IBM IC35L020 - Deskstar 20 GB Hard Drive Specifications page 145

Sector Number
Cylinder High/Low
H
The sector number of the last transferred sector. (L=0)
In LBA mode this register contains current LBA bits 0–7. (L=1)
The cylinder number of the last transferred sector. (L=0)
In LBA mode this register contains current LBA bits 8–15 (Low), 16–23 (High).
(L=1)
The head number of the last transferred sector. (L=0)
In LBA mode this register contains current LBA bits 24–27. (L=1)
Deskstar 60 GXP Hard disk drive specification
131