Example patterns written by secure erase or secure erase enhanced for various drives

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Seagate ST3500312CS Video 3.5, Firmware version SC13, 500GB

I've started this discussion to document the sort of data that is finally written to a drive when the drives own firmware is responsible for the erase.

This information will be useful to learn more about the data that can be expected and if repeatable and not random, how I can then write code that verifies a secure erase.

Starting with a Seagate ST3500312CS Video 3.5 500GB HDD, Firmware version SC13 - Erased using Secure Erase Enhanced which writes a repeating pattern 0x33CC55AA on this particular model and firmware.

Same drive as above but Secure Erase selected, which writes zeros, as opposed to Secure Erase Enhanced which writes a repeating pattern.

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Western Digital WDC WD20EURS-63SPKY0, firmware revision 80.00A80, 2TB

For both secure erase and security erase enhanced the resulting pattern is all zeros. 278 minutes to complete security erase. 278 minutes to complete security erase enhanced. Makes you wonder what a enhanced security erase does that's different if the time is the same and the pattern is the same.

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Seagate EXOS ST000NM0007-2A1101, firmware revision SN02, 12TB

Secure erase enhanced writes 0x33CC55AA