[sf-lug] About USB partitioning and formatting
rick at linuxmafia.com
Thu Sep 17 17:35:42 PDT 2009
Quoting jim (jim at well.com):
> i am, of course, interested in how my surmises
> are wrong-headed and what might be misinformation
> or omissions from the linked page.
The basic advice is good (in that they qualify why they're saying what
they say, and tell you why most repartitioning of NAND flash devices is
likely to be actively harmful.
I covered the same topic back in 2003 in an article I wrote for _Linux
Journal_, back when these drives were a relatively new problem (and some
of us ran still systems with 2.4 kernels):
You'll note that I said I was avoiding re-doing the drive formatting
to cut device fatigue, and because the provided FAT filesystem has
the advantage of ubiquitous support, even though I referred to FAT as
an "antique disk format". Detailing why would take a while, but
basically it depends entirely too much on repeated reads/writes to a
few fixed data structures. When the 65-byte (or whatever applies) blocks
those key structures live on wear out, the entire NAND flash drive
One could argue that you'd be better off doing a one-time conversion to,
say, JFFS2, which deliberately "levels" the NAND wear over the entire
device. As the wiki page implies, you'd want to plan your mkfs.jffs2
approach with some attention to the device's physical characteristics.
I haven't personally played with JFFS or other NAND-appropriate
filesystems, because flash drives are cheap, and the lingua-franca
aspects of FAT are too useful.
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