Hitachi T7K250 - Deskstar - Hard Drive Specifications page 240

H
The drive internally uses 52 bytes of ECC on all data read or writes. The 4-byte mode of operation is provided by
means of an emulation technique. As a consequence of this emulation it is recommended that 52-byte ECC mode
be used for all tests to confirm the operation of the ECC hardware of the drive. Unexpected results may occur if
such testing is performed using 4-byte mode.
This indicates the head number of the sector to be transferred. (L = 0)
In LBA mode this register contains current the LBA bits 24–27. (L = 1)
Deskstar T7K250 Hard Disk Drive Specification
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