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C141-E090-01EN5 - 28
(11) INITIALIZE DEVICE PARAMETERS (X'91')
The host system can set the number of sectors per track and the maximum head number
(maximum head number is "number of heads minus 1") per cylinder with this command.
Upon receipt of this command, the device sets the BSY bit of Status register and saves the
parameters. Then the device clears the BSY bit and generates an interrupt.
When the SC register is specified to X'00', an ABORTED COMMAND error is posted. Other
than X'00' is specified, this command terminates normally.
The parameters set by this command are retained even after reset or power save operation
regardless of the setting of disabling the reverting to default setting.
In LBA mode
The device ignores the L bit specification and operates with the CHS mode specification. An
accessible area of this command within head moving in the LBA mode is always within a default
area. It is recommended that the host system refers the addressable user sectors (total number of
sectors) in word 60 to 61 of the parameter information by the IDENTIFY DEVICE command.
At command issuance (I/O registers setting contents)
1F7
H
(CM) 1 0 0 1 0 0 0 1
1F6
H
(DH)
× × ×
DV Max. head No.
1F5
H
(CH)
1F4
H
(CL)
1F3
H
(SN)
1F2
H
(SC)
1F1
H
(FR)
xx
xx
xx
Number of sectors/track
xx
At command completion (I/O registers contents to be read)
1F7
H
(ST) Status information
1F6
H
(DH)
× × ×
DV Max. head No.
1F5
H
(CH)
1F4
H
(CL)
1F3
H
(SN)
1F2
H
(SC)
1F1
H
(ER)
xx
xx
xx
xx
Error Information
(12) IDENTIFY DEVICE (X'EC')
The host system issues the IDENTIFY DEVICE command to read parameter information (512
bytes) from the device. Upon receipt of this command, the drive sets the BSY bit of Status
register and sets required parameter information in the sector buffer. The device then sets the
DRQ bit of the Status register, and generates an interrupt. After that, the host system reads the
information out of the sector buffer. Table 5.5 shows the arrangements and values of the
parameter words and the meaning in the buffer.