[Cryptography] LUKS on ATA versus on SSD

[John Gilmore]

John Levine <johnl at iecc.com> wrote:
> To loop back around, modern disks present themselves to the computer
> as a list of fixed sized blocks numbered from 0 to N.  ... There's all
> sorts of other stuff going on underneath but it's generally hidden
> from the computer unless it uses maintenance features.

To perhaps finish off this long digression from cryptography, here's a
modern (2019) analysis of what's actually going on underneath the
interface inside modern disk drives.  Accompanying source code for Linux
can be used to characterize your own drives' peculiar underbelly.

  https://blog.stuffedcow.net/2019/09/hard-disk-geometry-microbenchmarking/

This software is being partly incorporated into the GNU ddrescue program,
an awesome tool for recovering remaining data from damaged drives:

  https://lists.gnu.org/archive/html/bug-ddrescue/2026-01/msg00000.html

	John

PS: Post-2019, Shingled Magnetic Recording (SMR) added more ugly stuff
underneath some high-capacity drives -- but too much ugly was visible in
system performance, so most customers decline to buy SMR drives.  As of
2025, the first production Heat-Assisted Magnetic Recording drives are
now shipping from Seagate (at 30 Tbyte capacity).  These don't have the
problems of SMR but have Even More "other stuff" going on behind the
simple block-oriented interface to spinning-rust platters.