On Tue, Mar 1, 2011 at 9:09 PM, Pete2s <[email protected]> wrote:

> Very cool. Thanks for the explanation. I think I understand the
> basics--let me know if I'm on the right track:
>
> Before HC, the filesystem in kernel space had a limited size partition
> for data and a limited size partition for media. The data partition
> was invisible and inaccessible to the user.
>
> Yep, two different fixed-size partitions (actually, there is also the cache
partition, which is crucial for OTAs, but let's forget about this one for
now).


> In HC, we have a data folder and media folder on the same partition in
> kernel space. The FUSE in user space allows the user access to the
> media folder but not the data folder.
>
>
The FUSE stuff is used to make the media folder appear as a FAT32 partition
to applications. I don't remember the details for MTP, but it might be using
a different way to expose the media data to the connected PC. The detail is
probably not important for applications and end-users though, as long as the
illusion is preserved.

The big difference is that you are now able to share the same space more
efficiently.


> On Mar 1, 11:04 am, David Turner <[email protected]> wrote:
> > On Fri, Feb 25, 2011 at 5:59 PM, Pete2s <[email protected]> wrote:
> > > Thanks for the link--it's a lot of helpful information.
> >
> > > Could you or someone explain what Google made different in HC to tear
> > > down the distinction between app memory and media memory?
> >
> > We removed USB mass storage support (which essentially *requires* to
> expose
> > a FAT32 partition/volume to the connect PC, which then requires the
> > partition to be FAT32).
> > Instead, we now use the MTP protocol, which is a higher-level protocol
> that
> > allows the device to use any kind of partition/filesystem scheme to
> expose
> > the data.
> >
> > The data itself appears to applications through a FUSE daemon that
> ensures
> > that the typical FAT32 brain-damage (e.g. total lack of permissions) is
> > maintained when accessed
> > through the /media folder. But it is really stored in the internal
> (shared)
> > flash storage.
> >
> > >  I thought
> > > for security and copyright reasons, a secured partition that stored
> > > apps could not be mounted as a drive.  With the Xoom, it appears you
> > > can still mount the drive that stores both apps and media.
> >
> > > I can't really comment on this, sorry. I doubt you can mount the /data
> >
> > partition though.
> >
> >
> >
> > > On Feb 25, 12:50 am, Al Sutton <[email protected]> wrote:
> > > > Yes -
> http://groups.google.com/group/android-contrib/msg/36507d312cfcae00
> >
> > > > Al.
> > > > ======
> > > > Funky Android Limited is registered in England & Wales with the
> company
> > > number  6741909.
> >
> > > > The views expressed in this email are those of the author and not
> > > necessarily those of Funky Android Limited, it's associates, or it's
> > > subsidiaries.
> >
> > > > On 25 Feb 2011, at 06:32, Pete2s wrote:
> >
> > > > > On the Motorola Xoom, there is no longer a distinction between
> memory
> > > > > for apps and memory for media.  In the past, Android devices had a
> > > > > secure partition only for apps.  For the user, this often resulted
> in
> > > > > wasted space--if you liked apps, you could quickly run out of app
> > > > > space even though GBs were free for media; or you could fill up
> your
> > > > > media space and be unable to store more songs despite having GBs of
> > > > > free space allocated only for apps.
> >
> > > > > Will we see a similar memory architecture on phones?
> >
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