Last technical review: September 14, 2026 by PC-Doctor Engineering

A software overwrite writes to logical addresses. On a modern drive, the logical address the host writes to is not necessarily the physical location where the earlier data lives. Wear-leveling remaps writes on solid-state drives, retired sectors on any drive fall out of the address space, and ATA features such as HPA and DCO hide entire ranges from the host. Sanitization therefore has to be performed by the drive’s own firmware, which knows where every block is, rather than by a host that can only see the addresses it has been shown.

That is the whole argument. The rest of this article is about why it holds, where the exceptions are, and what a tool has to do about it.