Read Stream Dma (2Ah); Table 118.Read Stream Dma Command (2Ah) - Hitachi 7K80 - Deskstar - Hard Drive Specifications

12.25 Read Stream DMA (2Ah)

Table 119: Read Stream DMA Command (2Ah)
Command Block Output Registers
Register
Data Low
Data High
Current
Feature
Previous
Current
Sector
Count
Previous
Current
Sector
Number
Previous
Current
Cylinder
Low
Previous
Cylinder Current
Previous
High
Device/Head
Command
Error Register
7 6 5
CRC UNC 0
V V 0
The Read Stream DMA 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 operate 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 to one. 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 pro-
vide 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.
7 6 5 4 3 2 1 0
- - - - - - - -
- - - - - - - -
V V V - V V V V
V V V V V V V V
V V V V V V V V
V V V V V V V V
V V V V V V V V
V V V V V V V V
V V V V V V V V
V V V V V V V V
V V V V V V V V
V V V V V V V V
1 1 1 D - - - -
0 0 1 0 0 1 0 0
4 3 2 1
IDN 0 ABT T0N AMN
V 0 V 0
Deskstar 7K80 Hard Disk Drive Specification
Command Block Input Registers
Register
Data Low
Data High
Error
Sector
Count
Sector
Number
Cylinder
Low
Cylinder
High
Device/Head
Status
0 7 6
BSY RDY DF DSC DRQ
V 0 V
172
7 6 5 4 3 2 1 0
- - - - - - - -
- - - - - - - -
see below
HOB=0 - - - - - - - -
HOB=1 - - - - - - - -
HOB=0 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
HOB=1 V V V V V V V V
HOB=0 V V V V V V V V
HOB=1 V V V V V V V V
- - - - - - - -
See below ...
Status Register
5 4 3 2
COR IDX
V V - 0
1 0
ERR
- V