Re: FreeBSD's embedded agenda

Hi Andrew!

> Yes, exactly... that's precisely what 'wear-leveling' is meant to do ..
>
> I think I mentioned wear-leveling further back in the email chain ..

You did indeed mention it.

> Yes, you definitely want wear-leveling. The debate is whether the
> filesystem knows about it, versus it being managed by a lower level
> 'driver'.

If I were told to start the design now, I would advocate to keep all
Flash-specific features in a low-level driver and let the filesystem take care
of upper concepts. After all, the cylinder concept of a spinning disk does not
always match the physical structure so we could follow the same logic.

By Flash-specific features, I mean:
- Erased bits set to 1 (that's another constraint, common to NAND and NOR, you
can't write a 1 on a 0)
- Seek time of 0
- Wear-leveling
- Garbage collection

For the filesystem, we could think of a standard one - why reinvent the wheel
when FreeBSD already has a good one that could be used, possibly with a few
tweaks? Unless we want to plug compression in, what could be helpful and is
sometimes desired.

Just a tought
--
Olivier Gautherot
[email protected]
Tel: +56 8 730 9361
_______________________________________________
[email protected] mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-small
To unsubscribe, send any mail to "[email protected]"