Re: Fw: nftl

[Ollie Lho <ollie@sis.com.tw>]

David Woodhouse wrote:
> 
> jimmy@soft-v.com said:
> > Our system is the VR4121 using the Intel Strata Flash. If we use your code
> > to establish a sector of 1MB as a drive, can we also have XIP on it?
> > That is, can we execute on the flash instead of from the SDRAM?
> 
> You cannot use NFTL on that. Technically, you could use FTL, but in some
> countries patents may prevent you from doing so. If you want a writable
> filesystem, JFFS is probably the best bet.
> 
> We don't yet have support for XIP. It would require a special filesystem
> which aligns pages of the files at page-aligned addresses in the flash
> chips. In general, compression is far more useful than XIP, because RAM is
> cheaper than flash, so nobody's yet implemented this.
> 
> I started hacking on such an xipfs once. I don't recall how far I got with
> it - you're welcome to a copy of that if you want it, although I suspect
> you'd to better to start with a clean copy of romfs and do it again.
> 
> If you require a _writable_ filesystem, it's going to be extremely
> difficult to do XIP.
> 

Agenda PDA seems to have XIP CRAMfs. You probably should take a look
at that.

Ollie