data cartridge has an invalid MIR, its contents
cannot be read into the T9840D drive's memory and the user data pointer
information will be unavailable. This causes a performance degradation.
T9840C tape Drive Loaded With a T9840D Data Cartridge
The T9840C drive will not be able to read the MIR written by a T9840D drive. Because
it was written by a T9840D there will be no T9840A/B MIR. The T9840C drive will read
the Format Identity Burst (FIB) written by the T9840D tape drive.
Note – The T9840C drive identifies the tape cartridge as high-density data format, and
Ready H
(high-density) appears in the T9840C operator panel display.
Since the T9840D written data cannot be read by the T9840C tape drive, the only actions
available to the drive are:
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Unload the data cartridge
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Reclaim the data cartridge
If the data cartridge is reclaimed, the T9840C drive will include the statistical
information from the T9840D FIB when it writes the T9840C MIR and FIB.
T9840C Tape Drive Loaded With a T9840A/B Data Cartridge
When a data cartridge is loaded into a T9840C, the drive first looks for a MIR at the
high-density MIR designated location; and will not find a MIR if the data cartridge is in
low-density data format. The high-density MIR location will be blank if it is the first
time the low-density data cartridge is loaded into a T9840C drive. This causes the drive
to look at the low-density MIR designated location, where it finds a MIR and reads it
into drive memory (invalid flag is not set).
The T9840C drive uses the memory-resident MIR for user data pointers for read-only
functions. During the first mount session, the drive captures statistical counters from
the MIR into a memory area called the Format Identity Burst (FIB), and continues to
build it with drive activity.
Note – The FIB is written in a special format which can also be read by T9840A/B
drives with the appropriate drive firmware level.
During the unload routine, the T9840C drive writes the FIB to the high-density MIR
designated tape location. The tape-resident, low density MIR remains intact and valid.
Notes:
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The T9840C drive identifies the tape cartridge as low-density data format, which
results in the display of
Ready L
(low-density) on the T9840C operator panel.
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The T9840C tape drive cannot cause nor correct an invalid MIR on a low-density
data cartridge. A low-density MIR can only become invalid during a mount on a
T9840A/B tape drive.