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12.30 Read Stream Ext (2Bh)
The Read Stream DMA Ext command reads one to 65536 sectors as specified in the Sector Count register. A value
of 0000h in the Sector Count register requests 65536 sectors.
The RC bit indicates that the drive operates in a continuous read mode for the Read Stream command. When RC is
cleared to zero the drive shall operate in normal Streaming read mode.
When the Read Continuous mode is enabled, the device shall transfer data of the requested length without setting
the ERR bit. The SE bit shall be set to one if the data transferred includes errors. The data may be erroneous in this
case.
If the Read Continuous bit is set to one, the device shall not stop execution of the command due to errors. If the RC
bit is set to one and errors occur in reading or transfer of the data, the device shall continue to transfer the amount of
data requested and then provide ending status with the BSY bit cleared to zero, the SE bit set to one, the ERR bit
cleared to zero, and the type of error, ICRC,UNC,IDNF, or ABRT, reported in the error log. If the RC bit is set to one
and the Command Completion Time Limit expires, the device shall stop execution of the command and provide
ending status with BSY bit cleared to zero, the SE bit set to one, the ERR bit cleared to zero, and report the fact that
the Command Completion Time Limit expired by setting the CCTO bit in the error log to one. In all cases, the device
shall attempt to transfer the amount of data requested within the Command Completion Time Limit event if some data
transferred is in error.
Table 176 Read Stream Ext Command (2Bh)
Command Block Output Registers
Command Block Input Registers
Register
7
6
5
4
3
2
1
0
Register
7
6
5
4
3
2
1
0
Data Low
-
-
-
-
-
-
-
-
Data Low
-
-
-
-
-
-
-
-
Data High
-
-
-
-
-
-
-
-
Data High
-
-
-
-
-
-
-
-
Current
V
V V
V
-
V
V
V
Feature
Error
…See Below…
Previous
V
V
V
V V
V
V
V
Current
V
V V
V
V
V
V
V
HOB=0
-
-
-
-
-
-
-
-
Sector Count
Sector Count
Previous
V
V
V
V V
V
V
V
HOB=1 -
-
-
-
-
-
-
-
HOB=0
V
V
V
V V
V
V
V
Sector
Number
Current
V
V V
V
V
V
V
V
Sector
Number
Previous
V
V
V
V V
V
V
V
HOB=1 V
V
V
V
V
V V
V
Current
V
V V
V
V
V
V
V
HOB=0
V
V
V
V V
V
V
V
Cylinder Low
Cylinder Low
Previous
V
V
V
V V
V
V
V
HOB=1 V
V
V
V
V
V V
V
HOB=0
V
V
V
V V
V
V
V
Cylinder
High
Current
V
V V
V
V
V
V
V
Cylinder
High
Previous
V
V
V
V V
V
V
V
HOB=1 V
V
V
V
V
V V
V
Device/Head
1
1
1
D -
-
-
-
Device/Head
-
-
-
-
-
-
-
-
Command
0
0
1
0
1
0
1
1
Status
…See Below…
Error Register
Status Register
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
CRC UNC 0
IDN
0
ABT
T0N
CCTO BSY RDY SE
DWE DRQ COR IDX
ERR
V
V
0
V
0
V
0
V
0
V
V
0
-
0
-
V
244
Hard Disk Drive Specification