Support for WD Advanced Format disks

Valentin Nechayev netch at
Wed Aug 11 11:37:59 UTC 2010

>>>>> des@ wrote:

> There's a jumper setting for
> "Windows XP compatibility", but apparently, it only affects the (fake)
> geometry the disk reports to the BIOS.

No, this jumper internally increases any linear block number learned from bus
request by 1. I.e. the block number 1 without this jumper is seen as block
number 0 with this jumper, and so on. So with this jumper, block 63
(internally it is 64) is at begin of physical sector.
These data are from my own tests with WD15EARS, see links earlier.

I didn't see any difference in fake reported geometry - moreover, with
this WD15EARS instance all 512 bytes of identification page were equal
with or without jumper. As I already told, it didn't shorten reported size
and any tool which tries to read last block (RAID check, GPT reading)
had failed with I/O error. I guess this is temporary error and future
firmware editions would fix it.


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