Do we still need ATA disk CHS addressing?

Takahashi Yoshihiro nyan at
Tue Aug 11 10:56:12 UTC 2009

In article <20090810.162424.846948847.imp at>
"M. Warner Losh" <imp at> writes:

> There's also some oddities at the lowest levels for pc98 controllers,
> but I don't think this change would affect that.  However, like I
> said, ask the pc98 guys for sure.
> I've cc'd nyan@, since he can answer the question: "What breaks in
> pc98 if we lose support for CHS-based disk I/O?"

The following document in Japanese says: "PC-98 usually use CHS
addressing.  PC-98 does not use LBA addressing."

But I could use 400MB HDD with LBA addressing on my pc98, so it seems
that my pc98 supports LBA addressing at least.  I don't know older
pc98 supports it or not.

TAKAHASHI Yoshihiro <nyan at>

More information about the freebsd-arch mailing list