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Interface
5-26 C141-E239
(6) Cylinder High Field (exp)
The contents of this field indicates high-order 8 bits of the disk-access start
cylinder address.
At the end of a command, the contents of this field are updated to the current
cylinder number. The high-order 8 bits of the cylinder address are set to the
Cylinder High Register.
Under the LBA mode, this field indicates LBA bits 23 to 16. Under the LBA
mode of the EXT system command, LBA bits 47 to 40 are set in the Cylinder
High Field, and LBA bits 23 to 16 are set in the Cylinder High Field (exp).
(7) Device/Head Field
The contents of this field indicate the device and the head number.
When executing INITIALIZE DEVICE PARAMETERS command, the contents
of this field defines “the number of heads minus 1” (a maximum head No.).
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
X L X X HS3 HS2 HS1 HS0
- Bit 7: Unused
- Bit 6: L. 0 for CHS mode and 1 for LBA mode.
- Bit 5: Unused
- Bit 4: Unused
- Bit 3: HS3 CHS mode head address 3 (2
3
). bit 27 for LBA mode.
Unused under the LBA mode of the EXT command.
- Bit 2: HS2 CHS mode head address 2 (2
2
). bit 26 for LBA mode.
Unused under the LBA mode of the EXT command.
- Bit 1: HS1 CHS mode head address 1 (2
1
). bit 25 for LBA mode.
Unused under the LBA mode of the EXT command.
- Bit 0: HS0 CHS mode head address 0 (2
0
). bit 24 for LBA mode.
Unused under the LBA mode of the EXT command.