NAND Full Requirement

[Erik Garrison]

On Tue, Jul 22, 2008 at 12:27:46PM -0700, Deepak Saxena wrote:
> On Jul 22 2008, at 16:16, Erik Garrison was caught saying:
> > See: http://dev.laptop.org/ticket/7587#comment:4
> > 
> > On boot, check NAND discomfort level.  If high, use unionfs(4) to mount
> > a read/write tmpfs over top of a read-only jffs2 rootfs.  Set unionfs
> > flags to enable file deletion from the 'ro' root partition (or if this
> > is impossible, mount the fs in another location to allow deletions).
> > Set a flag to tell olpc-session or Sugar to enter into a deletion
> > dialog.  
> 
> I'm wondering if we should/can implement the file deletion UI as a small
> standalone app that can be launched from the intramfs itself? This
> would allow us to solve the the issues on deployed systems by just 
> updating the olpcrd file?
> 

I like this idea.

Equivalently, we could also update /usr/bin/olpc-session to boot X with
this deletion interface.  Tomeu has suggested that we can use sugarlibs
to make the interface as familiar as possible.

> > Benefits:
> > This solution theoretically allows all software to run an a NAND-full
> > machine.  Thus students who arrive at school with a NAND-full machine
> > could still work with their XO through lessons and manage flash cleanup
> > as time is available.  Requires minimal code-level changes to enable.
> 
> One issue here is that if the user launches an activity and changes to
> documents go to the tmpfs, they are lost at boot up unless there is 
> an explicit sync to the real filesystem; however, that sync can't happen
> until space has been cleared.

Hm.  I realize now that this is a totally tangential and potentially
meaningless benefit ^_^.

Erik