Hitachi IC25N040ATCS04-0 - Travelstar 40GN 40GB UDMA/100 4200RPM 2MB 2.5" IDE Hard Drive Specifications page 123

The following symbols are used in the command descriptions:
Output Registers
0 This indicates that the bit must be set to 0.
1 This indicates that the bit must be set to 1.
D The device number bit. Indicates that the device number bit of the Device/Head Register
should be specified. Zero selects the master device and one selects the slave device.
H Head number. This indicates that the head number part of the Device/Head Register is an
output parameter and should be specified.
L LBA mode. This indicates the addressing mode. Zero specifies CHS mode and one
specifies LBA addressing mode.
R Retry. Original meaning is already obsolete, there is no difference between 0 and 1.
(Using 0 is recommended for future compatibility.)
B Option Bit. This indicates that the Option Bit of the Sector Count Register be specified.
(This bit is used by Set Max ADDRESS command.)
V Valid. This indicates that the bit is part of an output parameter and should be specified.
x This indicates that the hex character is not used.
- This indicates that the bit is not used.
Input Registers
0 This indicates that the bit is always set to 0.
1 This indicates that the bit is always set to 1.
H Head number. This indicates that the head number part of the Device/Head Register is an
input parameter and will be set by the device.
V Valid. This indicates that the bit is part of an input parameter and will be set by the device
to 0 or 1.
N Not recommended condition for start up. Indicates that the condition of the device is not
recommended for start up.
- This indicates that the bit is not part of an input parameter.
The command descriptions show the contents of the Status and Error Registers after the device has
completed processing the command and has interrupted the host.
Hitachi Travelstar 60GH & 40GN hard disk drive specifications
110