strange problem with Intenso 4GB SDHC card

[Doug Jones]

Mikael Berthe wrote:
> * Doug Jones <dj6mf at frombob.to> [2008-07-24 01:21 +0200]:
>> There have been some indications that partition type may have some 
>> effect on this problem on the OLPC.
> 
> I doubt it.
> 
>> So, shrink the default vfat partition that came on the card and put
>> an ext3 on there too.  If you want to be adventurous, try some other
>> types.
> 
> Happens to me with ext3 partitions as well (or mixed vfat/ext3
> partitions).
> 
> However if I restore the partition table the data are not corrupted,
> at least so far it's been all right...


Most people who use SD cards on OLPC are leaving them formatted as vfat, 
because Sugar can't see any other type.  I don't recall seeing any 
reports of partition table mangling from these people, who are the vast 
majority of OLPC users.

It's when they try something other than vfat that the corruption occurs. 
  When it happened to me, I had one vfat and one ext3 on there.

So on the OLPC at least, the corruption does seem to be correlated with 
partition type.


Because the number of people trying different file systems on the SD 
card was relatively small, and because the corruption was happening sort 
of randomly, it's been difficult to figure out what's happening.  Sample 
size too small.

People were making all kinds of assumptions based on the limited 
reports, some of them wrong.  If you look through that bug ticket and 
also various reports on forums and lists, you find contradictory 
information regarding which builds were affected, which file systems 
were affected, and so on.  This kind of noise makes it a lot harder to 
debug.  It's still not clear that this problem is understood, even six 
months later.

This is why I suggested that lots of people try various file systems in 
their Neos, even if they don't need to have a card in there right now. 
If there is indeed an SD problem in the Neo, we need lots of reports, 
otherwise the sampling size problem might drag out the debugging for 
months as happened with OLPC.

If there is no problem with SD, then there's no harm done.  You'll just 
have a lot of people walking around with SD cards they aren't using yet 
sitting inside their phones.



And of course it's entirely possible that the OLPC / SD problem has 
nothing to do with the Neo.