Re: which file system for sd card - for Wiki

2009-01-25 Thread Martin Bernreuther
Hello,

Am Sonntag, 25. Januar 2009 schrieb Fernando Martins:
> I got a new SD card. Which file system is the best?
> 
> In general, vfat or ext2 are the most recommended.
> 
> Vfat might already be the fs in your card when you got a new one. It has 
> the advantage of being recognised in many other systems. The data 

...if this is needed.
(the FR uSD card slot is quite difficult to access and if
USB 1.1/WLAN/Bluetooth is not too slow many people
might prefer to leave the uSD card there most time...)

[...]

> ext is Linux centric but one of the most tested and tuned. It is also a 
> faster file system than vfat (citation?) and most importantly, if you 
> need, it supports permissions, which vfat doesn't.

What about the support for owners/groups, (symbolic/hard) links and device 
files?

And the Linux vfat seems to have problems with filenames containing colons,
see http://lists.kde.org/?l=kdepim-users&m=123210608518115&w=2
where someone did a "Backup" copy of his maildir files to vfat and didn't notice
that the destination directories where emty...

For me vfat was therefore always a makeshift/stopgap/... for a data exchange
with the Windows etc world, but not a competitive Linux alternative and not
"most recommended".

Good night
Martin Bernreuther
-- 
_
Martin Bernreuther  martinb...@web.de

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Re: which file system for sd card - for Wiki

2009-01-25 Thread Fernando Martins
arne anka wrote:
> if it is not yet in the wiki, somebody should probably gather the bits  
>  from the archives and put it there -- it seem to be a rather recurrent  
> question.
>
>   
I wrote the following text which I can put somewhere in the wiki. Since 
I'm no authority on the matter, I would appreciate feedback from the 
list beforehand.

=
I got a new SD card. Which file system is the best?

In general, vfat or ext2 are the most recommended.

Vfat might already be the fs in your card when you got a new one. It has 
the advantage of being recognised in many other systems. The data 
structures are simpler which might mean less writes on the sd-card and 
less code being executed (this statement should have some objective 
verification) and you'll find more tools available to recover 
information when you get errors.

ext is Linux centric but one of the most tested and tuned. It is also a 
faster file system than vfat (citation?) and most importantly, if you 
need, it supports permissions, which vfat doesn't.

What about file systems like jffs2 and ubifs, which are aware of flash 
card wearing?

SD cards, according to SanDisk specs, should have wear leveling logic, 
which controls the number of writes and remaps blocks as needed. 
Wear-aware file systems might actually play against the logic of the 
card are usually not recommendable.

What about journaled file systems like ext3?
The advantage is that it will maintain your data in a consistent state. 
However, the journal uses extra space and will impose more writes in the 
sd card, thus decreasing performance and wearing the card.

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