svn commit: r216269 - head/sys/geom/part

Bruce Cran bruce at
Tue Dec 7 23:06:30 UTC 2010

On Tue, 07 Dec 2010 23:54:17 +0200
Andriy Gapon <avg at> wrote:

> You repeated that statement, so I am picking on you :-)
> Can someone show me how/where exactly modern drives fakes CHS
> geometry? Let me specifically ask that question about modern (S)ATA
> drives directly connected to a system (controller).
> My impression is at least since ATA-7 there is no mentioning of
> anything CHS-related in the specification.  The fact that we keep
> reading and interpreting some historically defined bytes that are now
> marked as unused/reserved doesn't mean that those bytes actually mean
> anything.

You're right: I last looked at the IDENTIFY data about 7 years ago when
those fields were defined; now they're marked as "obsolete".  I guess
the fields are still defined to keep old tools happy. Both atacontrol
and camcontrol are still reading the IDENTIFY data and outputting
the CHS fields even on ATA-8 drives, which I guess they shouldn't be.


More information about the svn-src-all mailing list