Quantum TC2201 manual Perform Configuration

Perform Configuration

•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.

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.

•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.

Quantum TC2201 User’s Guide 89