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12.2 Configure Stream (51h)
Table 87 Configure Stream Command (51h)
Command Input
Field
Description
FEATURE
Bit Description
15:8 DEFAULT CCTL field
7 ADD/REMOVE STREAM bit
6 Obsolete
5:3 Reserved
2:0 STREAM ID field
COUNT
Allocation Unit
LBA
N/A
DEVICE
Bit Description
7:5 Reserved
4 Transport Dependent
3:0 Reserved
Command
7:0 51h
The Configure Stream command specifies the operating parameters of an individual stream. A Configure Stream
command may be issued for each stream that is to be added or removed from the current operating configuration. If
A/R = 1 and the specified ID is already valid at the device, the new parameters shall replace the old parameters,
unless Command Abort is returned (see abort conditions for Error Register). In this case the old parameters for the
specified Stream ID shall remain in effect.
Abort conditions for Error register are the following.
• The device does not support the Streaming Feature Set.
• A/R is cleared to zero and the Feature field contains a Stream ID that has not been sent in a previous
CONFIGURE STREAM command.
Output Parameters To The Device
Feature Current bit 7 (A/R)
If set to one, a request to add a new stream.
If cleared to zero, a request to remove a previous configured stream is
specified.
Feature Current bit 6 (R/W)
R/W specifies a read stream if cleared to zero and a write stream if set
to one.
Feature Current bit 0..2 (Stream ID)
The Stream ID shall be a value between 0 and 7.
Feature Previous
The default Command Completion Time Limit (CCTL).
The value is calculated as follows:
(Default CCTL) = ((content of the Features register)* (Identify
Device words (99:98))) microseconds.
This time shall be used by the device when a streaming command with
the same stream ID and a CCTL of zero are issued. The time is
measured from the write of the command register to the final INTRQ for
command completion. The device has minimum CCTL value. When the
specified value is shorter than the minimum value, CCTL is set to the
minimum value. Actual minimum CCTL value is described in the
“Deviations from Standard” section.
Sector Count Current
Allocation Unit Size In Sectors (7:0)
Sector Count Previous
Allocation Unit Size In Sectors (15:8)
140
Hard Disk Drive Specification