XO-1.5 users: need your SD card data

[Daniel Drake]

On 15 April 2011 03:10, James Cameron <quozl at laptop.org> wrote:
> G'day Daniel,
>
> As an alternative, consider identifying the unused blocks in the
> filesystem, and avoid including them in the .zd file.  This would make
> it unnecessary to know whether the bits will be set or cleared by the
> card.  ext2, ext3, and ext4 care nothing for the bits in unused blocks.

I'm not sure about that. I have been working under the assumption that
ext* requires unused blocks to be zeroed out (or to read back 0s if
read), which seems to be in agreement with the rest of your mail.

However, if we use a SD card that reads back all-ones for unused
blocks, I think we would run into problems.

Daniel