Choosing drive geometry (it's all lies anyway)

[Kevin O'Gorman]

On Sun, Nov 13, 2011 at 3:01 PM, compdoc <compdoc at hotrodpc.com> wrote:
>>> Nr AF  Hd Sec  Cyl  Hd Sec  Cyl     Start      Size ID
>>  1 00  32  33    0  80  63  513       2048 3907027120 83
>>
>> As you can see from the above fdisk output, partitioning seems to throw
> away 2048 sectors off the bat
>
>
> If you mean the  Start = 2048 in the output, that's done automatically to
> accommodate what are called "Advanced Format drives". AKA "4k sector
> drives".

That makes some sense.  I'm figuring that means the real sector size
is 2MiB, and this size is buffered on the drive.  For 2TB drives,
having actual 512-byte sectors had to waste 'way too much space in
inter-sector gaps.

> Starting the partition there is said to greatly increase performance for
> those drives because it causes a correct alignment of the partition.
>
> Current versions of Gparted will suggest you start the partition there.
> Ubuntu does the same thing when installing the default drive layout.
> (letting it use the entire disk)
>
> Windows 7, and I think Vista does this too.
>
> Can't help with the heads vs. sectors differences. That is something that
> they can vary like that. Were they the same model? Made in the same country?

Yes, purchased in a single transaction, the exact same model.
Besides, I've reconfigured them and rebuilt the partition table and
filesystems.  I've even written out to the end to make sure there's
really a there there.

-- 
Kevin O'Gorman, PhD