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Re: Areas of Emdebian to integrate into Debian


On Mon, Apr 4, 2011 at 4:18 PM, Brendan Simon <Brendan@brendansimon.com> wrote:
> I've seen other distros also use the kernel with uclibc initramfs, then
> switch/mount rootfs using glibc.  It obviously works but it makes me feel
> uneasy.  I'd feel more comfortable if the same libraries were in initramfs
> and main rootfs.  Indeed it may be that the external fs does not even have
> libc and other necessary boot files.  They could stay as part of the
> initramfs and the external fs could have everything else.  Yes ??

The problem I see with this is that compared with uClibc, glibc is
HUGE.  I just can't see using glibc as part of an initramfs.  The
risks of using uClibc in one place but glibc in the other are
completely manageable; the initramfs has much more limited
functionality, and doesn't need to chance much, so testing to a high
degree of confidence it before deployment is realistic.

Even on the lowest-end embedded systems, having an initramfs
unexpectedly (to some) makes a lot of sense.  It lets me get away with
a brain-dead bootloader, and defer the mkfs.jffs2, ubifs, etc. etc.
etc. to the initramfs.  Then I pivot to the final root filesystem.
And if for some reason the root filesystem isn't there, I get the
functionality of the initramfs to help me recover.

In particular, a suitable initramfs lets me wget raw NAND images for
the target platform, and also have a small web server for diagnosing
hardware and other problems.  I can't do that with a bootloader unless
the bootloader has TCP/IP.  And any bootloader that has TCP/IP is too
sophisticated for me to feel comfortable using it.  :)

I'm talking about a target system that has 64MB of NAND, total.
That's all the storage there is.  I'll gladly eat 4MB of that for a
kernel and initramfs that gives me in return a nearly un-brickable
system.  Any larger than that, however, and I really start to feel the

And before you all tell me to just get a larger system, I'll just say
that if you can do real work in 64MB of flash, a whooooooole lot of
interesting possibilities open up--- and I can prove it to you.
Emdebian is making that possible for me.  But that's a topic for
another email.  :)

Bill Gatliff

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