I recently bought the WDC WD20EARS-00MVWB0 because it was really cheap for a drive with 64 MB cache, and I wanted to try out a 4k sector size disk ... Now the drive performs quite well, is rather silent and doesn't use much power or produce much heat, but at first I didn't find anything in Linux indicating that this drive would actually use 4k sectors. To shorten things, I asked around on IRC, had a chat with some other folks, found a jumper description on the WD site talking about an 'Advanced Format' jumper and finally contacted WD in a lengthy email thread. The results of all this are: - the drive doesn't report 4k sectors at all, not even as physical sector size. - the 'Advanced Format' jumper shifts access to the the drive by one sector. I did some tests to verify that, and I can confirm the behaviour of the jumper in question with certain benchmark tests (using dm and bonnie++) with and without the jumper in place. My question now is, how can I tell the kernel that this drive actually has 4k physical sectors and that it would be a smart thing to send requests in some kind of 4k I/O chunks? Many thanks in advance, Herbert PS: if somebody is interested in the tests done to verify the jumper, please let me know ... -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
