Seagate ST9120826A, ST960814A manual Device 0 only configurations, ATA Security policy exceptions

4.1.1.4Device 0 only configurations

Per the ATA-ATAPI-7, Rev. 4B specification, Clause 5.16.1 (see italicized excerpt below), the specification expects Device 0 to return the Task File Register when Device 1 is selected as follows:

In a single device configuration where Device 0 is the only device and the host selects Device 1, Device 0 shall respond as follows:

...

If the device does not implement the PACKET Command feature set, a read of the Control Block or Command Block registers, other than the Status or Alternate Status registers, shall complete as if Device 0 was selected. A read of the Status or Alternate status register shall return the value 00h.

Under the described conditions, and the host selecting Device 1 in a Device 0 only configuration, the Momen- tus 5400 FDE will not respond for the request to Slave (Device 1) and the returned value will be indeterminate.

4.1.1.548-bit (Extended mode) Sector Count register must be written twice

Per the ATA-ATAPI-7, Rev. 4B specification, Clause 4.14:

In a device implementing the 48-bit Address feature set, the Feature register, the Sector Count register, the LBA Low register, the LBA Mid register, and the LBA High register are each a two-byte deep FIFO. Each time one of these registers is written, the new content written is placed into the “most recently written” location and the previous content of the register is moved to “previous content” location.

When using the 48-bit Address feature set, the Momentus 5400 FDE assumes that the host will always write the sector count register twice, even though the address may only require one write. Failure to write the sector count register twice will result in the subsequent read likely hanging due to a mismatch in the sector count.

All registers identified above should always be written twice in when using the 48-bit Address Feature set.

4.1.2ATA Security policy exceptions

In the ATA Security Interface mode, the drive conforms to the ATA Security Policy, except the following desir- able exceptions to implement the desired Momentus 5400 FDE behavior:

Upon execution of the Secure Erase Sequence, the drive will have the following behavior:

•All modes of Secure Erase will instantaneously delete the encryption key rendering all user data unintelligi- ble.

•A new encryption key will be generated inside the drive replacing the previous encryption key.

•The new encryption/decryption key will be applied to the data for all subsequent writes/reads prior to the next Secure Erate sequence.

•The User password will be cleared to a null value.

•The Master password will retain the current value per the ATA specification.

Note. On completion of this sequence, the user is assured that all sectors on the drive are unintelligible, and the drive is returned to the default factory state. It is then immediately ready for disposal or re-purpos- ing.

The ATA Security Erase Unit Command provides for normal and enhanced erase modes as follows:

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