Re: BootLDR, FLASH and progress?

Am So, den 30.05.2004 schrieb Holger Freyther um 18:54:
> On Sunday 30 May 2004 17:41, Nils Faerber wrote:
> > What can wear out flash pretty easily is using the wrong tools, e.g. a
> > wrong filesystem. A regular ext2/ext3 filesystem in flash without any
> > extra options (like noatime) will kill your flash within days... :)
> I was aware of ext3 issues with the fixed place of the journal but what with 
> ext2? The superblock + backup super blocks or  Inode List at fixed position?

It is not only the journal problem.
ext2/ext3 stores a lot of information inside an inode, information like
last access time (atime). If you are not coreful even any read access
causes a subsequent write access because the inode has to updated. So
frequently accessed files will wear out their inode pretty fast.
But also even with noatime ext2/ext3 are suboptimal choices. The wy they
distribute the data in the "address space" is quite bad for flash. Ext
FSs are optimized for clustering files, i.e. to avoid having them
scattered alle around the device. This is good practice for harddisks to
reduce seek times but bad for flash because you tend to erase/write the
some sectors over and over again and keep other almost unused.

Those and other factors are taken into account by the specialised flash
filesystems liek JFFS, JFFS2 and YAFS.

But since it seems that the EU will soon legalise patents on software we
will soon get into trouble. Sandisk has a patent on wear-leveling which
is for sure infringed by the above mentioned filesystems. If they
enforce their patent on our OS software we will have to remove this
feature from any production binary :((

So, support FFII and fight against software patents wherever you can!
See
	http://www.ffii.org

> anyway thanks.

Sure ;)

> regards holger
CU
  nils faerber

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