Do we still need ATA disk CHS addressing?

Alexander Motin mav at
Sun Aug 9 14:15:52 UTC 2009

Ed Schouten wrote:
> * Takahashi Yoshihiro <nyan at> wrote:
>> In article <4A7DF076.4070203 at>
>> Alexander Motin <mav at> writes:
>>> While preparing wrapping ATA(4) low-level drivers code into CAM SIM, I
>>> would like to remove CHS addressing support to make code cleaner. CHS
>>> addressing is officially declared obsoleted and replaced by LBA. Since
>>> ATA/ATAPI-6 specification (October 2001) it is even no longer
>>> documented.
>>> Have anybody seen ATA drive without LBA support in last years?
>>> Any other objections against removing it?
>> PC98 uses CHS addressing because the internal interface works for very
>> old HDD only, so I hope it remains if possible.  But if you need a lot
>> of works for CHS support, I agree to remove it.
> Wouldn't it be possible to keep the old ATA code in the tree for users
> who want to use stuff like this?

I am going to make it switchable via kernel option, until new code 
completely settle. It should be possible to keep CHS support in this 
legacy mode.

Alexander Motin

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