Hitachi HDS721050CLA362 - Flush to Disk Bit; Handle Streaming Error Bit; Not Sequential Bit; Read Continuous Bit

HITACHI Deskstar & CinemaStar 7K1000.B & Deskstar E7K1000 Hard Disk Drive specification
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9.16.1.1 Urgent bit
The Urgent bit in the Read Stream and Write Stream commands specifies that the command should be
completed in the minimum possible time by the device and shall be completed within the specified Command
Completion Time Limit.
9.16.1.2 Flush to Disk bit
The Flush to Disk bit in the Write Stream command specifies that all data for the specified stream shall be
flushed to the media before posting command completion. If a host requests flushes at times other than the
end of each Allocation Unit, streaming performance may be degraded. The Set Features command to
enable/disable caching shall not affect caching for streaming commands.
9.16.1.3 Not Sequential bit
The Not Sequential bit specifies that the next read stream command with the same Stream ID may not be
sequential in LBA space. This information helps the device with pre-fetching decisions.
9.16.1.4 Read Continuous bit
If the Read Continuous bit is set to one for the command, the device shall transfer the requested amount of data
to the host within the Command Completion Time Limit even if an error occurs. The data sent to the host by
the device in an error condition is vendor specific.
9.16.1.5 Write Continuous bit
If the Write Continuous bit is set to one for the command, and an error is encountered, the device shall complete
the request without posting an error. If an error cannot be resolved within the Command Completion Time Limit,
the erroneous section on the media may be unchanged or may contain undefined data. A future read of this
area may not report an error, even though the data is erroneous.
9.16.1.6 Handle Streaming Error bit
The Handle Streaming Error bit specifies to the device that this command starts at the LBA of a recently reported
error section, so the device may attempt to continue its corresponding error recovery sequence where it left off
earlier. This mechanism allows the host to schedule error recovery and defect management for content critical
data.
9.16.2 Streaming Logs
The Streaming Data Transfer feature set requires two error logs and one performance log. These logs are
accessed via the Read Log Ext command; the information included in the error logs is volatile and is not
maintained across power cycles, hard resets, or sleep. These error logs are 512 bytes in length and retain the
last 31 errors that occurred during any Streaming Data transfer.