Spinpoint M8-DVR OEM Product Manual REV 1.0
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• ABRT (Aborted Command) indicates the requested co mmand has been aborted due to a
drive status error (Not Ready, Write Fault, etc.) or because the command code is invalid.
• # Indicates the content of this bit is command depende nt.
NOTE: Unused bits are cleared to zero.
6.3.4.5 Sector Count Register and Sector Count Extended Register (Ex. 1F2h)
This register contains the number of sect ors of data requested to be transferred on a read or write operation
between the host and the drive. In 28-bit addressing, if the value in this register is zero, a count of 256 sectors
is specified. In 48-bit addressing, the Sector Count Register is the low order byte of the 16-bit sector count
value and the Sector Count Extended Register is the high order byte of the 16-bit sector count value.
If this register is zero at command completion, the command was successful. If not successfully completed,
the register contains the number of sectors, which need to be transferred in order to complete the requ est.
The contents of this register may be defined otherwise on some commands (e.g., Initialize Drive Parameters
command, Format Track command).
6.3.4.6 Cylinder High Register and Cylinder High Extended Register (Ex. 1F5h)
In CHS mode the C ylinder High Register contains the high order bits of the starting cylinder address for any
disk access. In LBA mode the Cylinder High Register contains bits 16-23 of the LBA. The Cylinder High
Extended Register contains bits 40-47 of the 4 8-bit LBA.
At the end of the command, t his register is updated to reflect the current disk address. The most signif icant
bits of the cylinder address are loaded into the Cylinder High register.
6.3.4.7 Cylinder Low Register and Cylinder Low Extended Register (Ex. 1 F4h)
In CHS mode the Cylinder Lo w Register contains the low order 8 bits of the starting cylinder address for any
disk access. In LBA mode the Cylinder Low Register contains bits 8-15 of the LBA. The Cylinder Low
Extended Register contains bits 32-39 of the 48-bit LBA. At the end of the command, this register is updated
to reflect the current disk address.
6.3.4.8 Command Register (Ex. 1F7h)
This register contains the command code being sent to the drive. Command execution begins immediately
after this register is written. The executable commands, the command codes, and the necessary parameters for
each command are listed.
6.3.4.9 Device Register (Ex. 1F6h)
This register contains the drive and head numbers. When executing an Initialize Drive Parameters command,
the content of this register defines the number of heads minus 1.
7
6
5
4
3
2
1
0
Obsolete
LBA
Obsolete
DEV
#
#
#
#