Maxtor 10K III manual Feature Descriptions

The Verify Error Recovery Page of the MODE SELECT COMMAND controls the drive's response to error conditions that arise during the VERIFY command and during the verify operation of the WRITE AND VERIFY command.

Feature Descriptions

￿￿￿￿￿&CVCIn￿5GEVQTany SCSI￿4GCNNQECVKQPdisk drive, bad￿blocks'TTQT￿2TQVGEVKQPmay be reallocated. However, a power failure or unrecoverable data could threaten data integrity during a block reallocation.

The reallocation and defect list storage algorithms prevent a reallocation from being lost due to a power failure. Once a reallocation starts, the information about the data block to be moved is stored on the media. As the reallocation progresses, checkpoint information about the reallocation (such as the new destination and the data in transit) is recorded. If the reallocation is interrupted, the process can automatically continue from the last checkpoint without data loss.

If a block reallocation is performed on unrecoverable data (rare), a Bad Data Mark is set in the new location. Thus, there is no chance of undetected bad data being generated from a reallocation.

￿￿￿￿￿&CVCData￿8GTKHKECVKQPcan be verified in two ways. First, the integrity of data in selected areas of the media can be checked using the VERIFY command. Secondly, the WRITE AND VERIFY command writes host-supplied data and then verifies that it was written correctly.

￿￿￿￿6#))'&The drive￿%1//#0&supports all three￿37'7+0)SCSI-defined queue tag messages. When queuing is enabled (default condition), the drive can accept any of the following:

•Simple - specifies that the command is to be placed in the drive's command task set (queue). If several commands are present, the drive may reorder them to increase overall throughput.

•Head of Queue - directs the drive to place the command at the beginning of the queue, to be executed next. Consecutive commands with Head of Queue specified are executed in last-in-first-out (LIFO) order. Queue depth is 64.

•Ordered - specifies that commands in the drive's task set are to be executed in the order received (FIFO).

The DQue bit (disable queuing) of the Control Mode page can be used to disable tagged command queuing.

￿￿￿￿%1//#0&The drive uses￿4'14&'4+0)Optimized Reordering Command Algorithm (ORCA) and tagged command queuing to provide greater throughput by reordering any commands queued on the drive to minimize rotational latency, seek time and head selection time. The performance improvement is significant in heavily loaded applications where queue depth exceeds 10-15 commands.

Maxtor Atlas 10K III 6-5