From: Jens Arnold <arnold-j_at_t-online.de>
Date: Sat, 10 Jun 2006 11:22:33 +0200

On 10.06.2006, Jürgen Hestermann wrote:

> Hi Joel,

> you wrote:
>> No, Rockbox correctly identified the HDD. The IDE interface
>> is an electrical interface. The 137GB barrier is more of the
>> limitation of the older ATA protocol. Newer ATA commands
>> provide 48-bit LBA, breaking through the 137GB barrier. I
>> also used Partition Magic 8.0 to format the drive in FAT32.

> In November Linus Nielsen Feltzing wrote:
>> Yes, it's physical. The USB ATA bridge chip can't do 48-bit
>> addressing. The Rockbox ATA driver can easily be adapted to
>> 48-bit addressing, but you won't be able to transfer any
>> files via USB. :-(

> The question now is: Is this wrong and it IS possible to use
> more than 137 GB?

It seems this is *slightly* wrong. From what I gathered from
reports on irc, disks with more than 137GB(manufacturer) resp.
128GB(real) automatically limit their capacity to that barrier
when controlled via LBA28. So it is possible to use e.g. an
160GB drive in an archos, but both rockbox and the ata bridge
only access 137(128)GB.

The rockbox ATA driver could be extended to access the full
capacity, but then the disk needs to be partitioned in a way
that it has 2 FAT32 partitions, the first of which must not
cross the barrier and the second one should be hidden (by using
a "wrong" partition type - rockbox doesn't care). Accessing
2 partitions then just needs enabling multivolume support -
rockbox is already prepared for that.

One could then put music on the first partition from the PC, and
use rockbox to move some of the data to the second partition,
freeing up space on the first partition to stuff more music on
it.

The second partition could be created in 2 ways:
(1) Hook up the disk directly to a PC (via an ata adapter) and
create the partition
(2) Make a aspecial rockbox plugin that does it


Regards, Jens
Received on 2006-06-10