RE: Another try at the run-from-Flash issue for MPC8xx/MBX/custom

I agree, 40 seconds is too long: he must be doing something wrong.
But even 5 seconds is annoyingly long for an embedded system.

I haven't found anything better than LZO for compressing flash.
It is wicked fast, takes very little code, and no dynamic memory for
decompression.
Compressing takes some memory, and can be slow at higher compression levels,
but that happens once on the host so it isn't an issue.

LZO is available under GPL.  Perhaps someone could investigate using this
for compressing the Linux kernel and initrd.  Alas, I don't have time right
now.
--
Dave Brown [off-list ref]
Principal Software Engineer, Harris Corporation

http://wildsau.idv.uni-linz.ac.at/mfx/lzo.html

-----Original Message-----
From: Dan Malek [mailto:dan@netx4.com]
Sent: Wednesday, March 29, 2000 8:26 PM
To: Doug Rogers
Cc: linuxppc-embedded@lists.linuxppc.org
Subject: Re: Another try at the run-from-Flash issue for
MPC8xx/MBX/custom



Doug Rogers wrote:

quoted

..... It is simply a matter of size.

So, what methods are you planning to use for storing the applications,
libraries and other files you need to use and update?

quoted

....... I've timed the decompression of our smaller test image
and it takes over 40 seconds on a 40MHz MBX860 board.

That's too slow.

You are doing something very wrong.  I have worked on production
set top boxes that uncompress a kernel and 16 Mbyte ram disk from an
8-bit flash rom that are executing in the application in
under 5 seconds.
This is a 50 Mhz 860......turn on some caches, align some data, use
faster memory.....

quoted

I was hoping that Linux was to that point, but apparently not. Just
having the kernel run from ROM would be helpful for now,

That saves only about 800K or so of memory.  If you are counting bytes
at that level you are in trouble already.


	-- Dan

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

"Brown, David (dbrown03)" wrote:

I agree, 40 seconds is too long: he must be doing something wrong.
But even 5 seconds is annoyingly long for an embedded system.

That's for compressed kernel and initrd.  I wanted to compare apples
to apples.

You can put an uncompressed kernel and ROM file system in the Flash.
Just copy the kernel (or kernel data) to RAM and you are all set.  That
should boot pretty fast.

The trouble with using Linux is you have lots of choices.  You actually
have to _think_ about which is best for you and how you want to
implement the solution.  I don't particularly like other software
packages that proclaim "we did it for you", hide the code in a binary
somewhere, and you spend your time working around their rules.

With all of the GUIs and "click here to make it happen", people have
forgotten (or never learned) to think for themselves.  I have yet to
find a (reasonable) product requirement that can't be solved with Linux.

I implement what is useful to me and my customers.  If you want
something else, and it isn't there, just do it.  I'm not going to
guess at what you may want.  My challenges have been systems with
lots of RAM and not much Flash ROM.  If you can actually purchase
the flash ROM and are happy with the high prices, go ahead and load
it up.

(I am not picking on you David, this is just a summary of past
messages :-).




	-- Dan

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/