Re: HOWTO: Creating a root file system < 32 MB

Jon,

in message <m15cnZX-001SysC@bucks> you wrote:

Objective:
    Create a Linux root file system that is under 32MB for a MPC8260 target.

Ummm... 32 MB? That's HUGE!!! Most of the systems I see  in  products
have root filesystems in the size of 2...8 MB.

Direction:

...

    board.  We will start with all the packages in HHL 1.2, and
    removed the fluff until we hit our target size.

I  disagree  with  this  method  in  general.  Taking  any  "standard
distribution" and removing things will always be a poor way to design
an   embedded   system.   You  will  always  get  caught  in  strange
interdependencies, where you cannot remove A (which you don't  need),
because  it's  needed  for  some  function of B (which you also don't
need), but another function of B is used by C, which is important  to
you.

If you want to build a lean system you have to do it  the  other  way
round: bottom up.

See also: .sig below :-)

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Perfection is reached, not when there is no longer anything  to  add,
but when there is no longer anything to take away.
- Antoine de Saint-Exupery

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Wolfgang:

quoted

Objective:
    Create a Linux root file system that is under 32MB for a MPC8260 target.

Ummm... 32 MB? That's HUGE!!! Most of the systems I see  in  products
have root filesystems in the size of 2...8 MB.

There is one point that I didn't make clear. We are booting the board
over the wire, and we can afford the cost of 64MB DIMM instead of a 16
MB DIMM.  We have a modest amount of flash on the board 2-4MB -- This
is more than enough to hold PPCBoot.

If the board needed to be self contained, then the size of the root
file system would be much smaller.  The cost of flash is greater than
a DIMM, so it justifies the additional work in creating a 2-8 MB root
file system.

If you want to build a lean system you have to do it the other way
round: bottom up.

I would of taken this approach, if my goal was root filesystem that
was less 8 MB.


Open Question:

How have other people have dealt with the creation of a root file
system?


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