Gordon,

mketfs creates a full filesystem image, composed of page-sized
transactions.  Etfsctl simply writes them to the device through fs-etfs,
through the raw device (/dev/etfs2).  Because etfsctl goes through the
raw device, there is no knowledge of existing filesystem structures on
the flash.  This is the same mechanism used by things like dinit,
mkqnx6fs, and mkdosfs, in that the previous filesystem is completely
overwritten.  One of the technical problems is that mketfs has no
knowledge of the existing inode numbers being used in the filesystem you
are running, which results in an mketfs transaction file that will
overwrite existing files, as opposed to adding new files.

If you simply wish to update the contents of the filesystem, then I
would suggest using a simpler method like tar or zip to carry the new
files.

Because of how NAND flash works, it is necessary to erase the flash
before writing new transactions.

David

> -----Original Message-----
> From: Gordon Molek [mailto:community-noreply@qnx.com] 
> Sent: April 9, 2010 6:55 AM
> To: general-filesystems
> Subject: Non destructive update using efsctl?
> 
> Is it possible to use etfsctl to non-destructively (i.e. 
> without erasing the flash partition first) update an existing 
> flash partition?  Maybe I'm misunderstanding what mketfs does 
> in building the set of "transactions" represented by the 
> commands in the build file, but it would be very useful to 
> use mketfs/etfsctl to update an existing flash partition 
> without completely blowing it away by erasing it first.
> 
> Thanks,
> 
> Gordon Molek
> 
> 
> 
> _______________________________________________
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> http://community.qnx.com/sf/go/post51361
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