212
Western Digital Hard Disk Drive OEM Specification
11.30
Read Sector(s) Ext (24h)
Com m and Block Output Registers
Com m and 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
-
-
-
-
-
-
-
-
Feature
Current
-
-
-
-
-
-
-
-
Error
…See Below …
Previous
-
-
-
-
-
-
-
-
Sector Count
Current
V
V
V
V
V
V
V
V
Sector Count
HOB=0
-
-
-
-
-
-
-
-
Previous
V
V
V
V
V
V
V
V
HOB=1
-
-
-
-
-
-
-
-
Sector Number
Current
V
V
V
V
V
V
V
V
Sector
Number
HOB=0
V
V
V
V
V
V
V
V
Previous
V
V
V
V
V
V
V
V
HOB=1
V
V
V
V
V
V
V
V
Cylinder Low
Current
V
V
V
V
V
V
V
V
Cylinder Low
HOB=0
V
V
V
V
V
V
V
V
Previous
V
V
V
V
V
V
V
V
HOB=1
V
V
V
V
V
V
V
V
Cylinder High
Current
V
V
V
V
V
V
V
V
Cylinder
High
HOB=0
V
V
V
V
V
V
V
V
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
0
1
0
0
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
AMN
BSY
RDY
DF
DSC
DRQ
COR
IDX
ERR
0
V
0
V
0
V
0
0
0
V
0
V
-
0
-
V
Table 188 Read Sector(s) Ext Command (24h)
The Read Sector(s) Ext command reads from 1 to 65,536 sectors of data from disk media, and then transfers the
data from the device to the host.
The sectors are transferred through the Data Register 16 bits at a time.
If an uncorrectable error occurs, the read will be terminated at the failing sector.
Output Parameters To The Device
Sector Count Current
The number of continuous sectors to be transferred low order, bits (7:0)
Sector Count Previous
The number of continuous sectors to be transferred high order, bits (15:8). If zero is
specified in the Sector Count register, then 65,536 sectors will be transferred.
Sector Number Current
LBA (7:0).
Sector Number Previous
LBA (31:24).
Cylinder Low Current
LBA (15:8).
Cylinder Low Previous
LBA (39:32).
Cylinder High Current
LBA (23:16).
Cylinder High Previous
LBA (47:40).
Input Parameters From The Device
Sector Number (HOB=0)
LBA (7:0) of the address of the first unrecoverable error.
Sector Number (HOB=1)
LBA (31:24) of the address of the first unrecoverable error.
Cylinder Low (HOB=0)
LBA (15:8) of the address of the first unrecoverable error.
Cylinder Low (HOB=1)
LBA (39:32) of the address of the first unrecoverable error.
Cylinder High (HOB=0)
LBA (23:16) of the address of the first unrecoverable error.
Cylinder High (HOB=1)
LBA (47:40) of the address of the first unrecoverable error.
