Quantum TC2201E, Руководство пользователя

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Perform Configuration
Quantum TC2201E User’s Guide 121
• Select 1 to toggle Buffered Tape Writes to enabled or disabled. The
default setting is enabled. Buffered Tape Writes is an option designed
to enhance system performance. By returning status on consecutive
write commands prior to the tape device receiving data, Buffered
Tape Writes remove the latency of waiting for responses from the
tape device. In the event that data does not transfer correctly for any
reason, the router will return a check condition on a subsequent
command.
Commands other than Write(6) are not issued until status is received
for any pending write. Also, status is not returned until the device
completes the command. For instance, when a synchronizing
command is sent to a drive, such as sending a Write File mark, a good
status means all prior commands have been successfully completed
and data has been successfully written to the medium. This is
appropriate for such tasks as file backup/restore.
• Select 2 to set Maximum Writes Outstanding. This setting determines
the maximum number of writes that can be buffered. Any additional
writes beyond the maximum level allowed will be sent to the storage
device without using buffering, but these writes may also be
subsequently buffered when completion notices for earlier writes are
received.
• Select 3 to set Maximum Bytes Outstanding. This setting determines
the maximum number of write bytes (shown in units of kilobytes)
that can be buffered. Any additional writes beyond the maximum
level allowed will be sent to the storage device without using
buffering, but these writes may also be subsequently buffered when
completion notices for earlier writes are received.
Note:
If an application requires confirmation of individual blocks
being written to the medium, such as audit trail tapes or log
tapes, Buffered Tape Writes should be disabled.