[ECOS] jffs2 write in 4kB blocks over the network?

Gary Thomas gary@mlbassoc.com
Mon Apr 7 13:08:00 GMT 2008


Jürgen Lambrecht wrote:
> Hello,
> 
> the default block size in jffs2 is 4kB. But with FTP, packets have at 
> most 1448 B payload.
> If I put a file of 12kB, is the file then put in 3 nodes if 4kB, or is 
> it put in 9 nodes (because FTP uses 9 packets) ?

JFFS2 will pack your data in the most efficient way into your
actual FLASH blocks.  In fact, depending on configuration and
settings, it will even compress it along the way, so you've
no real idea how many FLASH blocks a given set of data will
require (except that it will be less than the actual data
size divided by the FLASH block size - compression is never
used if it causes the data to grow).

The fact that your incoming data via FTP or whatever comes
in smaller chunks is irrelevant - writes are buffered as
needed.

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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