Can L4 modules be accessed as files from L4Linux?

Adam Lackorzynski adam at
Mon Mar 7 11:16:02 CET 2011


On Sun Mar 06, 2011 at 18:45:49 +0200, Dan Haim wrote:
> I'm trying to find a solution to the following scenario - I want to have an
> L4Linux instance running (from a CD) where the root filesystem is several
> hundred MB's big, so it is not feasible to run it from a ramdisk (the
> filesystem is larger than the amount of RAM available) - I need to run it
> directly from the CD.
> A possible solution I'm thinkning about is to give the L4Linux instance
> access to the CD-ROM drive, then store a SquashFS image as a file on the
> drive and UnionFS it with a tmpfs when the system starts.
> Now here's the catch - While this solution may technically work, it is still
> not 'good enough' because I can't give the L4Linux instance direct access to
> the CD-ROM drive - I need to have it completely isolated so a user working
> on the L4Linux instance will not have access to any files stored on the CD
> (other than the SquashFS image) even if he/she has root access over the
> L4Linux instance.
> I was thinking - is it possible to specify the SquashFS image as an L4
> module and then somehow mount it from within L4Linux in-place (i.e. without
> completely loading it to RAM)? Is there any other way to accomplish what's
> needed in this scenario?

If the image is not loaded into RAM upon boot you'll need a driver for
the CD-ROM somewhere. Of course, L4Linux is a convenience place to have
that driver in. If that is not possible another L4Linux could be used
that drives the CD-ROM and both are connected via virtual network. Would
that second L4Linux be acceptable in your setup?

Adam                 adam at

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